JP2007151203A - Motor generator control system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor generator control system which can control a motor generator so as not to restrict rotation of a load such as a wheel, and a motor generator control system where energy consumption is reduced when brake torque is applied. <P>SOLUTION: A vehicle drive system 100 is mounted on a motor vehicle. A control section 32 can control the motor vehicle in a nondrive mode for opening the switching elements Sw1-Sw6 of an inverter circuit 14. When a brake pedal 22 is stepped while the motor vehicle is traveling while being controlled in a nondrive mode, the control section 32 controls the output voltage Vo from a voltage converter circuit 12 such that a regeneration current flows through a motor generator 16. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a system for controlling a motor generator.

  An electric motor driven vehicle driven by a motor generator is used. FIG. 4 shows the configuration of a vehicle drive system that drives an electric motor drive vehicle. The vehicle drive system includes a battery 10, a voltage converter circuit 12, an inverter circuit 14, a motor generator 16, a torque transmission mechanism 18, and wheels 20.

  The operation state of the motor-driven vehicle is divided into a drive mode in which acceleration torque is transmitted to the wheels 20 and a non-drive mode in which acceleration torque is not transmitted to the wheels 20. In the drive mode, the voltage converter circuit 12 adjusts and outputs the voltage value of the DC voltage output from the battery 10 to a value sufficient to give the wheel 20 acceleration torque. The inverter circuit 14 converts the DC voltage output from the voltage converter circuit 12 into a three-phase AC voltage and outputs it. The motor generator 16 generates acceleration torque by the three-phase AC voltage applied from the inverter circuit 14. The torque transmission mechanism 18 transmits the acceleration torque generated by the motor generator 16 to the wheels 20. On the other hand, in the non-drive mode, the inverter circuit 14 does not perform an operation of converting the DC voltage output from the voltage converter circuit 12 into an AC voltage. As a result, no acceleration torque is generated in the motor generator 16 and no acceleration torque is transmitted to the wheels 20.

JP-A-6-225402 JP-A-8-182109

  An engine-driven vehicle driven by an engine can generally be controlled to a neutral mode in which the rotation of wheels is not restricted by the engine. In the neutral mode, torque transmission between the engine and the wheels is mechanically disconnected by the torque transmission mechanism. This eliminates the need to keep stepping on the brake pedal, clutch pedal, or the like by using the side brake when the engine is temporarily stopped while waiting for a signal or the like. In addition, when the neutral mode is controlled during traveling, the rotation of the wheels is not restrained by the engine, so that the vehicle continues traveling due to inertia.

  The operability of such engine-driven vehicles has been accepted by users of engine-driven vehicles for many years. Therefore, it is preferable that the motor-driven vehicle can be controlled so as to give the user a sense that the rotation of the wheels is not restricted by the motor generator, and the operability difference from the engine-driven vehicle is eliminated.

  In an electric motor-driven vehicle that does not have a mechanism for mechanically separating torque transmission between the motor generator and wheels, the motor generator continues to rotate due to the inertia of the electric motor-driven vehicle even when the non-drive mode is set during traveling. Thus, in the non-drive mode, depending on the magnitude relationship between the power generation voltage of the motor generator 16 and the voltage output from the voltage converter circuit 12, braking torque may be generated on the wheel 20 by the power generation of the motor generator 16. Therefore, even if the motor-driven vehicle is controlled to the non-drive mode, the rotation of the wheels 20 is not necessarily restricted, and the difference in operability from the vehicle that can be controlled to the neutral mode is completely eliminated. I can't.

  Further, in a state where the rotation of the wheel is not restrained by a driving source such as an engine or a motor generator, there is a problem that kinetic energy is consumed as heat energy when a braking torque is mechanically applied to the wheel by a brake or the like.

