JP2014054037A - One phase-modulation variable speed motor drive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an easy-to-control one-phase modulation variable speed motor drive.SOLUTION: Three phase current command values are calculated for a voltage type inverter supplying a three-phase current to a three-phase motor. Average output current of a step-up DC/DC converter is controlled based on a maximum phase current command value, which is a phase current command value having a largest absolute value, out of three phase currents of the three-phase motor. For example, when the detection value of the maximum phase current is larger than the maximum phase current command value, the PWM duty ratio of the upper arm switch of the step-up DC/DC converter is reduced. Similarly, when the detection value of the maximum phase current is smaller than the maximum phase current command value, the PWM duty ratio of the upper arm switch of the step-up DC/DC converter is increased.

Description

The present invention relates to a variable speed motor drive device, and more particularly to a voltage source inverter driven variable speed motor drive device driven by a one-phase modulation method.

Variable speed motors used for applications such as traction motors have a large back EMF in the high-speed rotation range. Therefore, the current that can be supplied to the motor by the inverter decreases in the high-speed rotation region. In particular, a permanent magnet synchronous motor using a permanent magnet rotor has a large back EMF.

By increasing the DC link voltage applied to the inverter, the motor can generate an effective motor torque in the high-speed rotation region. For example, Japanese Patents 3597591, 3277825, 3797361, 4746986 describe a variable speed motor drive device that applies a DC link voltage boosted by a boost DCDC converter to an inverter.

The 591 'patent describes stopping the boosting operation of the DCDC converter during low-speed rotation and increasing the boosted voltage as the rotational speed increases. Japanese Patent 3541238 describes that the PWM duty ratio of a DCDC converter is determined in accordance with the power command value of the motor. The '361' patent describes determining the PWM duty ratio of a DCDC converter based on the DC link voltage determined by both the motor speed and the torque command value.

Japanese Patent 4764986, obtained by the inventor, describes a one-phase modulation method for driving a variable speed three-phase motor. According to this one-phase modulation method, a DC link voltage having a substantially three-phase full-wave rectified waveform is applied to the three-phase voltage source inverter by PWM control of the step-up DCDC converter. Only one phase leg of the three-phase voltage source inverter is PWM controlled. The DC link voltage has a ripple voltage of about 15%. However, the frequency of the ripple voltage proportional to the motor rotation speed is several tens of Hz or less in the low speed region.

The DC / DC converter of the '986' patent controls a DC link voltage with voltage ripple. This DC link voltage is equal to the maximum interphase voltage having the largest absolute value among the three interphase voltages applied to the motor. In order to reduce the difference between the detected value of the DC link voltage and the command value, the PWM duty ratio of the step-up DCDC converter is feedback controlled. Hereinafter, this one-phase modulation method is referred to as a voltage-controlled one-phase modulation method. However, according to the 986 'patent, the control operation of the motor controller is complicated.

The 591 'patent which determines the PWM duty ratio of the DCDC converter by increasing the rotational speed does not describe the control of the PWM duty ratio of the DCDC converter according to the motor torque. The 238 'patent controlling the PWM duty ratio of the DCDC converter according to the motor power command value does not describe the control of the PWM duty ratio of the DCDC converter according to the rotational speed. The 361 ′ patent that determines the PWM duty ratio of the DCDC converter based on the DC link voltage determined according to the motor speed and the torque command value requires a comparison between the detected value of the DC link voltage and the command value. . Since the DC link voltage is periodically changed in synchronization with the rotation angle of the motor, the control of the 986 'patent is further complicated.

Japanese Patent 4833156 describes a one-phase modulation type three-phase current-type power converter that converts DC power into three-phase AC power and transmits it to a three-phase commercial power system. This three-phase current source power converter includes a three-phase current source inverter that supplies three-phase AC power to a three-phase commercial power system, and a DCDC converter that supplies DC current to the three-phase current source inverter.

However, the 156 'patent does not mention the possibility of applying this current controlled single phase modulation method to a variable speed motor drive. Further, since a three-phase current source inverter is required, the current control type single-phase modulation method of the 156 'patent has the problem of increased loss, manufacturing cost and weight.

