JP2020065433A - Magnetic pole initial position detection device using direct-current excitation method and magnetic pole position detection device - Google Patents

Abstract

To provide a magnetic pole initial position detection device using a direct-current excitation method, capable of acquiring a magnetic pole initial position of a rotor of a synchronous motor in a short period of time, and a magnetic pole position detection device including the same.SOLUTION: A magnetic pole initial position detection device 1 for detecting a magnetic pole initial position of a rotor of a synchronous motor 2 includes: a direct-current excitation command generation section 11 configured to generate a first command for causing a constant excitation current with a current phase fixed to a first phase to flow through the synchronous motor 2; a torque-zero determination section 12 configured to determine whether or not a torque generated in the rotor of the synchronous motor 2 is zero when the excitation current based on the first command flows through the synchronous motor 2; and a magnetic pole initial position acquisition section 13 configured to acquire the magnetic pole initial position of the rotor of the synchronous motor 2 on the basis of a rotor actual position in the vicinity of a point in time when the torque-zero determination section 12 determines that the torque is zero, the number of pole pairs of the synchronous motor 2, and an excitation phase during direct-current excitation under the first command.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a DC excitation type magnetic pole initial position detection device and a magnetic pole position detection device.

  In a synchronous motor, a dq coordinate control system is used to pass a current through an appropriate excitation phase winding according to the magnetic pole position of a rotor to generate a desired torque. The synchronous motor includes a synchronous motor having a magnetic pole position sensor such as an encoder for detecting the magnetic pole position of the rotor and a synchronous motor having no magnetic pole position sensor.

  In the case of a synchronous motor that does not have a magnetic pole position sensor, magnetic pole position detection processing is performed every time the synchronous motor is powered on (started) to detect the initial position of the magnetic pole (hereinafter referred to as the "magnetic pole initial position"). The rotation of the synchronous motor is controlled based on the magnetic pole position based on this magnetic pole initial position. As a method for detecting the magnetic pole initial position, for example, there is a DC excitation method in which the current phase is fixed to the synchronous motor, a constant exciting current is continuously supplied, and the finally stopped position is set as the magnetic pole initial position.

  For example, an energizing unit that applies an exciting current to the drive coil to generate a rotating magnetic field in the stator, a rotor having a permanent magnet that is rotationally driven by the rotating magnetic field, and a phase shift depending on the rotation of the rotor. And an encoder that outputs a two-phase pulse rotation signal, and a rotation speed detection that detects the rotation angular velocity of the rotor from the number of rotation signal pulses per unit time and that detects the rotation direction of the rotor from the rotation signal. Means, logical operation means for controlling energization to the drive coil after a certain time of energization, and for calculating the initial position of the rotor by the output of the rotation speed detecting means, and inputting the rotation signal to initialize the rotor. And a counter that counts the amount of rotation from the position to the present, and the logical operation means determines the current rotor position from the initial position of the rotor and the amount of rotation to the present. Driving circuit of the brushless motor, characterized in that the constant is known (e.g., see Patent Document 1.).

  For example, in a permanent magnet synchronous motor controlled by a variable voltage and a variable frequency output from a power converter, and a controller for a permanent magnet synchronous motor in a mechanical device driven by the permanent magnet synchronous motor, the machine comprising: The permanent magnet is released when the brake device that holds the stop of the device is released and the motor-generated torque and the load torque are almost balanced when a predetermined armature current is applied regardless of the rotational position of the permanent magnet synchronous motor. There is known a control device for a permanent magnet type synchronous motor, which estimates the magnetic pole phase of the synchronous motor from the armature current and the load torque or from the armature current (for example, Patent Document 2). reference.).

  For example, an AC synchronous motor including a speed control unit that calculates a command torque (command current) from a command speed, a current control unit that drives the AC synchronous motor according to the command torque (command current), and a PWM power converter. In an initial magnetic pole estimating device for an AC synchronous motor provided in a control device, speed deviation calculating means for calculating a speed deviation by subtracting the detected speed from the command speed generated from a command speed pattern generating means, and speed to the speed deviation. A speed gain control unit that multiplies a gain to calculate a command torque (command current), a mode interval determination unit that performs a process of determining a mode interval (first cycle interval and second cycle interval) from the command speed, and the mode interval. A mode switch for switching to one of the first period section and the second period section according to the result of the determination means; When the first period section is selected, a data acquisition speed section determination unit that determines whether the command speed is a data acquisition speed section, and the command torque (the command current) in the determined data acquisition speed section. ), The first command torque calculation means (first command current calculation means) for calculating the first command torque data (first command current data) and the second cycle section are selected. And a second command torque data (second command current data) from the command torque (the command current) in the determined data acquisition speed section. Second command torque calculation means (second command current calculation means) for calculating, the first command torque data (the first command current data), and the second command torque data (the second command torque data). There is known an initial magnetic pole estimation device for an AC synchronous motor, which has an estimated initial magnetic pole calculating means for calculating an estimated initial magnetic pole position by using information of command current data) (for example, refer to Patent Document 3). ).

JP-A-2-276492 JP-A-2000-78878 JP 2001-157482 A

  In the magnetic pole initial position processing by the DC excitation method, for example, the synchronous motor is DC-excited with a magnetic pole of 0 degree, waits for the rotor of the synchronous motor to stop, then the DC is excited with a magnetic pole of 90 degrees, and the position after the stop is the magnetic pole initial position. It is acquired as a position. In this way, the time from the start of DC excitation to the synchronous motor to the stop of the rotor of the synchronous motor is very long, and it takes time to acquire the magnetic pole initial position. In particular, in a synchronous motor such as a synchronous motor having a hydrostatic bearing that has very low friction and high acceleration performance, it may take several minutes to acquire the magnetic pole initial position. Therefore, in the magnetic pole position detection processing by the DC excitation method, there is a demand for a technique capable of acquiring the magnetic pole initial position of the rotor of the synchronous motor in a short time.

  According to one aspect of the present disclosure, a magnetic pole initial position detection device for detecting a magnetic pole initial position of a rotor of a synchronous motor issues a first command that causes a constant exciting current having a current phase fixed to the first phase to flow to the synchronous motor. Zero torque determination for determining whether or not the torque generated in the rotor of the synchronous motor is zero when the direct-current excitation command generation unit to generate and the excitation current based on the first command flow in the synchronous motor Part, based on the rotor actual position in the vicinity of the time when the torque is determined to be zero by the torque zero determination part, the number of pole pairs of the synchronous motor, and the excitation phase during direct-current excitation by the first command, A magnetic pole initial position acquisition unit that acquires the magnetic pole initial position of the rotor of the synchronous motor.

