JP4661744B2 - Vehicle motor control device - Google Patents

Description

  The present invention relates to a vehicle motor control device that controls a vehicle driving motor.

2. Description of the Related Art A vehicle motor control device is known in which a rotation angle (position) of a rotor with respect to a motor stator is detected by a rotation angle sensor, and a current flowing from the inverter to the motor is controlled according to the rotation angle (for example, a patent Reference 1).
In this device, the voltage waveform of the power supplied to the motor is switched between the sine wave PWM control mode and the rectangular wave control mode in accordance with the rotation speed and output torque of the motor, and the motor operates at low speed and high torque. When in the operating region, the sine wave PWM control mode is set, and when in the high speed operating region, the rectangular wave control mode is set.

Prior art documents related to the invention of this application include the following.
JP-A-11-285288

  However, in the conventional vehicle motor control device described above, when a large vibration due to resonance occurs in the transaxle during traveling on a wavy road, the amount of change in the rotational speed of the traveling motor increases as the amplitude and frequency of the vibration increase. There is a problem that current control from the inverter to the motor is not normally performed according to the motor rotation angle detected by the angle sensor, and overcurrent flows.

  In the vehicle motor control device that detects the rotation angle of the motor for driving and supplies the motor with the motor torque command value and the current corresponding to the motor rotation angle by the inverter, the motor rotation speed changes based on the motor rotation angle. In addition to detecting the amount, the presence / absence of vehicle body resonance is determined based on the amount of change in rotational speed. If it is determined that vehicle body resonance is occurring, the motor torque command value is reduced.

  According to the present invention, it is possible to prevent overcurrent of the inverter due to vehicle body resonance.

  An embodiment in which the vehicle motor control device of the present invention is applied to a parallel hybrid vehicle PHEV having an engine, a motor and a generator will be described. The vehicle motor control device of the present invention is not limited to a parallel hybrid vehicle. For example, a pure electric vehicle EV, a series hybrid vehicle SHEV, a parallel hybrid vehicle having only an engine and a motor, and a fuel cell vehicle FCV are also included. Can be applied.

  FIG. 1 is a diagram showing a configuration of an embodiment. The output shafts of the motor 1, the generator 2, and the engine 3 are connected to the transaxle 4, and the wheels 5 are driven via the transaxle 4 by one or a plurality of driving forces of the motor 1, the generator 2, and the engine 3. Drive driving. Rotation angle sensors 6 and 7 are connected to the motor 1 and the generator 2, respectively, and detect the rotation angle (rotation position) of the rotor (not shown) of the motor 1 and the generator 2. For the rotation angle sensors 6 and 7, a resolver, a pulse generator, or the like can be used. It is to be noted that the rotational speeds of the motor 1 and the generator 2 (the rotational speed per minute; hereinafter simply referred to as the rotational speed) [r / m] can be obtained by integrating the rotational angles of the rotational angle sensors 6 and 7.

The motor 1 and the generator 2 are driven by inverters 8 and 9, respectively. The inverters 8 and 9 convert the DC power of the battery 10 into AC power by PWM control or rectangular wave control. The inverters 8 and 9 also charge the battery 10 by converting AC power generated by the motor 1 and the generator 2 into DC power. The motor controller 10 includes a microcomputer and responds to the rotation angles θm and θg based on the motor torque command value Tm ^* from the vehicle controller 11 and the motor rotation angle θm and the generator rotation angle θg detected by the rotation angle sensors 6 and 7. The current command values Im ^* and Ig ^* are calculated, and the inverters 8 and 9 are controlled.

The vehicle controller 11 includes a microcomputer, calculates a user request torque command value T ^* based on the vehicle speed Vs detected by the vehicle speed sensor 12 and the depression amount Acc of an accelerator pedal (not shown) detected by the accelerator sensor 13, and travels. The engine torque command value Te ^* and the motor torque command value Tm ^* for obtaining force are distributed. The vehicle controller 11 is connected to a memory 14 for storing a torque limit rate map (details will be described later) with respect to the resonance duration. The engine controller 15 controls the throttle valve opening θv so that the output torque of the engine 3 coincides with the engine torque command value Te ^* .

  The vehicle controller 11, the motor controller 10, and the engine controller 15 exchange information with each other via a communication line and share information with each other.

