JP6166601B2 - Motor control device and generator control device - Google Patents

Description

  The present invention relates to a motor control device and a generator control device.

Conventionally, direct torque control (DTC) has been proposed as a control method for a three-phase motor. In an example of direct torque control, a three-phase current i is detected. The three-phase current i is converted into the two-phase current i _αβ . From the two-phase current i _αβ and the target two-phase voltage v _αβ ^* , using the equations (A-1) to (A-4), the armature linkage flux of the three-phase motor and the armature linkage flux The phase and motor torque are estimated. That is, the estimated magnetic flux [psi _{.alpha..beta,} the estimated magnetic flux [psi _.alpha..beta phase theta _S, is determined and the estimated torque T. The alpha axial estimated magnetic flux [psi _alpha, an alpha-axis component of the estimated magnetic flux [psi _{.alpha..beta.} The beta axis estimated magnetic flux [psi _beta, is a beta-axis component of the estimated magnetic flux [psi _{.alpha..beta.} The α-axis current i _α is an α-axis component of the two-phase current i _αβ . The β-axis current i _β is a β-axis component of the two-phase current i _αβ . The target α-axis voltage v _α ^* is an α-axis component of the target two-phase voltage v _αβ ^* . The target β-axis voltage v _β ^* is a β-axis component of the target two-phase voltage v _αβ ^* . _ψ α _{| t = 0} is the value of [psi _alpha at time t = 0 (initial value of [psi _{alpha). ψ} β _{| t = 0} is the value of [psi _beta at time t = 0 ([psi initial value of _beta). R _a is a resistance value per phase of the armature winding of the three-phase motor. P _n is the number of pole pairs of the motor.

Next, an error (torque error ΔT = T ^* −T) between the estimated torque T and the target torque T ^* is obtained. The target vector (target magnetic flux vector) ψ _αβ ^{* of} the armature interlinkage magnetic flux is obtained from the torque error ΔT, the phase θ _S and the target value (target magnetic flux) | ψ _S ^* | It is done. The target magnetic flux | ψ _S ^* | is specified according to the target torque T ^* using table data representing the relationship between the target magnetic flux | ψ _S ^* | and the target torque T ^* . Table data is prepared in advance.

The target two-phase voltage v _αβ ^* is obtained by using equations (A-5) and (A-6) so that the estimated magnetic flux _ψαβ matches the target magnetic flux vector _ψαβ ^* . [psi _alpha ^* is the target flux vector [psi _.alpha..beta ^* of alpha axis component. [psi _beta ^* is a target flux vector [psi _.alpha..beta ^* of beta axis component.

The target two-phase voltage v _αβ ^* is converted into a target three-phase voltage v _uvw ^* (v _u ^* , v _v ^* and v _w ^* ). A voltage vector corresponding to the target three-phase voltage v _uvw ^* is generated by the inverter. This voltage vector is applied to the three-phase motor.

  In the motor control system described above, a target magnetic flux vector is specified using a command magnetic flux calculator (RFVC: Reference Flux Vector Calculator). For this reason, the above motor control method can be referred to as RFVC DTC (Reference Flux Vector Calculation Direct Torque Control).

  Patent Document 1 and Non-Patent Document 1 describe examples of motor control devices using direct torque control.

JP 2009-33876 A

Inoue and three others, “Torque ripple reduction, and flux-weakening control for interior permanent magnet synchronous motor based on direct torque control”, 2006 Electric Proceedings of National Conference of the Society, The Institute of Electrical Engineers of Japan, March 2006, 4th volume, 4-106, p. 166

  The conventional motor control device using direct torque control does not sufficiently cope with the high speed of the three-phase motor. The present invention has been made in view of such circumstances.

That is, this disclosure
A motor control device that applies a voltage vector to the three-phase motor by an inverter so that the armature interlinkage magnetic flux and the motor torque of the three-phase motor follow the target magnetic flux and the target torque, respectively.
A magnetic flux amplitude command calculation unit for specifying the target magnetic flux;
A magnetic flux command calculation unit that identifies a target magnetic flux vector based on the target magnetic flux and the estimated phase of the armature linkage flux;
From the difference between the target magnetic flux vector and the estimated armature flux linkage, a voltage command calculation unit that identifies the voltage vector;
With
The magnetic flux amplitude command calculation unit includes (i) a first magnetic flux amplitude command calculation unit that identifies a first target magnetic flux as the target magnetic flux from the target torque, (ii) the first target magnetic flux, A second magnetic flux amplitude command calculation unit that specifies a second target magnetic flux to be given to the magnetic flux command calculation unit from the rotation speed of the three-phase motor or the estimated armature linkage magnetic flux;
When the second target magnetic flux is given to the magnetic flux command calculation unit, the current flowing through the three-phase motor or the power loss generated in the three-phase motor is replaced with the first target magnetic flux instead of the second target magnetic flux. The motor in which the second magnetic flux amplitude command calculation unit is configured to be less than a current flowing through the three-phase motor or a power loss generated in the three-phase motor when a magnetic flux is applied to the magnetic flux command calculation unit. A control device is provided.

  According to said technique, the increase in the motor current accompanying the increase in the speed of a three-phase motor or the increase in electric power loss can be suppressed.

Block diagram of three-phase motor, inverter and motor control device Diagram for explaining the dq coordinate system Diagram for explaining αβ coordinate system 1 is a block diagram of a motor control device according to a first embodiment. Block diagram explaining the method of specifying the target magnetic flux vector A graph showing the relationship between the rotation speed of the three-phase motor and the ratio of the estimated magnetic flux amplitude to the target magnetic flux vector amplitude The graph showing the relationship between the rotation speed of the three-phase motor and the coefficient multiplied by the first target magnetic flux to obtain the second target magnetic flux in the first embodiment. The graph showing the relationship between the rotation speed of a three-phase motor at the time of using the motor control apparatus which concerns on 1st Embodiment, and the ratio of the amplitude of the estimation magnetic flux with respect to a 1st target magnetic flux. Graph showing the relationship between coefficient K and phase current and the relationship between coefficient K and power loss in the modification Block diagram of a motor control device according to the second embodiment A block diagram for explaining a method for determining a magnetic flux amplitude correction amount in the second embodiment Block diagram of a motor control device according to the third embodiment A block diagram for explaining a method of determining a magnetic flux amplitude correction amount in the third embodiment Block diagram of a motor control device according to the fourth embodiment Graph _showing the relationship between coefficient _Kte and phase current in the fourth embodiment Block diagram of a generator control device according to a fifth embodiment

The first aspect of the present disclosure is:
A motor control device that applies a voltage vector to the three-phase motor by an inverter so that the armature interlinkage magnetic flux and the motor torque of the three-phase motor follow the target magnetic flux and the target torque, respectively.
A magnetic flux amplitude command calculation unit for specifying the target magnetic flux;
A magnetic flux command calculation unit that identifies a target magnetic flux vector based on the target magnetic flux and the estimated phase of the armature linkage flux;
From the difference between the target magnetic flux vector and the estimated armature flux linkage, a voltage command calculation unit that identifies the voltage vector;
With
The magnetic flux amplitude command calculation unit includes (i) a first magnetic flux amplitude command calculation unit that identifies a first target magnetic flux as the target magnetic flux from the target torque, (ii) the first target magnetic flux, A second magnetic flux amplitude command calculation unit that specifies a second target magnetic flux to be given to the magnetic flux command calculation unit from the rotation speed of the three-phase motor or the estimated armature linkage magnetic flux;
When the second target magnetic flux is given to the magnetic flux command calculation unit, the current flowing through the three-phase motor or the power loss generated in the three-phase motor is replaced with the first target magnetic flux instead of the second target magnetic flux. The motor in which the second magnetic flux amplitude command calculation unit is configured to be less than a current flowing through the three-phase motor or a power loss generated in the three-phase motor when a magnetic flux is applied to the magnetic flux command calculation unit. A control device is provided.

  According to the first aspect, it is possible to suppress an increase in motor current or an increase in power loss accompanying an increase in the speed of the three-phase motor.

  According to a second aspect of the present disclosure, in addition to the first aspect, the second magnetic flux amplitude command calculation unit provides a motor control device that specifies the second target magnetic flux that is smaller than the first target magnetic flux. According to the configuration of the second aspect, the target magnetic flux vector specified based on the second target magnetic flux approaches a vector for minimizing the motor current or power loss.

  According to a third aspect of the present disclosure, in addition to the first aspect or the second aspect, the second magnetic flux amplitude command calculation unit increases the first target magnetic flux and the second target magnetic flux as the number of rotations increases. A motor control device for specifying the second target magnetic flux is provided so that the difference between the motor and the motor increases. According to the structure of the 3rd aspect, the 2nd target magnetic flux according to the rotation speed of a three-phase motor can be specified.