  According to one aspect of the present disclosure, the magnetic pole position detecting device outputs a magnetic pole position update for outputting the magnetic pole position of the rotor of the synchronous motor initialized at the magnetic pole initial position detected by the magnetic pole initial position detecting device. Section.

  According to one aspect of the present disclosure, it is possible to realize a magnetic pole initial position detection device by a direct current excitation method that can acquire the magnetic pole initial position of a rotor of a synchronous motor in a short time, and a magnetic pole position detection device including the same.

FIG. 3 is a block diagram showing a magnetic pole initial position detection device according to the first embodiment of the present disclosure. It is a figure which illustrates a behavior of a rotor of a synchronous motor when a current phase is fixed and a constant exciting current is continuously supplied to the synchronous motor, and FIG. Yes, (B) is an enlarged view of (A) in the time axis direction. It is a figure which shows the relationship between the dq coordinate system which concerns on a synchronous motor, and the dq coordinate system which concerns on the motor control device which controls a synchronous motor. It is a figure explaining the magnitude of the exciting current sent in order to acquire the magnetic pole initial position of the synchronous motor which has salient polarity. It is a figure which illustrates the relationship between the temperature of the permanent magnet provided in a synchronous motor, and the magnetic flux density of the main magnetic flux of a synchronous motor. FIG. 6 is a diagram illustrating magnetic pole initial position acquisition processing in the first embodiment of the present disclosure, in which (A) illustrates the acceleration of the rotor of the synchronous motor, (B) illustrates the speed of the rotor of the synchronous motor, and C) illustrates the actual rotor position of the synchronous motor. 3 is a flowchart showing an operation flow of the magnetic pole initial position detection device according to the first embodiment of the present disclosure. FIG. 3 is a block diagram showing a motor control device including a magnetic pole position detection device including the magnetic pole initial position detection device according to the first embodiment of the present disclosure. It is a block diagram showing the composition of the magnetic pole initial position detecting device concerning a 2nd embodiment of this indication. 7 is a flowchart showing an excitation phase determination process for determining an excitation phase used for detecting a magnetic pole initial position. 6 is a graph showing the relationship between the phase of the exciting current and the torque in the case of a synchronous motor having non-salient polarity. It is a figure for demonstrating the relationship between the phase of an exciting current, and the rotation direction of a rotor.

  A DC excitation type magnetic pole initial position detection device and a magnetic pole position detection device will be described below with reference to the drawings. For ease of understanding, the drawings are scaled accordingly. The embodiment shown in the drawings is an example for carrying out the invention, and the present invention is not limited to the embodiment shown.

First Embodiment FIG. 1 is a block diagram showing a magnetic pole initial position detection device according to a first embodiment of the present disclosure.

  As shown in FIG. 1, a magnetic pole initial position detection device 1 for detecting a magnetic pole initial position of a rotor of a synchronous motor 2 according to this embodiment includes a DC excitation command generation unit 11, a torque zero determination unit 12, and a magnetic pole initial position acquisition unit. 13, a rotor actual position acquisition unit 14, and a storage unit 15.

  The direct-current excitation command generation unit 11 issues a command for flowing a constant exciting current to the synchronous motor 2 with a current phase fixed to a predetermined phase (hereinafter, also referred to as a first phase) (hereinafter, also referred to as a first command). Generate). The command generated by the DC excitation command generator 11 is sent to the current controller 33 in the motor controller 1000 for controlling the drive of the synchronous motor 2 (see FIG. 8). The current control unit 33 in the motor control device 1000 generates a voltage command based on the command received from the DC excitation command generation unit 11 and the current feedback converted at the fixed current phase, and the power conversion unit 35 By applying a voltage to the synchronous motor 2 based on the received voltage command, a constant exciting current with a fixed current phase is generated. The rotor of the synchronous motor 2 vibrates in the rotation direction by using this exciting current as a drive source, and the vibration is gradually attenuated and finally stopped.

  The torque zero determination unit 12 generates zero torque (0) in the rotor of the synchronous motor 2 when a constant excitation current based on the first command generated by the DC excitation command generation unit 11 is flowing in the synchronous motor 2. Is determined. In the rotor vibrating in the rotation direction, the time (timing) at which the torque becomes zero exists a plurality of times before the rotor completely stops. , There are multiple opportunities to make a zero torque determination. Of the plurality of torque zero determination opportunities, the more the DC excitation command generation unit 11 adopts the torque zero determination opportunity closer to the start time point of the DC excitation command for the synchronous motor 2, the more the DC excitation command generation unit 11 outputs the DC excitation command for the synchronous motor 2. The acquisition process of the magnetic pole initial position of the rotor of the synchronous motor 2 by the magnetic pole initial position acquisition unit 13 can be completed in a short time from the start time. For example, the torque zero determination unit 12 detects the torque zero that occurs first after the DC excitation command generation unit 11 starts the DC excitation command for the synchronous motor 2 and obtains this detection result (that is, torque zero determination) as the magnetic pole initial position. It is most preferable to notify the section 13.

  The magnetic pole initial position acquisition unit 13 determines the position of the rotor of the synchronous motor 2 (actual rotor position) near the time when the torque zero determination unit 12 determines that the torque has become zero, the number of pole pairs of the synchronous motor 2, and DC excitation. The magnetic pole initial position of the rotor of the synchronous motor 2 is acquired based on the excitation phase of the.

  The actual rotor position acquisition unit 14 acquires the actual rotor position, which is the position of the rotor of the synchronous motor 2, from the sensor 51 provided in the synchronous motor 2.

  The storage unit 15 stores information regarding the number of pole pairs of the synchronous motor 2. The storage unit 15 is composed of an electrically erasable / recordable non-volatile memory such as EEPROM (registered trademark), or a random access memory such as DRAM and SRAM that can be read and written at high speed. .

  Here, the principle of acquiring the magnetic pole initial position of the rotor of the synchronous motor 2 based on the actual rotor position at or near the time when the torque generated in the rotor of the synchronous motor 2 becomes zero is shown in FIGS. This will be described with reference to FIG.

  FIG. 2 is a diagram illustrating the behavior of the rotor of the synchronous motor when the current phase is fixed and a constant exciting current is continuously supplied to the synchronous motor. FIG. It is a figure which illustrates and (B) is the figure which expanded (A) in the time-axis direction. 2 (A) and 2 (B), the solid line shows the elapsed time of the rotor actual position of the synchronous motor 2, and the alternate long and short dash line shows the speed (rotational angular speed) of the synchronous motor 2. When the current phase is fixed and a constant exciting current is continuously supplied to the synchronous motor 2, the rotor of the synchronous motor 2 vibrates in the rotation direction as illustrated in FIG. The vibration of the synchronous motor 2 is gradually attenuated, and the rotor finally stops.

