JP2013013201A - Electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable protecting of an element of a boost converter.SOLUTION: The boost converter is controlled so that the voltage VH of the drive voltage system power line becomes the set target voltage VH*, when the target voltage VH* of the drive voltage system power line set according to the drive of the motor becomes beyond the limits of twice the plus or minus α the voltage VL of the battery voltage system power line when the driving wheel slips (S130, S150). When the target voltage VH* becomes within the range of twice the plus or minus α of the voltage VL, the value exceeding the range of the twice the plus or minus α of the voltage VL is set again as the target voltage VH* and the boost converter is controlled so that the voltage VH of the drive voltage system power line becomes the reset target voltage VH* (S130-S150). As a result, when the driving wheel slips, the excessive grow of the current IL that flows to the reactor of the boost converter can be controlled and the element of the boost converter can be protected more.

Description

  The present invention relates to an electric vehicle, and more particularly, a motor connected to a motor by boosting power of a battery voltage system having a motor that inputs / outputs power to / from drive wheels, a battery, a reactor, and a switching element and to which the battery is connected. The present invention relates to an electric vehicle including a boost converter that can be supplied to the drive voltage system and a boost control unit that controls the boost converter so that the voltage of the drive voltage system becomes a target voltage according to the driving conditions of the vehicle.

  Conventionally, this type of technology includes a storage battery, a booster circuit that boosts the voltage of the storage battery, an inverter that converts the boosted DC voltage into an AC voltage, and a booster circuit that suppresses fluctuations in the boosted DC voltage. And a voltage control unit that performs closed loop control, and a response time constant of the voltage control unit is set to be equal to or greater than one cycle of the AC voltage (see, for example, Patent Document 1). In this technique, by taking a long response time constant of the closed loop control, an excessive response to the frequency fluctuation of the AC voltage is slowed down, and the ripple current of the storage battery is reduced.

JP 2010-148164 A

  In an electric vehicle including a boost converter capable of boosting electric power from a battery and supplying it to a motor, it is considered as one of important issues to protect the elements of the boost converter. In particular, when the drive wheel slips, the power consumption of the motor tends to increase due to an increase in the rotation speed of the motor, and the current flowing through the reactor of the boost converter tends to increase. It is desirable to reduce the components.

  The main object of the electric vehicle of the present invention is to protect the elements of the boost converter.

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

The electric vehicle of the present invention is
A motor that inputs / outputs power to / from the drive wheels, a battery, a reactor, and a switching element, boosts the power of a battery voltage system to which the battery is connected, and can be supplied to the drive voltage system to which the motor is connected In an electric vehicle comprising: a boost converter; and a boost control means for controlling the boost converter so that the voltage of the drive voltage system becomes a target voltage corresponding to a driving condition of the vehicle.
The step-up control means is means for controlling the step-up converter so that when the drive wheel slips, the voltage of the drive voltage system is outside a predetermined range including twice the voltage of the battery voltage system.
This is the gist.

  In the electric vehicle of the present invention, when the drive wheel slips, the boost converter is controlled so that the voltage of the drive voltage system is outside a predetermined range including twice the voltage of the battery voltage system. The magnitude ΔIL of the ripple component of the current flowing through the reactor is as follows, assuming that the voltage of the battery voltage system is VL, the voltage of the drive voltage system is VH, the inductance of the reactor is L, and the switching frequency (carrier frequency) of the switching element is fc. When the driving voltage system voltage VH is twice the battery voltage system voltage VL (when the ratio of the battery voltage system voltage VL to the driving voltage system voltage VH is 1: 2). To the maximum. As described above, when the drive wheel slips, the current flowing through the reactor tends to increase. Therefore, by controlling the boost converter so that the voltage of the drive voltage system is outside the predetermined range including twice the voltage of the battery voltage system. The voltage of the drive voltage system can be adjusted in a range where the ripple component of the current flowing through the reactor is not maximized, and the peak value of the current flowing through the reactor can be suppressed from becoming excessive. As a result, the boost converter element can be further protected. Of course, when the driving wheel is not slipping, the boost converter is not controlled so that the voltage of the driving voltage system is out of a predetermined range including twice the voltage of the battery voltage system. The voltage system power can be boosted and supplied to the drive voltage system.

