JP2013153617A - Power supply system for electric vehicle and electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply system for an electric vehicle capable of instantaneously generating drive voltage of battery voltage or more without reducing output current, increasing drive torque of a motor though instantaneously, and allowing a step-up circuit to be configured simply.SOLUTION: In a circuit connecting a motor drive circuit 1 and a battery 2, a step-up circuit 5 is interposed. The step-up circuit 5 is provided with a step-up capacitor C1, is provided with a charging/step-up change-over switch SW1, a reverse current prevention diode D1, and bypass diodes D2, D3 and is configured. By switching of the charging/step-up change-over switch SW1, the capacitor C1 is charged during regular travel. If sudden acceleration is further required in a maximum output region of base rotation speed or more of the motor M, the charging/step-up change-over switch SW1 is switched to a step-up side, and the capacitor 6 and the battery 2 are brought into a series connection state.

Description

  The present invention relates to a power supply system in an in-wheel motor type or one-motor type electric vehicle, and an electric vehicle equipped with the power supply system.

  In general, the output characteristics of a driving motor in an electric vehicle are such that the torque is constant below the base rotational speed (the rotational speed at which the sum of the induced voltage peak of the motor and the driving current is equal to the power supply voltage), and if it exceeds that, The output (relationship between rotation speed and torque) is controlled to be constant.

  In the prior art, when the motor drive voltage is desired to be higher than the battery voltage, as shown in FIG. 6, a booster circuit combining a reactor 71, a semiconductor switch 72, and a smoothing capacitor 73 is used (for example, Patent Document 1). ).

Japanese Patent Laying-Open No. 2005-212659

  In an electric vehicle, there is a case where it is desired to instantaneously increase the drive torque during traveling. However, it is limited by the voltage of the battery, and the driving torque cannot be increased instantaneously beyond that. Further, even in a power supply system provided with a lifting circuit, since the conventional system has a configuration in which a reactor 71, a semiconductor switch 72, and a smoothing capacitor 73 are combined as shown in FIG. 6, the output power of a battery as an input does not change. The output current decreases and the motor drive torque cannot be increased. In addition, the configuration of the lift circuit is complicated.

  An object of the present invention is to instantaneously generate a driving voltage higher than the battery voltage without reducing the output current, to instantaneously increase the driving torque of the motor, and to make the booster circuit simple. To provide a power supply system for an electric vehicle and an electric vehicle.

  In the power supply system for an electric vehicle according to the present invention, one electrode of a boosting capacitor C1 is connected to a positive wiring 3 that connects a motor driving circuit 1 that drives a traveling motor M and a battery 2, and the capacitor C1 Is provided with a charge / step-up changeover switch SW1 for switching and connecting the other electrode to a charge-side terminal b and a boost-side terminal c. The charge-side terminal b is connected to the negative-side wiring 4 between the motor drive circuit 1 and the battery 2. The boost side terminal c is connected to the positive side wiring 3 on the motor drive circuit 1 side from the connection point 3a where the one electrode of the capacitor C1 is connected to the positive side wiring 3, and this boosting side terminal c is connected to the positive side wiring 3. A reverse current prevention diode D1 is inserted in the positive wiring 3 on the motor drive circuit 1 side further than the connection point 3b to which the side terminal c is connected, and the charging / boost switch SW1 is connected to the positive wiring 3 in front. If in the conductive state to the boost side terminal c, is provided with a diode D2, D3 for bypass to be connected in parallel with said capacitor C1.

According to this configuration, by setting the charging / boost changeover switch SW1 to a switching state in which the charging / boost changeover switch SW1 is electrically connected to the charging side terminal b, the boosting capacitor C1 is connected to the battery 2 in parallel, and the capacitor C1 is charged while the vehicle is running. Is done. In the maximum output region above the base rotational speed of the motor M, both the output voltage and current of the battery 2 are maximum values, and normally no further output is possible. When further acceleration is required in this state, the charging / boost changeover switch SW1 is switched to a conductive state with the booster side terminal c. As a result, the battery 2 and the capacitor C1 are connected in series to the motor drive circuit 1. Therefore, although it is instantaneous, the output voltage can be increased while the maximum current is secured. Although the time during which the output can be increased depends on the capacity of the capacitor C1, there are not many cases where acceleration as described above is required.
Since the reverse current prevention diode D1 is provided, it is possible to prevent a current from flowing from the motor M to the capacitor C1 due to the electromotive force of the motor M during braking rotation. Further, since the bypass diodes D2 and D3 that are connected in parallel with the capacitor C1 are provided, even if the charge of the capacitor C1 is completely consumed while the battery 2 and the capacitor C1 are connected in series, The current of the battery 2 flows to the motor M side via the bypass diode, and the capacitor C1 does not hinder the current flow.