FIG. 3 is a diagram showing the relationship between the dq coordinate system related to the synchronous motor and the dq coordinate system related to the motor control device controlling the synchronous motor. The coordinate axes of the dq coordinate system related to the synchronous motor are d _m and q _m , and the coordinate axes of the dq coordinate system related to the motor control device that controls the synchronous motor are d _c and q _c . Further, the deviation amount of the d axis between the coordinate systems (that is, the angle formed by the coordinate axis d _m and the coordinate axis d _c ) is θ. The shift amount θ is also the shift amount of the q axis between the coordinate systems (that is, the angle between the coordinate axis q _m and the coordinate axis q _c ).

A constant exciting current whose current phase is fixed at 0 degree in the dq coordinate system related to the motor controller is defined as I _e . At this time, the exciting current I _e is represented by Expression 1 in the dq coordinate system related to the synchronous motor.

When the number of pole pairs of the synchronous motor 2 is pp, the main magnetic flux is Φ, the d-phase inductance is L _d , and the q-phase inductance is L _q , the torque generated when the exciting current I _e is passed through the synchronous motor having saliency. T _r is expressed as in Equation 2.

In a non-saliency synchronous motor (that is, a synchronous motor without salient polarity), the d-phase inductance L _d and the q-phase inductance L _q are equal. Therefore, the torque T _r generated when the exciting current I _e is passed through the synchronous motor having the non-salient polarity is expressed by Expression 3 by modifying Expression 2.

When the current phase is fixed and a constant exciting current is continuously supplied to the synchronous motor, as illustrated in FIG. 2, the rotor of the synchronous motor vibrates in the rotation direction, the vibration is gradually attenuated, and finally, the vibration is finally attenuated. Stop. When the rotor of the synchronous motor is at the final stop position, the stop position of the rotor matches the excitation phase, and the shift amount θ between the coordinate systems becomes zero. While the excitation current is continuously supplied to the synchronous motor and the rotor is vibrating in the rotation direction, the deviation amount θ changes every moment. Expressions 2 and 3 include “sin θ”, but when the shift amount θ is zero, “sin θ” becomes zero, and therefore the torque _Tr becomes zero. Conversely, when the torque T _r is zero, “sin θ” in the equations 2 and 3 is zero, that is, the shift amount θ can be zero. Therefore, when the current phase is fixed and a constant exciting current is continuously supplied to the synchronous motor, the time when the torque _Tr becomes zero is detected, and the initial magnetic pole position is determined based on the actual rotor position at this time. get.

However, in the case of a synchronous motor having saliency, depending on the magnitude of the exciting current I _e , when θ is not zero, “{Φ− (L _q −L _d ) · I _e · cos θ}” in Equation 2 is obtained. May become zero, that is, the torque T _r expressed by the equation 2 may become zero. That is, in the case of a synchronous motor having saliency, even if the torque T _r is zero, the deviation amount θ does not necessarily mean zero. Accordingly, in applying the present embodiment to the synchronous motor having saliency, does not flow _{"{Φ- (L q -L d)} · I e · cosθ} " is zero such excitation current I _e Need to do so. On the other hand, in the case of a non-salient-polarity synchronous motor, the deviation amount θ is expressed by the equation 3, and therefore the torque _Tr is zero only when the deviation amount θ is zero. When this embodiment is applied to, it is not necessary to set an upper limit value to the constant exciting current I _e having a fixed current phase.

Here, the magnitude of the exciting current I _{e to} be passed in order to acquire the magnetic pole initial position of the synchronous motor having saliency will be described with reference to FIGS. 4 and 5.

FIG. 4 is a diagram for explaining the magnitude of the exciting current passed to acquire the magnetic pole initial position of the synchronous motor having saliency. In FIG. 4 (A), the horizontal axis represents the deviation amount θ and the vertical axis represents the torque _Tr . In FIG. 4B, the horizontal axis represents the deviation amount θ, and the vertical axis represents the expression of the generated torque divided by the q-phase current. Further, in FIGS. 4A and 4B, the two-dot chain line shows the case where the exciting current I _e is 30 Arms, the one-dot chain line shows the case where the exciting current I _e is 60 Arms, and the solid line shows the exciting current I _e. Shows 80 Arms. The magnitude of the exciting current I _e shown in FIGS. 4A and 4B is merely an example.

When the exciting current I _e is 30 Arms and 60 Arms, the torque _Tr becomes zero only when the deviation amount θ is zero as shown in FIG. 4 (A). On the other hand, when the exciting current I _e is 80 Arms, the torque _Tr becomes zero not only when the deviation amount θ is zero but also near “−44 degrees”. As described above, when the exciting current I _e is 80 Arms, the torque T _r becomes zero even when the deviation amount θ is other than zero, as shown in FIG. 4B. This is because a negative region is generated in the value obtained by dividing Q by the q-phase current. Therefore, when the present embodiment is applied to the synchronous motor having saliency, the torque Tr represented by the equation 2 is positive (that is, larger than zero) in all cases except when the deviation amount θ is zero. It is necessary to set the exciting current Ie such that Specifically, it is as follows.

Applying “T _r > 0” and “θ ≠ 0” in Expression 2 and rearranging them yields inequality 4.

  Since “−1 ≦ cos θ ≦ 1” is satisfied in the inequality 4, the inequality 4 to the inequality 5 are obtained.

  By rearranging the inequality 5, the inequality 6 is obtained.

Therefore, when the present embodiment is applied to the synchronous motor having the saliency, the constant exciting current I _e with the fixed current phase should be set to a value that satisfies the inequality 6. In the present embodiment, when the synchronous motor whose magnetic pole initial position is to be acquired is a synchronous motor having a salient polarity, the DC excitation command generation unit 11 has a value less than the upper limit value “Φ / (L _q −L _d )”. A command for flowing the exciting current I _e to the synchronous motor 2 is generated.

The main magnetic flux Φ decreases as the temperature of the permanent magnet provided in the synchronous motor 2 increases. Therefore, the upper limit of the exciting current I _e may be set in consideration of the temperature rise of the permanent magnet that is assumed when the synchronous motor 2 having the saliency is driven. Here, the magnitude of the exciting current I _{e to} be passed in order to obtain the magnetic pole initial position in consideration of the temperature rise of the permanent magnet of the synchronous motor having saliency will be described with reference to FIG.