  In such an electric vehicle according to the present invention, the boost control means is configured such that when the drive voltage system voltage falls within the predetermined range when the drive wheel slips, the drive voltage system voltage is higher than the target voltage and the predetermined voltage. It may be a means for controlling the boost converter to be out of range. If it carries out like this, drive control of an electric motor can be performed with a margin.

1 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 20 as an embodiment of the present invention. It is a block diagram which shows the outline of a structure of the electric drive system containing motor MG1, MG2. 5 is a flowchart showing an example of a boost control routine executed by a hybrid electronic control unit 70. It is explanatory drawing which shows the relationship between the voltage VL of the battery voltage type | system | group electric power line 54b, and the ripple component (DELTA) IL. 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. FIG. 11 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 320 of a modified example. It is a block diagram which shows the outline of a structure of the electric vehicle 420 of a modification.

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

  FIG. 1 is a configuration diagram showing an outline of the configuration of a hybrid vehicle 20 as an embodiment of the present invention. As shown in the figure, the hybrid vehicle 20 of the embodiment includes an engine 22 that uses gasoline or light oil as fuel, an engine electronic control unit (hereinafter referred to as engine ECU) 24 that controls the drive of the engine 22, and a crank of the engine 22. A planetary gear 30 having a carrier connected to the shaft 26 and a ring gear connected to a drive shaft 36 connected to drive wheels 38a and 38b via a differential gear 37, and a rotor configured as a synchronous generator motor, for example. A motor MG1 connected to the sun gear, a motor MG2 configured as a synchronous generator motor and having a rotor connected to the drive shaft 36, inverters 41 and 42 for driving the motors MG1 and MG2, an inverter 41, 42 is controlled by switching control. A motor electronic control unit (hereinafter referred to as a motor ECU) 40 for driving and controlling the motors MG1 and MG2, a battery 50 configured as, for example, a lithium ion secondary battery, and a battery electronic control unit (hereinafter referred to as a battery control unit) that manages the battery 50 Battery ECU) 52, a power line (hereinafter referred to as drive voltage system power line) 54a to which inverters 41 and 42 are connected, and a power line (hereinafter referred to as battery voltage system power line) 54b to which battery 50 is connected. The voltage VH of the drive voltage system power line 54a connected is adjusted within the range of the voltage VL of the battery voltage system power line 54b to the maximum allowable voltage VHmax, and between the drive voltage system power line 54a and the battery voltage system power line 54b. Boost converter 55 for exchanging electric power and high for controlling the entire vehicle It comprises a lid electronic control unit 70. Here, the maximum allowable voltage VHmax may be a value slightly lower than the breakdown voltage of the capacitor 57 described later.

  Each of the motor MG1 and the motor MG2 is configured as a 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. As shown in the block diagram of the electric drive system including the motors MG1 and MG2 in FIG. 2, the inverters 41 and 42 are in reverse directions to the six transistors T11 to T16 and T21 to 26 and the transistors T11 to T16 and T21 to T26. 6 diodes D11 to D16, D21 to D26 connected in parallel. Two transistors T11 to T16 and T21 to T26 are arranged in pairs so as to be on the source side and the sink side with respect to the positive and negative buses of the drive voltage system power line 54a, respectively. The three-phase coils (U-phase, V-phase, W-phase) of the motors MG1, MG2 are connected to the connection points. Therefore, the three-phase coil is controlled by controlling the ratio of the on-time of the transistors T11 to T16 and T21 to T26 that make a pair while the voltage is acting between the positive electrode bus and the negative electrode bus of the drive voltage system power line 54a. Thus, a rotating magnetic field can be formed, and the motors MG1 and MG2 can be driven to rotate. Since the inverters 41 and 42 share the positive and negative buses of the drive voltage system power line 54a, the power generated by one of the motors MG1 and MG2 can be supplied to another motor. A smoothing capacitor 57 is connected to the positive and negative buses of the drive voltage system power line 54a.

