JP2012182912A - Electric vehicle and control method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress shock which occurs upon switching the control mode of an inverter that drives a motor when the step-up of a step-up converter is restricted.SOLUTION: When regenerative braking is performed using a rectangular wave control mode while closing the gate of a step-up converter, a mode change vehicle speed Vchng for changing the control mode of an inverter from the rectangular wave control mode to a PWM control mode based on a motor torque command Tm* is determined (S110). If the mode change vehicle speed Vchng is less than a threshold Vref1 predetermined as a range possibly causing a shock in a vehicle, the step-up converter performs step-up, and the control mode is changed when the vehicle speed V goes below a threshold Vref2 which is slightly larger than the threshold Vref1 (S150, S160). Consequently, the shock which occurs when the control mode of the inverter is changed can be suppressed.

Description

  The present invention relates to an electric vehicle and a control method therefor, and more specifically, an electric motor that inputs and outputs driving power, a rechargeable secondary battery, a battery voltage system to which the secondary battery is connected, and the electric motor. The present invention relates to an electric vehicle including a boost converter that is connected to the drive voltage system and boosts the voltage of the drive voltage system to a voltage higher than the voltage of the battery voltage system, and a method for controlling such an electric vehicle.

  Conventionally, this type of electric vehicle includes a DC power supply, a boost converter that boosts the voltage of the DC power supply, and a traveling motor that is driven by using the electric power boosted by the boost converter, and the fuel consumption switch reduces fuel consumption. There has been proposed one that prohibits boosting of a boost converter when a travel instruction is accepted (see, for example, Patent Document 1). In this vehicle, when the low fuel consumption travel instruction is received by the fuel consumption switch, the boosting of the boost converter is prohibited to improve the fuel consumption.

JP 2007-159214 A

  In general, an inverter for driving a motor for traveling uses a rectangular PWM control mode based on a pulse width modulation control system that applies a pseudo three-phase AC voltage obtained by modulating a pulse width with respect to a DC voltage. Control is performed by switching between a rectangular wave control mode by a rectangular wave control method for applying a wave voltage. Since the control becomes unstable when switching between the control modes, a shock such as vibration may be generated in the vehicle depending on the number of rotations of the motor.

  The main object of the electric vehicle and the control method thereof of the present invention is to suppress a shock that may occur when switching the control mode of the inverter that drives the electric motor when the boosting of the boost converter is restricted.

  The electric vehicle and the control method thereof according to the present invention adopt the following means in order to achieve the main object described above.

The electric vehicle of the present invention is
An electric motor that inputs and outputs driving power, an inverter that drives the electric motor, a chargeable / dischargeable secondary battery, a battery voltage system to which the secondary battery is connected, and a drive voltage system to which the inverter is connected A step-up converter for boosting the voltage of the drive voltage system to a voltage higher than the voltage of the battery voltage system and transferring power between the drive voltage system and the battery voltage system,
When the boosting by the boosting converter is limited to a predetermined limit voltage, a rotation speed range that can cause a shock such as vibration to the vehicle when the rotation speed of the motor changes the control mode of the inverter. The step-up converter and the inverter are driven so as to drive the electric motor within the range of the predetermined limit voltage when the predetermined mode change necessary state where the control mode of the inverter needs to be changed within a predetermined shock speed range is not reached. When the predetermined mode change necessary state is reached, the restriction to the predetermined limit voltage is temporarily released, and the voltage of the drive voltage system is set to a voltage higher than the predetermined limit voltage. Before the rotational speed is within the shock rotational speed range, or the rotational speed of the motor is within the shock rotational speed range. And control means for controlling said inverter and the boost converter to change the control mode of the inverter after becoming an outer,
It is a summary to provide.

  In the electric vehicle according to the present invention, when the boost by the boost converter is limited to a predetermined limit voltage, if the motor speed changes the control mode of the inverter, a shock such as vibration is generated in the vehicle. A boost converter to drive the electric motor within a predetermined limit voltage range when a predetermined mode change necessary state that requires changing the control mode of the inverter within a predetermined shock speed range as a rotation speed range to be obtained has not been reached. Controls the inverter. Thereby, the fuel consumption can be improved. On the other hand, when the boost limit switch is turned on and the boost by the boost converter is limited to the predetermined limit voltage, when the predetermined mode change is necessary, the limit to the predetermined limit voltage is temporarily released. The inverter control mode is set before the motor speed is within the shock speed range with the drive voltage system voltage higher than the predetermined limit voltage or after the motor speed is outside the shock speed range. The boost converter and the inverter are controlled so as to be changed. In other words, before the motor speed falls within the shock speed range, the boost converter boosts the voltage of the drive voltage system so as to be higher than the predetermined limit voltage, or the inverter control mode is changed, or the motor speed After the rotation speed is out of the range, the voltage of the drive voltage system is boosted by the boost converter so as to be higher than the predetermined limit voltage, and the control mode of the inverter is changed. As a result, the inverter control mode is changed when the motor speed is outside the shock speed range, so the inverter control mode is changed when the motor speed is within the shock speed range. It is possible to suppress vehicle shock (shock caused by vibration or the like) that may be caused by the operation.