That is, the three-phase current source inverter has six switches including a power transistor and a reverse blocking diode connected in series. On the other hand, the three-phase voltage source inverter generally employed in the variable speed motor driving device does not require these six reverse blocking diodes. For example, since a three-phase inverter used for an electric vehicle or a hybrid vehicle handles a large current, six large current reverse blocking diodes generate a large loss and heat.

Japanese Patent 3597591 Japanese Patent 3277825 Japanese patent 3541238 Japanese Patent 3797361 Japanese Patent 476986 Japanese patent 4833156

An object of the present invention is to provide a one-phase modulation type variable speed motor driving device that is easy to control.

The one-phase modulation variable speed motor driving device of the present invention includes a voltage source inverter and a step-up DCDC converter that applies a boosted DC voltage to the voltage source inverter. Each of the three legs of the voltage source inverter constitutes one of a high potential fixed leg, a low potential fixed leg and a switched leg. Of the three phase current command values transmitted to the voltage source inverter, the phase current command value having the largest absolute value is selected as the maximum phase current command value. Further, this maximum phase current command value is adopted as the output current command value of the step-up DCDC converter. This eliminates the need for referring to the DC link voltage in order to control the PWM duty ratio of the step-up DCDC converter. In other words, the variable speed motor driving apparatus employing the one-phase modulation method of the present invention can have an improved control response despite using a voltage source inverter.

In one preferred embodiment, the PWM duty ratio of the upper arm switch of the step-up DCDC converter is reduced when the detected value of the maximum phase current of the voltage source inverter is greater than the maximum phase current command value. Similarly, when the detected value of the maximum phase current is smaller than the maximum phase current command value, the PWM duty ratio of the upper arm switch of the step-up DCDC converter is increased. The maximum phase current of the voltage source inverter can be quickly controlled.

In another preferred embodiment, the step-up DCDC converter supplies a difference between the maximum phase current command value and the generated current. This generated current is supplied by a power generator connected to the DC link line. As a result, the step-up DCDC converter can quickly supply the necessary current to the DC link line to which the power generator is connected. Furthermore, this aspect can be adopted by a variable speed motor driving apparatus that employs a voltage-controlled single-phase modulation method.

In another preferred embodiment, the power generator mainly supplies a low frequency component of the maximum phase current command value, and the step-up DCDC converter mainly supplies a high frequency component of the maximum phase current command value. Thereby, the power generator can have a slow control response. Furthermore, this aspect can be adopted by a variable speed motor driving apparatus that employs a voltage-controlled single-phase modulation method.

In another preferred embodiment, this one-phase modulation method is employed in the low-speed rotation region of the motor and is not employed in the high-speed rotation region of the motor. This facilitates control of the step-up DCDC converter. Furthermore, the ripple frequency of the DC link voltage can be reduced. Furthermore, this aspect can be adopted by a variable speed motor driving apparatus that employs a voltage-controlled single-phase modulation method.

In another preferred embodiment, the single phase modulation method is employed in the large torque region. Since the switching loss of the voltage source inverter is very large in the large torque region, the inverter loss can be greatly reduced. Furthermore, the surge voltage generated by the voltage source inverter can be reduced. Furthermore, this aspect can be adopted by a variable speed motor driving apparatus that employs a voltage-controlled single-phase modulation method.

It is a circuit diagram which shows the motor drive device of an Example. It is a timing chart which shows the waveform of the three phase current supplied to a motor. It is a timing chart which shows the waveform of the supply current supplied to a three phase voltage source inverter. It is a figure which shows the operation state of a three-phase voltage source inverter. It is a flowchart which shows the control routine of a 1 phase modulation method. It is a figure which shows the area | region which implements 1 phase modulation mode, and the area | region which implements 3 phase modulation mode. It is a block diagram which shows the circuit which divides | segments the electric current command value of a step-up DCDC converter into a low frequency component and a high frequency component.

A preferred embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block circuit diagram showing a motor drive device of this embodiment. In the following description, in order to facilitate understanding, reference numerals that are not described in the drawings are used together with reference numerals that are described in the drawings.

The motor drive device includes a battery 1, a step-up DCDC converter 2, a voltage source inverter 3, a smoothing capacitor 4, a power generation device 5, and a motor controller 6. The step-up DCDC converter 2 includes a reactor 21, an upper arm switch 22, and a lower arm switch 23. The configuration of this motor drive device is the same as that of the conventional boost type three-phase motor drive device except for the motor controller 6.