  In the series / hybrid vehicle SHEV, the engine and the generator are connected, and only the motor is connected to the transaxle. Then, the generator is driven by the engine to generate power, and the generated power is supplied to the motor via the inverter. Further, in the fuel cell vehicle FCV, in addition to the configuration of FIG. 1, a fuel cell stack (not shown) is connected to the battery.

  2 to 3 are flowcharts showing a torque limiting program at the time of occurrence of vehicle body resonance according to one embodiment. The operation of the embodiment will be described with reference to this flowchart. The microcomputer of the vehicle controller 11 executes this torque limiting program every predetermined time.

  In step 1, the output of the motor rotation angle sensor 6 input via the motor controller 10 is subjected to band-pass filter processing, and the rotation speed change amount (rotation speed change amount) in a specific frequency region where the vehicle body resonance occurs, for example, 8 to 15 Hz. ) Is detected. Normally, when the vehicle travels on a wavy road, the motor 1 changes in rotational speed. However, the amount of motor rotational speed change due to vibration of the transaxle 4 due to vehicle body resonance is much larger, and is detected by the rotational angle sensor 6 as described above. Current control that flows from the inverter 8 to the motor 1 according to the motor rotation angle is not normally performed (referred to as inverter failure), and overcurrent flows. The same problem occurs in the generator 2, but here, the case of the motor 1 will be described as a representative. Further, in a hybrid vehicle in which the engine 3 is connected to the transaxle 4, the transaxle 4 vibrates and an inverter failure occurs when there is a rotational fluctuation due to misfire or the like of the engine 3.

  When the amount of change in the motor speed increases due to vehicle body resonance, the above-mentioned inverter failure occurs. However, a rectangular wave voltage is applied to the motor more than in the sine wave PWM control mode, which is driven by applying a sine wave PWM voltage to the motor. The probability of occurrence is higher in the rectangular wave control mode that is driven in this manner. This is because the sinusoidal PWM control mode, in which switching is performed at short time intervals by PWM control, immediately recovers even if current control corresponding to the motor rotation angle fails due to an increase in the motor rotation speed variation. This is because there is a high possibility that the current can be prevented. As described above, when the motor is in the low torque and high torque operation region, the operation is performed in the sine wave PWM control mode, and when the motor is in the high speed operation region, the operation is performed in the rectangular wave control mode.

In this embodiment, the vehicle body resonance is detected based on the amount of change in the motor speed, and the motor torque command value Tm ^* and the user requested torque command value T ^* are limited according to the duration of the resonance. The resonance duration is measured using the resonance continuation counter, but when operating in the rectangular wave control mode or in an operation state close to the rectangular wave control mode, there is a high probability that the inverter will fail. Increase the count of the resonance continuation counter and limit the torque quickly. Also, the greater the amount of change in the motor rotation speed due to resonance, the higher the probability that an inverter failure will occur. Therefore, the count-up amount of the resonance continuation counter is increased to quickly and greatly limit the torque.

  When the operation is performed in the rectangular wave control mode in Steps 2 to 9 or when the operation state is close to the rectangular wave control mode, a large count-up amount is set. First, the count-up amount CU1 is set according to the carrier frequency of the inverter 8. In this embodiment, the carrier frequency is changed in three stages according to the rotational speed (rotational speed) and torque of the motor. That is, when performing high torque operation at low speed, the carrier frequency is set to a low 1.25 kHz in order to suppress the heat generation of the inverter 8 and the motor 1. On the other hand, when driving at a high speed and a low torque, the carrier frequency is increased to 5 kHz in order to avoid an unpleasant driving at a low frequency. Furthermore, when performing a medium torque operation at a medium speed, the carrier frequency is set to an intermediate 2.5 kHz.

  The higher the carrier frequency, the higher the motor speed (rotational speed). When the motor speed is high, the motor operates in the rectangular wave control mode. Therefore, the higher the carrier frequency, the more the motor operates in the rectangular wave control mode. Probability is high. Therefore, the higher the carrier frequency, the higher the possibility of inverter failure. Therefore, the higher the carrier frequency, the faster and greatly restricts the torque by increasing the count-up amount of the resonance continuation counter, thereby preventing the occurrence of inverter failure.

