JP2010220431A - Driving device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To drive a three-phase AC motor in a rectangular-wave control mode as required. <P>SOLUTION: When a request for rectangular-wave control is made to drive a motor as a three-phase AC motor in a rectangular-wave control mode, a target voltage VH* of a high-voltage system is set so that a rectangular-wave control mode may be selected as a control mode for execution of a motor based on a map for setting a control mode (for example, a map as shown in Figure 2(2)) and a target driving point (for example, a target driving point B as shown in Figure 2(2)), instead of selecting a control mode of the motor after setting the target voltage VH* of the high-voltage system, in other words, without using a map for setting a target voltage. By this method, the motor 32 can be driven in a rectangular-wave control mode as required. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a drive device, and more particularly, to a drive device including a three-phase AC motor, an inverter that drives the three-phase AC motor, a battery, and a booster circuit that boosts power from the battery and supplies the boosted power to the inverter.

  Conventionally, as this type of drive device, an AC motor and an inverter that drives the AC motor, and an inverter that is controlled in a PWM (pulse width modulation) current control mode or a rectangular wave voltage control mode have been proposed ( For example, see Patent Document 1). In this device, in the rectangular wave voltage control mode, the current and voltage applied to the AC motor are detected at an intermediate timing between the switching timings in addition to the switching timing of the three-phase rectangular wave voltages in the AC motor. By calculating the power, the torque of the AC motor can be detected with high accuracy based on the average power.

JP 2002-223590 A

  The rectangular wave voltage control mode used in the above-described driving device does not perform switching control of the inverter at a high frequency unlike the PWM current control mode, so that noise due to switching is hardly generated and loss due to switching is small. The AC motor may be required to be driven by the wave control mode. In addition to the above-described configuration, a booster circuit that boosts the power from the battery and applies it to the inverter is provided, and the voltage applied to the inverter and the drive point of the AC motor are considered in consideration of advantages such as control response of PWM control. In the device for driving the AC motor by switching the PWM current control mode or the rectangular wave voltage control mode based on the above, basically, the relationship between the drive point of the AC motor and the voltage to be applied to the corresponding inverter is basically set. Accordingly, since the voltage to be applied to the inverter is set and the control mode is switched according to the voltage and the driving point, even when driving of the AC motor in the rectangular wave control mode is requested, the request is not always met. I can't.

  The drive device of the present invention is mainly intended to drive a three-phase AC motor in a rectangular wave control mode as required.

  The drive device of the present invention employs the following means in order to achieve the main object described above.

The drive device of the present invention is
A three-phase AC motor, an inverter that drives the three-phase AC motor, a battery, a booster circuit that boosts power from the battery and supplies the boosted power to the inverter, the rotational speed of the three-phase AC motor, and the three-phase The target voltage is set using a first predetermined relationship between the target drive point and a target voltage to be applied to the inverter based on a target drive point consisting of a torque command to drive the AC motor, and a pulse The pulse width modulation control mode for driving the three-phase AC motor using a pseudo three-phase AC voltage by width modulation and the overmodulation voltage as a sine wave voltage having an amplitude exceeding the amplitude of the carrier wave by pulse width modulation Three control modes, an overmodulation control mode for driving a three-phase AC motor and a rectangular wave control mode for driving the three-phase AC motor using a rectangular wave voltage, and the target voltage The three-phase AC motor selected as one of the three control modes by applying the set target voltage and the target drive point to a predetermined second relationship with the target drive point Control means for controlling the inverter and the booster circuit so that the three-phase AC motor is driven by the torque command in accordance with the execution control mode and the voltage applied to the inverter becomes the set target voltage. In a drive device comprising:
When the control means is requested to drive the three-phase AC motor in the rectangular wave control mode, the control means determines the three-phase AC motor based on the second relationship and the target drive point regardless of the first relationship. Setting the target voltage so that the rectangular wave control mode is selected as the execution control mode of the phase AC motor;
It is characterized by that.

  In the driving device of the present invention, when it is requested to drive the three-phase AC motor in the rectangular wave control mode, the rectangular wave is set as the execution control mode of the three-phase AC motor based on the second relationship and the target drive point. The target voltage is set so that the control mode is selected. Accordingly, the three-phase AC motor can be driven in the rectangular wave control mode as required.

It is a block diagram which shows the outline of a structure of the electric vehicle 20 carrying the drive device of an Example. 4 is an explanatory diagram showing an example of a part of a control mode setting map of a motor 32. FIG.