  According to a fourth aspect of the present disclosure, in addition to any one of the first to third aspects, the second magnetic flux amplitude command calculation unit uses the rotation speed to estimate the armature linkage magnetic flux estimated. Provided is a motor control device that specifies the second target magnetic flux so that the amplitude coincides with the first target magnetic flux.

  According to a fifth aspect of the present disclosure, in addition to any one of the first to third aspects, the second magnetic flux amplitude command calculation unit includes the estimated armature flux linkage and the first magnetic flux amplitude command. Using the first target magnetic flux specified by the calculation unit, the second amplitude is adjusted so that a difference between the estimated amplitude of the armature linkage magnetic flux and the first target magnetic flux converges to zero. A motor control device for specifying a target magnetic flux is provided.

  In a sixth aspect of the present disclosure, in addition to any one of the first to third aspects, the second magnetic flux amplitude command calculation unit calculates the first target magnetic flux based on a current flowing through the three-phase motor. Using the re-derived and estimated armature linkage magnetic flux and the re-derived first target magnetic flux, the estimated amplitude of the armature linkage magnetic flux and the re-derived first target Provided is a motor control device that specifies the second target magnetic flux so that a difference from the magnetic flux converges to zero.

  Since the second magnetic flux amplitude command calculation unit of the fourth aspect uses the rotation speed of the three-phase motor, the second target magnetic flux adapted to the rotation speed of the three-phase motor even when the rotation speed of the three-phase motor fluctuates. Can be identified. The second magnetic flux amplitude command calculation unit of the fifth aspect or the sixth aspect performs control (feedback control) such that the difference between the amplitude of the armature linkage magnetic flux and the first target magnetic flux becomes zero. Even when the rotation speed of the phase motor fluctuates, the second target magnetic flux suitable for the rotation speed of the three-phase motor can be specified.

  According to a seventh aspect of the present disclosure, in addition to any one of the first to sixth aspects, the motor torque is estimated based on the estimated armature flux linkage and the current flowing through the three-phase motor, Provided is a motor control device further comprising a torque estimation unit that corrects the estimated motor torque based on the current flowing through the three-phase motor and the rotation speed. According to the structure of the 7th aspect, a torque estimation part correct | amends a motor torque based on the rotation speed of a three-phase motor. Therefore, even when the rotation speed of the three-phase motor varies, the motor torque can be corrected so as to match the rotation speed of the three-phase motor.

The eighth aspect of the present disclosure is:
A generator control device that applies a voltage vector to the three-phase generator by a converter so that an armature interlinkage magnetic flux and a generator torque of the three-phase generator follow the target magnetic flux and the target torque, respectively.
A magnetic flux amplitude command calculation unit for specifying the target magnetic flux;
A magnetic flux command calculation unit that identifies a target magnetic flux vector based on the target magnetic flux and the estimated phase of the armature linkage flux;
From the difference between the target magnetic flux vector and the estimated armature flux linkage, a voltage command calculation unit that identifies the voltage vector;
With
The magnetic flux amplitude command calculation unit includes (i) a first magnetic flux amplitude command calculation unit that identifies a first target magnetic flux as the target magnetic flux from the target torque, (ii) the first target magnetic flux, A second magnetic flux amplitude command calculation unit for specifying a second target magnetic flux to be given to the magnetic flux command calculation unit from the rotation speed of the three-phase generator or the estimated armature linkage flux;
When the second target magnetic flux is given to the magnetic flux command calculation unit, the current flowing through the three-phase generator or the power loss generated in the three-phase generator is replaced with the first target magnetic flux instead of the first target magnetic flux. The second magnetic flux amplitude command calculation unit is configured to be less than the current flowing through the three-phase generator or the power loss generated in the three-phase generator when the target magnetic flux is applied to the magnetic flux command calculation unit. A generator control device is provided.

  According to such a generator control device, the same effect as that obtained by the first aspect can be obtained.

The ninth aspect of the present disclosure is:
A motor control method for applying a voltage vector to the three-phase motor by an inverter so that the armature interlinkage magnetic flux and the motor torque of the three-phase motor follow the target magnetic flux and the target torque, respectively.
A magnetic flux amplitude command calculating step for specifying the target magnetic flux;
A magnetic flux command calculation step for specifying a target magnetic flux vector based on the target magnetic flux and the estimated phase of the armature interlinkage magnetic flux;
From the difference between the target magnetic flux vector and the estimated armature flux linkage, a voltage command calculation step for specifying the voltage vector;
With
The magnetic flux amplitude command calculation step includes (i) a first magnetic flux amplitude command calculation step that specifies a first target magnetic flux as the target magnetic flux from the target torque, (ii) the first target magnetic flux, A second magnetic flux amplitude command calculation step for specifying a second target magnetic flux to be given to the magnetic flux command calculation unit from the number of rotations of the three-phase motor or the estimated armature flux linkage,
When the second target magnetic flux is given to the magnetic flux command calculation unit, the current flowing through the three-phase motor or the power loss generated in the three-phase motor is replaced with the first target magnetic flux instead of the second target magnetic flux. Provided is a motor control method that is less than a current flowing through the three-phase motor or a power loss generated in the three-phase motor when a magnetic flux is applied to the magnetic flux command calculation unit.

  According to such a motor control method, the same effect as that obtained by the first aspect can be obtained.

  Hereinafter, each embodiment of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, motor control devices 3, 103, 203, and 303 according to the embodiments of the present invention can be connected to an inverter (voltage conversion circuit) 2 and a three-phase motor 1.

(3-phase motor 1)
The three-phase motor 1 has a rotor and a stator. The rotor includes a permanent magnet. The stator has three-phase armature windings. The armature winding corresponding to the U phase of the three-phase motor 1 may be referred to as a U phase winding. The armature winding corresponding to the V phase of the three-phase motor 1 may be referred to as a V phase winding. The armature winding corresponding to the W phase of the three-phase motor 1 may be referred to as a W phase winding. The three-phase motor 1 is, for example, a three-phase permanent magnet synchronous motor.

(Inverter 2)
The inverter 2 is specifically a PWM (Pulse Width Modulation) inverter. More specifically, the inverter 2 has a DC power supply and a conversion circuit. The DC power supply outputs a DC voltage. The conversion circuit converts the DC voltage into a voltage vector (three-phase AC voltage) by PWM control. The inverter 2 applies a voltage vector to the three-phase motor 1.

  Hereinafter, the motor control device may be described based on the dq coordinate system. The motor control device may be described based on the αβ coordinate system. The dq coordinate system and the αβ coordinate system are two-dimensional orthogonal coordinate systems. The dq coordinate system and the αβ coordinate system will be described with reference to FIG.

  The dq coordinate system shown in FIG. 2A is a rotating coordinate system. The d-axis and the q-axis rotate at the same speed as the rotation speed (number of rotations) of the magnetic flux generated by the permanent magnet 1m. The counterclockwise direction is the phase advance direction. The permanent magnet 1 m represents a permanent magnet provided on the rotor of the three-phase motor 1. The d-axis is set as an axis extending in the direction of the magnetic flux generated by the permanent magnet 1m. The q-axis is set as an axis obtained by rotating the d-axis by 90 degrees in the advance direction. The U axis corresponds to the U phase winding. The V axis corresponds to the V phase winding. The W axis corresponds to the W phase winding. The U-axis, V-axis, and W-axis do not rotate even when the rotor rotates. That is, the U axis, the V axis, and the W axis are fixed axes. The angle (phase) θ is a lead angle of the d axis viewed from the U axis. The angle θ is also referred to as a rotor position or a magnetic pole position. The rotational speed ω represents the rotational speed of the rotor. In this specification, unless otherwise specified, an angle means an electrical angle. The angle between the d-axis and the q-axis, the angle θ and the rotational speed ω are values based on the electrical angle.

  The αβ coordinate system shown in FIG. 2B is a fixed coordinate system. The α axis and the β axis are fixed axes. The counterclockwise direction is the phase advance direction. The α axis is set as an axis extending in the same direction as the U axis. The β axis is set as an axis obtained by rotating the α axis by 90 degrees in the advance direction.

As shown in FIG. 1, the motor control devices 3, 103, 203, and 303 detect a three-phase current i that flows through the three-phase motor 1. The target torque T ^* is input to the motor control devices 3, 103, 203, and 303. The motor control devices 3, 103, 203 and 303 control the three-phase motor 1 via the inverter 2 using the three-phase current i and the target torque T ^* . Hereinafter, the motor control device of each embodiment will be described in order.

(First embodiment)
As shown in FIG. 3, the motor control device 3 includes a current sensor 5, a three-phase two-phase coordinate conversion unit 22, a magnetic flux / torque estimation unit 23, a subtraction unit 24, a first magnetic flux amplitude command calculation unit 25, a second A magnetic flux amplitude command calculation unit 31, a magnetic flux command calculation unit 26, a voltage command calculation unit 29, and a two-phase / three-phase coordinate conversion unit 30 are provided.