One end of the reactor 21 is connected to the positive terminal of the battery 1. The upper arm switch 22 is connected to the high potential DC terminal of the voltage source inverter 3 through the high potential DC link line 7. The lower arm switch 23 is connected to the low potential DC terminal of the voltage source inverter 3 through the low potential DC link line 8. The smoothing capacitor 4 connects a high potential DC link line 7 and a low potential DC link line 8.

The step-up DCDC converter 2 steps up the voltage Vb of the battery 1 and applies it to the smoothing capacitor 4. The DC link voltage Vx, which is the voltage of the smoothing capacitor 4, is applied to the voltage source inverter 3. The voltage-controlled inverter 3 that is PWM-controlled supplies a three-phase current having a three-phase sine wave waveform to the three-phase motor 9.

The voltage source inverter 3 includes a U-phase leg 31, a V-phase leg 32, and a W-phase leg 33, each of which is a half bridge. The U-phase leg 31 includes an upper arm switch S1 and a lower arm switch S2 connected in series. The V-phase leg 32 includes an upper arm switch S3 and a lower arm switch S4 connected in series. The W-phase leg 33 includes an upper arm switch S5 and a lower arm switch S6 connected in series. Each switch S1-S6 includes a power transistor and a freewheeling diode connected in antiparallel to the power transistor. The output terminals of the legs 31-33 of the voltage source inverter 3 are individually connected to the U-phase winding 91, the V-phase winding 92 and the W-phase winding 93 of the three-phase motor 9.

The power generator 5 supplies the generated current Ig to the high potential DC link line 7. The step-up DCDC converter 2 supplies a current Ico to the high potential DC link line 7. The smoothing capacitor 4 absorbs the smoothing current Ic. Therefore, the current difference Ix (= Ico + Ig−Ic) is supplied to the voltage source inverter 3. However, since the average value of the smoothing current Ic is generally small, the smoothing current Ic is ignored in the following description.

Next, the basic operation of this one-phase modulation method will be described with reference to FIGS. In the following description, each current is an average current, and its high frequency component is ignored. As already described, according to the one-phase modulation method, the voltage source inverter 3 has one high-potential fixed leg, one low-potential fixed leg, and one switched leg that are sequentially switched. Since the upper arm switch of the high potential fixed leg and the lower arm switch of the low potential fixed leg are always turned on, the high potential fixed leg and the low potential fixed leg output the DC link voltage Vx. A switched leg that is PWM-switched outputs a single phase voltage having a magnitude equal to or lower than the DC link voltage Vx. Due to the PWM switching of the step-up DCDC converter 2, the step-up DCDC converter 2 gives a substantially three-phase full-wave rectified waveform to the DC link voltage Vx. Therefore, DC link voltage Vx has a substantially three-phase full-wave rectified waveform.

FIG. 2 shows schematic waveforms of three phase currents IU, IV and IW supplied from the voltage source inverter 3 to the three-phase motor 9. FIG. 3 shows a waveform of the maximum phase current Im supplied from the DC link lines 7 and 8 to the three-phase motor 9. The maximum phase current Im indicates a phase current having the largest absolute value among the three phase currents IU, IV, and IW. FIG. 4 is a diagram showing the states of the switches S1 to S6 constituting the voltage source inverter 3. As shown in FIG. One motor cycle equal to 360 electrical angles is divided into six sub-periods A-F. The sub period A is an electrical angle of 30 to 90 degrees. The sub period B is an electrical angle of 90 to 150 degrees. The sub period C is an electrical angle of 150 degrees to 210 degrees. The sub period D is an electrical angle of 210 degrees to 270 degrees. The sub-period E is an electrical angle of 270 degrees to 330 degrees. The sub period F is an electrical angle of 330 degrees to 30 degrees.

In the sub-period A, the U-phase leg 31 is a high-potential fixed leg, the W-phase leg 33 is a low-potential fixed leg, and the V-phase leg 32 is a switched leg. In the sub-period B, the U-phase leg 31 is a high-potential fixed leg, the V-phase leg 32 is a low-potential fixed leg, and the W-phase leg 33 is a switched leg. In the sub-period C, the W-phase leg 33 is a high-potential fixed leg, the V-phase leg 32 is a low-potential fixed leg, and the U-phase leg 31 is a switched leg. In the sub-period D, the W-phase leg 33 forms a high potential fixed leg, the U-phase leg 31 forms a low potential fixed leg, and the V-phase leg 32 forms a switched leg. In the sub-period E, the V-phase leg 32 forms a high-potential fixed leg, the U-phase leg 31 forms a low-potential fixed leg, and the W-phase leg 33 forms a switched leg. In the sub-period F, the V-phase leg 32 forms a high-potential fixed leg, the W-phase leg 33 forms a low-potential fixed leg, and the U-phase leg 31 forms a switched leg.