  Next, the form for implementing this invention is demonstrated using an Example.

  FIG. 1 is a configuration diagram showing an outline of a configuration of an electric vehicle 20 equipped with a drive device as an embodiment of the present invention. As shown in the figure, the electric vehicle 20 of the embodiment is configured as a three-phase AC motor such as a synchronous generator motor, and the rotor is connected to a drive shaft 22 connected to drive wheels 26a and 26b via a differential gear 24. Motor 32, inverter 34 for driving motor 32, battery 40 configured as, for example, a secondary battery, and the voltage from power from battery 40 is boosted to inverter 34 side (hereinafter referred to as a high voltage system). The booster converter 42 that supplies the voltage to the battery 40 by lowering the voltage of the high voltage system and the state of the motor 32 and the inverter 34 such as the rotational position detection sensor 35 that detects the rotational position of the rotor of the motor 32. A high voltage system from a voltage sensor 43 provided between signals from various sensors for detecting the voltage and the output terminal of the boost converter 42 The voltage VH, signals from various sensors that detect the state of the battery 50, the shift position from the shift position sensor 52 that detects the position of the shift lever, and the accelerator opening from the accelerator pedal position sensor 54 that detects the amount of depression of the accelerator pedal Priority, brake position from the brake pedal position sensor 56 that detects the amount of depression of the brake pedal, vehicle speed from the vehicle speed sensor 58, driving priority of the motor 32 that is attached to the front of the driver's seat in the passenger compartment, and is described later. In addition, an instruction signal from an instruction switch 59 is input, and a switching element (not shown) of the inverter 34 is switched to control driving of the motor 32 or a switching element (not shown) of the boost converter 42 is switched. Comprising an electronic control unit 50 which controls the entire drive control to the equipment boost converter 42 by ring control, the. The drive device of the embodiment mainly corresponds to the motor 32, the inverter 34, the battery 40, the boost converter 42, and the electronic control unit 50.

  The electric vehicle 20 of the embodiment basically travels by drive control described below that is executed by the electronic control unit 50. In the electronic control unit 50, first, a required torque required for the drive shaft 22 for traveling is set according to the accelerator opening from the accelerator pedal position sensor 54 and the vehicle speed from the vehicle speed sensor 58, and the battery 40 is charged. The required torque is set in the torque command of the motor 32 within the range of the input / output restriction as the maximum power that can be discharged, and the target voltage to be applied to the inverter 34 is set based on the rotation speed of the motor 32 and the torque command. Then, switching control of the switching element of the inverter 34 is controlled so that the motor 32 is driven by the set torque command, and switching control of the boost converter 42 is controlled so that the high voltage system voltage VH becomes the set target voltage. . The electric vehicle 20 according to the embodiment travels by outputting the required torque corresponding to the accelerator opening to the drive shaft 22 within the range of the input / output limitation of the battery 40 by such control. Hereinafter, the rotational speed of the motor 32 calculated by the electronic control unit 50 based on the signal from the rotational position detection sensor 35 is set to the rotational speed Nm, and the torque command of the motor 32 set by the drive control by the electronic control unit 50 is performed. Is a torque command Tm *, and the drive point consisting of the rotational speed of the motor 32 and the torque command is a target drive point and is also expressed as a target drive point (Nm, Tm *).

  When executing the above-described drive control, the electronic control unit 50 uses the target voltage setting map preset based on the target drive point (Nm, Tm *) of the motor 32 at the target drive point of the motor 32. A target voltage VH * of the high voltage system is set as a voltage to be applied to the inverter 34 necessary for driving of. Then, one control mode is selected from the three control modes using a control mode setting map set in advance based on the target voltage VH * of the high voltage system and the target drive point (Nm, Tm *) of the motor 32. Then, the inverter 34 is subjected to switching control so that the motor 32 is driven by the torque command Tm * according to the selected control mode, and the boost converter 42 is subjected to switching control so that the high voltage system voltage VH becomes the target voltage VH *. Here, the target voltage setting map is an experiment as a relationship between the target drive point (Nm, Tm *) of the motor 32 and the target voltage VH * of the high voltage system necessary for driving the motor 32 at the target drive point. The map is stored in a ROM (not shown) of the electronic control unit 50 that is determined in advance by analysis or the like. Further, the control mode setting map is determined in advance by experiments and analysis as the relationship between the target voltage VH * of the high voltage system, the target drive point (Nm, Tm *) of the motor 32, and the control mode of the motor 32. 3 is a map stored in a ROM (not shown) of the control unit 50.

