JP2010206932A - Motor drive unit and electric vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor drive unit increasing its maximum voltage that can be output by a power converter, improving its efficiency by reducing a weaker magnetic filed current, and achieving the reduction of the cost and the size of the unit as a whole, and an electric vehicle. <P>SOLUTION: The motor drive unit includes an inverter 3 which feeds AC power to a motor M<SB>1</SB>, a lead accumulator 1 which serves as a first power supply and is connected between positive and negative DC bus bars of the inverter, an electric double-layer capacitor 2 which serves as a second power supply and is connected between a neutral point of the motor M<SB>1</SB>and positive electrodes or negative electrodes of the DC bus bars, and a control part 30 which on/off-controls a semiconductor switching element of the inverter 3. The motor drive unit can impart and receive energy between the capacitor 2 and the positive and negative DC bus bars by on/off-controlling the semiconductor switching element. A discharging finish voltage of the capacitor 2 is made to be almost half of a voltage between the positive and negative DC bus bars. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a motor drive device that uses a secondary battery and a voltage variable energy storage element in combination as a power source, and an electric vehicle equipped with the motor drive device.

In a motor drive device, in order to efficiently recover the energy during regeneration, a variable voltage energy storage element such as an electric double layer capacitor with excellent charge / discharge characteristics as a power source, and a stable power supply voltage with inferior efficiency in charge / discharge As a conventional technique in combination with a secondary battery such as a lead-acid battery that supplies the battery, a hybrid power supply system according to Patent Document 1 is known.
Further, in FIG. 3 of Patent Document 1, in order to adjust the storage energy amount of the voltage variable energy storage element, the terminal voltage of the energy storage element is controlled, and the energy is stored between the energy storage element and the secondary battery. A circuit for freely controlling the exchange of the information is disclosed.

Further, as a prior art that achieves the same effect as the circuit shown in FIG. 3 of Patent Document 1, there is a circuit described in FIG. 9 of Patent Document 2. This circuit connects a voltage variable energy storage element between the neutral point of a motor driven by an inverter and a DC bus, and transfers energy between the DC circuit of the inverter and the energy storage element. is there.
According to this prior art, there is an advantage that it is not necessary to separately add hardware constituting the DC-DC converter in order to control the terminal voltage of the voltage variable energy storage element.
On the other hand, in this prior art, a predetermined voltage setting range is provided in advance as a terminal voltage of the voltage variable energy storage element in order to transfer energy, and this causes the AC output voltage of the inverter to interfere. This causes a problem that the output voltage waveform is distorted.

  On the other hand, Patent Document 3 reads the voltage of the DC power source connected between the neutral point of the motor and the DC bus and the DC input voltage of the inverter, compares them, and outputs the output voltage command value of the inverter. A power output apparatus is disclosed in which distortion of the output voltage waveform is reduced by limiting the output voltage.

Japanese Patent No. 3874344 (paragraphs [0008], [0016] to [0030], FIG. 3, FIG. 4 etc.) Japanese Patent No. 3219039 (paragraph [0025], FIG. 9 etc.) JP 2002-291256 A (paragraphs [0040] to [0045], FIG. 6 etc.)

  According to the prior art described in Patent Document 3, the distortion of the output voltage waveform can be reduced. On the other hand, since the AC voltage that can be output by the inverter is reduced, the motor is operated in a high speed range. The field weakening current that does not contribute to the torque has to be increased, resulting in problems such as reduced efficiency and increased cost and size of the entire device due to an increase in the main circuit current capacity.

  The interference with the AC output voltage by the voltage variable energy storage element described above becomes more significant as the voltage setting range of the terminal voltage of the energy storage element is increased. Therefore, if the voltage setting range is reduced, the degree of interference However, in this case, it is necessary to increase the capacity of the required voltage variable energy storage element, which also causes an increase in cost.

  Therefore, the problem to be solved by the present invention is to increase the maximum voltage that can be output from the power converter, particularly in the high-speed operation region of the motor, to reduce the field weakening current and improve the efficiency, and to reduce the cost of the entire apparatus, It is an object of the present invention to provide a motor drive device that can be miniaturized and an electric vehicle equipped with the motor drive device.

  In order to solve the above problems, the present invention is characterized in that the minimum voltage (discharge end voltage) in the voltage setting range of the terminal voltage of the voltage variable energy storage element is approximately ½ of the voltage between the positive and negative DC buses of the power converter. It is what. The reason will be described below.