In the sub-period A, the PWM duty ratio of the V-phase upper arm switch S3 continuously changes from 100% to 0%. The PWM duty ratio of the V-phase lower arm switch S4 continuously changes from 0% to 100%. In the sub-period B, the PWM duty ratio of the W-phase upper arm switch S5 continuously changes from 0% to 100%. The PWM duty ratio of the V-phase lower arm switch S6 continuously changes from 100% to 0%.

In the sub-period C, the PWM duty ratio of the U-phase upper arm switch S1 continuously changes from 100% to 0%. The PWM duty ratio of the U-phase lower arm switch S2 continuously changes from 0% to 100%. In the sub period D, the PWM duty ratio of the V-phase upper arm switch S3 continuously changes from 0% to 100%. The PWM duty ratio of the V-phase lower arm switch S4 continuously changes from 100% to 0%.

In the sub-period E, the PWM duty ratio of the W-phase upper arm switch S5 continuously changes from 100% to 0%. The PWM duty ratio of the V-phase lower arm switch S6 continuously changes from 0% to 100%. In the sub-period F, the PWM duty ratio of the U-phase upper arm switch S1 continuously changes from 0% to 100%. The PWM duty ratio of the U-phase lower arm switch S2 continuously changes from 100% to 0%.

In the period T1 with an electrical angle of 360-60 degrees, the maximum phase current Im that is the phase current having the largest absolute value is the W-phase current IW. In the period T2 with an electrical angle of 60 to 120 degrees, the maximum phase current Im is the U phase current IU. Similarly, the maximum phase current Im is the V-phase current IV in the period T3 in which the electrical angle is 120 to 180 degrees. In the period T4 with an electrical angle of 180 to 240 degrees, the maximum phase current Im is the W phase current IW. Similarly, the maximum phase current Im is the U-phase current IU in the period T3 of the electrical angle of 240 to 300 degrees. In the period T4 with an electrical angle of 300-360 degrees, the maximum phase current Im is the V-phase current IV.

Therefore, when the current supply system including the power generation device 5, the smoothing capacitor 4, and the step-up DCDC converter 2 supplies the voltage source inverter 3 with the supply current Is equal to the maximum phase current Im, the voltage source inverter 3 is shown in FIG. The three-phase sine current shown is supplied to the three-phase motor 9. When the power generation current Ig of the power generation device 5 is 0, the output current Ico of the step-up DCDC converter 2 is equal to the maximum phase current Im of a substantially three-phase full-wave sine waveform shown in FIG.

According to this one-phase modulation method, each switch of the voltage source inverter 3 has the state shown in FIG. Further, the step-up DCDC converter 2 may output an output current Ico equal to the maximum phase current Im of the voltage source inverter 3. When the power generation device 5 outputs the generated current Ig, the step-up DCDC converter 2 outputs the difference between the maximum phase current Im and the generated current Ig.

The motor controller 6 shown in FIG. 1 has a three-phase modulation block 61, a one-phase modulation block 62, a command value switching block 63, a gate signal generation block 64, and a mode determination block 65. The three-phase modulation block 61 is the same as a conventional vector control type three-phase modulation motor controller. The detected value IUd of the U-phase current IU, the detected value IVd of the V-phase current IV, and the detected value IWd of the W-phase current IW detected by a current sensor (not shown) are transmitted to the three-phase modulation block 61. The rotation angle R of the motor 9 detected by a rotation angle sensor (not shown) is transmitted to the three-phase modulation block 61, the one-phase modulation block 62, and the mode determination block 65. Further, the torque command value Ti is transmitted to the inverter current command value generation block 61 and the mode determination block 65.