  As described above, the non-drive mode in the motor-driven vehicle is an operation state different from the neutral mode. However, depending on the magnitude relationship between the generated voltage of the motor generator 16 and the voltage output from the voltage converter circuit 12, the motor generator 16 may There are cases where the rotation of 20 is not constrained. At this time, if the braking torque is mechanically applied to the wheels, the above-described problem of energy consumption occurs.

  The present invention has been made for such a problem. That is, an object of the present invention is to provide a motor generator control system capable of controlling a motor generator in a state in which the rotation of a load such as a wheel is not restricted, and a motor generator control system that reduces energy consumption when braking torque is applied. And

  The present invention relates to a battery that outputs a DC voltage, a voltage adjustment circuit that adjusts and outputs a voltage value of a DC voltage that is output from the battery, a DC voltage that is output from the voltage adjustment circuit to an AC voltage, and a motor A motor comprising: an inverter circuit to be applied to a generator; and an inverter circuit control unit for controlling whether or not the inverter circuit performs DC / AC conversion for converting a DC voltage to an AC voltage according to an operating state of the motor generator. In the generator control system, in the operation state in which the DC / AC conversion is not performed in the inverter circuit, when the control for applying a braking force to the motor generator is performed, the voltage adjustment circuit collects the electric power generated by the motor generator. The voltage value of the DC voltage to be output is adjusted so as to be in a state of being performed.

  In the motor generator control system according to the present invention, in the operation state in which the DC / AC conversion is not performed in the inverter circuit, when performing control without applying braking force to the motor generator, the voltage adjustment circuit includes the motor It is preferable to adjust the voltage value of the output DC voltage so that the power generated by the generator is not recovered.

  In the motor generator control system according to the present invention, in the operation state in which the DC / AC conversion is not performed in the inverter circuit, when the control for applying a braking force to the motor generator is performed, the voltage adjustment circuit includes the motor generator It is preferable that the voltage value of the output DC voltage is adjusted according to braking force information indicating the magnitude of the braking force applied to the motor.

  In the motor generator control system according to the present invention, the inverter circuit includes a diode having a cathode terminal connected to an input terminal of the inverter circuit and an anode terminal connected to an output terminal of the inverter circuit, In the operation state in which the DC / AC conversion is not performed in the circuit, when performing control to apply a braking force to the motor generator, the voltage adjusting circuit outputs a DC voltage so that a current flows from the anode terminal to the cathode terminal. It is preferable that the voltage value is adjusted.

  The motor generator control system according to the present invention is preferably mounted on an electric motor driven vehicle driven by a motor generator.

  When the motor generator control system according to the present invention is mounted on an electric motor driven vehicle driven by the motor generator, it is preferable to provide the electric motor driven vehicle with an inclinometer that detects the inclination of the electric motor driven vehicle and outputs the value. is there. In such a configuration, in the operation state where the DC / AC conversion is not performed in the inverter circuit, when the control for applying a braking force to the motor generator is performed, the voltage adjustment circuit recovers the electric power generated by the motor generator. Further, it is preferable to adjust the voltage value of the DC voltage to be output based on the inclination output from the inclinometer.

  ADVANTAGE OF THE INVENTION According to this invention, the motor generator control system which can control a motor generator in the state which does not restrain rotation of load, and the motor generator control system which reduced the consumption of energy when giving braking torque are realizable. .

  FIG. 1 shows a configuration of a vehicle drive system 100 according to an embodiment of the present invention. The vehicle drive system 100 includes a battery 10, a voltage converter circuit 12, an inverter circuit 14, a motor generator 16, a torque transmission mechanism 18, wheels 20, a brake pedal 22, an accelerator pedal 24, a change lever 26, a speedometer 28, a voltmeter 30, A control unit 32 is provided. The same components as those in the vehicle drive system shown in FIG.

  The vehicle drive system 100 is mounted on an electric motor drive vehicle and controls the traveling of the electric motor drive vehicle. The control unit 32 determines whether to control the motor-driven vehicle in the drive mode or the non-drive mode according to the selection of the change lever 26. First, the operation when the motor-driven vehicle is controlled to the drive mode will be described.