  Some or all elements of the motor control device 3 may be provided by a control application executed in a DSP (Digital Signal Processor) or a microcomputer. The DSP or microcomputer may include peripheral devices such as a core, a memory, an A / D conversion circuit, and a communication port. Further, some or all of the elements of the motor control device 3 may be configured by a logic circuit.

(Outline of control by the motor control device 3)
Hereinafter, an outline of the operation of the motor control device 3 will be described. The current sensor 5 detects the U-phase current i _u and the V-phase current i _v . U-phase current i _u is a U-phase component of three-phase current i. V-phase current i _v is a V-phase component of three-phase current i. The three-phase two-phase coordinate conversion unit 22 converts the U-phase current i _u and the V-phase current i _v into a two-phase current i _αβ . From the two-phase current i _αβ and the target two-phase voltage v _αβ ^* , the magnetic flux / torque estimation unit 23 _obtains the estimated magnetic flux ψ _αβ , the phase θ _s of the estimated magnetic flux ψ _αβ , and the estimated torque T. That is, the motor torque and the armature flux linkage are estimated by the magnetic flux / torque estimation unit 23. The subtraction unit 24 obtains a difference (torque error ΔT: T ^* −T) between the estimated torque T and the target torque T ^* . The first target magnetic flux | ψ _S ^* | is specified by the first magnetic flux amplitude command calculation unit 25 from the target torque T ^* . The second target magnetic flux | ψ _S ^** | is specified by the second magnetic flux amplitude command calculation unit 31 from the first target magnetic flux | ψ _S ^* | and the rotational speed ω. The magnetic flux command calculation unit 26 specifies the target magnetic flux vector ψ _αβ ^* from the second target magnetic flux | ψ _S ^** |, the phase θ _s, and the torque error ΔT. The voltage command calculation unit 29 specifies the target two-phase voltage v _αβ ^* from the target magnetic flux vector ψ _αβ ^* , the estimated magnetic flux ψ _αβ, and the two-phase current i _αβ . The two-phase three-phase coordinate conversion unit 30 converts the target two-phase voltage v _αβ ^* into the target three-phase voltage v _uvw ^* . The target three-phase voltage v _uvw ^* is referred to by the inverter 2. By such control, the three-phase motor 1 is controlled such that the amplitude of the armature linkage magnetic flux and the motor torque follow the first target magnetic flux | ψ _S ^* | and the target torque command T ^* , respectively.

In the present specification, the two-phase current i _αβ means a current value transmitted as information, not a current that actually flows through the three-phase motor 1. Similarly, the target two-phase voltage v _αβ ^* , the estimated magnetic flux ψ _αβ , the phase θ _s , the estimated torque T, the target torque T ^* , the first target magnetic flux | ψ _S ^* |, and the second target magnetic flux | ψ _S ^** |, the target magnetic flux vector [psi _.alpha..beta ^* and the target 3-phase voltage v _uvw ^* also means a value to be transmitted as information.

  Next, details of the motor control device 3 will be described.

(Current sensor 5)
The current sensor 5 detects a three-phase current i. In the present embodiment, the current sensor 5 detects the U-phase current i _u and the V-phase current i _v. Current sensor 5 outputs a U-phase current i _u and the V-phase current i _v.

(Three-phase two-phase coordinate conversion unit 22)
The three-phase / two-phase converter 22 converts the three-phase current i into a two-phase current i _αβ . In the present embodiment, the three-phase / two-phase converter 22 converts the U-phase current i _u and the V-phase current _iv into an α-axis current i _α and a β-axis current i _β . The α-axis current i _α and the β-axis current i _β are given to the magnetic flux / torque estimation unit 23 and the voltage command calculation unit 29.

Note that the current sensor 5 may be provided so as to measure two-phase currents of a combination other than the U-phase and V-phase two phases. Also in this case, the three-phase two-phase coordinate conversion unit 22 can be configured so that the α-axis current i _α and the β-axis current i _β are specified based on the measured current.

(Magnetic flux / torque estimation unit 23)
The magnetic flux / torque estimation unit 23 estimates the motor torque and the armature linkage magnetic flux from the two-phase current i _αβ and the target two-phase voltage v _αβ ^* . In the present embodiment, the magnetic flux / torque estimation unit 23 uses the equations (1-1), (1-2), (1-3), and (1-4) to calculate the estimated magnetic flux ψ _αβ (estimated magnetic flux ψ _α , Ψ _β ), estimated magnetic flux ψ _αβ phase θ _s and estimated torque T. R _a in the expressions (1-1) and (1-2) is _a winding resistance per phase of the three-phase motor 1. The integration on the right side represents the time integration from the reference time (t = 0) to the present time. _ψ α _{| t = 0} are the values of the estimated magnetic flux [psi _alpha at t = 0 (initial value). _ψ β _{| t = 0} are the values of the estimated magnetic flux [psi _beta at t = 0 (initial value). P _n in Expression (1-4) is the _number of pole pairs of the three-phase motor 1. The estimated magnetic flux _ψαβ is given to the voltage command calculation unit 29. The phase θ _s is given to the magnetic flux command calculation unit 26. The estimated torque T is given to the subtracting unit 24.

It is not essential to obtain the estimated magnetic flux _ψαβ and the estimated torque T with a single estimation unit. A magnetic flux estimation unit may be provided as an estimation unit for _{obtaining the} estimated magnetic flux _ψαβ, and a torque estimation unit may be provided as an estimation unit for obtaining the estimated torque T. The magnetic flux estimation unit can be configured to obtain the estimated magnetic flux ψ _αβ from the two-phase current i _αβ and the target two-phase voltage v _αβ ^* . That is, the magnetic flux estimation unit can be configured to estimate the armature linkage magnetic flux based on the current flowing through the three-phase motor 1 and the voltage vector. The torque estimation unit can be configured to obtain the estimated torque T from the estimated magnetic flux _ψαβ and the two-phase current _iαβ . That is, the torque estimation unit can be configured to estimate the motor torque based on the estimated armature flux linkage and the current flowing through the three-phase motor 1.

Further, the magnetic flux / torque estimation unit 23 uses a two-phase voltage obtained by converting the detected value of the voltage applied to the three-phase motor 1 by three-phase to two-phase conversion instead of the target two-phase voltage v _αβ ^*. The estimated magnetic flux may be obtained.

(Subtraction unit 24)
The subtractor 24 obtains a difference (torque error ΔT: T ^* −T) between the estimated torque T and the target torque T ^* . A known operator may be used as the subtraction unit 24.

(First magnetic flux amplitude command calculation unit 25)
The first magnetic flux amplitude command calculation unit 25 specifies the first target magnetic flux | ψ _S ^* | as the target magnetic flux from the target torque T ^* . The target magnetic flux and the first target magnetic flux | ψ _S ^* | indicate the same scalar. The first target magnetic flux | ψ _S ^* | of the present embodiment is for minimizing the motor current. Control that controls a three-phase motor so that the ratio of the motor torque value to the motor current value is maximized while setting the motor torque as the target value is known as Maximum Torque Per Ampere (MTPA) control. It ’s been. Since maximum torque / current control is well known, detailed description of maximum torque / current control is omitted. In the present embodiment, the first magnetic flux amplitude command calculation unit 25 is configured to identify the first target magnetic flux | ψ _S ^* | from the target torque T ^* using a table. A correspondence relationship between the target torque T ^* and the first target magnetic flux | ψ _S ^* | in the table can be appropriately set by those skilled in the art. The first magnetic flux amplitude command calculation unit 25 may be configured to specify the first target magnetic flux | ψ _S ^* | by calculation.

In the present embodiment, the first target magnetic flux | ψ _S ^* | is corrected by the second magnetic flux amplitude command calculation unit 31. The corrected first target magnetic flux | ψ _S ^* | is described as a second target magnetic flux | ψ _S ^** |. Details of the second magnetic flux amplitude command calculation unit 31 will be described later.

(Magnetic flux command calculation unit 26)
Based on the first target magnetic flux | ψ _S ^* | and the phase θ _s , the magnetic flux command calculation unit 26 specifies the target magnetic flux vector ψ _αβ ^* that the armature linkage flux should follow. Specifically, the magnetic flux command calculation unit 26 uses the second target magnetic flux | ψ _S ^** |, the phase θ _s, and the torque error ΔT to target the magnetic flux vector ψ _αβ ^* that the armature linkage magnetic flux should follow ^. Is identified. The magnetic flux command calculation unit 26 in the present embodiment specifies the target magnetic flux vector _ψαβ ^* according to the block diagram shown in FIG. Specifically, the magnetic flux command calculation unit 26 includes a PI control unit 35, an addition unit 36, and a vector generation unit 37. The PI control unit 35 specifies the phase correction amount Δθ _S ^* by proportional-integral control for converging ΔT to zero. The adding unit 36 obtains the sum (θ _S ^* : θ _S + Δθ _S ^* ) of the phase θ _S and the phase correction amount Δθ _S ^* . The vector generation unit 37 specifies the target magnetic flux vector _ψαβ ^* from the second target magnetic flux | ψ _S ^** | and the total θ _S ^* . Specifically, the vector generation unit 37 obtains the target magnetic flux vector _ψαβ ^* using equations (1-5) and (1-6). The target magnetic flux vector _ψαβ ^* is given to the voltage command calculation unit 29.