  The motor ECU 40 is configured as a microprocessor centered on a CPU (not shown), and includes a ROM, a RAM, an input / output port, and a communication port in addition to the CPU. The motor ECU 40 receives signals necessary for driving and controlling the motors MG1 and MG2, for example, the rotational positions of the rotors of the motors MG1 and MG2 from the rotational position detection sensors 43 and 44 that detect the rotational positions of the rotors of the motors MG1 and MG2. The rotational position, the phase current applied to the motors MG1 and MG2 detected by a current sensor (not shown), the inverter temperature from a temperature sensor (not shown) attached to the inverters 41 and 42, and the like are input. Switching control signals to the transistors T11 to T16 and T21 to 26 of the inverters 41 and 42 are output. The motor ECU 40 is in communication with the hybrid electronic control unit 70, controls the driving of the motors MG1 and MG2 by a control signal from the hybrid electronic control unit 70, and, if necessary, data on the operating state of the motors MG1 and MG2. Output to the hybrid electronic control unit 70. The motor ECU 40 also calculates the rotational speeds Nm1, Nm2 of the motors MG1, MG2 based on the rotational positions of the rotors of the motors MG1, MG2 from the rotational position detection sensors 43, 44.

  As shown in FIG. 2, the boost converter 55 is configured as a boost converter including two transistors T31 and T32, two diodes D31 and D32 connected in parallel to the transistors T31 and T32 in a reverse direction, and a reactor L. . The two transistors T31 and T32 are connected to the positive bus of the drive voltage system power line 54a and the negative bus of the drive voltage system power line 54a and the battery voltage system power line 54b, respectively, and the reactor L is connected to the connection point. Has been. Further, the positive terminal and the negative terminal of the battery 50 are connected to the reactor L and the negative buses of the drive voltage system power line 54a and the battery voltage system power line 54b, respectively. Therefore, by turning on and off the transistors T31 and T32, the battery voltage power line 54b is boosted and supplied to the drive voltage power line 54a, or the drive voltage power line 54a is stepped down to reduce the battery voltage. Or can be supplied to the system power line 54b. A smoothing capacitor 58 is connected to the reactor L and the negative bus of the drive voltage system power line 54a and the battery voltage system power line 54b.

  The battery ECU 52 is configured as a microprocessor centered on a CPU (not shown), and includes a ROM, a RAM, an input / output port, and a communication port in addition to the CPU. In the battery ECU 52, signals necessary for managing the battery 50, for example, voltage between terminals from a voltage sensor (not shown) installed between the terminals of the battery 50, battery voltage system power connected to the output terminal of the battery 50 A charge / discharge current from a current sensor (not shown) attached to the line 54b, a battery temperature from a temperature sensor (not shown) attached to the battery 50, and the like are input, and data on the state of the battery 50 is communicated as necessary. Output to the hybrid electronic control unit 70. Further, the battery ECU 52 calculates the remaining capacity (SOC) based on the integrated value of the charging / discharging current detected by the current sensor in order to manage the battery 50, and calculates the remaining capacity (SOC) and the battery temperature Tb. The input / output limits Win and Wout, which are the maximum allowable power that may charge / discharge the battery 50, are calculated based on the above. The input / output limits Win and Wout of the battery 50 are set to the basic values of the input / output limits Win and Wout based on the battery temperature Tb, and the output limiting correction coefficient and the input are set based on the remaining capacity (SOC) of the battery 50. It can be set by setting a correction coefficient for restriction and multiplying the basic value of the set input / output restrictions Win and Wout by the correction coefficient.