FIG. 5: is a figure which illustrates the relationship between the temperature of the permanent magnet provided in a synchronous motor, and the magnetic flux density of the main magnetic flux of a synchronous motor. In FIG. 5, the horizontal axis represents the temperature of the permanent magnet provided in the synchronous motor 2, and the vertical axis represents the ratio of the magnetic flux density when the magnetic flux density is 100% when the permanent magnet is 20 ° C. The numerical values shown in FIG. 5 are merely examples, and other numerical values may be used. For example, when the maximum temperature of the permanent magnet assumed when driving the synchronous motor 2 having saliency is 160 degrees, the generated torque may be zero when the deviation amount θ is other than zero even when the permanent magnet is 160 degrees. In order to prevent this, the exciting current I _e is limited in consideration of the magnetic flux Φ _min (minimum magnetic flux density) at the maximum temperature of the assumed permanent magnet of the synchronous motor 2. That is, inequality 7 can be obtained from inequality 6.

Therefore, when the present embodiment is applied to the synchronous motor having saliency, the constant exciting current I _e with the fixed current phase is taken into consideration in consideration of the temperature rise of the permanent magnet that is assumed when the synchronous motor is driven. The size may be set to satisfy the inequality 7. In this case, the direct-current excitation command generation unit 11 generates a command that causes the excitation current _Ie less than the upper limit value "Φ _min / (L _q -L _d )" to flow to the synchronous motor 2.

  Next, the torque zero determination processing by the torque zero determination unit 12 will be described with reference to FIG.

As shown in FIG. 2, when the current phase is fixed and a constant exciting current is continuously supplied to the synchronous motor 2, the rotor of the synchronous motor 2 vibrates in the rotation direction. The vibration of the synchronous motor 2 is gradually attenuated, and the rotor finally stops. While the rotor of the synchronous motor 2 vibrates in the rotation direction, the torque T _r generated in the rotor of the synchronous motor 2 becomes zero because the polarity of the acceleration of the rotor of the synchronous motor 2 changes from positive to negative, or It is the time when it changed from negative to positive. Further, the speed of the synchronous motor 2 shows the maximum (maximum) at the time when the polarity of the acceleration of the synchronous motor 2 changes from positive to negative, and the synchronous motor 2 at the time when the polarity of the acceleration of the synchronous motor 2 changes from negative to positive. Shows the minimum (minimum) speed. Therefore, in the present embodiment, the zero torque determination unit 12 acquires the acceleration (of the rotor) of the synchronous motor 2 and determines the time when the polarity of the acceleration of the synchronous motor 2 changes as the time when the torque becomes zero. Alternatively, the torque zero determination unit 12 acquires the (rotor) speed of the synchronous motor 2 and determines that the time when the speed of the synchronous motor 2 becomes maximum or minimum is the time when the torque becomes zero. The acceleration of the synchronous motor 2 can be acquired by second-order differentiating the actual rotor position acquired by the actual rotor position acquisition unit 14. The speed of the synchronous motor 2 can be acquired by first-order differentiating the actual rotor position acquired by the actual rotor position acquisition unit 14. The rotor real position differential calculation processing may be executed by the torque zero determination unit 12, the rotor real position acquisition unit 14, or another processing unit.

  Next, the magnetic pole initial position acquisition processing by the magnetic pole initial position acquisition unit 13 will be described with reference to FIG.

  6A and 6B are diagrams illustrating a magnetic pole initial position acquisition process according to an embodiment of the present disclosure. FIG. 6A illustrates the acceleration of the rotor of the synchronous motor, and FIG. 6B illustrates the speed of the rotor of the synchronous motor. , (C) exemplify the actual rotor position of the synchronous motor.

The magnetic pole initial position acquisition unit 13 is based on the actual rotor position near the time point when the torque zero determination unit 12 determines that the torque T _r has become zero, the number of pole pairs of the synchronous motor 2, and the excitation phase during DC excitation. , The magnetic pole initial position of the rotor of the synchronous motor 2 is acquired. In the illustrated example, _assuming that the sampling cycle of the rotor actual position acquired by the rotor actual position acquisition unit 14 is T _s , the rotor actual position acquisition unit 14 acquires the rotor actual position at time 0 and then the rotor actual position is acquired. The position is acquired at time T _s . At time T ₀ between time 0 and time T _s, the polarity of the acceleration a of the synchronous motor 2 rotor changes from positive to negative (i.e., the acceleration a of the rotor crosses zero). At time 0, the rotor acceleration of the synchronous motor 2 is A ₀ , the rotor speed is V ₀ , and the actual rotor position is P _{0. At} time T _s , the rotor acceleration of the synchronous motor 2 is A ₁ and the rotor speed is V ₁ , And the actual rotor position is P ₁ . The actual rotor position at time T ₀ is P _e . In the illustrated example, the deviation between the actual rotor position P _{e at} time T ₀ when the torque T _r becomes zero and the actual rotor position P ₁ at time T _s is obtained by multiplying the number of pole pairs of the synchronous motor 2. The value obtained by adding the excitation phase during the DC excitation to the above value corresponds to the magnetic pole initial position of the rotor of the synchronous motor 2. That is, of the sampling intervals of the rotor actual position acquired by the rotor actual position acquisition unit 14, two sampling time points defining a sampling interval including the time point when the torque zero determination unit 12 determines that the torque T _r becomes zero. The time point between the time 0 and the time T _s is the time point when it is determined that the torque _Tr becomes zero. In the present embodiment, among the sampling sections of the rotor actual position acquired by the rotor actual position acquisition section 14, the sampling section including the time point when the torque zero determination section 12 determines that the torque _Tr becomes zero is defined 2 Any time point between the two sampling time points (time 0 and time T _{s in} the example of FIG. 6) is regarded as “time point when torque is determined to be zero”, and this is determined to be zero torque. It is expressed as the “neighborhood” of the time. That is, the “near the time point when the torque is determined to be zero” is the time between two sampling time points that define the sampling section including the time point when the torque zero determination unit 12 determines that the torque _Tr becomes zero. It may be at any time as long as it exists in the section. Here, the actual rotor position P _e at that time is calculated. Some examples of the calculation process of the rotor actual position P _e will be listed below.

In a first aspect of the calculation process of the rotor actual position P _e calculates the rotor actual position P _e as follows.

  The acceleration a of the rotor of the synchronous motor 2 at the time t is expressed by Expression 8.