  The battery 10 applies a DC voltage E to the input terminals a1 and b1 of the voltage converter circuit 12. The voltage converter circuit 12 boosts the DC voltage E at a boost ratio defined by the voltage control signal Su output from the control unit 32, and applies the boosted voltage to the input terminals a2 and b2 of the inverter circuit 14 as the converter output voltage Vo.

  The inverter circuit 14 includes switching elements Sw1 to Sw6 and diodes D1 to D6. One terminal of each of the switching elements Sw1 to Sw3 is connected to the input terminal a2. One terminal of each of the switching elements Sw4 to Sw6 is connected to the input terminal b2. The terminals on the opposite side to the terminals connected to the input terminals a2 of the switching elements Sw1 to Sw3 are connected to the terminals on the opposite side to the terminals connected to the input terminals b2 of Sw4 to Sw6, respectively. The connection point of switching elements Sw1 and Sw4, the connection point of switching elements Sw2 and Sw5, and the connection point of switching elements Sw3 and Sw6 are connected to terminals u, v, and w of the motor generator, respectively. The diodes D1 to D3 are connected in parallel to the switching elements Sw1 to Sw3 so that the input terminal a2 side is the cathode terminal. The diodes D4 to D6 are connected in parallel to the switching elements Sw4 to Sw6, respectively, so that the input terminal b2 side is an anode terminal. Control lines T1 to T6 drawn from the control unit 32 are connected to the switching elements Sw1 to Sw6, respectively. The switching elements Sw1 to Sw6 are controlled by control signals C1 to C6 supplied by control lines T1 to T6, respectively.

  The control signals C1 to C6 are rectangular wave voltages having a predetermined frequency. The duty ratio of the control signals C1 to C6 and the timing difference between the control signals C1 to C6 are the voltage Vuv between the terminal u and the terminal v, the voltage Vvw between the terminal v and the terminal w, and the terminal w. And the terminal u are set by the control unit 32 so as to form a three-phase AC voltage having a phase difference of 120 °. The voltmeter 30 detects peak values of the voltages Vuv, Vvw, and Vwu, and outputs the detected values to the control unit 32 as detected voltage peak values Euv, Evw, and Ewu, respectively.

  The motor generator 16 generates acceleration torque by a three-phase AC voltage generated by the voltages Vuv, Vvw, and Vwu. The torque transmission mechanism 18 transmits the acceleration torque generated by the motor generator 16 to the wheels 20. The electric motor drive vehicle travels with the acceleration torque transmitted to the wheels 20.

  The acceleration of the motor-driven vehicle can be adjusted by the voltage or frequency of the three-phase AC voltage formed by the converter output voltage Vo, the voltages Vuv, Vvw, and Vwu. That is, the control unit 32 determines the converter output voltage Vo according to the degree of depression of the accelerator pedal 24 and the speed of the motor-driven vehicle detected by the speedometer 28, and the determined converter output voltage Vo is applied to the voltage converter circuit 12. Is outputted to the voltage converter circuit 12. The control unit 32 also provides control signals C1 to C6 for setting the frequency of the three-phase AC voltage according to the degree of depression of the accelerator pedal 24 and the speed of the motor-driven vehicle detected by the speedometer 28, respectively, as switching elements Sw1 to Sw6. Output to.

  The brake pedal 22 mechanically applies braking torque to the wheel 20 via the torque transmission mechanism 18. Further, a brake depression amount B indicating the depression amount of the brake pedal 22 is output to the control unit 32.

  Next, an operation when the motor-driven vehicle is controlled to the non-drive mode will be described. In the non-drive mode, the switching elements Sw1 to Sw6 are controlled to be in an open state. When the switching elements Sw1 to Sw6 are opened, the terminals u, v, and w are respectively connected to the input terminal a2 via the diodes D1, D2, and D3, and the terminals u, v, and w are respectively the diode D4. , D5, and D6 to be electrically connected to the input terminal b2.