  The hybrid electronic control unit 70 is configured as a microprocessor centered on the CPU 72, and in addition to the CPU 72, a ROM 74 for storing processing programs, a RAM 76 for temporarily storing data, an input / output port and communication not shown. And a port. In the hybrid electronic control unit 70, the voltage of the capacitor 57 (the voltage of the drive voltage system power line 54 a) VH from the voltage sensor 57 a attached between the terminals of the capacitor 57 and the voltage sensor attached between the terminals of the capacitor 58. The voltage of the capacitor 58 from 58a (the voltage of the battery voltage system power line 54b) VL, the ignition signal from the ignition switch 80, the shift position SP from the shift position sensor 82 that detects the operation position of the shift lever, and the depression amount of the accelerator pedal Accelerator opening degree Acc from the accelerator pedal position sensor 84 for detecting the brake pedal position BP from the brake pedal position sensor 86 for detecting the depression amount of the brake pedal, the vehicle speed V from the vehicle speed sensor 88, etc. are input ports. Through and has been entered. From the hybrid electronic control unit 70, switching control signals to the transistors T31 and T32 of the boost converter 55 are output via an output port. As described above, the hybrid electronic control unit 70 is connected to the engine ECU 24, the motor ECU 40, and the battery ECU 52 via the communication port, and exchanges various control signals and data with the engine ECU 24, the motor ECU 40, and the battery ECU 52. ing.

  The hybrid vehicle 20 of the embodiment thus configured calculates a required torque to be output to the drive shaft 36 based on the accelerator opening Acc and the vehicle speed V corresponding to the amount of depression of the accelerator pedal by the driver, and this required torque. The engine 22, the motor MG 1, and the motor MG 2 are controlled for operation so that the required power corresponding to is output to the drive shaft 36. As the operation control of the engine 22, the motor MG1, and the motor MG2, the operation of the engine 22 is controlled so that power corresponding to the required power is output from the engine 22, and all of the power output from the engine 22 is transmitted to the planetary gear 30 and the motor MG1. The motor MG2 converts the torque of the motor MG1 and the motor MG2 so that the motor MG1 and the motor MG2 are driven and controlled, and the power suitable for the sum of the required power and the power required for charging and discharging the battery 50 is obtained. The operation of the engine 22 is controlled so as to be output from the engine 22, and all or a part of the power output from the engine 22 with charging / discharging of the battery 50 is converted by the planetary gear 30, the motor MG1, and the motor MG2. Accordingly, the required power is output to the drive shaft 36. Charge-discharge drive mode for driving and controlling the motor MG1 and the motor MG2, there is a motor operation mode in which operation control to output a power commensurate to stop the operation of the engine 22 to the required power from the motor MG2 to the drive shaft 36. Note that both the torque conversion operation mode and the charge / discharge operation mode are modes in which the engine 22 and the motors MG1, MG2 are controlled so that the required power is output to the drive shaft 36 with the operation of the engine 22. Can be considered as an engine operation mode.