The three-phase modulation block 61 calculates a U-phase current target value IUx, a V-phase current target value IVx, and a W-phase current target value IWx based on the torque command value Ti and the rotation angle R. First, the q-axis current command value Iqi and the d-axis current command value Idi are determined based on the torque command value Ti and the rotation angle R. A map showing the relationship among the torque command value Ti, the rotation angle R, the q-axis current command value Iqi, and the d-axis current command value Idi is used. Next, based on the q-axis current command value Iqi, the d-axis current command value Idi, and the rotation angle R, the U-phase current target IUx, the V-phase current target value IVx, and the W-phase current target value IWx are calculated.

Further, the three-phase modulation block 61 calculates the U-phase current command value IUi based on the difference between the U-phase current target IUx and the U-phase current detection value IUd. Similarly, V-phase current command value IVi is calculated based on the difference between V-phase current target value IVx and V-phase current detection value IVd. Further, W-phase current command value IWi is calculated based on the difference between W-phase current target value IWx and W-phase current detection value IWd. The calculated three phase current command values IUi, IVi, and IWi are transmitted to the one-phase modulation block 62 and the command value switching block 63.

The one-phase modulation block 62 assigns a high potential fixed leg, a low potential fixed leg, and a switched leg separately to each leg 31-33 of the voltage source inverter 3 based on the rotation angle R. In other words, the one-phase modulation block 62 transmits a leg state designation signal that designates the operation of each leg of the voltage source inverter 3 to the command value switching block 63.

Next, the one-phase modulation block 62 selects the maximum phase current command value Im having the largest absolute value in order from the three phase current command values IUi, IVi, and IWi based on the rotation angle R. FIG. 4 shows the relationship between the maximum phase current command Im and the phase current command values IUi, IVi, and IWi. Further, the one-phase modulation block 62 calculates a current difference Id between the determined maximum phase current Im and the generated current Ig, and uses this current difference Id as a command value of the output current Ico of the step-up DCDC converter 2 as a command value switching block. 63.

The mode determination block 65 determines a modulation mode from the motor rotation speed N obtained from the rotation angle R and the torque command value Ti, and outputs the determined modulation mode to the command value switching block 63. In this embodiment, the one-phase modulation mode is selected when the motor speed is less than a predetermined threshold value and the torque command value Ti is less than the predetermined threshold value, and the three-phase modulation mode is selected under other conditions. adopt. FIG. 6 is a diagram illustrating a motor operation region surrounded by a solid line 100 indicating the maximum torque. In region A, the one-phase modulation mode is executed, in region B the three-phase modulation mode is executed, and in region C the one-pulse mode is executed.

When the mode determination block 65 commands the command value switching block 63 to the three-phase modulation mode, the command value switching block 63 uses the three phase current command values IUi, IVi, IWi received from the three-phase modulation block 61 as gate signals. Transmit to generation block 64. The gate signal generation block 64 determines the PWM duty ratio of the gate signal of each power transistor included in the six switches S1 to S6 of the voltage source inverter 3 based on the phase current command values IUi, IVi, and IWi. Transmit to generation block 64.

Further, in order to maintain the DC link voltage Vx at a predetermined target value, the gate signal generation block 64 performs feedback control of the switches 22 and 23 of the step-up DCDC converter 2. In other words, the gate signal generation block 64 determines the PWM duty ratio of the switches 22 and 23 based on the difference between the detected value of the DC link voltage Vx and the predetermined target value, and transmits it to the boost DCDC converter 2.

When the mode determination block 65 transmits the one-phase modulation mode to the command value switching block 63, the command value switching block 63 determines each of the voltage source inverters 3 based on the leg state designation signal received from the one-phase modulation block 62. Specifies the state of the leg. FIG. 4 shows the states of the switches S1-S6 designated by the leg state designation signal. When one leg of the three legs 31-33 operates as a switched leg, the PWM duty ratio of the upper arm switch and the lower arm switch of this switched leg is determined by the rotation angle and the map. This map shows the relationship between the PWM duty ratio and the rotation angle of the upper arm switch and the lower arm switch of the switch leg. An example of the change in PWM duty ratio according to the rotation angle is shown in FIG.

Next, when the mode determination block 65 transmits the one-phase modulation mode to the command value switching block 63, the command value switching block 63 receives the command value of the output current Ico of the step-up DCDC converter 2 received from the one-phase modulation block 62. , To the gate signal generation block 64. The gate signal generation block 64 determines the PWM duty ratio of the switches 22 and 23 of the step-up DCDC converter 2 based on the received command value of the output current Ico, and transmits it to the step-up DCDC converter 2.