  In such an electric vehicle according to the present invention, the control means regeneratively controls the electric motor, and when the predetermined mode change necessary state is reached when the rotational speed of the electric motor is decreasing, the rotational speed of the electric motor is Means for controlling the boost converter and the inverter so as to change the control mode of the inverter in a state where the voltage of the drive voltage system is set to a voltage higher than the predetermined limit voltage before being in a shock rotation speed range; Or when the predetermined mode change necessary state is reached when the rotational speed of the electric motor is increasing within the shock rotational speed range by controlling the electric power of the electric motor. After the rotational speed of the electric motor is out of the shock rotational speed range with the voltage of the drive voltage system set to a voltage higher than the predetermined limit voltage A means for controlling the boost converter and the inverter to change the control mode of serial inverters may be a thing.

  In the electric vehicle of the present invention, the boost limiting switch may be a switch that prohibits boosting of the drive voltage system by the boost converter. The shock rotation speed range may be a range of a predetermined rotation speed or less.

The electric vehicle control method of the present invention includes:
An electric motor that inputs and outputs driving power, an inverter that drives the electric motor, a chargeable / dischargeable secondary battery, a battery voltage system to which the secondary battery is connected, and a drive voltage system to which the inverter is connected And a step-up converter for boosting the voltage of the drive voltage system to a voltage higher than the voltage of the battery voltage system and transferring power between the drive voltage system and the battery voltage system. There,
When the boosting by the boosting converter is limited to a predetermined limit voltage, a rotation speed range that can cause a shock such as vibration to the vehicle when the rotation speed of the motor changes the control mode of the inverter. The step-up converter and the inverter are driven so as to drive the electric motor within the range of the predetermined limit voltage when the predetermined mode change necessary state where the control mode of the inverter needs to be changed within a predetermined shock speed range is not reached. When the predetermined mode change necessary state is reached, the restriction to the predetermined limit voltage is temporarily released, and the voltage of the drive voltage system is set to a voltage higher than the predetermined limit voltage. Before the rotational speed is within the shock rotational speed range, or the rotational speed of the motor is within the shock rotational speed range. For controlling said inverter and the boost converter to change the control mode of the inverter after becoming an outer,
It is characterized by that.

  In the electric vehicle control method of the present invention, when the boosting by the boosting converter is limited to a predetermined limit voltage set in advance, if the motor rotation speed changes the control mode of the inverter, the The motor is driven within the range of the predetermined limit voltage when the predetermined mode change necessary state has arisen in which it is necessary to change the control mode of the inverter within the shock rotational speed range that is predetermined as the rotational speed range that can cause a shock. The boost converter and the inverter are controlled. Thereby, the fuel consumption can be improved. On the other hand, when the boost limit switch is turned on and the boost by the boost converter is limited to the predetermined limit voltage, when the predetermined mode change is necessary, the limit to the predetermined limit voltage is temporarily released. The inverter control mode is set before the motor speed is within the shock speed range with the drive voltage system voltage higher than the predetermined limit voltage or after the motor speed is outside the shock speed range. The boost converter and the inverter are controlled so as to be changed. In other words, before the motor speed falls within the shock speed range, the boost converter boosts the voltage of the drive voltage system so as to be higher than the predetermined limit voltage, or the inverter control mode is changed, or the motor speed After the rotation speed is out of the range, the voltage of the drive voltage system is boosted by the boost converter so as to be higher than the predetermined limit voltage, and the control mode of the inverter is changed. As a result, the inverter control mode is changed when the motor speed is outside the shock speed range, so the inverter control mode is changed when the motor speed is within the shock speed range. It is possible to suppress vehicle shock (shock caused by vibration or the like) that may be caused by the operation.

It is a block diagram which shows the outline of a structure of the electric vehicle 20 as one Example of this invention. 2 is a configuration diagram of an electric drive system centered on a motor 32 and an inverter 34. FIG. 7 is a flowchart showing an example of a regeneration-time control mode change control routine that is executed by the electronic control unit 50 when the motor 32 is regeneratively controlled using the rectangular wave control mode with the eco switch 69 turned on. . 7 is a flowchart showing an example of a power running control mode change control routine executed by the electronic control unit 50 when the motor 32 is power running controlled using the PWM control mode in a state where the eco switch 69 is turned on. It is explanatory drawing which shows an example of a mode which derives | leads-out an example of control mode relationship map at the time of regeneration, and mode change vehicle speed Vchng. It is explanatory drawing which shows an example of a mode deriving mode change vehicle speed Vchng and an example of a power running control mode relationship map. FIG. 11 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 120 according to a modification. FIG. 11 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 220 of a modified example.

  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 as an embodiment of the present invention. As shown in the figure, an electric vehicle 20 according to the embodiment includes, for example, a motor 32 that is configured as a synchronous generator motor and that can input and output power to a drive shaft 22 that is connected to drive wheels 26a and 26b via a differential gear 24. An inverter 34 for driving the motor 32, a battery 36 configured as, for example, a lithium ion secondary battery, a power line (hereinafter referred to as a high voltage system power line) 42 to which the inverter 34 is connected, and a battery 36 are connected. Connected to a power line (hereinafter referred to as a battery voltage system power line) 44 and adjusts the voltage VH of the high voltage system power line 42 within the range of the voltage VL of the battery voltage system power line 44 and the maximum allowable voltage VHmax. And a booster converter that exchanges power between the high voltage system power line 42 and the battery voltage system power line 44. It comprises a chromatography motor 40, the electronic control unit 50 that controls the whole vehicle, the. Here, as the maximum allowable voltage VHmax, a voltage that is predetermined as a voltage equal to or lower than the withstand voltage of the capacitor 46 described later can be used.