Therefore, the time T ₀ when the acceleration of the rotor of the synchronous motor 2 changes from positive to negative is expressed by Expression 9 by substituting t = T ₀ and a (T ₀ ) = 0 into Expression 8.

At this time, since the actual rotor position also monotonically increases almost proportionally, the polarity of the acceleration a of the rotor of the synchronous motor 2 at the time when the torque T _r becomes zero changes from positive to negative (that is, the rotor's position). The actual rotor position P _e at the time point when the acceleration a crosses zero) is expressed as in Expression 10.

In the first form of the calculation process of the rotor actual position P _e , the magnetic pole initial position acquisition unit 13 calculates the rotor actual position based on the expression 10.

In the second embodiment of the calculation process of the rotor actual position P _e calculates the rotor actual position P _e as follows.

In the section including the time point when the torque zero determination unit 12 determines that the torque _Tr becomes zero, the rotor speed of the synchronous motor 2 is small, so that the rotor speed of the synchronous motor 2 is the constant speed V ₀ . Assuming that there is, the rotor actual position P _e at the time when the torque T _r becomes zero can be expressed by Expression 11.

In the second form of the calculation process of the rotor actual position P _e , the magnetic pole initial position acquisition unit 13 calculates the rotor actual position based on Expression 11.

In a third embodiment of the calculation process of the rotor actual position P _e calculates the rotor actual position P _e as follows.

Since the rotor actual position has increased substantially proportionally monotonous, regarded as the time of the midpoint of the sampled segment of the rotor actual position torque T _r becomes zero, the rotor actual position at the time when the torque T _r becomes zero P _e can be expressed as in Expression 12.

In the third embodiment of the calculation process of the rotor actual position P _e , the magnetic pole initial position acquisition unit 13 calculates the rotor actual position based on Expression 12.

The magnetic pole initial position acquisition unit 13 determines that the actual rotor position P _e and the torque T _r at the time T ₀ when the torque T _r calculated by any one of the first to third modes becomes zero. Using the rotor actual position P ₁ at the next sampling time T _s after becoming zero and the number of pole pairs pp of the synchronous motor 2, the magnetic pole initial position is calculated based on Expression 13.

The magnetic pole position counter (not shown) to initialize at the detected magnetic pole initial position by the magnetic pole initial position detecting device 1, subsequent incremental pulse amount for each sampling cycle _{(= P n -P n-1} ) electrode The logarithmic multiple is added to the magnetic pole position counter.

  FIG. 7 is a flowchart showing an operation flow of the magnetic pole initial position detection device according to the embodiment of the present disclosure.

  In step S101, the direct-current excitation command generator 11 generates a first command for flowing a constant excitation current with the current phase fixed to the first phase to the synchronous motor 2. The current phase (first phase) is fixed to 0 degree, for example. The first command generated by the DC excitation command generation unit 11 is sent to the current control unit in the motor control device (not shown) for controlling the drive of the synchronous motor 2. The current control unit in the motor control device generates a voltage command based on the command received from the DC excitation command generation unit 11 and the current feedback converted at the fixed current phase, and the power conversion unit (not shown). Applies a voltage to the synchronous motor 2 based on the received voltage command to generate a constant exciting current with a fixed current phase.

  In step S102, the magnetic pole initial position detection device 1 determines whether or not the rotor of the synchronous motor 2 has moved. When it is determined in step S102 that the rotor of the synchronous motor 2 has moved, the process proceeds to step S103, and when it is not determined that the rotor of the synchronous motor 2 has moved, the process proceeds to step S105.

  In step S103, the torque zero determination unit 12 determines that the torque generated in the rotor of the synchronous motor 2 is zero when the constant excitation current based on the command generated by the DC excitation command generation unit 11 is flowing in the synchronous motor 2. Determine whether or not For example, the torque zero determination unit 12 determines that the time when the polarity of the acceleration of the synchronous motor 2 changes is the time when the torque becomes zero. Further, for example, the torque zero determination unit 12 determines that the time point when the speed of the synchronous motor 2 becomes maximum or minimum is the time point when the torque becomes zero. When it is determined in step S103 that the torque has become zero, the process proceeds to step S104, and when it is determined that the torque has not become zero, the process returns to step S102.

  In step S104, the magnetic pole initial position acquisition unit 13 determines the actual rotor position of the synchronous motor 2 near the time when the torque zero determination unit 12 determines that the torque has become zero, the number of pole pairs of the synchronous motor 2, and the DC excitation status. The magnetic pole initial position of the rotor of the synchronous motor 2 is acquired based on the excitation phase.

  When it is not determined in step S102 that the rotor of the synchronous motor 2 has moved, in step S105, the DC excitation command generation unit 11 shifts the current 90 degrees from the current phase (for example, 0 degrees) set in step S101. In phase, a command for flowing a constant exciting current to the synchronous motor 2 is generated. In this way, when it is not determined in step S102 that the rotor of the synchronous motor 2 has moved, the current phase is shifted by 90 degrees and a constant exciting current is flowed again. This is to avoid this because the rotor of the synchronous motor 2 does not vibrate even if an exciting current is passed when it is already near the magnetic pole initial position, and the magnetic pole initial position cannot be obtained accurately.

  In step S106, the magnetic pole initial position detection device 1 determines whether or not the rotor of the synchronous motor 2 has moved. If it is determined in step S106 that the rotor of the synchronous motor 2 has moved, the process proceeds to step S103, and if it is not determined that the rotor of the synchronous motor 2 has moved, the process proceeds to step S107.

  If it is not determined in step S106 that the rotor of the synchronous motor 2 has moved, there is a possibility that the rotor of the synchronous motor 2 is in some restrained state such as being fixed by a fastener. Generate an alarm and stop the operation.

  FIG. 8 is a block diagram showing the motor control device 1000 including the magnetic pole position detection device 100 including the magnetic pole initial position detection device 1 according to the embodiment of the present disclosure.

  The magnetic pole position detecting device 100 includes a magnetic pole initial position detecting device 1 and a magnetic pole position updating unit 41. The motor control device 1000 includes a magnetic pole position detection device 100, a speed control unit 31, a current command generation unit 32, a current control unit 33, a dq three-phase conversion unit 34, a power conversion unit 35, and a three-phase dq conversion. The unit 36 and the speed acquisition unit 37 are provided.

The speed control unit 31 generates the torque command T _cmd based on the speed command ω _cmd and the rotor speed ω _m of the synchronous motor 2 acquired by the speed acquisition unit 37.