(Voltage command calculation unit 29)
The voltage command calculation unit 29 specifies the target two-phase voltage v _αβ ^* from the difference between the target magnetic flux vector ψ _αβ ^* and the estimated magnetic flux ψ _αβ and the two-phase current i _αβ . In the present embodiment, the voltage command calculation unit 29 obtains the target α-axis voltage v _α ^* and the target β-axis voltage v _β ^* using Expression (1-7). T _s in Expression (1-7) is a control period (sampling period). Incidentally, when the 3-phase motor 1 is rotated at a high speed, the voltage drop based on the winding resistance R _a is very small. For this reason, the voltage command calculation unit 29 ignores the second term on the right side of Equation (1-7) and determines the target two-phase voltage v _αβ ^* from the difference between the target magnetic flux vector ψ _αβ ^* and the estimated magnetic flux ψ _αβ. It may be configured to specify. The target two-phase voltage v _αβ ^* is given to the two-phase three-phase coordinate conversion unit 30.

(2-phase 3-phase coordinate conversion unit 30)
The two-phase three-phase coordinate conversion unit 30 converts the target two-phase voltage v _αβ ^* into the target three-phase voltage v _uvw ^* . Thereafter, a voltage vector corresponding to the target three-phase voltage v _uvw ^* is generated by the inverter 2 and applied to the three-phase motor 1.

(Second magnetic flux amplitude command calculation unit 31)
The second magnetic flux amplitude command calculating unit 31 specifies the second target magnetic flux | ψ _S ^** | to be given to the magnetic flux command calculating unit 26 from the first target magnetic flux | ψ _S ^* | and the rotational speed ω. To do. The second target magnetic flux | ψ _S ^** | is a scalar. The second magnetic flux amplitude command calculation unit 31 applies the second target magnetic flux | ψ _S ^** | to the magnetic flux command calculation unit 26 so that the current flowing through the three-phase motor 1 becomes the second target magnetic flux | ψ _S. The first target magnetic flux | ψ _S ^* | is given to the magnetic flux command calculation unit 26 instead of ^** |, so that the current flowing through the three-phase motor 1 is lower. In the present embodiment, the second target magnetic flux | ψ _S ^** | is specified based on the following theory.

  When the initial values of the expressions (1-1) and (1-2) are ignored, the expression (1-8) is obtained from the expressions (1-1) and (1-2). In formula (1-8), s is a Laplace operator.

Equation (1-7) in the target 2-phase voltage v _.alpha..beta ^*, rather than the target 2-phase voltage v _.alpha..beta ^* in the equation (1-8), those after one control period (= T _s). That is, strictly speaking, they do not represent the same thing. When Expression (1-7) is expressed using the target two-phase voltage v _αβ ^* in Expression (1-8), Expression (1-9) is obtained.

From the formulas (1-8) and (1-9), the formula (1-10) is obtained. Further, when the 3-phase motor 1 is rotated at a high speed, the voltage drop based on the winding resistance R _a is very small. When this is taken into consideration and the second term on the right side of equation (1-10) is ignored, equation (1-11) is obtained.

In the present embodiment, as shown in the equation (1-11), the second target magnetic flux | ψ _S is considered in consideration that | ψ _αβ | and | ψ _αβ ^* | ^{** A} second magnetic flux amplitude command calculation unit 31 for specifying | is provided. Specifically, the second magnetic flux amplitude command calculating unit 31 specifies the second target magnetic flux | ψ _S ^** | using (1-13). Expression (1-13) is an approximate expression of expression (1-12). The calculation of formula (1-13) is advantageous in that it is simpler than the calculation of formula (1-12). However, you may comprise the 2nd magnetic flux amplitude command calculating part 31 so that 2nd target magnetic flux | (phi) _S ^** | may be specified using Formula (1-12). The second target magnetic flux | ψ _S ^** | based on the formula (1-12) or (1-13) may be specified by calculation or may be specified using a table.

The effect of this embodiment is demonstrated using FIGS. 5 to 7 are graphs showing the results obtained by the simulation. A curve 40 in FIG. 5 represents the ratio of the amplitude of the estimated magnetic flux _{ψαβ to} the amplitude of the target magnetic flux vector _ψαβ ^* (| _ψαβ | / | _ψαβ ^* |). From FIG. 5, it can be seen that the larger the number of revolutions ω, the larger the ratio and the deviation from 1. When the second magnetic flux amplitude command calculation unit 31 does not exist, the amplitude of the target magnetic flux vector _ψαβ ^* coincides with the first target magnetic flux | ψ _S ^* |. Thus, the greater rotational speed ω is the first target flux | ψ _S ^* | estimated magnetic flux [psi _.alpha..beta the ratio of the amplitude with respect to _{(| ψ αβ | / | ψ} S * |) also increases, deviates from 1 To go. This means that the conventional motor control device matches the amplitude of the estimated magnetic flux _ψαβ with a value that deviates from the first target magnetic flux | ψ _S ^* | during high-speed rotation. Since the conventional motor control device is designed on the assumption that this deviation is zero, even if the first target magnetic flux | ψ _S ^* | is set for maximum torque / current control, the motor The current deviates from the minimum value. The greater the rotational speed ω, the greater the deviation of the estimated magnetic flux _ψαβ from the first target magnetic flux | ψ _S ^* |. The deviation from the minimum value of the motor current also increases. Although not shown, the same tendency appears when the control cycle T _s is long (the current sampling frequency is low).

On the other hand, in the present embodiment, the second magnetic flux amplitude command calculation unit 31 refers to the curve 41 in FIG. 6 showing a coefficient (cos (ωT _s ) smaller than 1 for the first target magnetic flux | ψ _S ^* | ) Is specified, the second target magnetic flux | ψ _S ^** | smaller than the first target magnetic flux | ψ _S ^* | is specified. The motor control device 3 tries to make the amplitude of the estimated magnetic flux ψ _αβ coincide with the second target magnetic flux | ψ _S ^** |. However, for the above reason, the estimated magnetic flux ψ _αβ is actually the second target magnetic flux. This corresponds to a value deviating from | ψ _S ^** |. Specifically, the estimated magnetic flux _ψαβ coincides with a value larger than the second target magnetic flux | ψ _S ^** |. Since the first target magnetic flux | ψ _S ^* | is larger than the second target magnetic flux | ψ _S ^** |, as a result, the first target magnetic flux | ψ _S ^* | than the case of specifying the target magnetic flux vector [psi _.alpha..beta ^*, first the target magnetic flux of the estimated magnetic flux [psi _.alpha..beta amplitude | ψ _S ^* | can be reduced deviation amount from. That is, the motor current can be brought close to the minimum value.

As described above, the second magnetic flux amplitude command calculation unit 31 uses the rotation speed ω so that the estimated amplitude of the armature linkage magnetic flux matches the first target magnetic flux | ψ _S ^* |. 2 target magnetic fluxes | ψ _S ^** | Since the second magnetic flux amplitude command calculation unit 31 uses the rotational speed ω of the three-phase motor 1, even when the rotational speed ω of the three-phase motor 1 fluctuates, Target magnetic flux | ψ _S ^** |

Specifically, the second magnetic flux amplitude command calculation unit 31 increases the difference between the first target magnetic flux | ψ _S ^* | and the second target magnetic flux | ψ _S ^** | as the rotational speed ω increases. Thus, the second target magnetic flux | ψ _S ^** | is specified (see curve 41 in FIG. 6 showing cos (ωT _s )). Therefore, the second magnetic flux amplitude command calculation unit 31 can prevent a decrease in control accuracy resulting from an increase in the rotational speed ω.

In addition, the second magnetic flux amplitude command calculation unit 31 is configured so that the lower the current sampling frequency is (the larger the control period T _s is), the first target magnetic flux | ψ _S ^* | and the second target magnetic flux | The second target magnetic flux | ψ _S ^** | is specified so that the difference from ψ _S ^** | increases (see the curve 41 in FIG. 6 showing cos (ωT _s )). Therefore, according to the second magnetic flux amplitude command calculation unit 31, control accuracy is maintained even when the current sampling frequency is low. Therefore, according to the motor control device 3, it is possible to suppress the calculation amount of a CPU such as a DSP or a microcomputer while maintaining control accuracy. That is, even if a relatively low performance DSP or microcomputer is used, the three-phase motor 1 can be controlled without reducing accuracy. This is advantageous from a cost standpoint. Therefore, the motor control device 3 can be suitably used even when the three-phase motor 1 rotates at a low speed.