In the present invention, a regenerative control means 12 is provided in which a semiconductor switch is provided in parallel with the reverse current prevention diode D1 inserted in the positive side wiring 3, and the semiconductor switch Q1 is turned on when the motor M is in a regenerative braking state. May be provided.
By providing the semiconductor switch Q1 in parallel with the reverse current prevention diode D1, if the semiconductor switch Q1 is turned on when the traveling motor M is in the regenerative braking state, the regenerative current from the motor M supplies the battery 2 to the battery 2. Charging becomes possible.

  In the present invention, the charge / step-up changeover switch SW1 may be constituted by semiconductor switches Q2 and Q3. In the case of the semiconductor switches Q2 and Q3, unlike the switch that opens and closes the contacts, problems such as the generation of sparks at the time of switching do not occur.

In the present invention, a charging / boost determining means 11 for determining switching of the charging / boost switching switch SW1 based on an accelerator signal of the vehicle may be provided. In this case, the charging / boost determination means 11 is in a switching state in which the charging / boost selector switch SW1 is connected to the booster side terminal c when the time change of the accelerator signal is larger than a predetermined threshold value. It may be configured as follows.
The accelerator signal is a signal generated by the driver's accelerator operation. By switching the charge / boost selector switch SW1 based on the accelerator signal, the driving torque of the motor M according to the driver's desire for acceleration is determined. Instantaneous increase is possible. In particular, when the time change of the accelerator signal is larger than the threshold value, the driver desires rapid acceleration, and the drive torque can be increased according to the request. The threshold value may be arbitrarily set. For example, a value of a time change of an accelerator signal that is considered to be likely to require unsatisfactory acceleration in a maximum output region equal to or higher than the base rotation speed of the motor M is set. To do.

  In the present invention, the capacitor C1 may be an electric double layer capacitor. The electric double layer capacitor is generally called a super capacitor. The electric double layer capacitor C1 has a large capacity, and the time during which the output can be increased can be extended.

An in-wheel motor drive system 40 according to the present invention includes a power supply system 20 for an electric vehicle having any one of the above-described configurations according to the present invention, the motor drive circuit 1, and an in-wheel motor M driven by the motor drive circuit 1. Prepare. The electric vehicle according to the present invention may include the in-wheel motor drive system 40 according to the present invention.
The in-wheel motor M does not necessarily have to be housed in the wheel. For example, the motor M, the wheel bearing 24, and the motor M are driven by the rotating side wheel of the wheel bearing 24. An in-wheel motor device 28 composed of a reduction gear 27 that transmits to the wheel may be configured, and a part or the whole of the in-wheel motor device 28 may be housed in a wheel.
According to the in-wheel motor drive system 40 and the electric vehicle equipped with the in-wheel motor of the present invention, the power supply system 20 of the present invention is provided, so that the motor M can be operated even in the maximum output region above the base rotational speed of the motor M. The drive torque can be increased instantaneously.

The one-motor type vehicle drive system 50 of the present invention includes the power supply system 20 for the electric vehicle having any one of the above-described configurations of the present invention, the motor drive circuit 1, and the motor M driven by the motor drive circuit 1. The motor M is mounted on a one-motor type vehicle. The electric vehicle according to the present invention may be provided with the one motor type vehicle drive system 50 according to the present invention.
According to the one-motor type vehicle drive system 50 and the electric vehicle equipped with the one-motor type vehicle drive system 50, the motor power supply system 20 of the present invention is provided, so that the motor can be used even in the maximum output region above the base rotational speed of the motor M. The driving torque of M can be increased instantaneously.