  In step 2, the current carrier frequency of the inverter 8 is confirmed. When the carrier frequency is high (here, 5 kHz), the process proceeds to step 3 and 5 is set to the count-up amount CU1. If the carrier frequency is medium (2.5 kHz in this case), the process proceeds to step 4 where 3 is set as the count-up amount CU1. Further, when the carrier frequency is low (1.25 kHz in this case), the process proceeds to step 5 and 1 is set to the count-up amount CU1.

  Next, the count-up amount CU2 is set according to the current control mode of the motor 1. In this embodiment, as shown in FIG. 4, three types of control modes are set according to the rotation speed (rotation speed) and torque of the motor 1. Region (a) is an operation region in a sine wave PWM control mode in which the motor 1 is driven by applying a sine wave PWM voltage. Region (c) is an operation region in a rectangular wave control mode in which a rectangular wave voltage is applied to the motor for driving. An intermediate region (b) between the sine wave PWM control mode and the rectangular wave control mode is an overmodulation PWM control mode, and is an operation region in which a part of the sine wave PWM waveform is a rectangular wave. A large current can be passed with a small number of switching operations in the order of sine wave PWM control, overmodulation PWM control, and rectangular wave control.

  Since the number of times of switching decreases in the order of sine wave PWM control, overmodulation PWM control, and rectangular wave control, if current control according to the motor rotation angle fails due to an increase in the motor rotation speed change amount, it immediately recovers and overcurrent occurs. The possibility that it can be prevented is reduced. That is, the probability of occurrence of inverter failure increases in the order of sine wave PWM control, overmodulation PWM control, and rectangular wave control. Therefore, the count-up amount of the resonance continuation counter is increased in the order of sine wave PWM control, overmodulation PWM control, and rectangular wave control, and the torque limit is performed quickly and largely to prevent the occurrence of inverter failure.

  In step 6, the current motor control mode is confirmed. When the operation is in the rectangular wave control mode, the process proceeds to step 7 and 6 is set to the count-up amount CU2. On the other hand, when the operation is performed in the overmodulation PWM control mode, the process proceeds to step 8 to set 4 to the count-up amount CU2. Further, when the operation is performed in the sine wave PWM control mode, the process proceeds to step 9 and 2 is set to the count-up amount CU2.

  In steps 10 to 12, the count-up amount CU3 of the resonance continuation counter is set based on the motor rotation speed change amount due to resonance. In step 10, it is determined whether or not the motor rotational speed change amount is larger than a preset threshold value Δ1, and if the threshold value Δ1 is exceeded, the process proceeds to step 11 where the probability of occurrence of an inverter failure is high. A large value 7 is set for the up amount CU3. On the other hand, when the threshold value Δ1 is not exceeded, the routine proceeds to step 12 where 0 is set to the count-up amount CU3. The threshold value Δ1 is set to the amount of change in the motor rotational speed at which torque limitation needs to be executed promptly.

  In the above, the count-up amounts CU1, CU2, and CU3 of the resonance continuation counter are set based on the parameters of the carrier frequency, the motor control mode, and the motor rotation speed change amount, respectively, but the probability of generating an inverter failure is the carrier frequency, the motor Since the control mode and the motor speed change amount increase in this order, a large count-up amount is set for a parameter having a high probability of inverter failure.

  After setting the count-up amounts CU1, CU2, and CU3 of the resonance continuation counter based on the carrier frequency, the motor control mode, and the motor rotation speed change amount, the process proceeds to step 13, and the count-up amounts CU1, CU2, and CU3 The maximum value is set as the final count-up amount CU.

  In step 14, it is determined whether or not the motor rotational speed change amount exceeds a preset threshold value Δ2. Here, the threshold value Δ2 is a threshold value for determining whether or not the vehicle body resonance has occurred, and an optimum value is set by performing an actual machine test for each vehicle type. If the motor rotational speed change amount exceeds the resonance determination threshold value Δ2, the process proceeds to step 15, and the resonance continuation counter is incremented by the count-up amount CU. On the other hand, if the motor rotation speed change amount does not exceed the resonance determination threshold value Δ2, the process proceeds to step 16, and the resonance continuation counter is decremented by a predetermined countdown amount C0. For the count-up amounts CU1, CU2, CU3 and the count-down amount C0, optimum values that can reliably avoid an inverter failure are set by actual machine tests or simulations.