  The motor 32 is configured as a well-known synchronous generator motor including a rotor in which a permanent magnet is embedded and a stator around which a three-phase coil is wound, and generates a counter electromotive voltage with rotation. The inverter 34 is connected in parallel in the reverse direction to the transistors T11 to T16 as the six switching elements and the transistors T11 to T16 as shown in the block diagram of the electric drive system centering on the motor 32 and the inverter 34 in FIG. And six diodes D11 to D16. The transistors T11 to T16 are arranged in pairs so as to be on the source side and the sink side with respect to the positive electrode bus and the negative electrode bus of the high voltage system power line 42, and each of the connection points between the paired transistors. The three-phase coils (U-phase, V-phase, W-phase) of the motor 32 are connected to each other. Therefore, by controlling the ratio of the on-time of the transistors T11 to T16 while the voltage is applied to the inverter 34, a rotating magnetic field can be formed in the three-phase coil, and the motor 32 can be driven to rotate. A smoothing capacitor 46 is connected to the positive and negative buses of the high voltage power line 42.

  As shown in FIG. 2, the boost converter 40 is configured as a boost converter including two transistors T31 and T32, two diodes D31 and D32 connected in parallel in opposite directions to the transistors T31 and T32, and a reactor L. . The two transistors T31 and T32 are connected to the positive bus of the high voltage system power line 42 and the negative bus of the high voltage system power line 42 and the battery voltage system power line 44, respectively, and the reactor L is connected to the connection point. Has been. Further, the positive terminal and the negative terminal of the battery 36 are connected to the reactor L, the negative bus of the high voltage system power line 42 and the battery voltage system power line 44, respectively. Therefore, by turning on and off the transistors T31 and T32, the power of the battery voltage system power line 44 is boosted and supplied to the high voltage system power line 42, or the power of the high voltage system power line 42 is stepped down to reduce the battery voltage. Or can be supplied to the system power line 44. A smoothing capacitor 48 is connected to the reactor L, the negative bus of the high voltage system power line 42 and the battery voltage system power line 44.

  The electronic control unit 50 is configured as a microprocessor centered on the CPU 52, and includes a ROM 54 that stores a processing program, a RAM 56 that temporarily stores data, and an input / output port (not shown) in addition to the CPU 52. . The electronic control unit 50 is attached to the rotational position of the rotor of the motor 32 from the rotational position detection sensor 32 a that detects the rotational position of the rotor of the motor 32, or to a connection line (power line) between the motor 32 and the inverter 34. Phase current from a current sensor (not shown), voltage Vb between terminals from a voltage sensor (not shown) installed between terminals of the battery 36, current sensor (not shown) attached to a power line connected to the output terminal of the battery 36 Charge / discharge current, battery temperature from a temperature sensor (not shown) attached to the battery 36, voltage of the capacitor 46 from the voltage sensor 46a attached between terminals of the capacitor 46 (voltage of the high voltage system power line 42) VH and capacitor The voltage of the capacitor 48 from the voltage sensor 48a attached between the terminals of 48 ( The voltage of the battery voltage system power line 44) VL, the ignition signal from the ignition switch 60, the shift position SP from the shift position sensor 62 that detects the operation position of the shift lever 61, and the accelerator pedal position that detects the depression amount of the accelerator pedal 63 The accelerator opening Acc from the sensor 64, the brake pedal position BP from the brake pedal position sensor 66 for detecting the depression amount of the brake pedal 65, the vehicle speed V from the vehicle speed sensor 68, and the vicinity of the driver's seat are instructed. A switch signal ESW and the like from the eco switch 69 is input via the input port. From the electronic control unit 50, switching control signals to the transistors T11 to T16 of the inverter 34, switching control signals to the transistors T31 and T32 of the boost converter 40, and the like are output via an output port. The electronic control unit 50 also calculates the rotational speed Nm of the motor 32 based on the rotational position of the rotor of the motor 32 from the rotational position detection sensor 32a.

  The electric vehicle 20 of the embodiment configured in this way is driven and controlled by a drive control routine (not shown). As the drive control, when the switch signal ESW from the eco switch 69 is OFF, the required torque to be output to the drive shaft 22 according to the accelerator opening Acc from the accelerator pedal position sensor 64 and the vehicle speed V from the vehicle speed sensor 68. Tr * is set, the set required torque Tr * is set as a torque command Tm * to be output from the motor 32, and the motor 32 is driven at an operating point consisting of the set torque command Tm * and the rotation speed Nm. A necessary voltage is set as the target voltage VH * of the high voltage system power line 42, and the transistors T11 to T16 of the inverter 34 are switched and controlled so that the motor 32 is driven by the set torque command Tm *. The transistors T31, T3 of the boost converter 40 so that the voltage VH of 42 becomes the target voltage VH *. It is performed for switching control. On the other hand, when the switch signal ESW from the eco switch 69 is OFF, the transistors T31 and T32 of the boost converter 40 are controlled so that the transistors T31 and T32 of the boost converter 40 are gated, and the accelerator opening from the accelerator pedal position sensor 64 is opened. The required torque Tr * to be output to the drive shaft 22 is set according to the degree Acc and the vehicle speed V from the vehicle speed sensor 68, the set required torque Tr * is set as the torque command Tm * to be output from the motor 32, Switching control of the transistors T11 to T16 of the inverter 34 is performed so that the motor 32 is driven by the torque command Tm * set within the range of the voltage VL of the battery voltage system power line 44.