First, FIG. 6 is a basic configuration diagram of the main circuit of the motor drive device according to the present invention. The circuit shown in FIG. 6 is substantially the same as the circuit described in FIG. 9 of Patent Document 2, wherein 1 is a lead-acid battery as a secondary battery (terminal voltage is E _dc ), 2 is voltage possible the electric double layer capacitor as deformation energy storage device (the terminal voltage is V _c), the three-phase inverter comprising a semiconductor switching element T ₁₁ through T ₁₆ such as an IGBT bridge connection 3 (three-phase voltage source inverter), M ₁ is a motor such as a permanent magnet synchronous motor.

Further, according to Japanese Patent No. 3223842 relating to the multiphase output power conversion circuit, in the circuit shown in FIG. 6, all the switching elements of the upper arm or the lower arm constituting the inverter 3 are turned on (other arms are turned off). It is described that if a zero voltage vector is outputted, the zero phase equivalent circuit of FIG. 6 becomes as shown in FIG. 7, 3 ′ is an inverter equivalent to the inverter 3 in FIG. 6, T ₁ is a switching element equivalent to the switching elements T _{11 to} T ₁₃ of the upper arm of FIG. 6, and T ₂ is a switching element T _{14 of the} lower arm. through T ₁₆ equivalent to the switching element, L is a reactor according to the stator-winding motor M ₁ in FIG.

Therefore, by adjusting the on-ratio switching elements T _1, T ₂ of the upper and lower arms, it is possible to adjust the voltage V _c of the capacitor 2. The relational expression is shown in Formula 1. In Equation 1, T ₁ and T ₂ are ON periods of the switching elements T ₁ and T ₂ having the same reference numerals.

In this case, in order to adjust the ON ratio of the switching elements T ₁ and T ₂ of the upper and lower arms, the relational expression between the ON-time ratio D ₁ of the upper arm and the zero-phase voltage amplitude command value λ ₀ shown in Equation 2 is used. it may be added to the zero-phase-sequence to the AC voltage command value of the inverter to generate a necessary on-time ratio D _1.

FIG. 8 is a block diagram for generating the gate signal of the switching element of the three-phase inverter 3, and 4 _u , 4 v, 4 w are output voltage command values V _u ^* , V _v ^* , V for each phase of the inverter 3. _An adder for adding the _zero- phase voltage amplitude command value λ ₀ to _w ^* , 8 is a triangular wave comparison type PWM generator, 5u, 5v and 5w are the output signals of the adders 4u, 4v and 4w and the triangular wave of the carrier wave. A comparator for comparison, 6 is a carrier wave generation unit, and 7 is a distribution unit for generating gate signals for the switching elements T _{11 to} T ₁₆ of the upper and lower arms of the inverter 3.

Here, when the amplitude of the triangular wave as a carrier wave is 1.0, the sum of the AC voltage amplitude command value λ _ac and the zero-phase voltage amplitude command value λ ₀ is 1.0 or less in order to avoid waveform distortion. The maximum amplitude value λ _acmax of the AC voltage command value is determined by Equation 3. From this Equation 3, the maximum AC voltage that can be output from the inverter 3 (the positive phase component involved in torque generation) V _outmax is _expressed by Equation 4.

  Substituting Equations 2 and 3 into Equation 4 yields Equation 5.

Further, from Equation 1, since D ₁ , V _c , and E _dc have the relationship of Equation 6, V _c and V _outmax have the relationship as shown in FIG. 9, and V _c is E _dc. It can be seen that at / 2, V _outmax is maximized (the interference that the zero-phase voltage amplitude command value λ ₀ has on the AC output voltage is minimized).

Next, considering the relationship between the motor speed and the terminal voltage of the variable-voltage energy storage element, the terminal voltage is set to a high voltage to store energy for acceleration when the motor speed is low, and when the motor is decelerating at high speed. In order to absorb the regenerative energy, the terminal voltage should be kept low. In particular, the terminal voltage is set to the end-of-discharge voltage V _cmin near the maximum motor speed n _max .
Therefore, it is desirable to set the relationship between the motor speed and the terminal voltage of the voltage variable energy storage element as shown in FIG.