  In the engine operation mode, the hybrid electronic control unit 70 sets the required torque Tr * to be output to the drive shaft 36 based on the accelerator opening Acc from the accelerator pedal position sensor 84 and the vehicle speed V from the vehicle speed sensor 88. The required power Trd required for traveling is multiplied by the set required torque Tr * and the rotational speed Nr of the drive shaft 36 (for example, the rotational speed obtained by multiplying the rotational speed Nm2 of the motor MG2 or the vehicle speed V by a conversion factor). * Is calculated and the charge / discharge required power Pb * of the battery 50 obtained based on the remaining capacity (SOC) of the battery 50 is subtracted from the calculated traveling power Pdrv * (positive value when discharging from the battery 50) The required power Pe * is set as the power to be output from the engine 22, and the required power Pe * is efficiently set to the engine 22 A target rotational speed Ne * and a target torque Te * of the engine 22 are set using an operation line (for example, a fuel efficiency optimal operation line) as a relationship between the rotational speed Ne of the engine 22 and the torque Te that can be output from A torque command Tm1 * as a torque to be output from the motor MG1 is set by the rotational speed feedback control for rotating the engine 22 at the target rotational speed Ne * within the range of the input / output limits Win and Wout of the battery 50 and the motor. A torque command Tm2 * of the motor MG2 is set by subtracting the torque acting on the drive shaft 36 via the planetary gear 30 from the required torque Tr * when the MG1 is driven with the torque command Tm1 *, and the target rotational speed Ne * and the target torque are set. Te * is transmitted to the engine ECU 24, and torque commands Tm1 * and Tm2 * are transmitted. And transmits it to the motor ECU40. The engine ECU 24 that has received the target rotational speed Ne * and the target torque Te * then controls the intake air amount and the fuel injection control in the engine 22 so that the engine 22 is operated by the target rotational speed Ne * and the target torque Te *. Perform ignition control. The motor ECU 40 that has received the torque commands Tm1 * and Tm2 * performs switching control of the transistors T11 to T16 and T21 to T26 of the inverters 41 and 42 so that the motors MG1 and MG2 are driven by the torque commands Tm1 * and Tm2 *. Do. In this engine operation mode, when the required power Pe * of the engine 22 falls below a threshold value Pstop determined to stop the engine 22 in order to efficiently operate the engine 22, the operation of the engine 22 is performed. To stop and shift to motor operation mode.

  In the motor operation mode, the hybrid electronic control unit 70 sets the required torque Tr * to be output to the drive shaft 36 based on the accelerator opening Acc and the vehicle speed V, and sets the torque command Tm1 * of the motor MG1 to the value 0. The torque command Tm2 * of the motor MG2 is set so that the required torque Tr * is output to the drive shaft 36 within the range of the input / output limits Win and Wout of the battery 50, and these are transmitted to the motor ECU 40. The motor ECU 40 that receives the torque commands Tm1 * and Tm2 * performs switching control of the transistors T11 to T16 and T21 to 26 of the inverters 41 and 42 so that the motors MG1 and MG2 are driven by the torque commands Tm1 * and Tm2 *. Do. In this motor operation mode, the required power Pe * of the engine 22 obtained by subtracting the charge / discharge required power Pb * of the battery 50 from the traveling power Pdrv * obtained by multiplying the required torque Tr * by the rotational speed Nr of the drive shaft 36. When the engine 22 reaches a threshold value Pstart which is determined to be better for starting the engine 22 in order to operate the engine 22 efficiently, the engine 22 is started to shift to the engine operation mode.

  Next, the operation of the hybrid vehicle 20 of the embodiment thus configured, particularly the control for adjusting the voltage VH of the drive voltage system power line 54a will be described. FIG. 3 is a flowchart showing an example of a boost control routine executed by the hybrid electronic control unit 70. This routine is repeatedly executed every predetermined time (for example, every several msec).

  When the boost control routine is executed, first, the CPU 72 of the hybrid electronic control unit 70 first determines the accelerator opening Acc from the accelerator pedal position sensor 84, the vehicle speed V from the vehicle speed sensor 88, the torque command Tm1 * of the motors MG1 and MG2. , Tm2 *, rotation speed Nm1, Nm2, voltage of capacitor 58 from voltage sensor 58a (voltage of battery voltage system power line 54b) VL, voltage of capacitor 57 from voltage sensor 57a (voltage of drive voltage system power line 54a) Data necessary for control, such as VH and slip determination flag F, are input (step S100). Here, the rotational speeds Nm1 and Nm2 of the motors MG1 and MG2 are input from the motor ECU 40 by communication from those calculated based on the rotational positions of the rotors of the motors MG1 and MG2 detected by the rotational position detection sensors 43 and 44. To do. Further, the torque commands Tm1 * and Tm2 * for the motors MG1 and MG2 are input as those set in the above-described drive control process. The slip determination flag F is set to a value of 0 as an initial value, set to a value of 1 when a slip occurs due to idling of the drive wheels 38a and 38b, and set to a value of 0 when the slip converges from that state. Flag. Whether or not the drive wheels 38a and 38b have slipped is determined by attaching a wheel speed sensor to the drive wheels 38a and 38b and using the rate of change of the wheel speed detected by the wheel speed sensor, or by the rotational speed of the motor MG2. It can be determined by using the rate of change of Nm2.