  Thus, when the wheel 20 is stopped and the motor generator 16 is stopped, the voltages Vuv, Vvw, and Vwu are not applied from the inverter circuit 14 to the motor generator 16, and the motor generator 16 does not generate acceleration torque.

  In vehicle drive system 100, a mechanism for mechanically disconnecting torque transmission between motor generator 16 and wheels 20 is not provided. Therefore, if the non-drive mode is controlled during traveling, motor generator 16 continues to rotate due to the inertia of the motor-driven vehicle. At this time, the motor generator 16 generates power generation voltages Vguv, Vgvw, and Vgwu between the terminal u and the terminal v, between the terminal v and the terminal w, and between the terminal w and the terminal u, respectively. The generated voltages Vguv, Vgvw, and Vgwu form a three-phase AC voltage.

  In the state controlled to the non-drive mode, the motor generator 16 is based on the magnitude relationship between the magnitude of the converter output voltage Vo and the magnitudes of the generated voltages Vguv, Vgvw, and Vgwu by the rectifying action of the diodes D1 to D6. Whether or not a regenerative current flows is determined. Further, when the regenerative current flows, the magnitude of the regenerative current is determined based on the magnitude of the converter output voltage Vo. The regenerative current causes the motor generator 16 to generate a regenerative braking torque.

  Therefore, in the vehicle drive system 100 according to the present embodiment, the regenerative braking torque generated in the motor generator 16 is adjusted by changing the converter output voltage Vo, and the battery 10 is charged by the regenerative current.

  A specific process in which the control unit 32 controls the vehicle drive system 100 to the non-drive mode will be described with reference to a flowchart shown in FIG. When the change lever 26 selects the drive mode control from the non-drive mode control, this process is interrupted during execution of any step and shifts to the drive mode.

  When the change lever 26 selects control in the non-drive mode, the control unit 32 outputs control signals C1 to C6 that open the switching elements Sw1 to Sw6 to the switching elements Sw1 to Sw6, respectively (S1). As a result, the switching elements Sw1 to Sw6 are opened.

  The control unit 32 reads the speed detected by the speedometer 28 and determines whether or not the motor-driven vehicle is traveling (S2). When it is determined that the motor-driven vehicle is traveling, the control unit 32 proceeds to step S3, and when it is determined that the motor-driven vehicle is not traveling, the determination of step S2 is repeated. The control unit 32 determines whether or not the brake pedal 22 is depressed in step S3 (S3).

  When it is determined that the brake pedal 22 is not depressed (S3), the control unit 32 reads the detected voltage peak values Euv, Evw, and Ewu output from the voltmeter 30 (S4). Then, the control signal SuG that sets the magnitude of the converter output voltage Vo to a value larger than any of the detected voltage peak values Euv, Evw, and Ewu is output to the voltage converter circuit 12 (S5). After finishing Step S5, control part 32 starts processing of Step S3 again.

  When it is determined that the brake pedal 22 is depressed (S3), the control unit 32 reads the brake depression amount B from the brake pedal 22, and reads the detected voltage peak values Euv, Evw, and Ewu from the voltmeter 30 (S6). ). The control unit 32 includes a brake depression amount B and detected voltage peak values Euv, Evw, and Ewu, and a target converter output voltage VoT that is a converter output voltage Vo for generating a regenerative braking torque corresponding to the brake depression amount B. Is stored in advance. FIG. 3 shows an example of the voltage determination table. The uppermost column indicates the brake depression amount B, and the leftmost column indicates the maximum value among the detected voltage peak values Euv, Evw, and Ewu. In the area surrounded by a thick frame in FIG. 3, the target converter voltage VoT corresponding to the brake depression amount B and the maximum value among the detected voltage peak values Euv, Evw, and Ewu is described. The control unit 32 refers to the voltage determination table and determines the read brake depression amount B and the target converter output voltage VoT corresponding to the read detected voltage peak values Euv, Evw, and Ewu (S7). The control unit 32 outputs a control signal SuT that causes the converter output voltage Vo to coincide with the target converter voltage VoT to the voltage converter circuit (S8). After finishing Step S8, control part 32 starts processing of Step S2 again.