On the other hand, the voltage characteristics of the motor are generally low in the driving voltage in the low speed range, but the voltage increases as the speed increases.
In summary, the terminal voltage V _c of the voltage variable energy storage element near the maximum motor speed n _max is the discharge end voltage V _cmin , and the value is approximately E _dc / 2 (E _dc is a secondary battery, that is, a positive / negative DC bus) with voltage) between, the _{V OUTmax} is maximized at the motor maximum speed _{n max} vicinity as shown in FIG. 11, it is characteristic _{that V OUTmax} decreases as motor speed decreases, the voltage characteristic of the motors described above Can match.

  As described above, the feature of the present invention is that the discharge of the second power supply is stopped so that the interference with the AC output voltage of the power converter is minimized at a motor speed (near the maximum speed) where a high AC voltage is required. The purpose is to keep the voltage at a predetermined value.

That is, the motor drive device according to claim 1 includes a power converter that supplies AC power to the motor, a secondary battery as a first power source connected between the positive and negative DC buses of the power converter, and the motor. A variable voltage energy storage element as a second power source connected between the neutral point of the DC bus and the positive or negative electrode of the DC bus, and a control circuit for controlling on / off of the semiconductor switching element of the power converter, Prepared,
In the motor drive device that enables on / off control of the semiconductor switching element by the control circuit to enable energy transfer between the second power source and the positive / negative DC bus,
The discharge end voltage of the second power source is approximately ½ of the voltage between the positive and negative DC buses.

The motor drive device according to claim 2 is the motor drive device according to claim 1,
The control circuit includes:
Means for calculating a terminal voltage target value of the second power source from the speed of the motor, means for calculating a zero phase current command value using the terminal voltage target value and the terminal voltage detection value of the second power source, and zero phase Means for calculating a zero-phase voltage command value using a current command value and a zero-phase current detection value; and means for adding the zero-phase voltage command value to the output voltage command value of the power converter. is there.

A motor driving device according to a third aspect of the present invention includes a first power converter that supplies AC power to the first motor, a neutral point of the first motor, and a positive or negative electrode of a DC bus of the first power converter. A secondary battery as a first power source connected between and a first main circuit comprising:
A second power converter for supplying AC power to the second motor; and a second power converter connected between a neutral point of the second motor and a positive or negative electrode of a DC bus of the second power converter. A voltage variable energy storage element as a power source, a second main circuit comprising:
A control circuit for controlling on / off of the semiconductor switching elements of the first and second power converters,
The first and second power converters are connected by a common positive / negative DC bus,
In the motor drive device that enables on / off control of the semiconductor switching element of the second power converter by the control circuit to enable energy to be transferred between the second power source and the positive / negative DC bus,
The discharge end voltage of the second power source is approximately ½ of the voltage between the positive and negative DC buses.

The motor drive device according to claim 4 is the motor drive device according to claim 3,
The control circuit includes:
Means for calculating a terminal voltage target value of the second power source from the speed of the second motor, means for calculating a zero-phase current command value using the terminal voltage target value and the terminal voltage detection value of the second power source, Means for calculating the zero-phase voltage command value using the zero-phase current command value and the zero-phase current detection value; and means for adding the zero-phase voltage command value to the output voltage command value of the second power converter. It is provided.

  Furthermore, an electric vehicle according to a fifth aspect is characterized in that the motor drive device according to any one of the first to fourth aspects is mounted.

According to the present invention, it is possible to increase the maximum voltage that can be output by a power converter such as an inverter in the high-speed operation region of the motor, thereby reducing the field-weakening current and improving the efficiency.
In addition, the main circuit current capacity of the power converter is reduced, and the entire device can be reduced in cost and size.

It is a block diagram which shows 1st Embodiment of this invention. It is a block diagram which shows the structure of the control circuit in FIG. It is a block diagram which shows 2nd Embodiment of this invention. It is a block diagram which shows the structure of the control circuit in FIG. It is a block diagram of the zero phase current control block in FIG. It is a basic lineblock diagram of the main circuit of the motor drive unit concerning the present invention. FIG. 7 is a zero phase equivalent circuit diagram of FIG. 6. FIG. 7 is a block diagram for generating a gate signal of a switching element that drives the three-phase inverter of FIG. 6. It is a figure which shows the relationship between the terminal voltage of the voltage variable energy storage element in this invention, and the largest alternating voltage which can be output of an inverter. It is a figure which shows the relationship between the motor speed in this invention, and the terminal voltage of a voltage variable type energy storage element. It is a figure which shows the relationship between the motor speed in this invention, and the maximum alternating voltage which an inverter can output.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a first embodiment of the present invention. This embodiment corresponds to the inventions according to claims 1, 2 and 5. In FIG. In FIG. 1, an electric vehicle equipped with the motor drive device according to the present invention is assumed, and the semiconductor switching element of the three-phase inverter 3 is turned on and off by a control circuit 30 to which an acceleration command and a braking command are input from the outside. current of the motor M ₁ on the basis of the respective instruction, is configured to control the generated torque.