  In the power supply system for an electric vehicle according to the present invention, one electrode of a boosting capacitor is connected to a positive side wiring that connects a motor driving circuit that drives a traveling motor and a battery, and the other electrode of the capacitor is A charge / boost switch for switching between the charge side terminal and the boost side terminal is provided, the charge side terminal is connected to a negative side wire between the motor drive circuit and the battery, and the boost side terminal is connected to the capacitor. One electrode is connected to the positive wiring on the motor driving circuit side than the connection point connected to the positive wiring, and further to the positive wiring on the motor driving circuit side than the connection point connecting the boosting side terminal. When a reverse current prevention diode is inserted and the charge / boost changeover switch is in a conductive state with the booster side terminal in the positive wiring, the bypass is connected in parallel with the capacitor Since a diode is provided, even in the maximum output region above the base rotational speed of the motor, it is possible to instantaneously generate a drive voltage that exceeds the battery voltage without reducing the output current, and the motor drive torque cannot be instantaneously generated. However, it can be increased, and the booster circuit can be simply configured.

  According to the in-wheel motor drive system of the present invention, the electric vehicle equipped with the in-wheel motor drive system, the one-motor vehicle drive system of the present invention, and the electric vehicle equipped with the one-motor vehicle drive system, Even in the maximum output range above the base rotational speed of the motor, it is possible to instantaneously generate a drive voltage that exceeds the battery voltage without reducing the output current, and the motor drive torque can be increased instantaneously, A simple booster circuit is sufficient.

1 is an electric circuit diagram of a power supply system for an electric vehicle according to a first embodiment of the present invention. It is an electric circuit diagram of the power supply system of the electric vehicle which concerns on 2nd Embodiment of this invention. It is an electric circuit diagram of the power supply system of the electric vehicle which concerns on 3rd Embodiment of this invention. It is explanatory drawing which shows the conceptual structure of the in-wheel motor type electric vehicle carrying the power supply system. It is explanatory drawing which shows the conceptual structure of the one motor type electric vehicle carrying the power supply system. It is an electric circuit diagram of a conventional example.

  A first embodiment of the present invention will be described with reference to FIG. The electric vehicle power supply system 20 is configured by interposing a booster circuit 5 in a circuit in which a motor drive circuit 1 for driving a traveling motor M and a battery 2 are connected by a positive wiring 3 and a negative wiring 4. Is done. The booster circuit 5 is provided with a boosting capacitor C1, and a charging / boost changeover switch SW1, a reverse current prevention diode D1, and bypass diodes D2 and D3. The step-up capacitor 6 preferably has a large capacity, for example, an electric double layer capacitor. The electric double layer capacitor is generally called a super capacitor. The charge / step-up changeover switch SW1 may be of any type as long as it can be connected by switching the common terminal a to the two terminals b and c, and may be of any type such as an electromagnetic type or a semiconductor type. In this specification, the two terminals b and c are referred to as a charging side terminal b and a boosting side terminal c in this specification.

  The boosting capacitor C1 has one electrode ca connected to the positive wiring 3 at a connection point 3a, and the other electrode cb connected to the common terminal a of the charge / boost selector switch SW1. A charging side terminal b of the charging / boost changeover switch SW1 is connected to the negative side wiring 4 at a connection point 4a. The step-up terminal c is connected to the positive wiring 3 at a connection point 3b that is closer to the motor drive circuit side 1 than a connection point 3a to which the capacitor C1 is connected. The reverse current prevention diode D1 is inserted into the positive wiring 3 on the motor drive circuit side 1 further than the connection point 3b.

  The bypass diodes D2 and D3 are provided so as to be connected in parallel with the capacitor C1 when the charge / boost selector switch SW1 is in conduction with the boost side terminal c. Specifically, one bypass diode D2 is inserted into the wiring 6 connecting the connection point 3a of the positive wiring 3 and one terminal ca of the capacitor C1 in a direction in which a current flows to the capacitor C1 side. Another bypass diode D3 is connected to the wiring 7 that connects the output side terminal of the diode D2 and the connection point 3c on the motor drive circuit 1 side further than the reverse current prevention diode D1 in the positive side wiring 3. insert.

  The charge / boost changeover switch SW1 is switched by a command from the boost control circuit 8. The step-up control circuit 8 switches the charge / step-up changeover switch SW <b> 1 according to a command output from the vehicle control device 9 serving as a host control means. The vehicle control device 9 is, for example, a computer-type ECU (electric control unit) (also referred to as a VCU (vehicle control unit)) that performs integrated control, cooperative control, and the like of the entire vehicle.