Thereby, it is possible to switch between the three-phase modulation mode and the one-phase modulation mode according to the operating conditions of the three-phase motor 9. Furthermore, the three-phase sine current can be supplied to the three-phase motor 9 by executing the one-phase modulation mode (see FIG. 2). Further, in this one-phase modulation mode, the PWM duty ratio of the step-up DCDC converter 2 is the maximum determined by sequentially selecting the three phase current command values IUi, IVi, and IWi calculated for the three-phase modulation. It can be determined based on the phase current command value.

As another embodiment of the one-phase modulation method, a control routine for executing this one-phase modulation operation by software will be described with reference to a flowchart shown in FIG. First, in step S10, the detected value IUd of the U-phase current IU, the detected value IVd of the V-phase current IV, the detected value IWd of the W-phase current IW, the torque command value Ti, the rotation angle R of the rotor, and the generated current Ig are read. It is. Further, the rotation speed N is calculated based on the rotation angle R.

In the next step S12, the q-axis current command value Iqi and the d-axis current command value Idi are determined based on the torque command value Ti, the rotation angle R, and the rotation speed N. A map showing the relationship among the torque command value Ti, the rotation angle R and the rotation speed N, the q-axis current command value Iqi, and the d-axis current command value Idi is used. The motor controller 6 has maps on a plurality of rotational coordinate systems, and one map is selected according to the driving situation of the vehicle.

In the next step S14, based on the q-axis current command value Iqi, the d-axis current command value Idi, the rotation angle R, and the rotation speed N, the U-phase current command value IUi, the V-phase current command value IVi, and the W-phase current command The value IWi is determined. A map showing the relationship among each phase current command value IUi, IVi, and IWi, rotation angle R, and rotation speed N is used.

In the next step S16, it is determined whether or not to select the one-phase modulation mode based on the torque command value Ti and the rotation speed N. A map (see FIG. 6) showing the relationship among the torque command value Ti, the rotational speed N, and the modulation mode is used. In this routine, if the rotation speed N is less than a predetermined value and the torque command value Ti is less than a predetermined value, the one-phase modulation mode is adopted. When the one-phase modulation mode is adopted, step S18 is executed. Since the one-pulse mode and the three-phase modulation mode are well-known motor control operations, description thereof is omitted.

In step S18, a high potential fixed leg, a low potential fixed leg, and a switched leg are determined based on the rotation angle R of the rotor. This determination uses the map shown in FIG. One leg of the voltage source inverter 3, which is a high potential fixed leg, has an upper arm switch that is turned on and a lower arm switch that is turned off. Another leg of the voltage source inverter 3, which is a low potential fixed leg, has an upper arm switch that is turned off and a lower arm switch that is turned on. The other leg of the voltage source inverter 3 which is a switched leg is PWM-switched.

FIG. 4 shows the PWM duty ratio of the upper arm switch of the switch leg. The PWM duty ratio of the switched leg is determined based on the rotation angle R and the map. This map shows the relationship between the rotation angle R and the PWM duty ratio of the upper arm switch and the lower arm switch of the switch leg. The motor controller 6 performs PWM control of the switched leg based on the determined PWM duty ratio.

In the next step S20, a supply current Is that is the sum of the generated current Ig and the output current Ico of the step-up DCDC converter 2 is determined. The current of the smoothing capacitor 4 is ignored. The motor controller 6 selects one of the U-phase current command value IUi, the V-phase current command value IVi, and the W-phase current command value IWi in turn based on the rotation angle R and the map, so that the supply current Is Determine the command value Isi.

As shown in FIG. 4, the command value Isi of the supply current Is is an absolute value of the U-phase current command value IUi in the range of an electrical angle of 60 to 120 degrees. The command value Isi is an absolute value of the V-phase current command value IVi in the electric angle range of 120 to 180 degrees. The command value Isi is an absolute value of the W-phase current command value IVi in the electric angle range of 180 to 240 degrees. The command value Isi is an absolute value of the U-phase current command value IUi in the electrical angle range of 240 to 300 degrees. The command value Isi is an absolute value of the V-phase current command value IVi in the electrical angle range of 300-360 degrees. The command value Isi is an absolute value of the W-phase current command value IVi in the electrical angle range of 360-60 degrees.