  Based on the rotational speed Nm of the motor 32 and the torque command Tm *, the transistors T11 to T16 of the inverter 34 are controlled by the PWM control mode when the rotational speed Nm of the motor 32 is relatively small or when the torque command Tm * is relatively small. Switching control is performed, and when the rotational speed Nm of the motor 32 is relatively large or when the torque command Tm * is relatively large, the switching control is performed in the rectangular wave control mode. The PWM control mode is a PWM signal as a pseudo three-phase AC voltage generated by converting a sinusoidal output voltage command value 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. 34 is a control mode in which the transistors T11 to T16 are switched, and the rectangular wave control mode is a control mode in which the transistors T11 to T16 of the inverter 34 are switched with a rectangular wave voltage having a voltage phase corresponding to the torque command. As characteristics of the motor 32 and the inverter 34, the PWM control mode has better output response and controllability of the motor 32 than the rectangular wave control mode, the outputable torque is reduced, the switching loss of the inverter 34, etc. Since it is known that the output loss of the motor 32 increases, the output response and controllability of the motor 32 can be improved by controlling the inverter 34 using the PWM control mode in the region of low rotation speed and low torque. In the high rotation speed and high torque region, controlling the inverter 34 using the rectangular wave control mode makes it possible to output a larger torque and reduce losses such as switching loss of the inverter 34.

  Next, the operation of the electric vehicle 20 of the embodiment configured as described above, particularly the operation when changing the control mode of the inverter 34 when the eco switch 69 is turned on will be described. As described above, when the eco switch 69 is on, the transistors T31 and T32 of the boost converter 40 are gate-cut off, so that the voltage VL of the battery voltage system power line 44 is supplied to the inverter 34 (high voltage system power line 42). The motor 32 is driven and controlled by the voltage VL of the battery voltage system power line 44. Therefore, the control mode of the inverter 34 is changed between the PWM control mode and the rectangular wave control mode in a state where the rotational speed Nm of the motor 32 and the torque command Tm * are relatively small. Note that the switching loss of the transistors T31 and T32 of the boost converter 40 can be reduced by shutting off the gates of the transistors T31 and T32 of the boost converter 40 when the eco switch 69 is on, and the inverter 43 is switched to the rectangular wave control mode. The switching loss of the inverter 34 can be reduced by increasing the frequency of use and control.

  FIG. 3 shows an example of a regenerative control mode change control routine executed by the electronic control unit 50 when the motor 32 is regeneratively controlled using the rectangular wave control mode with the eco switch 69 turned on. FIG. 4 is a flowchart of a power running control mode change control routine executed by the electronic control unit 50 when the motor 32 is power running controlled using the PWM control mode with the eco switch 69 turned on. It is a flowchart which shows an example. First, the control when changing the control mode when the motor 32 is regeneratively controlled using the rectangular wave control mode with the eco switch 69 turned on will be described with reference to FIG. 4 and control when changing the control mode when the power control of the motor 32 is performed using the PWM control mode in a state where the eco switch 69 is turned on. Note that when the motor 32 is regeneratively controlled using the rectangular wave control mode, the control mode is changed when the driver depresses the brake pedal 65 during traveling and the motor is operated using the rectangular wave control mode. It is possible to assume a state of switching from the rectangular wave control mode to the PWM control mode when the rotational speed Nm (vehicle speed V) of the motor 32 is reduced by the braking force, and the PWM control mode is used. In order to change the control mode when the motor 32 is in the power running control, the driver 32 depresses the accelerator pedal 63 when the vehicle is stopped or at a low vehicle speed, so that the motor 32 is controlled by using the PWM control mode ( Acceleration torque is output), and after that, the speed Nm (vehicle speed V) of the motor 32 increases due to acceleration. Thus it is possible to assume a state of switching from the PWM control mode to the rectangular wave control mode.

  When the regenerative control mode change control routine of FIG. 3 is executed, the CPU 52 of the electronic control unit 50 first inputs the torque command Tm * of the motor 32 and the vehicle speed V (step S100), and the motor at the time of regenerative control. A mode change vehicle speed Vchng that requires a change from the rectangular wave control mode to the PMW control mode based on the regenerative control mode relationship map showing the relationship between the torque Tm, the vehicle speed V, and the control mode and the torque command Tm *. Set (step S110). FIG. 5 shows an example of the regenerative control mode relationship map. As shown by the broken line in FIG. 5, the mode change vehicle speed Vchng can be derived from the map and the torque command Tm *.

  When the mode change vehicle speed Vchng is thus set, it is determined whether or not the mode change vehicle speed Vchng is less than the threshold value Vref1 (step S120). Here, the threshold value Vref1 is a vehicle speed corresponding to the upper limit number of rotations of the rotation number range of the motor 32 that is determined as being able to cause a shock such as vibration when the vehicle is changed from the rectangular wave control mode to the PWM control mode. It can be determined by experiment. When it is determined that the mode change vehicle speed Vchng is equal to or higher than the threshold value Vref1, the vehicle is shocked even if the control mode is changed from the rectangular wave control mode to the PWM control mode when the vehicle speed V reaches less than the mode change vehicle speed Vchng. When it is determined that the vehicle speed V has become less than the mode change vehicle speed Vchng (step S130), the control mode is changed from the rectangular wave control mode to the PWM control mode (step S160), and this routine is terminated.