  FIG. 2 shows an example of a part of the control mode setting map. FIG. 2 (1) shows a map when the target voltage VH * is a value VH1 corresponding to the voltage of the battery 40, and FIG. 2 (3) is a value VH3 which is the maximum voltage allowed for the apparatus. 3 (2) shows a map when the target voltage VH * is set to a value VH2 larger than the value VH1 and smaller than the value VH3. In the figure, the broken line shows the relationship between the rotational speed when the target voltage VH * is the value VH3 and the torque command corresponding to the predetermined upper limit torque, and the region of the high rotational speed and high torque defined by the broken line and the solid line is The target voltage VH * at that time indicates a region where the motor 32 cannot be driven. As the predetermined upper limit torque, in the embodiment, the rated torque of the motor 32 when the voltage of the battery 40 is applied to the inverter 34 without being boosted, that is, when the target voltage VH * is set to the value VH1 is used. In the figure, as indicated by the areas separated by solid lines, a sine wave output with an amplitude equal to or smaller than the amplitude of the triangular wave in the pulse width modulation (PWM) control by the triangular wave comparison in order from the region where the rotation speed and torque are small to the large region A sinusoidal control mode in which the inverter is switched by a PWM signal as a pseudo three-phase AC voltage that generates a voltage command value, PWM as an overmodulation voltage that generates a sinusoidal output voltage command value with an amplitude exceeding the amplitude of the triangular wave An overmodulation control mode in which the inverter is switched by a signal and a rectangular wave control mode in which the inverter is switched by a rectangular wave voltage having a voltage phase corresponding to the torque command are selected in advance. Therefore, the motor 32 can be driven with high responsiveness by using the sine wave control mode in the low rotation speed and low torque region, and the inverter 34 can be driven by using the rectangular wave control mode in the high rotation speed and high torque region. The modulation rate, which is the ratio of the output voltage (amplitude of the fundamental wave component) to the input voltage (high voltage system voltage VH), is increased so that a larger torque can be output and the switching loss of the inverter 34 is reduced. be able to.

  Next, when the driver makes a rectangular wave control request such as when the instruction switch 59 is turned on or when control is necessary, the motor 42 is given priority over the sine wave control mode or overmodulation control mode. Processing when driving in the rectangular wave control mode will be described. When the rectangular wave control request is made, the CPU (not shown) of the electronic control unit 50 inputs the rotational speed Nm of the motor 32 and the torque command Tm * of the motor 32 set by the drive control described above. Based on the control mode setting map and the target drive point (Nm, Tm *), the target voltage VH * of the high voltage system is selected so that the rectangular wave control mode is selected as the execution control mode used for the actual control of the motor 32. Set. Then, by applying the target voltage VH * and the target driving point (Nm, Tm *) set in the control mode setting map, the execution control mode of the motor 32 is set, and the set execution control mode, that is, a rectangular wave is set. Switching control of the inverter 34 is performed so that the motor 32 is driven by the torque command Tm * according to the control mode, and switching control of the boost converter 42 is performed so that the high voltage system voltage VH becomes the set target voltage VH *. Here, the target voltage VH * is set, for example, as shown in FIG. 2 (1), with the target drive point A out of a plurality of maps for the target drive point A of the low speed and high torque of the motor 32. The value VH1 is set to the target voltage VH * based on the map when the target voltage VH *, which is a map determined to be included in the region of the wave control mode, is set to the value VH1, and is shown in FIG. Similarly, the target voltage VH * is set to the target voltage VH * based on the map when the target voltage VH * is set to the value VH2 for the target drive point B of the torque at the medium rotation speed of the motor 32, as shown in FIG. As shown in (3), the value VH3 is set to the target drive point VH * in the same manner for the target drive point C of the motor 32 with high rotation speed and low torque. It should be noted that the control mode setting map of the embodiment corresponds to the target drive point in the region on the higher rotation speed and higher torque side than the line L that divides the overmodulation control mode and the rectangular wave control mode shown in FIG. The plurality of maps are defined so that the rectangular wave control mode can be selected without fail by using one of the plurality of predetermined maps. In the embodiment, since the rectangular wave control mode cannot be selected for the target drive point in the region at the low rotation speed and low torque side from the line L of the control mode setting map, the target drive point in this region cannot be selected. On the other hand, regardless of the control mode setting map, the value VH1 is set to the target voltage VH * and the motor 32 is forcibly driven in the rectangular wave control mode. When the motor 32 is forcibly driven in the rectangular wave control mode, the motor 32 is operated in the sine wave control mode in consideration of control responsiveness in an extremely low torque region where the torque command Tm * is near zero. It may be driven. As described above, when the rectangular wave control request is made, the rectangular wave control mode is not set as the execution control mode of the motor 32, but the control mode of the motor 32 is not selected after setting the target voltage VH * of the high voltage system. Since the target voltage VH * of the high voltage system is set so that is selected, the motor 32 can be driven in the rectangular wave control mode as required. As a result, the motor 32 can be driven in a state in which noise due to switching of the inverter 34 hardly occurs and loss due to switching is reduced.