The current command generation unit 32 generates the d-axis current command I _dc and the q-axis current command I _qc based on the torque command T _cmd and the rotor speed ω _m of the synchronous motor 2 acquired by the speed acquisition unit 37. .

The three-phase dq converter 36 performs three-phase dq conversion on the three-phase currents I _u , I _v , and I _w output from the power converter 35 based on the magnetic pole position detected by the magnetic pole position detection device 100, and the d-axis. The current I _d and the q-axis current I _q are output to the current controller 33.

During normal motor control, the current control unit 33, based on the d-axis current command I _dc and the q-axis current command I _qc, and the d-axis current I _d and the q-axis current I _q , d-axis voltage commands V _dc and q. An axis voltage command V _qc is generated. Further, the current control unit 33 is based on the DC excitation command (I _d = I _e , I _q = 0) output from (the DC excitation command generation unit 11 of) the magnetic pole initial position detection device when the magnetic pole initial position is detected. Then, a d-axis voltage command V _dc and a q-axis voltage command V _qc for flowing a constant exciting current with a fixed current phase are generated.

The dq three-phase conversion unit 34 performs dq three-phase conversion on the d-axis voltage command V _dc and the q-axis voltage command V _{qc based} on the magnetic pole position detected by the magnetic pole position detection device 100, and three-phase voltage commands V _uc , V _uc . _It outputs _vc and V _wc to the power converter 35.

The power conversion unit 35 includes, for example, an inverse converter (three-phase inverter) including a full-bridge circuit of semiconductor switching elements, and turns on / off the semiconductor switching elements based on the received three-phase voltage commands V _uc , V _vc , and V _wc. And outputs three-phase currents I _u , I _v , and I _w for controlling the synchronous motor 2 and driving the synchronous motor 2.

  The magnetic pole position updating unit 41 in the magnetic pole position detecting device 100 initializes the magnetic pole position counter with the magnetic pole initial position output from (the magnetic pole initial position acquiring unit 13 of) the magnetic pole initial position detecting device 1. After the initialization of the magnetic pole position counter, the magnetic pole position updating unit 41 adds the incremental pulse amount multiplied by the number of pole pairs to the magnetic pole position counter and outputs the magnetic pole position.

  The DC excitation command generation unit 11, the torque zero determination unit 12, the magnetic pole initial position acquisition unit 13, the rotor actual position acquisition unit 14, the speed control unit 31, the current command generation unit 32, the current control unit 33, and the dq three-phase conversion described above. The unit 34, the three-phase dq conversion unit 36, the speed acquisition unit 37, and the magnetic pole position updating unit 41 may be constructed in, for example, a software program format, or may be constructed by a combination of various electronic circuits and a software program. . For example, when these are constructed in the software program format, the functions of the above-mentioned respective parts can be realized by operating the arithmetic processing unit in the motor control device 1000 according to the software program. Alternatively, the DC excitation command generation unit 11, the torque zero determination unit 12, the magnetic pole initial position acquisition unit 13, the rotor actual position acquisition unit 14, the speed control unit 31, the current command generation unit 32, the current control unit 33, the dq three-phase conversion unit. The 34, the three-phase dq conversion unit 36, the speed acquisition unit 37, and the magnetic pole position update unit 41 may be realized as a semiconductor integrated circuit in which a software program that realizes the functions of each unit is written.

Second Embodiment Hereinafter, a magnetic pole initial position detection device 1A according to a second embodiment of the present disclosure will be described. The magnetic pole initial position detection device 1A corresponds to a modified example of the magnetic pole initial position detection device 1 in the first embodiment. FIG. 9 is a block diagram showing the configuration of the magnetic pole initial position detection device 1A. The magnetic pole initial position detection device 1A has a first command generation unit 11A, an excitation phase determination unit 16, and a second command generation unit 11B as constituent elements that realize the function of the DC excitation command generation unit 11 according to the first embodiment. With. The first command generation unit 11A generates a first command, which has been described as a function of the DC excitation command generation unit 11 in the first embodiment and causes a constant excitation current having a current phase fixed to the first phase to flow to the synchronous motor 2. Have the function to The second command generation unit 11B generates a command (hereinafter, also referred to as a second command) in which a constant excitation current whose current phase is fixed to the arbitrarily set second phase is supplied to the synchronous motor 2. The excitation phase determination unit 16 determines, based on the rotation direction of the synchronous motor 2 when the excitation current based on the second command is applied to the synchronous motor 2 and the rotation direction of the speed command (ω _cmd ) for the synchronous motor 2, The 1st command determines the 1st phase for generating the 1st command so that synchronous motor 2 may rotate in the same direction as the rotation direction of a speed command ((omega) _cmd ). With this configuration, the direction in which the rotor rotates due to the DC excitation based on the first command generated by the first command generation unit 11A can be aligned with the rotation direction of the rotor based on the speed command (ω _cmd ), and the magnetic pole initial position detection operation is performed. The transition to speed control can be performed smoothly, and the time required to reach the command speed can be shortened. In the following, description will be made focusing on the above-described functions of the magnetic pole initial position detection device 1A according to the second embodiment.

The outline of the operation of detecting the magnetic pole initial position by the magnetic pole initial position detection device 1A according to the second embodiment is as follows. First, the second command generator 11B DC-excites the synchronous motor 2 with a current phase of the arbitrarily set second phase (θ ₀ ). In this case, DC excitation may be performed in an extremely short time. As a result, the rotor starts to rotate from the initial position in the direction corresponding to the DC excitation at the current phase of the second phase. Next, the excitation phase determination unit 16 acquires the relationship between the excitation phase (second phase) at this time and the rotation direction of the rotor. Based on this relationship, the excitation phase determination unit 16 generates the first command so that the direction (polarity) in which the rotor rotates by the first command matches the rotational direction (polarity) in the speed command (ω _cmd ). Determine a first phase for The first command generation unit 11A generates the first command by using the excitation phase (first phase) determined by the excitation phase determination unit 16. When direct-current excitation is performed by the first command generated by the first command generation unit 11A, the magnetic pole initial value is acquired by the operations of the torque zero determination unit 12 and the magnetic pole initial position acquisition unit 13. In this case, the torque zero determination unit 12 detects the torque zero that occurs first after the first command generation unit 11A starts the first command to the synchronous motor 2 and notifies the magnetic pole initial position acquisition unit 13 of the detection result. To do. When the magnetic pole initial position is acquired, the speed control of the synchronous motor 2 is performed by the speed command (ω _cmd ).