  By such processing of the control unit 32, the control signal SuG is output from the control unit 32 to the voltage converter circuit 12 when the motor-driven vehicle is controlled to be in the non-drive mode and the brake pedal 22 is not depressed. (S3-S5). As a result, the voltage converter circuit 12 outputs a voltage VoG whose magnitude is larger than any of the detected voltage peak values Euv, Evw, and Ewu. At this time, since a reverse bias voltage is always applied between the terminals of the diodes D <b> 1 to D <b> 6, the terminals u, v, and w are open ends, and no regenerative current flows through the motor generator 16. Therefore, the motor-driven vehicle is in a state where the rotation of the wheels 20 is not restricted by the motor generator 16.

  On the other hand, when the motor driven vehicle is controlled to the non-drive mode and the brake pedal 22 is depressed, the control signal SuT is output from the control unit 32 to the voltage converter circuit 12 (S3, S6 to S8). As a result, the voltage converter circuit 12 outputs the target converter output voltage VoT.

  The target converter output voltage VoT is such that the larger the brake depression amount B is, the larger the regenerative current for generating the regenerative braking torque in the motor generator 16 is. That is, the larger the brake depression amount B is, the larger the target converter output voltage VoT is. Decided to be smaller. The target converter output voltage VoT determined in this way is smaller in magnitude than any of the detected voltage peak values Euv, Evw, and Ewu. Further, the generated voltages Vguv, Vgvw, and Vgwu are three-phase AC voltages whose peak values match the detected voltage peak values Euv, Evw, and Ewu, respectively, and are therefore applied between the respective terminals of the diodes D1 to D6. The voltage has a period during which it becomes a forward bias voltage.

  During the period when the forward bias voltage is applied between the terminals of the diodes D2 and D4, the regenerative current flows from the terminal u and the regenerative current flows from the terminal v. During a period in which a forward bias voltage is applied between the terminals of the diodes D1 and D5, the regenerative current flows from the terminal v and the regenerative current flows from the terminal u. During the period when the forward bias voltage is applied between the terminals of the diodes D3 and D5, the regenerative current flows from the terminal v and the regenerative current flows from the terminal w. During a period in which a forward bias voltage is applied between the terminals of the diodes D2 and D6, the regenerative current flows from the terminal w and the regenerative current flows from the terminal v. During a period in which a forward bias voltage is applied between the terminals of the diodes D1 and D6, a regenerative current flows from the terminal w and a regenerative current flows from the terminal u. During the period in which the forward bias voltage is applied between the terminals of the diodes D3 and D4, the regenerative current flows from the terminal u and the regenerative current flows from the terminal w.

  A regenerative braking torque is generated when a regenerative current flows through the motor generator 16. The magnitude of the regenerative braking torque is determined according to the brake depression amount B. Therefore, the braking effect of the motor-driven vehicle can be enhanced by mechanically applying braking torque to the wheel 20 by depressing the brake pedal 22 and applying the regenerative braking torque of the motor generator 16 to the wheel 20.

  Further, since there is a period in which the voltage applied between the respective terminals of the diodes D1 to D6 becomes the forward bias voltage, the rectified current ID rectified by the diodes D1 to D6 is supplied from the inverter circuit 14 to the input terminal a2. The rectified current ID as the return current flows into the inverter circuit via the input terminal b2.

  The rectified current ID flows into the voltage converter circuit 12 through the input terminal a2, and the rectified current ID as a return current flows out from the voltage converter circuit 12 through the input terminal b2. The voltage converter circuit 12 charges the battery 10 with the rectified current ID.