  According to the electric vehicle 20 equipped with the driving device of the embodiment described above, when a rectangular wave control request for driving the motor 32 in the rectangular wave control mode is made, the target voltage VH * of the high voltage system is set. Instead of selecting the control mode of the motor 32, that is, without using the target voltage setting map, the rectangular wave control mode is selected as the execution control mode of the motor 32 based on the control mode setting map and the target drive point. Therefore, the target voltage VH * of the high voltage system is set so that the motor 32 can be driven in the rectangular wave control mode as required.

  The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problems will be described. In the embodiment, the motor 32 corresponds to “three-phase AC motor”, the inverter 34 corresponds to “inverter”, the battery 40 corresponds to “battery”, the boost converter 42 corresponds to “boost circuit”, and the target The voltage setting map corresponds to the “first relationship”, the control mode setting map corresponds to the “second relationship”, and is used for setting the target voltage based on the target drive point (Nm, Tm *) of the motor 32. The target voltage VH * is set using the map, and the motor is selected according to the control mode of the motor 32 selected by applying the target voltage VH * and the target drive point (Nm, Tm *) set in the control mode setting map. The inverter 34 is controlled to be switched by the torque command Tm *, and the boost converter 42 is controlled to be controlled so that the high voltage system voltage VH becomes the target voltage VH *. When the control request is made, the rectangular wave control mode is selected as the execution control mode of the motor 32 based on the control mode setting map and the target drive point (Nm, Tm *) without using the target voltage setting map. The electronic control unit 50 for setting the target voltage VH * corresponds to “control means”.

  As mentioned above, although the form for implementing this invention was demonstrated using the Example, this invention is not limited at all to such an Example, In the range which does not deviate from the summary of this invention, it is with various forms. Of course, it can be implemented.

  The present invention can be used in the manufacturing industry of drive devices.

  20 electric vehicle, 22 drive shaft, 24 differential gear, 26a, 26b drive wheel, 32 motor, 34 inverter, 35 rotational position detection sensor, 40 battery, 42 boost converter, 43 voltage sensor, 50 electronic control unit for hybrid, 52 shift Position sensor, 54 accelerator pedal position sensor, 56 brake pedal position sensor, 58 vehicle speed sensor, 59 indicator switch.

Claims (1)

A three-phase AC motor, an inverter that drives the three-phase AC motor, a battery, a booster circuit that boosts power from the battery and supplies the boosted power to the inverter, the rotational speed of the three-phase AC motor, and the three-phase The target voltage is set using a first predetermined relationship between the target drive point and a target voltage to be applied to the inverter based on a target drive point consisting of a torque command to drive the AC motor, and a pulse The pulse width modulation control mode for driving the three-phase AC motor using a pseudo three-phase AC voltage by width modulation and the overmodulation voltage as a sine wave voltage having an amplitude exceeding the amplitude of the carrier wave by pulse width modulation Three control modes, an overmodulation control mode for driving a three-phase AC motor and a rectangular wave control mode for driving the three-phase AC motor using a rectangular wave voltage, and the target voltage The three-phase AC motor selected as one of the three control modes by applying the set target voltage and the target drive point to a predetermined second relationship with the target drive point Control means for controlling the inverter and the booster circuit so that the three-phase AC motor is driven by the torque command in accordance with the execution control mode and the voltage applied to the inverter becomes the set target voltage. In a drive device comprising:
When the control means is requested to drive the three-phase AC motor in the rectangular wave control mode, the control means determines the three-phase AC motor based on the second relationship and the target drive point regardless of the first relationship. Setting the target voltage so that the rectangular wave control mode is selected as the execution control mode of the phase AC motor;
A drive device characterized by that.

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