The inverter 3 is configured by bridging semiconductor switching elements T _{11 to} T ₁₆ as in FIG. 6, and a lead storage battery 1 as a secondary battery as a first power source is connected between the positive and negative DC buses. Has been. As the first power source, a lithium ion secondary battery or a nickel / hydrogen storage battery may be used.

Output terminal U of the inverter 3, V, the W, for example, the motor M ₁ such as a permanent magnet synchronous motor is connected between the neutral point and the negative DC bus of the stator winding, the second An electric double layer capacitor (hereinafter also simply referred to as a capacitor) 2 as a voltage variable energy storage element as a power source is connected. Here, the capacitor 2 is to store energy to be regenerated from the motor M ₁ during deceleration of the vehicle, the stored energy during acceleration of the vehicle is intended to be used for power generation. Of course, the second power source may be a voltage variable energy storage element other than the capacitor 2.
The output shaft of the motor M ₁ is connected to the differential gear 11 via a reduction gear, thereby transmitting power to the left and right wheels 12.

The control circuit 30 includes a microcomputer 31 and a storage device 32 that stores programs and data, and includes an interface circuit (not shown) for inputting / outputting signals to / from the outside. .
Further, the control circuit 30 includes each phase current (motor current) I _u , I _v , I _{w of} the inverter 3 detected by the current detection means 21 of the main circuit, and the terminal voltage of the capacitor 2 detected by the voltage detection means 22. and V _c, and a θ motor pole position M ₁ detected is inputted by the magnetic pole position detection means 23.

FIG. 2 is a block diagram showing the configuration of the control circuit 30. As shown in FIG. The control circuit 30 roughly performs the following two controls.
The first control is for controlling the torque by controlling the motor current. That is, in the inverter control unit 310 of FIG. 2, the motor control block 311 generates torque based on the acceleration command and braking command input from the outside, the current detection values I _u , I _v , I _w and the magnetic pole position θ. Voltage command values V _u ^* , V _v ^* , V _w ^* for the positive phase involved are generated. The PWM generating unit 313 outputs gate voltages G _{11 to} G ₁₆ for the switching elements T _{11 to} T ₁₆ by PWM calculation so that the inverter 3 outputs the voltage command values V _u ^* , V _v ^* , and V _w ^*. Create Since the control method by the inverter control unit 310 is well known, detailed description thereof is omitted here.
Incidentally, addition means 312 u, 312v, the voltage command value _V ^u * by _312w, ^V v _*, the correction operation of the _V ^{w *} will be described later.

The motor control block 311 sends a motor speed n obtained by time differentiation of the magnetic pole position θ to the zero-phase current control block 320.
Further, in the motor control block 311, the current detection values I _u ′ and I _v ′ for the positive phase obtained by removing the zero phase components included in the current detection values I _u , I _v , and I _{w according} to Equations 7 to 9, respectively. , I _w ′, and these current detection values I _u ′, I _v ′, I _w ′ are used for calculating the voltage command values V _u ^* , V _v ^* , V _w ^* .

Next, zero phase current control as the second control will be described.
In the zero-phase current control block 320 of FIG. 2, the terminal voltage target value calculation means 322 determines the target terminal voltage of the capacitor 2 based on the motor speed n sent from the motor control block 311 according to Equation 12 described later. This is calculated and output as the terminal voltage target value V _c ^* .
A deviation between the terminal voltage target value V _c ^* and the detected terminal voltage is obtained by the adding means 323, and the PI adjusting means 324 performs an adjustment operation so that this deviation becomes zero, and the current command value (zero phase current) of the capacitor 2 is calculated. Command value) I _c ^* is output. A deviation between the zero-phase current command value I _c ^* and the zero-phase current detection value I _c calculated by the zero-phase current calculation unit 321 is obtained by the adding means 325, and the PI adjusting means 326 is adjusted so that the deviation becomes zero. The adjustment calculation is performed and the zero-phase voltage command value V ₀ ^* is output.
This zero-phase voltage command value V ₀ ^* is added to the voltage command values V _u ^* , V _v ^* , V _w ^* of each phase by the adding means 312u, 312v, 312w in the inverter control unit 310 to obtain a final voltage. Get the command value.