More specifically, the second magnetic flux amplitude command calculation unit 31 specifies the second target magnetic flux | ψ _S ^** | by multiplying the first target magnetic flux | ψ _S ^* | by cos (ωT _s ). doing. In this _{case, | ψ αβ | / | ψ} S * | of the curve (the curve 42 in FIG. 7) is substantially _{| ψ αβ | / | ψ S} * | = a first linear. According to this embodiment, the amount of deviation of the amplitude of the armature interlinkage magnetic flux from the first target magnetic flux | ψ _S ^* | is substantially zero. The amount of deviation from the minimum value of the motor current is also substantially zero.

The ability to adjust the motor current to the minimum value means that the copper loss in the three-phase motor 1 can be adjusted to the minimum value. Further, when the second magnetic flux amplitude command calculation unit 31 exists, the amplitude of the estimated magnetic flux _ψαβ is adjusted to a smaller value than when the second magnetic flux amplitude command calculation unit 31 does not exist. That is, according to the present embodiment, the amplitude of the armature interlinkage magnetic flux actually applied to the three-phase motor 1 is reduced, so that the iron loss (eddy current loss) is also reduced. Therefore, according to this embodiment, the three-phase motor 1 can be driven efficiently.

  In this embodiment, the 1st magnetic flux amplitude command calculating part 25 and the 2nd magnetic flux amplitude command calculating part 31 are comprised by the several element. However, the first magnetic flux amplitude command calculation unit 25 and the second magnetic flux amplitude command calculation unit 31 may be configured by a single element. That is, when the magnetic flux command amplitude calculation unit is expressed as having the first magnetic flux amplitude command calculation unit 25 and the second magnetic flux amplitude command calculation unit 31, the magnetic flux command amplitude calculation unit is configured by a plurality of elements. It may be composed of a single element. This also applies to embodiments and modifications described later.

In addition, when the first magnetic flux amplitude command calculation unit 25 and the second magnetic flux amplitude command calculation unit 31 are configured by a single element, this single element is obtained using a single table. The second target magnetic flux | ψ _S ^** | may be specified.

The first magnetic flux amplitude command calculation unit 25 of the present embodiment determines the first target magnetic flux | ψ _S ^* | so that the motor current is minimized. However, the first magnetic flux amplitude command calculation unit 25 may determine the first target magnetic flux | ψ _S ^* | for other purposes. For example, the voltage that can be output from the inverter 2 has an upper limit. For this reason, the voltage that the inverter 2 can output may be set to a predetermined value or less. In this case, the first magnetic flux amplitude command calculation unit 25 may be configured to determine the first target magnetic flux | ψ _S ^* | using Equation (1-14). In other words, the first magnetic flux amplitude command calculation unit 25 may specify the first target magnetic flux | ψ _S ^* | for field weakening control. In this case, field-weakening control with high accuracy is possible. Note that V _om in Equation (1-14) is an upper limit value of the voltage (magnitude of voltage vector) applied to the three-phase motor 1 in field weakening control. ω _a is the number of rotations of the rotor of the three-phase motor 1 (electrical angular velocity of the d axis).

Further, the first magnetic flux amplitude command calculation unit 25 may determine the first target magnetic flux | ψ _S ^* | so that the sum of the copper loss and the iron loss is minimized. In this case, the motor control device 3 can accurately adjust the sum of the copper loss and the iron loss to the minimum value. In short, even if the first magnetic flux amplitude command calculation unit 25 determines the first target magnetic flux | ψ _S ^* | so that any control amount is set to any target value, the motor control device 3 The controlled variable can be accurately adjusted to the target value.

  The matters described for the motor control device in the present embodiment can also be applied to the motor control method. This also applies to the modified examples and embodiments described later.

(Modification)
The motor control device according to the modified example includes a second magnetic flux amplitude command calculation unit A instead of the second magnetic flux amplitude command calculation unit 31 in the first embodiment.

The first magnetic flux amplitude command calculation unit 25 in the modification example is similar to the first magnetic flux amplitude command calculation unit 25 in the above-described embodiment, as the amplitude of the armature linkage magnetic flux for minimizing the motor current. The first target magnetic flux | ψ _S ^* | is specified. The second magnetic flux amplitude command calculation unit A specifies the second target magnetic flux | ψ _S ^** | so that the sum of the copper loss and the iron loss approaches the minimum value. Specifically, the second magnetic flux amplitude command calculation unit A specifies the second target magnetic flux | ψ _S ^** | using Equation (1-15). In the modification, K in Expression (1-15) is an arbitrary coefficient larger than 1.

The second target magnetic flux | ψ _S ^** | specified based on the formula (1-15) is more than the second target magnetic flux | ψ _S ^** | specified based on the formula (1-13). small. For this reason, the amplitude of the target magnetic flux vector _ψαβ ^* in the modification is adjusted to a value smaller than the amplitude of the target magnetic flux vector _ψαβ ^* in the first embodiment. That is, the motor control device according to the modification adjusts the amplitude of the armature linkage magnetic flux to a smaller value than the motor control device 3 according to the first embodiment. Thereby, the iron loss in a modification is adjusted to a smaller value than the iron loss in 1st Embodiment.

  The effect based on the second magnetic flux amplitude command calculation unit 31 in the first embodiment and the effect based on the second magnetic flux amplitude command calculation unit A in the modification will be compared using FIG. FIG. 8 is a graph showing the results obtained by the simulation. A curve 43 represents an effective value (unit: A) of the phase current. A curve 44 represents power loss (unit: W). The power loss is a total value of copper loss and iron loss. When K = 1, the phase current is minimum. From this, it can be seen that the phase current is minimized when the second magnetic flux amplitude command calculation unit 31 operates based on the equation (1-13). On the other hand, power loss is minimized when K> 1. From this, it is understood that the power loss is minimized when the second magnetic flux amplitude command calculation unit A operates based on the equation (1-15) in which K (> 1) is appropriately set. That is, it can be seen that the motor control device can perform the maximum efficiency control by appropriately setting K.

As described above, in the modification, the second magnetic flux amplitude command calculation unit A uses the first target magnetic flux | ψ _S ^* | and the rotational speed ω to provide the second target to be given to the magnetic flux command calculation unit 26. Specify the magnetic flux | ψ _S ^** |. Further, the second magnetic flux amplitude command calculation unit A causes the power loss generated in the three-phase motor 1 when the second target magnetic flux | ψ _S ^** | Instead of the magnetic flux | ψ _S ^** |, the first target magnetic flux | ψ _S ^* | is applied to the magnetic flux command calculation unit 26 so as to be less than the power loss generated in the three-phase motor 1. Since the operation (fine adjustment) of K is easy, the motor control device 3 having the second magnetic flux amplitude command calculation unit A performs the maximum efficiency control in consideration of the iron loss that depends on the rotational speed ω. It can be carried out easily. Further, since the operation of K is easy, motor control that can easily switch between MTPA control and maximum efficiency control if the second magnetic flux amplitude command unit is configured so that K can be adjusted within a range of 1 or more. The device can be configured.

(Second Embodiment)
Hereinafter, the motor control apparatus of the second embodiment will be described with reference to FIGS. Note that in the second embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

The motor control device 103 according to the second embodiment includes a second magnetic flux amplitude command calculation unit 50 that is different from the second magnetic flux amplitude command calculation unit 31 of the motor control device 3. The second magnetic flux amplitude command calculation unit 50 obtains the second target magnetic flux | ψ _S ^** | to be given to the magnetic flux command calculation unit 26 from the first target magnetic flux | ψ _S ^* | and the estimated magnetic flux ψ _αβ. Identify. In addition, the second magnetic flux amplitude command calculation unit 50 applies the second target magnetic flux | ψ _S ^** | to the magnetic flux command calculation unit 26 so that the current flowing through the three-phase motor 1 is the second target magnetic flux | Instead of ψ _S ^** |, the first target magnetic flux | ψ _S ^* | is applied to the magnetic flux command calculation unit 26 so as to be less than the current flowing through the three-phase motor 1. Specifically, the second magnetic flux amplitude command calculation unit 50 obtains the second target magnetic flux | ψ _S ^** | according to the block diagram shown in FIG.

The second magnetic flux amplitude command calculation unit 50 includes an amplitude calculation unit 51, a PI control unit 52, a subtraction unit 53, and an addition unit 54. The amplitude calculator 51 obtains the amplitude | ψ _αβ | of the estimated magnetic flux ψ _αβ from the estimated magnetic flux ψ _αβ . The subtracting unit 53 obtains a difference (| ψ _S ^* | − | ψ _αβ |) between the first target magnetic flux | ψ _S ^* | and the amplitude | ψ _αβ |. The PI control unit 52 obtains the magnetic flux amplitude correction amount Δ | ψ _S ^* | by proportional-integral control that converges the difference between the first target magnetic flux | ψ _S ^* | and the amplitude | ψ _αβ | to zero. The adding unit 54 obtains the sum (| ψ _S ^* | + Δ | ψ _S ^* |) of the first target magnetic flux | ψ _S ^* | and the magnetic flux amplitude correction amount Δ | ψ _S ^* |. The second magnetic flux amplitude command calculation unit 50 outputs this sum as a second target magnetic flux | ψ _S ^** |.