  In step 17, the motor torque limit rate is set according to the value of the resonance continuation counter, and in the subsequent step 18, the user request torque limit rate is set according to the value of the resonance continuation counter. Here, as shown in FIG. 5, the motor torque limit rate and the user request torque limit rate with respect to the resonance continuation counter value decrease the torque limit rate as the resonance continuation counter value increases. In this embodiment, the torque limiting rate is defined by setting the limiting rate when the torque is not limited to 100% and the limiting rate when limiting the torque to 0 as 0%. The motor torque limiting rate is set to a value such that the operating range of the motor 1 does not enter the rectangular wave control region (c) shown in FIG. The motor torque limit rate and the user request torque limit rate are stored in advance in the memory 14 as separate map data.

The user request torque limit rate is for limiting the user request torque command value T ^* determined based on the vehicle speed Vs and the accelerator pedal depression amount Acc. In order to prevent inverter failure, the motor torque command value Tm ^* may be limited at the time of resonance. However, when the electric power generated by the generator 2 is supplied to the motor 1 and operated, the motor torque command value Tm ^* is limited ^. If only this is limited, the generated power of the generator 2 may be supplied to the battery 10 and the battery 10 may be overcharged, or the DC link voltage between the inverters 8 and 9 and the battery 10 may become an overvoltage. Therefore, in this embodiment, when the resonance occurs, the motor torque command value Tm ^* is limited and at the same time, the user request torque command value T ^* is limited to prevent overcharging of the battery 10 and overvoltage of the DC link voltage.

  Next, at step 19, as shown in FIG. 6, a motor torque limit value (shown by a broken line) is set by multiplying the maximum rated torque (shown by a solid line) of the motor 1 by the motor torque limit rate described above. In the subsequent step 20, as shown in FIG. 7, the user request torque limit value (shown by a broken line) is set by multiplying the user request maximum torque (shown by a solid line) by the user request torque limit rate described above.

In step 21, control is performed so that the motor torque command value Tm ^* is equal to or less than the motor torque limit value corresponding to the current motor speed. In the following step 22, the motor torque command value Tm ^* and the engine torque command value Te ^* are controlled so that the user request torque command value T ^* is equal to or less than the user request torque limit value corresponding to the current vehicle speed.

FIG. 8 is a diagram illustrating a torque limit result when resonance is generated by the vehicle motor control device according to the embodiment. When the amount of motor speed change calculated by applying band-pass filter processing to the motor speed exceeds the threshold Δ2, and the occurrence of vehicle body resonance is detected, the resonance continuation counter value increases as the resonance continuation time increases. , the motor torque command value Tm ^* and user requested torque command value T ^* of the limit ratio is decreased, the motor torque command value Tm ^* and user requested torque command value T ^* is lowered. As a result, the motor is not operated in the rectangular wave control mode in the vehicle resonance region (see the broken line circle in the figure), the inverter failure does not occur, and the operation of the motor is continued. When the vehicle resonance is settled, the resonance continuation counter value is decreased, the motor torque command value Tm ^* and the user request torque command value T ^* are increased, and the motor torque command value Tm ^* and the user request torque command value T ^* are increased ^. Will increase.

  Thus, according to one embodiment, the vehicle motor control device that detects the rotation angle of the driving motor and supplies the motor with the motor torque command value and the current corresponding to the motor rotation angle by the inverter. , The amount of change in the rotation speed of the motor is detected based on the motor rotation angle, the presence / absence of the vehicle body resonance is determined based on the amount of change in the motor rotation speed, and if it is determined that the vehicle body resonance has occurred, the motor torque Since the command value is reduced, it is possible to prevent an inverter from failing due to an overcurrent generated in the inverter due to an erroneous current command.

  Further, according to one embodiment, when it is determined that vehicle body resonance has occurred, the motor torque command value is reduced so that the inverter operating region does not enter the operating region of the rectangular wave control mode. . An inverter failure in which an overcurrent flows to the inverter due to an incorrect current command has a high probability of occurring when the motor is operated in the rectangular wave control mode, and therefore does not enter the operation region of the rectangular wave control mode when a vehicle body resonance occurs. By doing so, it is possible to suppress the occurrence of inverter failure and to avoid unnecessary deterioration of the drivability by reducing the motor torque command value unnecessarily.