FIG. 10 is a process for determining the excitation phase (first phase) used for detecting the magnetic pole initial position, which is executed by the magnetic pole initial position detection device 1A (mainly the second command generation unit 11B and the excitation phase determination unit 16) ( Hereinafter, it will be described as an excitation phase determination process). First, the magnetic pole initial position detection device 1A confirms the value of the variable'STAGE '(step S1). Since the value of the variable'STAGE 'is initialized to zero at the start of this process, it is determined that'STAGE' = 0 when the step S1 is first executed, and the process proceeds to step S2. In step S2, the magnetic pole initial position detection device 1A acquires the rotor position (θ _m0 ) at the start of this processing from the rotor actual position acquisition unit 14 and stores it, and updates the variable'STAGE 'to 1.

Next, the second command generation unit 11B substitutes the value of the arbitrarily set current phase θ ₀ (second phase) into the variable Θe for setting the current phase of DC excitation, and generates the second command. . The second command is sent to the current control unit 33 of the motor control device 1000, and DC excitation is performed according to the second command (step S3). In step S4, the value of the variable'STAGE 'is confirmed. Currently, 'STAGE' = 1, so the process proceeds to step S5. In step S5, the magnetic pole initial position detection device 1A determines whether or not the rotor has moved. As a result, when the rotor is moving (S5: YES), the excitation phase determination unit 16 determines whether the direction (polarity) the rotor is moving matches the rotational direction (polarity) according to the speed command (ω _cmd ). It is determined (step S7). As a result, when the moving direction of the rotor and the rotating direction according to the speed command match (S7: YES), the excitation phase determining unit 16 substitutes the excitation phase for generating the first command with the variable Θ _w. The value of the current phase θ ₀ set in step S3 is substituted into (step S8).

On the other hand, when the moving direction of the rotor and the rotating direction according to the speed command (ω _cmd ) do not match (S7: NO), the excitation phase determination unit 16 sets the value obtained by adding 180 degrees to the current phase θ ₀ as a variable. Substitute in Θ _w (step S9). Here, the current phase θ ₀ plus 180 degrees is added to the variable Θ _{w because the} direction of rotation of the rotor in direct current excitation at the excitation phase (Θ _w ) is the rotor in the case of direct current excitation at the current phase θ _0. This is because the direction is opposite to the rotation direction of. Since the current rotor position is ahead of the rotor position (θ _m0 ) at the start of processing stored in step S2, the phase of the rotor advance is added to the variable Θ _w to give the final first command. The excitation phase (first phase) for generation is set (step S10). Specifically, in step S10, the variable Θ _w is determined as follows.
Θ _w = Θ _w + pp (P _c −θ _m0 )
Where Pc: current rotor position
pp: Number of pole pairs When the excitation phase (θ _w ) for generating the first command is determined in this way, the excitation phase determination unit 16 sets the determined excitation phase (θ _w ) to the first command generation unit 11A. And the variable'STAGE 'is updated to 3 indicating the completion of processing (step S11). When the variable'STAGE 'is updated to 3 in step S11, it is determined in step S1 that the variable'STAGE' is 3, and the main excitation phase determination process ends. By using the excitation phase (Θ _w ) determined as described above to generate the first command in the first command generation unit 11A, the rotation direction of the rotor in the DC excitation for the magnetic pole initial position detection operation is determined. , The rotational direction of the rotor by the speed command (ω _cmd ) can be matched.

When it is determined in step S5 that the rotor does not move, the magnetic pole initial position detection device 1A performs DC excitation with the current phase θ _{e obtained} by adding 90 degrees to the current phase θ ₀ (step S6). Here, it is determined in step S5 that the rotor does not move when the current phase θ ₀ is near the magnetic pole initial position (phase) of the rotor. Therefore, in order to avoid this, DC excitation is performed with the current phase θ _{e obtained} by adding 90 degrees to the current phase θ ₀ . In step S6, the variable'STAGE 'is updated to 2. When the variable'STAGE 'is updated to 2 in step S5 and the process returns to step S1, it is determined that the variable'STAGE' is 2, and the process proceeds to step S4. In this case, the value of the variable'STAGE 'is determined to be 2 in step S4, and the process proceeds to step S12.

In step S12, it is determined whether or not the rotor has moved as a result of performing DC excitation with the current phase θ _{e obtained} by adding 90 degrees to the current phase θ ₀ in step S6. As a result, when it is determined that the rotor has moved (S12: YES), the direction (polarity) in which the rotor has rotated is determined (step S13). As a result, when it is determined that the rotation direction of the rotor is the positive direction (S13: '+'), the current phase θ ₀ set in step S3 represents the magnetic pole initial position (phase). . In this case, a value (θ _w ) obtained by adding the phase of the amount of movement of the rotor after the start of this process to the current phase θ ₀ is obtained by the following mathematical expression and set as the magnetic pole initial position (step S14).
Θ _w = θ ₀ + pp (P _c −θ _m0 )

On the other hand, when it is determined in step S13 that the rotor rotation direction is the minus direction (S13: '-'), the value obtained by adding 180 degrees to the current phase θ ₀ set in step S3 is the magnetic pole initial position ( Phase). In this case, a value (Θ _w ) obtained by adding the phase that corresponds to the movement of the rotor after the start of this process to the value obtained by adding 180 degrees to the current phase θ ₀ is obtained by the following mathematical expression and is set as the magnetic pole initial position. Yes (step S15).
Θ _w = θ ₀ +180 degrees + pp (P _c −θ _m0 )

In step S16, Θ _w obtained in step S14 or S15 is determined as the magnetic pole initial position, and the variable'STAGE 'is updated to 3 to complete the main excitation phase determination process. In this case, the main excitation phase determination process ends, and the first command generation unit 11A does not generate the first command and the magnetic pole initial position detection based on the first command is not performed. Θ _w obtained in step S14 or S15 is used as the magnetic pole initial position output from the magnetic pole initial position detection device 1 to the magnetic pole position updating unit 41.

Here, it is explained that when DC excitation is performed at the current phase Θ _{e obtained} by adding 90 degrees to the current phase θ ₀ in step S6, the magnetic pole initial position can be determined as in steps S14 and S15 depending on the rotation direction of the rotor. To do. It is determined in step S5 that the rotor does not move when the current phase θ ₀ matches the phase of the magnetic pole initial value or differs from the phase of the magnetic pole initial position by 180 degrees. Consider a situation in which the rotor is moved by direct-current excitation at the current phase θ ₀ +90 degrees in step S6. As described with reference to FIG. 3, the rotor moves when there is a deviation of θ between the magnetic pole position and the excitation phase of the excitation current I _e (0 degrees in FIG. 3), that is, Equation 2 And the case where the torque shown in Formula 3 is generated. Here, the case of non-salient polarity (Formula 3) is considered. FIG. 11 is a graph showing the torque generated according to Expression 3 due to the deviation θ between the excitation phase and the magnetic pole position. As shown in FIG. 11, the torque takes a negative value when the deviation θ between the excitation phase and the magnetic pole position is in the positive range (0 to 180 degrees), and the torque is in the negative range (0 to −180 degrees). Takes a positive value.