  When it is determined in step S120 that the mode change vehicle speed Vchng is less than the threshold value Vref1, the vehicle is shocked when the control mode is changed from the rectangular wave control mode to the PWM control mode when the vehicle speed V reaches less than the mode change vehicle speed Vchng. It is determined that this may occur, the gate cutoff of the transistors T31 and T32 of the boost converter 40 is released, and boosting is performed according to the rotational speed Nm of the motor 32 and the torque command Tm * (step S140), and the vehicle speed V is determined from the threshold value Vref1. When the value slightly falls below the threshold value Vref2 (step S150), the control mode is changed from the rectangular wave control mode to the PWM control mode (step S160), and this routine ends. Here, the boosting by the boosting converter 40 in step S140 is preferably a boosting up to a voltage that can be controlled using the PWM control mode when the vehicle speed V is the threshold value Vref2. As the threshold value Vref2, for example, a value larger than the threshold value Vref1 by 5 km / h or 10 km / h can be used. In this way, by controlling the inverter 34 by setting the vehicle speed V, which is boosted by the boost converter 40, to change from the rectangular wave control mode to the PWM control mode to a threshold value Vref2 that is less than the threshold value Vref1 and greater than a range that can cause a shock to the vehicle. Shock that may occur when switching modes can be suppressed.

  When the power running control mode change control routine of FIG. 4 is executed, the CPU 52 of the electronic control unit 50 first inputs the torque command Tm * of the motor 32 and the vehicle speed V (step S200), and the motor during power running control. A mode change vehicle speed Vchng that requires a change from the PWM control mode to the rectangular wave control mode based on the power running control mode relationship map showing the relationship between the torque Tm of 32, the vehicle speed V, and the control mode and the torque command Tm *. Set (step S210). FIG. 6 shows an example of the power running control mode relationship map. As shown by the broken line in FIG. 6, the mode change vehicle speed Vchng can be derived from the map and the torque command Tm *.

  When the mode change vehicle speed Vchng is thus set, it is determined whether or not the mode change vehicle speed Vchng is less than the above-described threshold value Vref1 (step S220), and when it is determined that the mode change vehicle speed Vchng is equal to or greater than the threshold value Vref1, the vehicle speed V When the vehicle speed reaches the mode change vehicle speed Vchng or higher, it is determined that no shock will occur to the vehicle even if the control mode is changed from the PWM control mode to the rectangular wave control mode, and the vehicle speed V reaches the mode change vehicle speed Vchng or higher. (Step S230), the control mode is changed from the PWM control mode to the rectangular wave control mode (Step S260), and this routine is finished.

  When it is determined in step S220 that the mode change vehicle speed Vchng is less than the threshold value Vref1, the vehicle is shocked when the control mode is changed from the PWM control mode to the rectangular wave control mode when the vehicle speed V reaches the mode change vehicle speed Vchng or higher. It is determined that this can occur, the gate cutoff of the transistors T31 and T32 of the boost converter 40 is released, and boosting is performed according to the rotational speed Nm of the motor 32 and the torque command Tm * (step S240), and the vehicle speed V is determined from the threshold value Vref1. When a slightly larger threshold value Vref3 is reached (step S250), the control mode is changed from the PWM control mode to the rectangular wave control mode (step S260), and this routine is terminated. Here, the boosting by the boosting converter 40 in step S240 is preferably boosted to a voltage that allows the motor 32 to be controlled using the PWM control mode with the torque command Tm * when the vehicle speed V is the threshold value Vref3. The threshold value Vref3 can be, for example, a value larger by 5 km / h or 10 km / h than the threshold value Vref1, and may be the same as or different from the threshold value Vref2. In this way, the vehicle speed V boosted by the boost converter 40 and changed from the PWM control mode to the rectangular wave control mode is set to the threshold value Vref3 larger than the range in which the vehicle can be shocked from less than the threshold value Vref1, thereby controlling the control mode of the inverter 34. The shock that may occur when switching between can be suppressed.

  According to the electric vehicle 20 of the embodiment described above, regenerative control is performed using the rectangular wave control mode in a state where the transistors T31 and T32 of the boost converter 40 are shut off by turning on the eco switch 69. Sometimes, the mode change vehicle speed Vchng for changing the control mode of the inverter 34 from the rectangular wave control mode to the PWM control mode is obtained based on the rotational speed Nm of the motor 32 and the torque command Tm *, and the mode change vehicle speed Vchng shocks the vehicle. When it is less than a predetermined threshold value Vref1 as a range that can be generated, the gate cut-off of the transistors T31 and T32 of the boost converter 40 is released, and boosting according to the rotational speed Nm of the motor 32 and the torque command Tm * is performed. When V reaches a threshold value Vref2 slightly larger than the threshold value Vref1, The control mode by changing from the rectangular wave control mode to the PWM control mode, the shock that may occur when changing the control mode of inverter 34 can be suppressed to. Further, when the power running control is performed using the PWM control mode in a state where the gates of the transistors T31 and T32 of the boost converter 40 are turned off by turning on the eco switch 69, the rotational speed Nm of the motor 32 and the torque command Tm. * Based on the above, a mode change vehicle speed Vchng for changing the control mode of the inverter 34 from the PWM control mode to the rectangular wave control mode is obtained, and the mode change vehicle speed Vchng is less than a predetermined threshold Vref1 as a range in which the vehicle can be shocked. In this case, the gates of the transistors T31 and T32 of the boost converter 40 are released, and the boost is performed according to the rotational speed Nm of the motor 32 and the torque command Tm *, so that the vehicle speed V reaches a threshold Vref3 that is slightly larger than the threshold Vref1. When the control mode is By changing the wave control mode, the shock that may occur when changing the control mode of inverter 34 can be suppressed.