  According to one embodiment, the reduction amount of the motor torque command value is determined according to the carrier frequency of the inverter when the vehicle body resonance occurs. The higher the carrier frequency, the higher the probability of inverter failure, so it is possible to effectively escape from the operating region where the probability of inverter failure is high when vehicle body resonance occurs. It is possible to avoid deterioration of drivability by reducing the motor torque command value.

  According to one embodiment, the reduction amount of the motor torque command value is determined according to the control mode of the inverter when the vehicle body resonance occurs. Since the probability of occurrence of inverter failure increases in the order of sine wave PWM control mode, overmodulation PWM control mode, and rectangular wave control mode, it is possible to effectively escape from the control mode with high probability of inverter failure when vehicle body resonance occurs. In addition, the occurrence of inverter failure can be suppressed, and the motor torque command value can be reduced unnecessarily, thereby preventing the drivability from deteriorating.

  According to one embodiment, the reduction amount of the motor torque command value is determined according to the amount of change in the motor rotation speed when the vehicle body resonance occurs. The greater the amount of change in the motor rotation speed, the higher the probability of inverter failure occurrence. Therefore, when vehicle body resonance occurs, it is possible to effectively escape from the motor operating area where the probability of inverter failure occurrence is high, and the occurrence of inverter failure can be suppressed. In addition, it is possible to avoid deterioration of drivability by reducing the motor torque command value unnecessarily.

  According to one embodiment, the reduction amount of the motor torque command value is increased as the duration of occurrence of vehicle body resonance is longer. Even if the amount of change in the motor rotation speed due to the vehicle body resonance is small, the longer the duration, the higher the probability of occurrence of inverter failure, so that the occurrence of inverter failure can be suppressed.

  According to one embodiment, when the control mode of the inverter when the vehicle body resonance occurs is the rectangular wave control mode and the overmodulation PWM control mode, the reduction amount of the motor torque command value even if the duration of the vehicle body resonance occurrence is short As a result, the motor torque command value can be reduced early in the rectangular wave control mode and overmodulation PWM control mode, which have a high probability of inverter failure, and the occurrence of inverter failure can be reliably suppressed. Unnecessarily reducing the motor torque command value can prevent the drivability from deteriorating.

  According to one embodiment, the amount of reduction in the motor torque command value is increased as the inverter carrier frequency is higher even if the duration of vehicle body resonance occurrence is short. It is possible to reduce the motor torque command value early in the driving state, and to reliably suppress the occurrence of inverter failure, and to avoid unnecessary deterioration of the drivability by reducing the motor torque command value unnecessarily. .

  According to one embodiment, the detected value of the motor rotation angle by the rotation angle sensor is subjected to a bandpass filter process having a predetermined frequency characteristic, and the amount of change in the rotation speed of the motor is detected based on the rotation angle after the filter process. Therefore, the vehicle body resonance can be reliably detected.

  The correspondence between the constituent elements of the claims and the constituent elements of the embodiment is as follows. That is, the motor 1 and the generator 2 are motors, the rotation angle sensors 6 and 7 are rotation angle detection means, the inverters 8 and 9 are inverters, the vehicle controller 11 is rotation speed variation detection means, resonance determination means, and torque reduction means. Respectively. The above description is merely an example, and when interpreting the invention, the correspondence between the items described in the above embodiment and the items described in the claims is not limited or restricted.

  In the above-described embodiment, the sine wave PWM control mode, the overmodulation PWM control mode, and the rectangular wave control mode are described as examples of the inverter control mode. However, the control mode is the control mode of the embodiment. It is not limited. Further, the count-up amount of the resonance continuation counter according to the carrier frequency, the control mode, and the motor rotation speed change amount is not limited to the numerical values of the above-described embodiment.