  When the data is thus input, the target voltage VH * of the drive voltage system power line 54a is set based on the torque commands Tm1 *, Tm2 * of the motors MG1, MG2 and the rotation speeds Nm1, Nm2 (step S110). Here, the target voltage VH * of the drive voltage system power line 54a is, in the embodiment, the voltage that can drive the motor MG1 at the target operating point (torque command Tm1 *, rotation speed Nm1) of the motor MG1 and the target operating point of the motor MG2. The larger voltage of the voltages that can drive the motor MG2 with (torque command Tm2 *, rotation speed Nm2) is set.

  Next, the value of the slip determination flag F is checked (step S120). When the slip determination flag F is 0, it is determined that no slip has occurred in the drive wheels 38a, 38b, and the transistor of the boost converter 55 is set so that the voltage VH of the drive voltage system power line 54a becomes the set target voltage VH *. Switching control of T31 and T32 is performed (step S150), and this routine is finished. In this case, since the target voltage VH * is set to a value necessary for driving the motors MG1 and MG2, by setting the voltage VH of the drive voltage system power line 54a as the target voltage VH *, the driver Can be run as required.

  On the other hand, when the slip determination flag F is a value of 1 in step S120, it is determined that slip of the drive wheels 38a, 38b has occurred, and the target voltage VH * of the drive voltage system power line 54a is set to the battery voltage system power line 54b. It is determined whether or not the voltage VL is within a range of twice plus or minus α (step S130), and the target voltage VH * of the driving voltage system power line 54a is twice or minus the voltage VL of the battery voltage system power line 54b. When it is determined that it is out of the range of α, switching control of the transistors T31 and T32 of the boost converter 55 is performed so that the voltage VH of the drive voltage system power line 54a becomes the set target voltage VH * (step S150). This routine ends. The magnitude ΔIL (hereinafter abbreviated as ripple component ΔIL) of the current IL flowing through the reactor L of the boost converter 55 when the voltage VH of the drive voltage system power line 54 a is the target voltage VH * When the inductance of the reactor L is L and the switching frequency (carrier frequency) of the transistors T31 and T32 of the boost converter 55 is fc, the calculation can be performed by the following equation (2). From this equation (2), it can be seen that the relationship between the reactor L of the battery voltage system power line 54b and the ripple component ΔIL is as shown in FIG. That is, it can be seen that the ripple component ΔIL becomes maximum when the ratio of the voltage VL of the battery voltage system power line 54b to the voltage VH of the drive voltage system power line 54a is 1: 2. When the drive wheels 38a and 38b slip, the power consumption of the motor MG2 increases due to the increase in the rotational speed Nm2 of the motor MG2, and the current IL flowing through the reactor L tends to increase. It is preferable to further suppress the ripple component ΔIL of the current IL of the reactor L. Whether or not the target voltage VH * of the drive voltage system power line 54a in step S130 is within the range of plus or minus α twice the voltage VL of the battery voltage system power line 54b is determined when the drive wheels 38a and 38b slip. This is a process for determining whether or not the ripple component ΔIL of the current IL of the reactor L is within a range that increases. Therefore, when the target voltage VH * of the drive voltage system power line 54a is outside the range of plus or minus α twice the voltage VL of the battery voltage system power line 54b, the ripple component ΔIL of the current IL of the reactor L is not in a large range. Therefore, the switching control of the transistors T31 and T32 of the boost converter 55 is performed using the target voltage VH * of the drive voltage system power line 54a set in step S110. For “α”, for example, a value of 0.05, a value of 0.1, a value of 0.15, or the like can be used.