In this case, as shown in FIG. 12, when the magnetic pole position (phase) exists in the first quadrant and the second quadrant with respect to the coordinate system in which the exciting current I _e is set to the phase of 0 degrees on the _dc axis, the rotor Rotates in the negative direction, and when the magnetic pole position (phase) is in the third and fourth quadrants, the rotor rotates in the positive direction. Here, note that the plus direction of the phase is the counterclockwise direction in FIG. 12, and it is determined that the rotor rotation direction is positive in the DC excitation at the current phase (θ ₀ +90 degrees) (S13: ′ +). It can be understood that it is a case where the magnetic pole initial position is at a position deviated by 90 degrees in the negative direction with respect to the current phase (θ ₀ +90 degrees) (that is, the position of the current phase θ ₀ ). On the other hand, in DC excitation at the current phase (θ ₀ +90 degrees), the rotor rotation direction is determined to be negative (S13: '−') because the magnetic pole initial position is relative to the current phase (θ ₀ +90 degrees). This is the case where the position is deviated by 90 degrees in the plus direction (that is, the position obtained by adding 180 degrees to the current phase θ ₀ ). Therefore, in step S14, a value (Θ _w ) obtained by adding the phase corresponding to the movement of the rotor to the current phase θ ₀ can be determined as the magnetic pole initial value, and in step S15, the value obtained by adding 180 degrees to the current phase θ ₀ A value (Θ _w ) obtained by adding the phase corresponding to the movement of the rotor can be determined as the magnetic pole initial value.

  Returning to the description of FIG. 10, it is determined that the rotor does not move in step S12 when the synchronous motor 2 is in the restricted state or the power line is broken. Therefore, in this case, the magnetic pole initial position detection device 1A issues an alarm and updates the variable'STAGE 'to 3 in order to stop this process.

As described above, according to the second embodiment, the direction in which the rotor rotates due to the DC excitation based on the first command generated by the first command generator 11A is aligned with the rotation direction of the rotor based on the speed command (ω _cmd ). Therefore, it is possible to smoothly perform the transition from the magnetic pole initial position detection operation to the speed control.

  Although the present invention has been described above by using the typical embodiments, those skilled in the art can make changes to the above-described embodiments and various other modifications and omissions without departing from the scope of the present invention. It will be appreciated that additions can be made.

1, 1A Magnetic pole initial position detection device 2 Synchronous motor 11 DC excitation command generation unit 11A First command generation unit 11B Second command generation unit 12 Torque zero determination unit 13 Magnetic pole initial position acquisition unit 14 Rotor actual position acquisition unit 15 Storage unit 16 Excitation Phase determination unit 31 Speed control unit 32 Current command generation unit 33 Current control unit 34 dq Three-phase conversion unit 35 Power conversion unit 36 Three-phase dq conversion unit 37 Speed acquisition unit 41 Magnetic pole position update unit 100 Magnetic pole position detection device 1000 Motor control device

Claims (9)

A magnetic pole initial position detection device for detecting a magnetic pole initial position of a rotor of a synchronous motor,
A direct-current excitation command generation unit that generates a first command that causes a constant excitation current whose current phase is fixed to the first phase to flow to the synchronous motor;
A torque zero determination unit that determines whether or not the torque generated in the rotor of the synchronous motor is zero when the exciting current based on the first command is flowing in the synchronous motor;
The synchronous motor based on the rotor actual position in the vicinity of the time point when the torque is determined to be zero by the torque zero determination unit, the number of pole pairs of the synchronous motor, and the excitation phase during DC excitation by the first command. A magnetic pole initial position acquisition unit for acquiring the magnetic pole initial position of the rotor of
A magnetic pole initial position detection device comprising:   The magnetic pole initial position detection device according to claim 1, wherein the zero torque determination unit determines that the torque has become zero when the polarity of the acceleration of the synchronous motor changes.   The magnetic pole initial position detection device according to claim 1, wherein the zero torque determination unit determines that the torque has become zero at a time point when the speed of the synchronous motor becomes maximum or minimum. A rotor actual position acquisition unit that acquires the position of the rotor from a sensor provided in the synchronous motor;
A storage unit that stores information related to the number of pole pairs of the synchronous motor;
The magnetic pole initial position detection device according to any one of claims 1 to 3, further comprising:   The rotor actual position in the vicinity of the time point when it is determined that the torque has become zero is zero torque by the torque zero determination unit in the sampling section of the position of the rotor acquired by the rotor actual position acquisition unit. The magnetic pole initial position detection device according to claim 4, which is the position of the rotor at any time point sandwiched between two sampling time points that define a sampling section that includes the time point determined to have occurred.   When the synchronous motor is a synchronous motor having saliency, the direct-current excitation command generation unit generates, as the first command, a command to flow the excitation current of less than a predetermined upper limit value to the synchronous motor. 6. The magnetic pole initial position detection device according to any one of items 1 to 5. When the magnitude of the main magnetic flux of the synchronous motor is Φ, the d-phase inductance is L _d , and the q-phase inductance is L _q , the predetermined upper limit value is

The magnetic pole initial position detection device according to claim 6, which is set based on The DC excitation command generation unit,
A second command generation unit that generates a second command that causes a constant exciting current whose current phase is fixed to the arbitrarily set second phase to flow to the synchronous motor;
Based on the rotation direction of the synchronous motor when the exciting current based on the second command is applied to the synchronous motor and the rotation direction of the speed command to the synchronous motor, the synchronous motor is controlled by the first command. An excitation phase determination unit that determines the first phase for generating the first command so as to rotate in the same direction as the rotation direction of the speed command;
The magnetic pole initial according to any one of claims 1 to 7, further comprising: a first command generation unit that generates the first command using the current phase of the first phase determined by the excitation phase determination unit. Position detection device.   A magnetic pole, comprising: a magnetic pole position updating unit that outputs the magnetic pole position of the rotor of the synchronous motor initialized at the magnetic pole initial position detected by the magnetic pole initial position detection device according to any one of claims 1 to 8. Position detection device.

Images