  In the electric vehicle 20 of the embodiment, the mode change vehicle speed Vchng for changing the control mode of the inverter 34 is obtained based on the rotational speed Nm of the motor 32 and the torque command Tm *, and the mode change vehicle speed Vchng can cause a shock to the vehicle. Although it is determined whether or not the range is less than a predetermined threshold value Vref1, the rotational speed of the motor 32 that changes the control mode of the inverter 34 based on the rotational speed Nm of the motor 32 and the torque command Tm *. (Mode change rotational speed Nchng) may be obtained, and it may be determined whether or not the mode change rotational speed Nchng is less than a predetermined threshold Nref1 as a rotational speed range of the motor 32 that can cause a shock to the vehicle. In this way, the vehicle speed V can be replaced with the rotational speed Nm of the motor 32 because the vehicle speed V is obtained by multiplying the rotational speed Nm of the motor 32 by a gear ratio such as the differential gear 24 from the configuration of the electric vehicle 20 of FIG. Because it matches. Note that the cause of the shock such as the vibration of the vehicle is that the rotational speed Nm of the motor 32 falls within the rotational speed range corresponding to less than the threshold value Vref1, so that the control is performed by the rotational speed Nm of the motor 32 rather than the vehicle speed V. Is considered essential.

  In the electric vehicle 20 of the embodiment, the mode change vehicle speed Vchng for changing the control mode of the inverter 34 is obtained based on the rotational speed Nm of the motor 32 and the torque command Tm *, and the mode change vehicle speed Vchng can cause a shock to the vehicle. It is determined whether or not the range is less than a predetermined threshold value Vref1, but the rotation speed range of the motor 32 that can cause a shock to the vehicle is not less than the rotation speed corresponding to the threshold value Vref1, and from the value 0 When determined by the large lower limit rotational speed and the upper limit rotational speed, it is determined whether or not the mode change vehicle speed Vchng is within a range determined by the lower limit threshold corresponding to the lower limit rotational speed and the upper limit threshold corresponding to the upper limit rotational speed. It should be. In this case as well, the determination may be based on the rotation speed Nm of the motor 32 instead of the vehicle speed V. That is, the rotation speed (mode change speed Nchng) of the motor 32 that changes the control mode of the inverter 34 is obtained based on the rotation speed Nm of the motor 32 and the torque command Tm *, and the mode change speed Nchng shocks the vehicle. It is also possible to determine whether or not it is within a range determined by the lower limit rotation speed and the upper limit rotation speed of the motor 32 that can be generated.

  In the hybrid vehicle 20 of the embodiment, when the eco switch 69 is turned on, the gates of the transistors T31 and T32 of the boost converter 40 are cut off. However, when the eco switch 69 is turned on, the boosting by the boost converter 40 is performed. May be limited to a predetermined voltage as a voltage between the maximum allowable voltage VHmax and the voltage VL of the battery voltage system power line 44, for example, a voltage calculated by VL + (Vmax−VL) / 5. Good.

  In the hybrid vehicle 20 of the embodiment, the gates of the transistors T31 and T32 of the boost converter 40 are cut off when the eco switch 69 is turned on, but the eco switch 69 is not provided and the vehicle runs at a relatively low vehicle speed. In normal driving where relatively rapid acceleration is not required, the transistors T31 and T32 of the inverter 40 are shut off, and boosting by the boost converter 40 is performed between the maximum allowable voltage VHmax and the battery voltage system power line 44. The voltage may be limited to a predetermined voltage as a voltage between the voltages VL, for example, a voltage calculated by VL + (Vmax−VL) / 5.

  In the embodiment, the present invention is applied to the electric vehicle 20 including the motor 32 that can input and output power to the drive shaft 22 connected to the drive wheels 26a and 26b and the inverter 34 for driving the motor 32. As illustrated in the hybrid vehicle 120 of the modified example of FIG. 7, an engine 122 and a motor 124 connected to the drive shaft 22 via a planetary gear mechanism 126, a motor 32 capable of inputting and outputting power to the drive shaft 22, The motor 32 may be applied to the hybrid vehicle 120 including the motor 32, and the motor 32 is attached to the drive shaft 22 and the rotation shaft of the motor 32 is connected to the rotation shaft of the motor 32 via the clutch 229 as illustrated in the hybrid vehicle 220 of the modified example of FIG. The engine 122 is connected, and the power from the engine 122 is output to the drive shaft 22 through the rotation shaft of the motor 32. It may alternatively be applied to a hybrid vehicle 220 for outputting power from the motor 32 to the drive shaft 22 as well as.