As described with reference to FIG. 5, when the conventional motor control device that does not have the second magnetic flux amplitude command calculation unit is used, the larger the rotational speed ω, the first target magnetic flux | ψ _S ^* | The ratio of the absolute value of the estimated magnetic flux _ψαβ with respect to increases and deviates from 1. The second magnetic flux amplitude command calculating unit 50 is estimated using the estimated armature flux linkage and the first target magnetic flux | ψ _S ^* | specified by the first magnetic flux amplitude command calculating unit 25. The second target magnetic flux | ψ _S ^** | is specified so that the difference between the amplitude | ψ _αβ | of the armature linkage magnetic flux and the first target magnetic flux | ψ _S ^* | converges to zero. Specifically, in the present embodiment, since the second magnetic flux amplitude command calculation unit 50 includes the PI control unit 52, the second target magnetic flux | ψ _S ^** | can be automatically specified. For this reason, the second magnetic flux amplitude command calculation unit 50 increases the difference between the first target magnetic flux | ψ _S ^* | and the second target magnetic flux | ψ _S ^** | as the rotational speed ω increases. Thus, the second target magnetic flux | ψ _S ^** | can be specified. Therefore, the second magnetic flux amplitude command calculation unit 50 can specify the second target magnetic flux | ψ _S ^** | that is suitable for the rotational speed ω.

Further, as described above, when the conventional motor control device that does not have the second magnetic flux amplitude command calculation unit is used, the lower the current sampling frequency, the lower the estimation for the first target magnetic flux | ψ _S ^* | The ratio of the absolute value of the magnetic flux _ψαβ increases and deviates from 1. The second magnetic flux amplitude command calculation unit 50 can specify the second target magnetic flux such that the lower the current sampling frequency, the greater the difference between the first target magnetic flux and the second target magnetic flux. Therefore, according to the second magnetic flux amplitude command calculation unit 50, the control accuracy is maintained even when the current sampling frequency is low.

Even when the first magnetic flux amplitude command calculation unit 25 determines the first target magnetic flux | ψ _S ^* | so that any control amount is set to any target value, the motor control device 103 does not control the control amount. Can be accurately adjusted to the target value. For example, if the first target magnetic flux | ψ _S ^* | is determined so that the first magnetic flux amplitude command calculation unit 25 minimizes the sum of the copper loss and the iron loss, the motor control device 103 Loss and iron loss can be accurately adjusted to the minimum value.

(Third embodiment)
Hereinafter, the motor control device of the third embodiment will be described with reference to FIGS. Note that in the third embodiment, parts that are the same as in the first embodiment are given the same reference numerals, and descriptions thereof are omitted.

The motor control device 203 according to the third embodiment includes a second magnetic flux amplitude command calculation unit 60 that is different from the second magnetic flux amplitude command calculation unit 31 of the motor control device 3. The second magnetic flux amplitude command calculation unit 60 uses the first target magnetic flux | ψ _S ^* |, the estimated magnetic flux ψ _αβ, and the two-phase current i _αβ to be supplied to the magnetic flux command calculation unit 26. Specify | ψ _S ^** |. In addition, the second magnetic flux amplitude command calculation unit 60 applies the second target magnetic flux | ψ _S ^** | to the magnetic flux command calculation unit 26 so that the current flowing through the three-phase motor 1 is the second target magnetic flux | Instead of ψ _S ^** |, the first target magnetic flux | ψ _S ^* | is applied to the magnetic flux command calculation unit 26 so as to be less than the current flowing through the three-phase motor 1. Specifically, the second magnetic flux amplitude command calculation unit 60 obtains the second target magnetic flux | ψ _S ^** | according to the block diagram shown in FIG.

The second magnetic flux amplitude command calculation unit 60 includes an amplitude calculation unit 61, a PI control unit 62, a subtraction unit 63, an addition unit 64, and an MTPA block 65. The amplitude calculator 61 obtains the amplitude | ψ _αβ | of the estimated magnetic flux ψ _αβ from the estimated magnetic flux ψ _αβ . The MTPA block 65 specifies the virtual amplitude (the amplitude of the virtual magnetic flux) | ψsi ^* | as the amplitude of the armature interlinkage magnetic flux for minimizing the motor current from the two-phase current i _αβ . Subtraction unit 63, virtual amplitude | ψsi ^* | amplitude | [psi _.alpha..beta | difference between ^{(| ψsi * | - | ψ} αβ |) determined. PI control unit 62, virtual amplitude | by a proportional integral control for converging the difference between the zero flux amplitude correction quantity Δ | | ψsi ^* | amplitude _| ψ αβ ψ _S ^* | a seek. The adding unit 64 obtains the sum (| ψ _S ^* | + Δ | ψ _S ^* |) of the first target magnetic flux | ψ _S ^* | and the magnetic flux amplitude correction amount Δ | ψ _S ^* |. The second magnetic flux amplitude command calculation unit 60 outputs this sum as a second target magnetic flux | ψ _S ^** |.

It can be understood that the MTPA block 65 re-derived the first target magnetic flux using the two-phase current i _αβ . Therefore, it can be said that the virtual amplitude | ψsi ^* | is the re-derived first target magnetic flux.

In the third embodiment, the second magnetic flux amplitude command calculation unit 60 re-derived the first target magnetic flux based on the current flowing through the three-phase motor 1. The second magnetic flux amplitude command calculation unit 60 further re-derived the estimated amplitude of the armature interlinkage magnetic flux using the estimated armature interlinkage magnetic flux and the re-derived first target magnetic flux. The second target magnetic flux | ψ _S ^** | is specified so that the difference from the first target magnetic flux converges to zero. According to the third embodiment, the same effect as in the second embodiment can be obtained. In the present specification, “re-deriving the first target magnetic flux” means that the first target magnetic flux | Ψ _s ^* | is a predetermined control amount (for example, phase current) of the three-phase motor 1. This means specifying the amplitude of the armature linkage magnetic flux for setting the predetermined control amount of the three-phase motor 1 to the predetermined target value when the target value (for example, the minimum value) is set. .

Even when the first magnetic flux amplitude command calculation unit 25 determines the first target magnetic flux | ψ _S ^* | so that any control amount is set to any target value, the control amount is accurately set to the target value. The motor control device 203 can be configured so that it can be adjusted. For example, when the first target magnetic flux | ψ _S ^* | is determined so that the first magnetic flux amplitude command calculation unit 25 minimizes the sum of the copper loss and the iron loss, instead of the MTPA block 65, A block that specifies the virtual amplitude as the amplitude of the armature interlinkage magnetic flux for minimizing the sum of the copper loss and the iron loss from the two-phase current i _αβ may be used.

Examples of the various blocks for specifying the virtual amplitude (re-derived the first target magnetic flux) include a block having a lookup table and a block having an operator storing a calculation formula (approximation formula). It is done. When using a block having a look-up table, a look-up table representing the correspondence between the two-phase current and the like and the virtual amplitude may be prepared in advance. A calculation formula in a block having an operator can also be prepared in advance. Such a lookup table and calculation formula can be set based on measurement data or theory performed in advance. The specific method of specifying the virtual amplitude is disclosed in publicly known literature (Yoji Takeda, Shigeo Morimoto, Nobuyuki Matsui, Yukio Honda, “Design and Control of Embedded Magnet Synchronous Motor”, Ohm Co., Ltd., published on October 25, 2001. , Etc.). In one example, the virtual amplitude | ψsi ^* | for MTPA control is | ψsi ^* | = √ (ψ _a ² + (I _a × L _a ), where I _a = √ (i _α ² + i _β ² ) ² ) can be specified. Ψ _a is a flux linkage caused by a permanent magnet in the three-phase motor 1. L _a is an inductance per phase of the armature winding of the three-phase motor 1. The virtual amplitude | ψsi ^* | for maximum efficiency control may be a value slightly smaller than the virtual amplitude for MTPA control. However, the virtual amplitude | ψsi ^* | for maximum efficiency control can be accurately specified based on the theory.

(Fourth embodiment)
Hereinafter, a motor control apparatus according to a fourth embodiment will be described with reference to FIGS. Note that in the fourth embodiment, parts that are the same as in the first embodiment are given the same reference numerals, and descriptions thereof are omitted.