The figure which shows the structure of one embodiment The flowchart which shows the torque limiting program at the time of vehicle body resonance of one embodiment FIG. 2 is a flowchart illustrating a torque limiting program at the time of occurrence of vehicle body resonance according to the embodiment, following FIG. Diagram showing motor control mode Diagram showing motor torque limit rate for resonance duration Diagram showing motor torque limit value Diagram showing user request torque limit value The figure which shows the torque limitation result at the time of resonance generation of one embodiment

Explanation of symbols

1 Motor 2 Generator 6, 7 Rotation angle sensor 8, 9 Inverter 11 Vehicle controller

Claims (9)

A rotation angle detection means for detecting the rotation angle of the traveling motor;
An inverter that drives the motor by supplying a current corresponding to the motor torque command value and the rotation angle to the motor;
A rotational speed change amount detecting means for detecting a rotational speed change amount of the motor based on the rotational angle;
Resonance determining means for determining the presence or absence of vehicle body resonance based on the amount of change in rotational speed;
Torque reduction means for reducing the motor torque command value when it is determined that vehicle body resonance has occurred ,
The inverter operates the motor in a rectangular wave control mode in the high speed region of the motor.
Drive,
When it is determined that the vehicle body resonance has occurred, the torque reducing means
The motor torque command value so that the operation area does not enter the operation area of the rectangular wave control mode.
A motor control device for a vehicle, characterized in that The vehicle motor control device according to claim 1,
The inverter has a variable carrier frequency according to the rotation speed of the motor,
The vehicle motor control apparatus, wherein the torque reduction means determines a reduction amount of the motor torque command value according to a carrier frequency of the inverter when a vehicle body resonance occurs. The vehicle motor control device according to claim 1,
The inverter switches the plurality of control modes including at least a sine wave PWM control mode and a rectangular wave control mode to drive the motor,
The vehicle motor control apparatus according to claim 1, wherein the torque reduction means determines a reduction amount of the motor torque command value in accordance with a control mode of the inverter when a vehicle body resonance occurs. The vehicle motor control device according to claim 1,
The vehicle motor control apparatus according to claim 1, wherein the torque reduction means determines a reduction amount of the motor torque command value in accordance with an amount of change in the rotation speed of the motor when a vehicle body resonance occurs. The vehicle motor control device according to claim 1,
The vehicle motor control device according to claim 1, wherein the torque reduction means increases the reduction amount of the motor torque command value as the duration of occurrence of vehicle body resonance is longer. In the vehicle motor control device according to claim 5,
The inverter switches the sine wave PWM control mode, overmodulation PWM control mode, rectangular wave control mode in order as the rotational speed of the motor increases, and drives the motor,
When the inverter control mode at the time of occurrence of vehicle body resonance is the rectangular wave control mode and the overmodulation PWM control mode, the torque reduction means is configured to set the motor torque command value even if the vehicle body resonance occurrence time is short. A vehicle motor control device characterized by increasing the amount of reduction. In the vehicle motor control device according to claim 5,
The inverter increases the carrier frequency as the rotational speed of the motor increases,
The vehicle motor control apparatus according to claim 1, wherein the torque reduction means increases the motor torque command value reduction amount as the carrier frequency of the inverter increases even if the duration of occurrence of vehicle body resonance is short. The vehicle motor control device according to claim 1,
The rotation speed change amount detection means performs a bandpass filter process having a predetermined frequency characteristic on the rotation angle detection value of the motor by the rotation angle detection means, and the rotation speed of the motor based on the rotation angle after the filter process A vehicle motor control device for detecting a change amount.   The vehicle motor control device according to claim 1,
  The inverter is
    The carrier frequency is variable according to the rotation speed of the motor,
    Driving the motor by switching a plurality of control modes including at least a sine wave PWM control mode and a rectangular wave control mode;
The torque reducing means includes
    A reduction amount of the first motor torque command value is set according to the carrier frequency of the inverter when the vehicle body resonance occurs,
    A reduction amount of the second motor torque command value is set according to the control mode of the inverter when the vehicle body resonance occurs,
    A reduction amount of the third motor torque command value is set according to the amount of change in the rotational speed of the motor when the vehicle body resonance occurs,
    Of the reduction amount of the first motor torque command value, the reduction amount of the second motor torque command value, and the reduction amount of the third motor torque command value, the reduction amount with the highest value is the final reduction amount. A vehicle motor control device characterized by determining as follows.

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