  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 the “electric motor”, the inverter 34 corresponds to the “inverter”, the battery 36 corresponds to the “secondary battery”, the boost converter 40 corresponds to the “boost converter”, the eco switch 69 corresponds to a “boost limit switch”, and when the eco-switch 69 is turned on, the transistors T31 and T32 of the boost converter 40 are gate-blocked and regenerative control is performed using the rectangular wave control mode. Based on the rotational speed Nm of the motor 32 and the torque command Tm *, a mode change vehicle speed Vchng for changing the control mode of the inverter 34 from the rectangular wave control mode to the PWM control mode is obtained, and the mode change vehicle speed Vchng causes a shock to the vehicle. When the obtained range is less than a predetermined threshold value Vref1, the traffic of the boost converter 40 is reduced. When the gate cut-off of the registers T31 and T32 is released, the pressure is increased according to the rotational speed Nm of the motor 32 and the torque command Tm *, and the control mode is rectangular when the vehicle speed V is less than the threshold value Vref2 slightly larger than the threshold value Vref1. The regenerative control mode change control routine shown in FIG. 3 for changing from the wave control mode to the PWM control mode is executed, and the PWM switch 69 is turned on so that the transistors T31 and T32 of the boost converter 40 are turned off. When the power running control is performed using the control mode, the mode change vehicle speed Vchng for changing the control mode of the inverter 34 from the PWM control mode to the rectangular wave control mode is obtained based on the rotational speed Nm of the motor 32 and the torque command Tm *. As a range in which the mode change vehicle speed Vchng can cause a shock to the vehicle, When the threshold value Vref1 is less than the predetermined threshold value Vref1, the gate cut-off of the transistors T31 and T32 of the boost converter 40 is released to boost the motor 32 in accordance with the rotational speed Nm and the torque command Tm *, and the vehicle speed V is slightly lower than the threshold value Vref1. The electronic control unit 50 that executes the power running control mode change control routine of FIG. 4 that changes the control mode from the PWM control mode to the rectangular wave control mode when the threshold value Vref3 is greater than or equal to the large threshold value Vref3 corresponds to the “control means”.

  Here, the “motor” is not limited to the motor 32 configured as a synchronous generator motor, but may be any type as long as it can input and output power to the axle and generate a back electromotive force with rotation. It may be an electric motor. The “inverter” is not limited to the inverter 34, and any type of inverter may be used as long as the motor is driven by switching of a plurality of switching elements. The “secondary battery” is not limited to the battery 36 configured as a lithium ion secondary battery, and any type of secondary battery such as a nickel hydride secondary battery, a nickel cadmium secondary battery, or a lead storage battery may be used. It does not matter. The “boost converter” is not limited to the boost converter 40, and the voltage of the drive voltage system is connected to the battery voltage system to which the secondary battery is connected and the drive voltage system to which the inverter is connected. Any device may be used as long as the voltage is boosted to a voltage higher than the system voltage and power is transferred between the drive voltage system and the battery voltage system. As the “control means”, when the regenerative control is performed using the rectangular wave control mode with the transistors T31 and T32 of the boost converter 40 being turned off by turning on the eco switch 69, the rotation of the motor 32 is performed. Based on the number Nm and the torque command Tm *, a mode change vehicle speed Vchng for changing the control mode of the inverter 34 from the rectangular wave control mode to the PWM control mode is obtained, and a range in which the mode change vehicle speed Vchng can cause a shock to the vehicle in advance. When the threshold value Vref1 is less than the predetermined threshold value Vref1, the gate cut-off of the transistors T31 and T32 of the boost converter 40 is released to boost the motor 32 in accordance with the rotational speed Nm and the torque command Tm *, and the vehicle speed V is slightly lower than the threshold value Vref1. When the threshold value is less than the large threshold Vref2, the control mode is a rectangular wave. The regenerative control mode change control routine shown in FIG. 3 for changing from the control mode to the PWM control mode is executed, and the PWM control is performed in a state where the transistors T31 and T32 of the boost converter 40 are shut off when the eco switch 69 is turned on. When the power running control is performed using the mode, the mode change vehicle speed Vchng for changing the control mode of the inverter 34 from the PWM control mode to the rectangular wave control mode is obtained based on the rotational speed Nm of the motor 32 and the torque command Tm *. When the mode change vehicle speed Vchng is less than a predetermined threshold value Vref1 as a range in which the vehicle can be shocked, the gate cutoff of the transistors T31 and T32 of the boost converter 40 is released, and the rotational speed Nm of the motor 32 and the torque command Tm * And the vehicle speed V is set to the threshold value Vref. 4 is not limited to executing the power running control mode change control routine of FIG. 4 for changing the control mode from the PWM control mode to the rectangular wave control mode when the threshold value Vref3 or more is reached. Based on the rotation speed Nm and the torque command Tm *, the rotation speed (mode change rotation speed Nchng) of the motor 32 that changes the control mode of the inverter 34 is obtained, and the mode change rotation speed Nchng can cause a shock to the vehicle. Of the motor 32 that determines whether or not the rotation speed range is less than a predetermined threshold Nref1 or changes the control mode of the inverter 34 based on the rotation speed Nm of the motor 32 and the torque command Tm *. Obtain the speed (mode change speed Nchng) and the mode change speed Nchng will shock the vehicle. When it is determined whether it is within a range determined by the lower limit rotation speed and the upper limit rotation speed of the motor 32 that can be generated, or when the eco switch 69 is turned on, boosting by the boost converter 40 is performed at the maximum allowable voltage. The boost limit switch is turned on such that the voltage between the voltage VHmax and the voltage VL of the battery voltage system power line 44 is limited to a predetermined voltage. When the motor speed is limited, changing the inverter control mode changes the inverter control mode within a predetermined shock speed range that can cause a shock such as vibration to the vehicle. When the required mode change required condition is not reached, the motor is driven within the specified limit voltage range. The motor is controlled in such a way that the boost converter and the inverter are controlled so that when the predetermined mode change is necessary, the restriction up to the predetermined limit voltage is temporarily released and the voltage of the drive voltage system is set to a voltage higher than the predetermined limit voltage. Any device that controls the boost converter and the inverter so as to change the control mode of the inverter before the rotational speed of the motor is within the shock rotational speed range or after the rotational speed of the motor is out of the shock rotational speed range. It does n’t matter.