  When it is determined in step S130 that the target voltage VH * of the drive voltage system power line 54a is within the range of plus or minus α twice the voltage VL of the battery voltage system power line 54b, the ripple component ΔIL of the current IL of the reactor L Is determined to be within a large range, the target voltage VH * of the drive voltage system power line 54a is reset (step S140), and the voltage VH of the drive voltage system power line 54a is boosted to the reset target voltage VH *. Switching control of the transistors T31 and T32 of the converter 55 is performed (step S150), and this routine is finished. Here, the resetting of the target voltage VH * of the drive voltage system power line 54a is larger than the value according to the driving of the motors MG1 and MG2 (the value set in step S110) in the embodiment, and the battery voltage system power. The voltage VL is set to be out of the range of twice plus or minus α of the voltage VL of the line 54b. Specifically, the minimum value exceeding the range of plus or minus α twice the voltage VL of the battery voltage system power line 54b is set as the target voltage VH * of the drive voltage system power line 54a by the following equation (3). . Thus, when the target voltage VH * of the drive voltage system power line 54a falls within the range of plus or minus α twice the voltage VL of the battery voltage system power line 54b when the drive wheels 38a and 38b slip, the drive voltage system power By controlling the boost converter 55 so that the target voltage VH * of the line 54a is outside the range of plus or minus α twice the voltage VL of the battery voltage system power line 54b, the current IL flowing through the reactor L becomes excessively large. Can be suppressed. As a result, the boost converter element can be further protected. In addition, the target voltage VH * to be reset is set larger than the value corresponding to the driving of the motors MG1 and MG2 (target voltage VH * set in step S110), so that there is no problem with the drive control of the motors MG1 and MG2. It does not occur.

  VH * = 2 ・ VL + α (3)

  According to the hybrid vehicle 20 of the embodiment described above, the target voltage VH * of the drive voltage system power line 54a set according to the drive of the motors MG1 and MG2 is the battery voltage system power when the drive wheels 38a and 38b slip. When the voltage VL of the line 54b is out of the range of plus or minus α twice the voltage VL, the boost converter 55 is controlled so that the voltage VH of the drive voltage system power line 54a becomes the set target voltage VH * to drive the motors MG1 and MG2. When the target voltage VH * of the drive voltage system power line 54a set accordingly falls within the range of plus or minus α of the voltage VL of the battery voltage system power line 54b plus twice the voltage VL of the battery voltage system power line 54b. The value exceeding the range of minus α is reset as the target voltage VH *, and the voltage VH of the drive voltage system power line 54a is Since the boost converter 55 is controlled so as to become the set target voltage VH *, that is, the target voltage VH * of the drive voltage system power line 54a is out of the range of plus or minus α twice the voltage VL of the battery voltage system power line 54b. Therefore, the current IL flowing through the reactor L of the boost converter 55 can be prevented from becoming excessively large, and the elements of the boost converter 55 can be further protected. In addition, since the target voltage VH * to be reset is set to a value larger than the value corresponding to the driving of the motors MG1 and MG2, there is no problem with the driving control of the motors MG1 and MG2.

  In the hybrid vehicle 20 of the embodiment, when the target voltage VH * of the drive voltage system power line 54a is within the range of plus or minus α of the voltage VL of the battery voltage system power line 54b when the drive wheels 38a and 38b slip, The value exceeding the range of twice plus or minus α of the voltage VL of the battery voltage system power line 54b is reset as the target voltage VH *, but the value of twice plus or minus α of the voltage VL of the battery voltage system power line 54b is set. A value below the range may be reset as the target voltage VH *. Further, when the target voltage VH * of the drive voltage system power line 54a falls within the range of plus or minus α twice the voltage VL of the battery voltage system power line 54b when the drive wheels 38a and 38b slip, the target voltage VH * is When the voltage is more than twice the voltage VL, the value exceeding the range of the voltage VL of the battery voltage system power line 54b plus or minus α is reset as the target voltage VH *, and the target voltage VH * is less than twice the voltage VL. In some cases, a value that is less than the range of twice plus or minus α of the voltage VL of the battery voltage system power line 54b may be reset as the target voltage VH *.