  The vehicle control device 9 has charging / boosting judgment means 11 for judging switching of the charging / boost switching switch SW1 based on an accelerator signal indicating the accelerator opening from the accelerator 10 of the vehicle. A command that is the determination result is given to the boost control circuit 8. For example, the charge / boost determination means 11 switches the charge / boost switch SW1 to the boost side terminal c when the time change of the accelerator signal is larger than a predetermined threshold. The charging / boosting determination means 11 gives a command for setting a switching state in which the charging side terminal b is connected after elapse of a set time after giving a command for switching to the boosting side terminal c. This set time is, for example, a time when it is assumed that all the amount of power stored in the capacitor C1 is consumed. The boost control circuit 8 may output a command for switching to the charging side terminal b after the set time has elapsed. Further, the charging / boosting determination means 11 may be provided not in the vehicle control device 9 but in the boosting control circuit 8, and the vehicle control device 9 may output the accelerator signal to the boosting control circuit 8.

  The operation of the above configuration will be described. By setting the charging / step-up changeover switch SW1 in a switching state in which the charging / step-up changeover switch SW1 is electrically connected to the charging side terminal b, the step-up capacitor C1 is connected in parallel with the battery 2, and the capacitor C1 is charged while the vehicle is running. In the maximum output region above the base rotational speed of the motor M, both the output voltage and current of the battery 2 are maximum values, and normally no further output is possible.

  When further acceleration is required in this state, the charging / boost changeover switch SW1 is switched to a conductive state with the booster side terminal c. Thereby, the battery 2 and the capacitor C1 are connected in series to the motor drive circuit 1. Therefore, although it is instantaneous, the output voltage can be increased while the maximum current is secured. Although the time during which the output can be increased depends on the capacity of the capacitor C1, there are not many cases where acceleration as described above is required. Therefore, sufficient charging can be performed by keeping the charging state during normal driving. In particular, when the capacitor C1 is an electric double layer capacitor, since the capacitance is large, the time during which the output can be increased for acceleration required during overtaking or the like is a satisfactory time.

  Since the reverse current prevention diode D1 is provided, it is possible to prevent a current from flowing from the motor M to the capacitor C1 due to the electromotive force of the motor M during braking rotation. Further, since the bypass diodes D2 and D3 that are connected in parallel with the capacitor C1 are provided, even if the charge of the capacitor C1 is completely consumed while the battery 2 and the capacitor C1 are connected in series, The current of the battery 2 flows to the motor M side via the bypass diodes D2 and D3, and the capacitor C1 does not hinder the current flow.

  The charging / boosting switch SW1 is determined by the charging / boosting determining means 11 based on the accelerator signal of the vehicle as follows. The charge / boost determination means 11 issues a command to switch the charge / boost selector switch SW1 to the boost side terminal c when the time change of the accelerator signal is larger than a predetermined threshold value. In response to this command, the boost control circuit 8 connects the charge / boost selector switch SW1 to the switching state connected to the boost side terminal c. After this switching, the charging / boost switching switch SW1 is returned to the switching state connected to the charging side terminal b after the set time, and the capacitor C1 is again charged by the traveling of the vehicle.

  The accelerator signal is a signal generated by the driver's accelerator operation. By switching the charge / boost selector switch SW1 based on the accelerator signal, the driving torque of the motor M according to the driver's desire for acceleration is determined. Instantaneous increase is possible. In particular, when the time change of the accelerator signal is larger than the threshold value, the driver desires rapid acceleration, and the drive torque can be increased according to the request. The threshold value may be arbitrarily set. For example, a value of a time change of an accelerator signal that is considered to be likely to require unsatisfactory acceleration in a maximum output region equal to or higher than the base rotation speed of the motor M is set. To do.

  FIG. 2 shows a second embodiment. This embodiment is different from the first embodiment shown in FIG. 1 in that a semiconductor switch Q1 is provided in parallel with the reverse current prevention diode D1 inserted in the positive-side wiring 3, and the semiconductor switch is in a regenerative braking state. A regeneration control circuit 12 is provided as a regeneration control means for bringing Q1 into a conductive state. The regenerative control circuit 12 sets the semiconductor switch Q1 to the conductive state while the regenerative braking state signal is on based on the signal indicating that the regenerative braking state is output from the vehicle control device 9 to the regenerative control circuit 12. maintain.