  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 problem is the same as that of the embodiment described in the column of means for solving the problem. Therefore, the elements of the invention described in the column of means for solving the problems are not limited. That is, the interpretation of the invention described in the column of means for solving the problems should be made based on the description of the column, and the examples are those of the invention described in the column of means for solving the problems. It is only a specific example.

  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 electric vehicles.

  20 electric vehicle, 22 drive shaft, 24 differential gear, 26 battery, 26a, 26b drive wheel, 32 motor, 32a rotational position detection sensor, 34 inverter, 36 battery, 40 boost converter, 42 high voltage system power line, 44 battery voltage System power line, 46 capacitor, 46a voltage sensor, 48 capacitor, 48a voltage sensor, 50 electronic control unit, 52 CPU, 54 ROM, 56 RAM, 60 ignition switch, 61 shift lever, 62 shift position sensor, 63 accelerator pedal, 64 Accelerator pedal position sensor, 65 Brake pedal, 66 Brake pedal position sensor, 68 Vehicle speed sensor, 120, 220 Hybrid vehicle, 122 Engine, 124 Motor, 12 Planetary gear mechanism 229 clutch, D11-D16, D31, D32 diodes, L reactor, T11 to T16, T31, T32 transistor.

Claims (6)

An electric motor that inputs and outputs driving power, an inverter that drives the electric motor, a chargeable / dischargeable secondary battery, a battery voltage system to which the secondary battery is connected, and a drive voltage system to which the inverter is connected A step-up converter for boosting the voltage of the drive voltage system to a voltage higher than the voltage of the battery voltage system and transferring power between the drive voltage system and the battery voltage system,
When the boosting by the boosting converter is limited to a predetermined limit voltage, a rotation speed range that can cause a shock such as vibration to the vehicle when the rotation speed of the motor changes the control mode of the inverter. The step-up converter and the inverter are driven so as to drive the electric motor within the range of the predetermined limit voltage when the predetermined mode change necessary state where the control mode of the inverter needs to be changed within a predetermined shock speed range is not reached. When the predetermined mode change necessary state is reached, the restriction to the predetermined limit voltage is temporarily released, and the voltage of the drive voltage system is set to a voltage higher than the predetermined limit voltage. Before the rotational speed is within the shock rotational speed range, or the rotational speed of the motor is within the shock rotational speed range. And control means for controlling said inverter and the boost converter to change the control mode of the inverter after becoming an outer,
An electric vehicle comprising: The electric vehicle according to claim 1,
The control means regeneratively controls the motor, and when the predetermined mode change necessary state is reached when the rotational speed of the motor is decreasing, before the rotational speed of the motor falls within the shock rotational speed range. Means for controlling the boost converter and the inverter to change the control mode of the inverter in a state where the voltage of the drive voltage system is higher than the predetermined limit voltage.
Electric vehicle. The electric vehicle according to claim 1 or 2,
The control means performs power running control of the electric motor, and when the predetermined mode change necessary state is reached when the rotational speed of the electric motor increases within the shock rotational speed range, the voltage of the drive voltage system is Means for controlling the boost converter and the inverter so as to change the control mode of the inverter after the rotational speed of the motor is outside the shock rotational speed range as a voltage higher than a predetermined limit voltage;
Electric vehicle. An electric vehicle according to any one of claims 1 to 3,
The boost limiting switch is a switch that prohibits boosting of the drive voltage system by the boost converter.
Electric vehicle. An electric vehicle according to any one of claims 1 to 4,
The shock speed range is a range equal to or lower than a predetermined speed.
Electric vehicle. An electric motor that inputs and outputs driving power, an inverter that drives the electric motor, a chargeable / dischargeable secondary battery, a battery voltage system to which the secondary battery is connected, and a drive voltage system to which the inverter is connected And a step-up converter for boosting the voltage of the drive voltage system to a voltage higher than the voltage of the battery voltage system and transferring power between the drive voltage system and the battery voltage system. There,
When the boosting by the boosting converter is limited to a predetermined limit voltage, a rotation speed range that can cause a shock such as vibration to the vehicle when the rotation speed of the motor changes the control mode of the inverter. The step-up converter and the inverter are driven so as to drive the electric motor within the range of the predetermined limit voltage when the predetermined mode change necessary state where the control mode of the inverter needs to be changed within a predetermined shock speed range is not reached. When the predetermined mode change necessary state is reached, the restriction to the predetermined limit voltage is temporarily released, and the voltage of the drive voltage system is set to a voltage higher than the predetermined limit voltage. Before the rotational speed is within the shock rotational speed range, or the rotational speed of the motor is within the shock rotational speed range. For controlling said inverter and the boost converter to change the control mode of the inverter after becoming an outer,
An electric vehicle control method characterized by the above.

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