  As a result, the kinetic energy possessed by the motor-driven vehicle can be recovered as electric energy in the battery 10, and energy consumption due to braking of the motor-driven vehicle can be reduced.

  The vehicle drive system 100 according to the present embodiment is configured to increase the regenerative braking torque when the motor-driven vehicle is running on a slope and is controlled to the non-drive mode and the brake pedal 22 is depressed. Is possible. In this case, the vehicle drive system 100 is provided with an inclinometer that detects the inclination of the motor-driven vehicle and outputs the value to the control unit 32. As the inclinometer, it is preferable to apply a device that detects gravitational acceleration.

  In step S7 of FIG. 2, the control unit 32 determines a corrected target converter voltage VoT that is smaller than the target converter voltage VoT determined with reference to the voltage determination table, according to the inclination read from the inclinometer. For example, when the inclination is α [rad] with respect to the horizontal plane, the target converter voltage VoT corrected by multiplying the target converter voltage VoT determined with reference to the voltage determination table by cos α is determined. However, depending on the configuration of the voltage converter circuit 12, the corrected target converter voltage VoT may not be made smaller than the voltage E output from the battery 10. In this case, when the value of the corrected target converter voltage VoT becomes smaller than the voltage E of the battery 10, it is preferable to perform a process for setting the voltage E to the corrected target converter voltage VoT.

  With such a configuration, it is possible to enhance the braking effect when the motor-driven vehicle is traveling on a slope.

It is a figure showing the composition of the vehicle drive system concerning an embodiment. It is a flowchart which shows the process in which a control part controls a vehicle drive system to non-drive mode. It is a figure which shows the example of a voltage determination table. It is a figure which shows the structure of the vehicle drive system which drives an electric motor drive vehicle.

Explanation of symbols

  10 batteries, 12 voltage converter circuits, 14 inverter circuits, 16 motor generators, 18 torque transmission mechanisms, 20 wheels, 22 brake pedals, 24 accelerator pedals, 26 change levers, 28 speedometers, 30 voltmeters, 32 control units, Sw1 Sw6 switching element, D1-D6 diode.

Claims (4)

A battery that outputs a DC voltage;
A voltage adjusting circuit that adjusts and outputs the voltage value of the DC voltage output by the battery;
An inverter circuit that converts the DC voltage output by the voltage adjustment circuit into an AC voltage and applies the motor voltage to the motor generator;
An inverter circuit control unit for controlling whether or not the inverter circuit performs DC / AC conversion for converting a DC voltage into an AC voltage according to an operation state of the motor generator;
A motor generator control system comprising:
In the operation state in which the inverter circuit does not perform the DC-AC conversion, when performing control to apply a braking force to the motor generator, the voltage adjustment circuit is in a state where the electric power generated by the motor generator is recovered. A motor generator control system characterized by adjusting a voltage value of a DC voltage to be output. The motor generator control system according to claim 1,
In an operation state in which the DC / AC conversion is not performed in the inverter circuit, when performing control without applying braking force to the motor generator, the voltage adjustment circuit is in a state in which the electric power generated by the motor generator is not recovered. A motor generator control system characterized by adjusting a voltage value of a DC voltage to be output. The motor generator control system according to claim 1 or 2,
In the operation state in which the DC / AC conversion is not performed in the inverter circuit, when performing control for applying a braking force to the motor generator, the voltage adjustment circuit uses braking force information indicating the magnitude of the braking force applied to the motor generator. The motor generator control system is characterized in that the voltage value of the output DC voltage is adjusted accordingly. The motor generator control system according to any one of claims 1 to 3,
The inverter circuit includes a diode having a cathode terminal connected to an input terminal of the inverter circuit and an anode terminal connected to an output terminal of the inverter circuit;
In the operation state where the inverter circuit does not perform the DC-AC conversion, when performing control to apply a braking force to the motor generator, the voltage adjustment circuit outputs so that a current flows from the anode terminal to the cathode terminal. A motor generator control system for adjusting a voltage value of a DC voltage.

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