  In the hybrid vehicle 20 of the embodiment, the power from the motor MG2 is output to the drive shaft 36 connected to the drive wheels 38a and 38b. However, as illustrated in the hybrid vehicle 120 of the modification of FIG. The power from MG2 may be output to an axle (an axle connected to wheels 39a and 39b in FIG. 5) different from an axle (an axle connected to drive wheels 38a and 38b) to which drive shaft 36 is connected. .

  In the hybrid vehicle 20 of the embodiment, the power from the engine 22 is output to the drive shaft 36 connected to the drive wheels 38a and 38b via the planetary gear 30, and the power from the motor MG2 is output to the drive shaft 36. However, as illustrated in the hybrid vehicle 220 of the modification of FIG. 6, a motor MG is attached to a drive shaft connected to the drive wheels 38 a and 38 b via a transmission 230, and a rotation shaft of the motor MG is connected to a rotation shaft via a clutch 229. The engine 22 is connected, and the power from the engine 22 is output to the drive shaft via the rotating shaft of the motor MG and the transmission 230, and the power from the motor MG is output to the drive shaft via the transmission 230. It is good also as what to do. Further, as exemplified in the hybrid vehicle 320 of the modification of FIG. 7, the power from the engine 22 is output to the axle connected to the drive wheels 38a and 38b via the transmission 330 and the power from the motor MG is driven. It is good also as what outputs to the axle different from the axle connected to wheel 38a, 38b (the axle connected to wheel 39a, 39b in FIG. 7).

  In the embodiment, the present invention is applied to the hybrid vehicle 20 including the engine 22 and the motor MG1 connected to the drive shaft 36 via the planetary gear 30 and the motor MG2 connected to the drive shaft 36. As illustrated in the electric vehicle 420 of the modified example of FIG. 8, the electric vehicle 420 may be applied to a simple electric vehicle including a motor MG that outputs driving power.

  Moreover, it is not limited to such a motor vehicle, It is good also as a form of electric vehicles, such as a train, and good also as a form of the voltage control method of an electric vehicle.

  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 MG2 corresponds to the “motor”, the battery 50 corresponds to the “battery”, the boost converter 55 corresponds to the “boost converter”, and the hybrid electronic control unit 70 corresponds to the “boost control means”. To do.

  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, 120, 220, 320 Hybrid vehicle, 22 engine, 24 engine electronic control unit (engine ECU), 26 crankshaft, 30 planetary gear, 36 drive shaft, 37 differential gear, 38a, 38b drive wheel, 39a, 39b wheel, 40 motor electronic control unit (motor ECU), 41, 42 inverter, 43, 44 rotational position detection sensor, 50 battery, 52 battery electronic control unit (battery ECU), 54a drive voltage system power line, 54b battery voltage system power Line, 55 Boost converter, 57, 58 Capacitor, 57a, 58a Voltage sensor, 70 Hybrid electronic control unit, 72 CPU, 74 ROM, 76 RAM, 80 Ignition switch, 82 Shift switch Sensor, 84 accelerator pedal position sensor, 86 brake pedal position sensor, 88 vehicle speed sensor, 229 clutch, 230, 330 transmission, 420 electric vehicle, D11-D16, D21-D26, D31, D32 diode, L reactor, MG1, MG2 motor, T11 to T16, T21 to T26, T31, T32 transistors.

Claims (1)

A motor that inputs / outputs power to / from the drive wheels, a battery, a reactor, and a switching element, boosts the power of a battery voltage system to which the battery is connected, and can be supplied to the drive voltage system to which the motor is connected In an electric vehicle comprising: a boost converter; and a boost control means for controlling the boost converter so that the voltage of the drive voltage system becomes a target voltage corresponding to a driving condition of the vehicle.
The step-up control means is means for controlling the step-up converter so that when the drive wheel slips, the voltage of the drive voltage system is outside a predetermined range including twice the voltage of the battery voltage system.
Electric vehicle.

Images