The motor control device 303 of the fourth embodiment has a magnetic flux / torque estimation unit 70 different from the magnetic flux / torque estimation unit 23 of the motor control device 3. Flux torque estimating unit 70, similarly to the magnetic flux, torque estimator 23, using equation (1-1) to (1-3), determining the estimated magnetic flux [psi _{.alpha..beta.} However, the magnetic flux / torque estimation unit 70 obtains the estimated torque T from the estimated magnetic flux _ψαβ , the two-phase current _iαβ, and the rotational speed ω. Specifically, the magnetic flux / torque estimation unit 70 obtains the estimated torque T using Expression (4-1). In the fourth embodiment, K _te in equation (4-1) is set to a value larger than zero. K _te is a αP _n T _s L _a. L _a is an inductance per phase of the armature winding of the three-phase motor 1. α is a correction coefficient, and is usually a value in the range of −1 or more and 1 or less.

In general, the estimated torque T is calculated using equations (1-1) to (1-4). According to the equations (1-1) and (1-2), when the phase difference between the two-phase current i _αβ and the target two-phase voltage v _αβ ^* is sufficiently small and can be approximated to zero, the estimated magnetic flux ψ _α , the [psi _beta can be determined accurately. However, when the rotational speed ω increases, the phase difference between the two-phase current i _αβ and the target two-phase voltage v _αβ ^* deviates from zero. In this case, the estimated magnetic fluxes ψ _α and ψ _β obtained by the equations (1-1) and (1-2) are deviated from the armature linkage magnetic flux actually applied to the three-phase motor 1. For this reason, the estimated torque T obtained by the equation (1-4) deviates from the torque (motor torque) actually generated in the three-phase motor 1. The target torque T ^* is set according to the estimated torque T (so as to match the estimated torque T) outside the motor control device. Therefore, when the estimated torque T deviates from the actual motor torque, an appropriate target torque T ^* is not set. When such a target torque T ^* is set, even if the first magnetic flux amplitude command calculation unit is configured to identify the first target magnetic flux for maximum torque / current control from the target torque T ^* , The first magnetic flux amplitude command calculation unit cannot specify the first target magnetic flux for minimizing the motor current. That is, the motor current deviates from the minimum value. A similar phenomenon appears when the current sampling frequency is low.

  In consideration of the above, in the present embodiment, the estimated torque T is obtained using Equation (4-1) instead of Equation (1-4). The magnetic flux / torque estimation unit 23 obtains an estimated torque T corresponding to the rotational speed ω and / or the current sampling frequency by referring to the rotational speed ω and / or the current control period (that is, the current sampling frequency). . Thereby, the estimated torque T close to the torque actually generated in the three-phase motor 1 is obtained.

The effect of obtaining the estimated torque T using Equation (4-1) will be described with reference to the simulation result shown in FIG. A curve 71 in FIG. 14 represents the effective value (unit: A) of the phase current. In FIG. 14, the phase current is minimum when K _te > 0. From this, it can be seen that the phase current is minimized when the magnetic flux / torque estimation unit 70 operates based on the equation (4-1) in which K _te (> 0) is appropriately set.

The magnetic flux / torque estimation unit 70 includes a torque estimation unit having a first part for obtaining the first term on the right side of the equation (4-1) and a second part for obtaining the second term on the right side. It can also be captured. That is, the magnetic flux / torque estimation unit 70 is based on the armature flux linkage estimated by the first unit and the current flowing through the three-phase motor 1 (from the estimated magnetic flux ψ _αβ and the two-phase current i _αβ ), Torque estimation by estimating the motor torque and correcting the estimated motor torque by the second part based on the current flowing through the three-phase motor 1 and the rotational speed (from the two-phase current i _αβ and the rotational speed ω) It can also be understood as having a part. The first part and the second part may be composed of a plurality of elements or may be composed of a single element.

  Even when the magnetic flux / torque estimation unit 70 uses the equation (4-2), the same effect as that obtained when the equation (4-1) is used can be obtained.

  Further, the magnetic flux / torque estimation unit 23 of the motor control devices 103, 203, 303 described above may be replaced with a magnetic flux / torque estimation unit 70.

(Fifth embodiment)
Hereinafter, the generator control apparatus of 5th Embodiment is demonstrated. The generator control device 403 shown in FIG. 15 can be connected to the converter (voltage conversion circuit) 2b and the three-phase generator 1b. The components of the generator control device 403 are the same as those of the motor control device 3.

  The three-phase generator 1b is a three-phase permanent magnet synchronous generator. Examples of the three-phase permanent magnet synchronous generator include an embedded magnet synchronous generator. The three-phase generator 1 b has the same configuration as that of the three-phase motor 1. Converter 2 b has the same configuration as inverter 2. Converter 2b is a PWM converter.

The three-phase generator 1b is connected to a turbine, for example. An example of the turbine is a small gas turbine. When the turbine rotates, the torque of the turbine is transmitted to the rotor of the three-phase generator 1b. As a result, torque is applied to the rotor. That is, the rotor rotates. A voltage is induced by the rotation of the rotor. Since the three-phase generator 1b is connected to the converter 2b and the converter 2b refers to the target three-phase voltage v _uvw ^* , the induced voltage follows the target three-phase voltage v _uvw ^* . The converter 2b also converts the induced voltage into a DC voltage by PWM modulation. The DC voltage (DC power derived from the DC voltage) is output from the voltage output unit 4b.

  In the first embodiment, electric power supplied from a power source (not shown) is converted into torque (rotational force) by the three-phase motor 1. On the other hand, in this embodiment, the torque applied to the three-phase generator 1b is converted into electric power. In both cases, the control aspects are substantially the same. Therefore, the matters described for the motor control device 3 can also be applied to the generator control device 403. The matters described for the motor control devices 103, 203, and 303 are the same. However, it should be noted that the terminology should be replaced when the description of the motor control devices 3, 103, 203, and 303 is used for the description of the generator control device 403. Since such replacement is obvious to those skilled in the art and will not be described in detail, for example, a motor and an inverter should be replaced with a generator and a converter, respectively.

DESCRIPTION OF SYMBOLS 1 3 phase motor 1b 3 phase generator 1m Permanent magnet 2 Inverter 2b Converter 3,103,203,303 Motor control apparatus 4b Voltage output part 5 Current sensor 22 3 phase 2 phase coordinate conversion part 23,70 Magnetic flux and torque estimation part 24 Subtraction unit 25 First magnetic flux amplitude command calculation unit 26 Magnetic flux command calculation unit 29 Voltage command calculation unit 30 Two-phase three-phase coordinate conversion unit 31, 50, 60 Second magnetic flux amplitude command calculation unit 35 PI control unit 36 Addition unit 37 Vector generator 40, 41, 42, 43, 44, 71 Curve 51, 61 Amplitude calculator 52, 62 PI controller 53, 63 Subtractor 54, 64 Adder 65 MTPA block 403 Generator controller

Claims (11)