Thus, the zero-phase voltage command value V ₀ ^* corresponding to the zero-phase current detection value I _c is calculated by the zero-phase current control block 320, and the zero-phase voltage command value V ₀ ^* is calculated as the voltage command values V _u ^* and V _u ^. _{v ^*,} by adding the V _w ^*, in parallel with the inverter control, a control for matching the terminal voltage V _c of the capacitor 2 to the terminal voltage target value V _c ^* it is executed.

Hereinafter, a method of calculating the terminal voltage target value V _c ^* of the capacitor 2 based on the motor speed n will be described.
_Assuming that the maximum voltage of the capacitor 2 is V _cmax and the minimum voltage (end-of-discharge voltage) is V _cmin , Equation 10 is established between the stored energy of the capacitor 2 and the vehicle kinetic energy. In Equation 10, C is the capacitance of the capacitor 2, k is a constant, and J is the vehicle inertia moment.

The terminal voltage V _c of the capacitor 2 when the motor speed is n is expressed by Equation 12 by arranging the following Equation 11 based on Equation 10 with respect to V _c .

The terminal voltage target value calculation means 322 calculates the terminal voltage target value V _c ^* using the motor speed n with V _c on the left side of Equation 12 as V _c ^* .
According to Equation 12, when the motor speed n is the minimum value (zero), the terminal voltage of the capacitor 2 is the maximum value V _cmax , and when the motor speed n is the maximum value n _max , the terminal voltage of the capacitor 2 is the minimum value V _cmax . It turns out that it becomes _cmin . This is because when the motor speed n is the minimum value (zero), the stored energy of the capacitor 2 is maximized in preparation for power consumption by the subsequent acceleration, and when the motor speed n is the maximum value n _max , the regeneration by the subsequent deceleration is performed. This means that the energy stored in the capacitor 2 is kept to a minimum in preparation for power storage.

From this, if the minimum voltage (end-of-discharge voltage) V _cmin of the capacitor 2 is set to E _dc / 2, the maximum AC voltage that can be output by the inverter 3 (motor torque generation) can be obtained from the characteristics shown in FIGS. 11 is a characteristic shown in FIG. 11, and it can be seen that a higher voltage can be output from the inverter 3 as the motor speed n is higher.
Here, according to the experiment by the inventor, the minimum voltage (end-of-discharge voltage) V _cmin of the capacitor 2 does not have to be strictly E _dc / 2, and even if it is a value near E _dc / 2, it is practically used. It has been confirmed that there is no problem.

The calculation formula of the zero-phase current I _c by the zero-phase current calculation unit 321 is as shown in Formula 13.

In the present embodiment, the capacitor 2 as the second power source is connected between the neutral point of the motor M ₁ and the negative DC bus, but the capacitor 2 is connected to the neutral point of the motor M ₁ and the positive DC. You may connect between bus lines.

Next, FIG. 3 is a block diagram showing a second embodiment of the present invention, and this embodiment corresponds to the inventions according to claims 3 and 4.
As shown in FIG. 3, the motor drive device according to the present embodiment includes first and second main circuits 20 </ b> A and 20 </ b> B sharing a positive and negative DC bus, and a control circuit 35. Reference numeral 24 denotes a capacitor (terminal voltage is E _dc ) connected between the positive and negative DC buses.

First main circuit 20A includes a first three-phase inverter comprising a semiconductor switching element T ₁₁ through T _16, the first neutral point of the motor M ₁ and the negative DC bus driven by the inverter A lead storage battery 1 as a first power source is connected between them. Power by the lead storage battery 1, the second main circuit 20A so as to compensate for the power of the capacitor 2 of the main circuit 20B (the terminal voltage is V _c), it is supplied to 20B. In the main circuit 20A, 21A is current detection means, and 23A is magnetic pole position detection means.

On the other hand, the second main circuit 20B is substantially have the same configuration as the main circuit in FIG. 1, T ₂₁ through T ₂₆ are semiconductor switching elements, M ₂ constituting the second three-phase inverter second , 2 is a capacitor as a second power source, 22 is voltage detection means, 21B is current detection means, and 23B is magnetic pole position detection means.
In the second main circuit 20B, as described as the first embodiment, the energy regenerating from the motor M ₂ and stored in the capacitor 2 during deceleration, use of this stored energy during acceleration.