In the next step S22, the current command value Icoi of the step-up DCDC converter 2 is determined. The current command value Icoi of the step-up DCDC converter 2 is equal to the difference between the command value Isi of the supply current Is and the generated current Ig. Next, the PWM duty ratio of the upper arm switch 22 and the lower arm switch 23 of the step-up DCDC converter 2 is determined based on the determined current command value Icoi and the map. This map shows the relationship between the PWM duty ratio and the current command value Icoi. This map can include a rotation angle R, a torque command value Ti, and a rotation speed N. The motor controller 6 performs PWM control of the step-up DCDC converter 2 based on the determined PWM duty ratio.

According to the modification, the power generation device 5 can control the generated current Ig according to a gradual change in the command value Isi of the supply current Is. In other words, the command value Isi of the supply current Is supplied to the voltage source inverter 3 by the current supply system including the power generation device 5 and the step-up DCDC converter 2 includes a low frequency component and a high frequency component. As shown in FIG. 7, the supply current command value Isi equal to the maximum phase current command value Im is generated by the filter 200 using the generated current command value Igi, which is a low frequency component, and the output current command value Icoi of the step-up DCDC converter, which is a high frequency component. And divided. The output current command value Icoi is obtained by subtracting the generated current command value Igi from the supply current command value Isi by the subtractor 400. Thereby, the electric power generating apparatus 5 can supply the low frequency generated electric current Ig. When the power generation device 5 is stopped, the step-up DCDC converter 2 supplies a current corresponding to the supply current command value Isi.

Claims (6)

A multi-phase voltage source inverter for driving a multi-phase motor, a step-up DCDC converter for applying a DC link voltage to the voltage source inverter through a high potential DC link line and a low potential DC link line, the voltage source inverter and the boost DCDC A motor controller for controlling the converter,
The voltage source inverter includes a U-phase leg that supplies a U-phase current to the motor, a V-phase leg that supplies a V-phase current to the motor, and a W-phase leg that supplies a W-phase current to the motor. ,
The voltage source inverter includes a high-potential fixed leg connected to a high-potential DC link line, a low-potential fixed leg connected to a low-potential DC link line, and a switched leg that is switched at high speed to the rotation angle of the motor. Depending on the U phase leg, V phase leg and W phase leg separately,
The step-up DCDC converter supplies power having an average amplitude that periodically changes according to the rotation angle of the motor to the voltage source inverter.
The motor controller calculates a U-phase current command value, a V-phase current command value, and a W-phase current command value to the voltage source inverter to control the U-phase current, V-phase current, and W-phase current. In the modulation type variable speed motor drive device,
The motor controller is selected from the U-phase current command value, the V-phase current command value, and the W-phase current command value, and is based on a maximum phase current command value constituted by a phase current command value having a maximum absolute value. And a step-up DCDC converter for controlling the step-up DCDC converter.   The motor controller reduces the output current of the step-up DCDC converter when the detected value of the maximum phase current is larger than the command value of the maximum phase current, and the detected value of the maximum phase current is a command of the maximum phase current The single-phase modulation type variable speed motor drive device according to claim 1, wherein the output current of the step-up DCDC converter is increased when the value is smaller than the value. A power generator that supplies a power generation current to the voltage source inverter through the high potential DC link line and the low potential DC link line;
2. The one-phase modulation variable speed motor driving device according to claim 1, wherein the power generation device and the step-up DCDC converter supply a current substantially equal to the maximum phase current command value to the voltage source inverter. The power generator supplies a low frequency component of the maximum phase current command value to the voltage source inverter,
4. The one-phase modulation type variable speed motor driving apparatus according to claim 3, wherein the step-up DCDC converter supplies at least a high-frequency component of the maximum phase current command value to the voltage source inverter. The motor controller has a three-phase modulation mode and a one-phase modulation mode,
The single-phase modulation type variable speed motor driving device according to claim 1, wherein the three-phase modulation mode is adopted in a low-speed rotation region of the motor. The motor controller has a three-phase modulation mode and a one-phase modulation mode,
2. The one-phase modulation type variable speed motor drive apparatus according to claim 1, wherein the three-phase modulation mode is employed in a large torque region where the motor generates a large motor torque.

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