  Thus, by providing the semiconductor switch Q1 in parallel with the reverse current prevention diode D1, if the semiconductor switch Q1 is turned on when the traveling motor M is in the regenerative braking state, the battery due to the regenerative current from the motor M is used. 2 can be charged. Other configurations and effects in this embodiment are the same as those in the first embodiment.

  FIG. 3 shows yet another embodiment. In this embodiment, in the second embodiment shown in FIG. 2, the charge / boost changeover switch SW1 is constituted by two semiconductor switches Q2 and Q3. If the semiconductor switches Q2 and Q3 are different from the contact type switches that open and close the contacts, problems such as the generation of sparks at the time of switching do not occur. Other configurations and effects in this embodiment are the same as those in the first embodiment.

  FIG. 4 shows an example of an in-wheel motor type electric vehicle provided with the power supply system 20 of the electric vehicle according to any one of the embodiments of the present invention, for example, the third embodiment shown in FIG. This electric vehicle is a four-wheeled vehicle in which the wheels 22 that are the left and right rear wheels of the vehicle body 21 are driving wheels and the wheels 23 that are the left and right front wheels are driven wheels. The front wheel 23 is a steering wheel. The left and right wheels 22 and 22 serving as driving wheels are driven by independent in-wheel motors M, respectively. The rotation of the motor M is transmitted to the wheel 22 via the reduction gear 27 and the rotation side wheel of the wheel bearing 24. The motor M, the speed reducer 27, and the wheel bearing 24 constitute an in-wheel motor device 28 that is one assembly part. The motor M is a three-phase synchronous motor, for example, an IPM type (embedded magnet type) synchronous motor. The battery 2 is used as a drive for the motor M and as a power source for the electric system of the entire vehicle.

  The control system will be described. A vehicle control device 9 that is the ECU and a plurality (two in the illustrated example) of inverter devices 32 that respectively control the motors M for traveling according to instructions from the vehicle control device 9 are mounted on the vehicle body 21. ing. The vehicle control device 9 includes a computer, a program executed on the computer, various electronic circuits, and the like. In addition, the vehicle control apparatus 9 may be comprised with the electronic circuit on a common computer and a common board | substrate with a weak electric system of each inverter apparatus 32. FIG.

  The vehicle control device 9 includes a torque distribution unit 38, the boost / charge determination unit 11, and a regenerative braking determination unit 39. The torque distribution means 38 is based on the accelerator opening signal output from the accelerator operating section 10, the deceleration command output from the brake operating section 37, and the turning command output from the steering means 35. The acceleration / deceleration command given to M is generated as a torque command value and output to each inverter device 32. In addition to the above controls, the vehicle control device 9 controls each part of the vehicle based on signals from various sensors such as a vehicle speed sensor, a load sensor, and a wheel rotation sensor (all not shown) provided in the vehicle. The function to perform.

  The inverter device 32 includes a motor drive circuit 1 and a control unit 41 that controls the motor drive circuit 1. The power supply system 20 may be provided independently of the inverter device 20 or may be provided as a part of the inverter device 32. When the power supply system 20 is a part of the inverter device 20, the single power supply system 20 may be shared by both inverter devices 32 or may be individually provided in each inverter device 32. The motor drive circuit 1 includes an inverter that converts the DC power of the battery 2 into three-phase AC power used to drive the motor M. The control unit 41 is a means for generating a current command to be a drive command for the motor drive circuit 1 composed of an inverter in accordance with a torque command value or the like commanded from the vehicle control device 9, and pulse width-modulates the generated current command, A PWM driver (not shown) that gives an on / off command to each switching element of the motor drive circuit 1 including an inverter is provided.

  The power supply system 20 is a power supply system for an electric vehicle according to any of the embodiments shown in FIGS. 1 to 3, and includes the booster circuit 5 and the booster control circuit 8 (FIGS. 1 to 3). In the case of the embodiment of FIGS. 2 and 3, the power supply system 20 further includes a regeneration control circuit 12. The regenerative control circuit 12 is controlled by a regenerative braking determination unit 32 provided in the vehicle control device 9.