Control circuit 35, first, is intended to control the second main circuit 20A, 20B, the main circuit 20A, the corresponding acceleration command respectively 20B, braking command is input from the outside, the semiconductor switching element _{T 11} respectively control the generation torque of the motor _M 1, _{M 2} and through T ₂₆ and on-off control.

In the second embodiment, the lead storage battery 1 and the capacitor 2 can exchange power with any main circuit 20A, 20B via a common DC bus, but for the convenience of energy operation of the capacitor 2. Here, it is as follows.
That is, the lead storage battery 1 supplies power to both the first and second main circuits 20A and 20B, and the capacitor 2 transmits and receives power only to the second main circuit 20B.
In the present embodiment, only the second main circuit 20 </ b> B including the capacitor 2 exhibits the operational effects of the present invention.

FIG. 4 is a block diagram showing a configuration of the control circuit 35.
As illustrated, the control circuit 35 includes a first inverter control unit 360A for controlling the first main circuit 20A, a second inverter control unit 360B for controlling the second main circuit 20B, The inverter control units 360A and 360B are provided with zero-phase current calculation units 364A and 364B attached to the inverter control units 360A and 360B, and a zero-phase current control block 370 common to the main circuits 20A and 20B.

The first inverter control unit 360A includes a motor control block 361A to which an acceleration command 1, a braking command 1, current detection values I _u1 , I _v1 , I _w1 and a magnetic pole position θ ₁ are input, an adding unit 362A, and PWM generation consists of a part 363A, a second inverter control unit 360B includes a motor control block 361B where acceleration command 2, a braking command 2, the current detection value _{I u2, I v2, I w2} and the magnetic pole position theta ₂ is input, adds It comprises means 362B and a PWM generator 363B. These configurations are substantially the same as those of the inverter control unit 310 shown in FIG.

The zero-phase current control block 370 controls power transfer between the lead storage battery 1 or the capacitor 2 and the DC bus in accordance with a DC bus voltage command value E _dc ^* given from the outside.
FIG. 5 is a configuration diagram of the zero-phase current control block 370. In FIG. 5, the deviation between the DC bus voltage command value E _dc ^* and the voltage detection value E _dc is calculated by the adding means 371A, and the PI adjusting means 372A makes the first and second values so that the deviation becomes zero. main circuit 20A, the generating summed zero-phase current command value 20B and ^{_{(I b * + I c *}} ). Here, the zero-phase current command value I _b ^* of the first main circuit 20A is the zero-phase current command value for the lead storage battery 1, and the zero-phase current command value I _c ^* of the second main circuit 20B is the zero-phase current for the capacitor 2. Current command value.

Further, in FIG. 5, like the zero-phase current control block 320 in FIG. 2, in the second main circuit 20B side, the terminal voltage target value computing unit 376B, the terminal voltage target value according to the speed n of the motor M ₂ V _c ^* is determined, and the zero-phase current command value I _c ^{* of the} capacitor 2 is determined via the adding means 371B and the PI adjusting means 372B. By controlling the zero-phase current I _c according to the zero-phase current command value I _c ^* , as in the first embodiment, the minimum voltage (discharge end voltage) of the capacitor 2 when the speed n of the motor M ₂ is the highest. Control is performed so that V _{MIN is} approximately E _dc / 2.
As a result, for the second main circuit 20B, the maximum voltage that can be output by the inverter (positive phase voltage related to the motor torque) becomes the characteristic of FIG. 11 from the characteristics of FIGS. 9 and 10, and the motor speed n is The higher the output voltage, the higher the inverter output voltage.

The lead storage battery 1 is provided by subtracting the zero-phase current command value I _c ^* on the second main circuit 20B side from the total zero-phase current command value (I _b ^* + I _c ^* ) in the adding means 373A. The zero-phase current command value I _b ^{* of} the first main circuit 20A is determined.
Deviations between the zero-phase current command values I _b ^* and I _c ^* thus determined and the zero-phase current detection values I _b and I _c are obtained by the adding means 374A and 374B, respectively, and these deviations are made zero. As described above, the PI adjustment means 375A and 375B perform adjustment calculation to generate zero phase voltage command values V ₀₁ ^* and V ₀₂ ^* to be given to the inverter control units 360A and 360B, respectively. Be controlled.
Further, by the above control, control is performed such that the voltage E _dc between the positive and negative DC buses coincides with the command value E _dc ^* and the terminal voltage V _c of the capacitor 2 coincides with the target value V _c ^*. become.