A motor control device that applies a voltage vector to the three-phase motor by an inverter so that the armature interlinkage magnetic flux and the motor torque of the three-phase motor follow the target magnetic flux and the target torque, respectively.
A magnetic flux amplitude command calculation unit for specifying the target magnetic flux;
A magnetic flux command calculation unit that identifies a target magnetic flux vector based on the target magnetic flux and the estimated phase of the armature linkage flux;
From the difference between the target magnetic flux vector and the estimated armature flux linkage, a voltage command calculation unit that identifies the voltage vector;
With
The magnetic flux amplitude command calculation unit includes (i) a first magnetic flux amplitude command calculation unit that identifies a first target magnetic flux as the target magnetic flux from the target torque, (ii) the first target magnetic flux, A second magnetic flux amplitude command calculation unit that specifies a second target magnetic flux to be given to the magnetic flux command calculation unit from the rotation speed of the three-phase motor or the estimated armature linkage magnetic flux;
When the second target magnetic flux is given to the magnetic flux command calculation unit, the current flowing through the three-phase motor or the power loss generated in the three-phase motor is replaced with the first target magnetic flux instead of the second target magnetic flux. as below power loss generated by the current or the 3-phase motor through the 3-phase motor when the magnetic flux imparted to the magnetic flux command computation unit, the second magnetic flux amplitude command computation unit is configured,
The second magnetic flux amplitude command calculation unit re-derived the first target magnetic flux based on the current flowing through the three-phase motor, and re-derived the estimated first armature linkage magnetic flux. Using the target magnetic flux, the second target magnetic flux is specified such that the difference between the estimated amplitude of the armature linkage magnetic flux and the re-derived first target magnetic flux converges to zero. Motor control device. A motor control device that applies a voltage vector to the three-phase motor by an inverter so that the armature interlinkage magnetic flux and the motor torque of the three-phase motor follow the target magnetic flux and the target torque, respectively.
A magnetic flux amplitude command calculation unit for specifying the target magnetic flux;
A magnetic flux command calculation unit that identifies a target magnetic flux vector based on the target magnetic flux and the estimated phase of the armature linkage flux;
From the difference between the target magnetic flux vector and the estimated armature flux linkage, a voltage command calculation unit that identifies the voltage vector;
With
The magnetic flux amplitude command calculation unit includes (i) a first magnetic flux amplitude command calculation unit that identifies a first target magnetic flux as the target magnetic flux from the target torque, (ii) the first target magnetic flux, A second magnetic flux amplitude command calculation unit that specifies a second target magnetic flux to be given to the magnetic flux command calculation unit from the rotation speed of the three-phase motor or the estimated armature linkage magnetic flux;
When the second target magnetic flux is given to the magnetic flux command calculation unit, the current flowing through the three-phase motor or the power loss generated in the three-phase motor is replaced with the first target magnetic flux instead of the second target magnetic flux. The second magnetic flux amplitude command calculation unit is configured to be less than a current flowing through the three-phase motor or a power loss generated in the three-phase motor when a magnetic flux is applied to the magnetic flux command calculation unit.
The amount of deviation from the first target magnetic flux of the amplitude of the armature linkage magnetic flux estimated when the second target magnetic flux is given to the magnetic flux command calculation unit is replaced with the second target magnetic flux. The motor control so as to reduce the amplitude of the armature linkage magnetic flux estimated when the first target magnetic flux is given to the magnetic flux command calculation unit as compared with the deviation amount from the first target magnetic flux. A motor control device in which the device is configured. The second magnetic flux amplitude command calculation unit identifies the second target magnetic flux using the rotation speed so that the estimated amplitude of the armature linkage magnetic flux matches the first target magnetic flux. The motor control device according to claim 2 . The second magnetic flux amplitude command calculation unit uses the estimated armature linkage magnetic flux and the first target magnetic flux specified by the first magnetic flux amplitude command calculation unit to estimate the electric machine 3. The motor control device according to claim 2, wherein the second target magnetic flux is specified such that a difference between the amplitude of the interlinkage magnetic flux and the first target magnetic flux converges to zero. A motor control device that applies a voltage vector to the three-phase motor by an inverter so that the armature interlinkage magnetic flux and the motor torque of the three-phase motor follow the target magnetic flux and the target torque, respectively.
A magnetic flux amplitude command calculation unit for specifying the target magnetic flux;
A magnetic flux command calculation unit that identifies a target magnetic flux vector based on the target magnetic flux and the estimated phase of the armature linkage flux;
From the difference between the target magnetic flux vector and the estimated armature flux linkage, a voltage command calculation unit that identifies the voltage vector;
With
The magnetic flux amplitude command calculation unit includes (i) a first magnetic flux amplitude command calculation unit that identifies a first target magnetic flux as the target magnetic flux from the target torque, (ii) the first target magnetic flux, A second magnetic flux amplitude command calculation unit that specifies a second target magnetic flux to be given to the magnetic flux command calculation unit from the rotation speed of the three-phase motor or the estimated armature linkage magnetic flux;
When the second target magnetic flux is given to the magnetic flux command calculation unit, the current flowing through the three-phase motor or the power loss generated in the three-phase motor is replaced with the first target magnetic flux instead of the second target magnetic flux. The second magnetic flux amplitude command calculation unit is configured to be less than a current flowing through the three-phase motor or a power loss generated in the three-phase motor when a magnetic flux is applied to the magnetic flux command calculation unit.
The motor control device, wherein the motor control device is configured such that the estimated amplitude of the armature linkage magnetic flux is larger than the second target magnetic flux and smaller than the first target magnetic flux. The motor control device according to any one of claims 1 to 5, wherein the second magnetic flux amplitude command calculation unit specifies the second target magnetic flux that is smaller than the first target magnetic flux. The second magnetic flux amplitude command calculation unit specifies the second target magnetic flux so that the difference between the first target magnetic flux and the second target magnetic flux increases as the rotational speed increases. The motor control apparatus of any one of Claims 1-6 . The motor torque is estimated based on the estimated armature flux linkage and the current flowing through the three-phase motor, and the estimated motor torque is calculated based on the current flowing through the three-phase motor and the rotational speed. correction to, further comprising a torque estimation unit, the motor control apparatus according to any one of claims 1-7. A generator control device that applies a voltage vector to the three-phase generator by a converter so that an armature interlinkage magnetic flux and a generator torque of the three-phase generator follow the target magnetic flux and the target torque, respectively.
A magnetic flux amplitude command calculation unit for specifying the target magnetic flux;
A magnetic flux command calculation unit that identifies a target magnetic flux vector based on the target magnetic flux and the estimated phase of the armature linkage flux;
From the difference between the target magnetic flux vector and the estimated armature flux linkage, a voltage command calculation unit that identifies the voltage vector;
With
The magnetic flux amplitude command calculation unit includes (i) a first magnetic flux amplitude command calculation unit that identifies a first target magnetic flux as the target magnetic flux from the target torque, (ii) the first target magnetic flux, A second magnetic flux amplitude command calculation unit for specifying a second target magnetic flux to be given to the magnetic flux command calculation unit from the rotation speed of the three-phase generator or the estimated armature linkage flux;
When the second target magnetic flux is given to the magnetic flux command calculation unit, the current flowing through the three-phase generator or the power loss generated in the three-phase generator is replaced with the first target magnetic flux instead of the first target magnetic flux. The second magnetic flux amplitude command calculation unit is configured to be less than the current flowing through the three-phase generator or the power loss generated in the three-phase generator when the target magnetic flux is applied to the magnetic flux command calculation unit. and,
The second magnetic flux amplitude command calculation unit re-derived the first target magnetic flux based on the current flowing through the three-phase generator, and re-derived the estimated armature flux linkage. The second target magnetic flux is specified so that the difference between the estimated amplitude of the armature linkage flux and the re-derived first target magnetic flux converges to zero using the target magnetic flux of , Generator control device. A generator control device that applies a voltage vector to the three-phase generator by a converter so that an armature interlinkage magnetic flux and a generator torque of the three-phase generator follow the target magnetic flux and the target torque, respectively.
A magnetic flux amplitude command calculation unit for specifying the target magnetic flux;
A magnetic flux command calculation unit that identifies a target magnetic flux vector based on the target magnetic flux and the estimated phase of the armature linkage flux;
From the difference between the target magnetic flux vector and the estimated armature flux linkage, a voltage command calculation unit that identifies the voltage vector;
With
The magnetic flux amplitude command calculation unit includes (i) a first magnetic flux amplitude command calculation unit that identifies a first target magnetic flux as the target magnetic flux from the target torque, (ii) the first target magnetic flux, A second magnetic flux amplitude command calculation unit for specifying a second target magnetic flux to be given to the magnetic flux command calculation unit from the rotation speed of the three-phase generator or the estimated armature linkage flux;
When the second target magnetic flux is given to the magnetic flux command calculation unit, the current flowing through the three-phase generator or the power loss generated in the three-phase generator is replaced with the first target magnetic flux instead of the first target magnetic flux. The second magnetic flux amplitude command calculation unit is configured to be less than the current flowing through the three-phase generator or the power loss generated in the three-phase generator when the target magnetic flux is applied to the magnetic flux command calculation unit. And
The amount of deviation from the first target magnetic flux of the amplitude of the armature linkage magnetic flux estimated when the second target magnetic flux is given to the magnetic flux command calculation unit is replaced with the second target magnetic flux. The generator so that the amplitude of the armature linkage magnetic flux estimated when the first target magnetic flux is given to the magnetic flux command calculation unit is reduced as compared with a deviation amount from the first target magnetic flux. A generator control device in which the control device is configured. A generator control device that applies a voltage vector to the three-phase generator by a converter so that an armature interlinkage magnetic flux and a generator torque of the three-phase generator follow the target magnetic flux and the target torque, respectively.
A magnetic flux amplitude command calculation unit for specifying the target magnetic flux;
A magnetic flux command calculation unit that identifies a target magnetic flux vector based on the target magnetic flux and the estimated phase of the armature linkage flux;
From the difference between the target magnetic flux vector and the estimated armature flux linkage, a voltage command calculation unit that identifies the voltage vector;
With
The magnetic flux amplitude command calculation unit includes (i) a first magnetic flux amplitude command calculation unit that identifies a first target magnetic flux as the target magnetic flux from the target torque, (ii) the first target magnetic flux, A second magnetic flux amplitude command calculation unit for specifying a second target magnetic flux to be given to the magnetic flux command calculation unit from the rotation speed of the three-phase generator or the estimated armature linkage flux;
When the second target magnetic flux is given to the magnetic flux command calculation unit, the current flowing through the three-phase generator or the power loss generated in the three-phase generator is replaced with the first target magnetic flux instead of the first target magnetic flux. The second magnetic flux amplitude command calculation unit is configured to be less than the current flowing through the three-phase generator or the power loss generated in the three-phase generator when the target magnetic flux is applied to the magnetic flux command calculation unit. And
The generator control device is configured such that the estimated amplitude of the armature linkage magnetic flux is larger than the second target magnetic flux and smaller than the first target magnetic flux. .

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