  The power supply system 20, the motor drive circuit 1, and the in-wheel type motor M constitute an in-wheel motor drive system 40.

  In such an in-wheel motor drive system 40 and an in-wheel motor type electric vehicle, the power supply system 20 having the booster circuit 5 is provided, so that the motor M can be operated even in the maximum output region that is equal to or higher than the base rotation speed of the motor M. The drive torque can be increased instantaneously.

  FIG. 5 shows an example of a one-motor type electric vehicle including the electric vehicle power supply system 20 according to any one of the embodiments of the present invention. This electric vehicle is a vehicle in which wheels 22 and 22 serving as left and right drive wheels are driven by a motor M via a transmission 51 having a transmission and a differential. The motor drive circuit 1 includes an inverter that drives the motor M. The power supply system 20, the motor drive circuit 1, and the motor M constitute a one-motor vehicle drive system 50.

  In such a one-motor type vehicle drive system 50 and a one-motor type electric vehicle, the power supply system 20 having the booster circuit 5 is provided, so that the drive torque of the motor M can be increased even in the maximum output region above the base rotational speed of the motor M. It can increase instantaneously.

DESCRIPTION OF SYMBOLS 1 ... Motor drive circuit 2 ... Battery 3 ... Positive side wiring 3a, 3b, 3c ... Connection point 4 ... Negative side wiring 5 ... Booster circuit 9 ... Vehicle control apparatus 11 ... Boosting / charging judgment part 12 ... Regeneration control circuit (regeneration control) means)
DESCRIPTION OF SYMBOLS 20 ... Power supply system 28 ... In-wheel motor apparatus 32 ... Inverter apparatus 40 ... In-wheel motor drive system 50 ... One motor type vehicle drive system a ... Common terminal b ... Charge side terminal c ... Boost side terminal C1 ... Boost capacitor D1 ... Reverse current prevention diodes D2, D3 ... Bypass diode M ... Motors Q1, Q2, Q3 ... Semiconductor switch SW1 ... Charging / boost switch

Claims (10)

  Connect one electrode of the capacitor for boosting to the positive wiring that connects the battery to the motor drive circuit that drives the motor for traveling, and switch the other electrode of this capacitor between the charging side terminal and the boosting side terminal A charge / boost changeover switch to be connected, the charging side terminal is connected to a negative side wiring between the motor drive circuit and the battery, and the boosting side terminal is connected to one electrode of the capacitor to the positive side wiring The positive drive wiring is connected to the positive wiring on the motor drive circuit side from the connection point, and a reverse current prevention diode is inserted into the positive wiring on the motor drive circuit side further than the connection point to which the boost side terminal is connected. When the charge / boost selector switch is connected to the booster side terminal in the side wiring, a bypass diode that is connected in parallel with the capacitor is provided. Temu.   2. The electric motor according to claim 1, wherein a semiconductor switch is provided in parallel with the reverse current prevention diode inserted in the positive-side wiring, and regenerative control means is provided to turn on the semiconductor switch when the motor is in a regenerative braking state. Vehicle power system.   3. The power supply system for an electric vehicle according to claim 1, wherein the charge / boost changeover switch is constituted by a semiconductor switch.   4. The electric vehicle power supply system according to claim 1, further comprising charging / boosting judgment means for judging switching of the charging / boost switching switch based on an accelerator signal of the vehicle. 5.   5. The charge / boost determination means according to claim 4, wherein the charge / boost selector switch is switched to the boost side terminal when the time change of the accelerator signal is larger than a predetermined threshold. Electric vehicle power supply system.   The power supply system for an electric vehicle according to any one of claims 1 to 5, wherein the capacitor is an electric double layer capacitor.   An in-wheel motor drive system comprising the power supply system for an electric vehicle according to any one of claims 1 to 6, the motor drive circuit, and an in-wheel motor driven by the motor drive circuit.   An electric vehicle comprising the in-wheel motor drive system according to claim 7.   A power supply system for an electric vehicle according to any one of claims 1 to 6 and the motor drive circuit, and the motor driven by the motor drive circuit, the motor being a one-motor type One-motor type vehicle drive system, which is a motor mounted on the vehicle. An electric vehicle comprising the one-motor vehicle drive system according to claim 9.

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