In the present embodiment, the lead storage battery 1 as the first power source is connected between the neutral point of the motor M ₁ and the negative DC bus, and the capacitor 2 as the second power source is in the motor M ₂ . The lead-acid battery 1 is connected between the neutral point of the motor M ₁ and the positive DC bus, and the capacitor 2 is connected to the neutral point of the motor M ₂ . And a positive DC bus.
Further, another main circuit having the same configuration as that of the first main circuit 20A can be further connected in parallel with the common positive / negative DC bus (capacitor 24).

  The motor drive device according to the present invention can be used for various motor drive devices that allow energy to be transferred between the first and second power sources using a power converter for motor drive, including an electric vehicle.

M _{1, M 2:} Motor T ₁₁ through T _26: semiconductor switching element 1: lead-acid battery 2: the electric double layer capacitor 3: Inverter 11: differential gear 12: wheels 20A, 20B: a main circuit 21, 21A, 21B: current detecting Means 22, 25: Voltage detection means 23, 23A, 23B: Magnetic pole position detection means 24: Capacitor 30, 35: Control circuit 31: Microcomputer 32: Storage device 310, 360A, 360B: Inverter control unit 311, 361A, 361B: Motor Control blocks 312u, 312v, 312w, 323, 325, 362A, 362B, 371A, 371B, 373A, 374A, 374B: addition means 313, 363A, 363B: PWM generator 320, 370: zero-phase current control blocks 321, 364A, 364B: Zero-phase electricity Current calculation unit 322, 376B: terminal voltage target value calculation means 324, 326, 372A, 372B, 375A, 375B: PI adjustment means

Claims (5)

A power converter for supplying AC power to the motor, a secondary battery as a first power source connected between the positive and negative DC buses of the power converter, a neutral point of the motor, and a positive or negative electrode of the DC bus A voltage variable energy storage element as a second power source connected between and a control circuit for controlling on / off of the semiconductor switching element of the power converter,
In the motor drive device that enables on / off control of the semiconductor switching element by the control circuit to enable energy transfer between the second power source and the positive / negative DC bus,
A motor driving device characterized in that the discharge end voltage of the second power source is approximately ½ of the voltage between the positive and negative DC buses. In the motor drive device according to claim 1,
The control circuit includes:
Means for calculating a terminal voltage target value of the second power source from the speed of the motor;
Means for calculating a zero-phase current command value using the terminal voltage target value and the terminal voltage detection value of the second power source;
Means for calculating a zero-phase voltage command value using the zero-phase current command value and the zero-phase current detection value;
Means for adding the zero-phase voltage command value to the output voltage command value of the power converter;
A motor driving device comprising: A first power converter for supplying AC power to the first motor; a first power source connected between a neutral point of the first motor and a positive or negative electrode of a DC bus of the first power converter; A first main circuit comprising a secondary battery as a power source;
A second power converter for supplying AC power to the second motor; and a second power converter connected between a neutral point of the second motor and a positive or negative electrode of a DC bus of the second power converter. A voltage variable energy storage element as a power source, a second main circuit comprising:
A control circuit for controlling on / off of the semiconductor switching elements of the first and second power converters,
The first and second power converters are connected by a common positive / negative DC bus,
In the motor drive device that enables on / off control of the semiconductor switching element of the second power converter by the control circuit so that energy can be transferred between the second power source and the positive / negative DC bus,
A motor driving device characterized in that the discharge end voltage of the second power source is approximately ½ of the voltage between the positive and negative DC buses. In the motor drive device according to claim 3,
The control circuit includes:
Means for calculating a terminal voltage target value of the second power source from the speed of the second motor;
Means for calculating a zero-phase current command value using the terminal voltage target value and the terminal voltage detection value of the second power source;
Means for calculating a zero-phase voltage command value using the zero-phase current command value and the zero-phase current detection value;
Means for adding the zero-phase voltage command value to the output voltage command value of the second power converter;
A motor driving device comprising: An electric vehicle comprising the motor drive device according to any one of claims 1 to 4.

Images