JP2014241662A - Power supply for electric vehicles - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply for electric vehicles capable of moving a vehicle by driving a traveling motor with power of a weak-electricity battery in a case where a strong-electricity battery is over-discharged or abnormal.SOLUTION: Power is fed from a weak-electricity battery 15 to an inverter 13 via a bidirectional dc-to-dc converter 16 in order to drive a traveling motor 14 and travel a vehicle. The bidirectional dc-to-dc converter 16 steps down the power of a strong-electricity battery 11 and feeds the resultant power to the weak-electricity battery 15. In addition, the bidirectional dc-to-dc converter 16 steps up the power of the weak-electricity battery 15 and feeds the resultant power to the inverter 13. In an emergency evacuation mode, a control unit 20 turns off a relay 12, controls the bidirectional dc-to-dc converter 16 so as to step up the power of the weak-electricity battery 15, and feeds the resultant power to the inverter 13 so as to activate the inverter 13.

Description

  The present invention relates to a power supply device for an electric vehicle that drives a vehicle by supplying electric power from a high-power battery to an inverter via a relay and rotating a driving motor.

  A conventional electric vehicle power supply device of this type is described in Patent Document 1, for example. In this electric vehicle power supply device, a vehicle is driven by turning on a relay, supplying electric power from a high-voltage battery to the inverter via the relay, and rotating a traveling motor. In addition, this electric vehicle power supply device supplies power to the converter from the high-power battery via a relay, steps down the voltage by the converter, and charges the low-power battery with the power from the high-power battery. Is supplying power.

JP 2004-135390 A

  In a power supply device for an electric vehicle, if the high-power battery is overdischarged (electricity shortage), the vehicle cannot travel. For example, if the vehicle stops at an intersection or the like, the traffic flow will be disturbed. Therefore, in the electric vehicle power supply device described in Patent Document 1, it has been proposed to transmit the power of the low-power battery to the high-power battery and transmit the power to the inverter / motor after the voltage of the high-power battery rises.

  However, in Patent Document 1, since the high-power battery has a large capacity, even if the power from the low-power battery is charged, the voltage rise is very small. It was difficult and the vehicle could not be evacuated.

  The subject of this invention is providing the power supply device for electric vehicles which can drive a motor for driving | running | working with the electric power of a weak electric battery, and can move a vehicle in the case of an overdischarge or abnormality of a high electric battery.

  In the present invention, electric power is supplied from a low-power battery to an inverter via a bidirectional DCDC converter to drive a traveling motor to travel the vehicle. The bi-directional DCDC converter steps down the power of the high power battery and supplies it to the weak battery, and boosts the power of the light battery and supplies it to the inverter. In the emergency evacuation mode, the control unit turns off the relay and controls the bidirectional DCDC converter to boost the power of the low-power battery and supply it to the inverter to operate the inverter.

  According to the present invention, in the emergency evacuation mode, the control unit turns off the relay and controls the bidirectional DCDC converter to boost the power of the low-power battery and supply it to the inverter to operate the inverter. Therefore, when the high-power battery is overdischarged or abnormal, the vehicle can be moved by driving the driving motor with the power of the low-power battery.

1 is a configuration block diagram illustrating a power supply device for an electric vehicle according to a first embodiment of the present invention. It is a flowchart which shows operation | movement of the power supply device for electric vehicles of the 1st Embodiment of this invention. It is a block diagram which shows the power supply device for electric vehicles of the 2nd Embodiment of this invention. It is a flowchart which shows operation | movement of the power supply device for electric vehicles of the 2nd Embodiment of this invention. It is a block diagram which shows the power supply device for electric vehicles of the 3rd Embodiment of this invention. It is a figure which shows the output characteristic of the inverter in the power supply device for electric vehicles of the 3rd Embodiment of this invention.

  Hereinafter, a power supply device for an electric vehicle according to an embodiment of the present invention will be described in detail with reference to the drawings.

(First embodiment)
FIG. 1 is a block diagram showing a configuration of an electric vehicle power supply device according to a first embodiment of the present invention. A power supply device for an electric vehicle shown in FIG. 1 includes a high-power battery 11, a relay 12, an inverter 13, a traveling motor 14, a low-power battery 15, a bidirectional DCDC converter 16, an instrument equipment 17, an electric unit 18, and voltage sensors 19, 19a. The controller 20 includes an emergency evacuation switch 21 and an emergency evacuation indicator 22.

  The high-power battery 11 is a lithium ion battery or a nickel metal hydride battery that stores electric power at a voltage of 100 V to 500 V, and is used to drive the traveling motor 14. The relay 12 is connected to the high-power battery 11 and the inverter 13 and is turned on or off by a signal from the control unit 20.

  The traveling motor 14 is a three-phase AC motor or the like, and causes the vehicle to travel by being rotated by the electric power of the inverter 13. The inverter 13 converts a direct current from the high-power battery 11 or the bidirectional DCDC converter 16 into an alternating current and supplies the alternating current to the traveling motor 14.

  The inverter 13 is configured by a circuit in which, for example, a series circuit in which two IGBTs (insulated gate bipolar transistors) as switching elements are connected in series is connected in parallel in three rows according to the three-phase AC motor of the traveling motor 14. . The inverter 13 converts the direct current into a three-phase alternating current by turning on / off the six IGBTs.

  The low-power battery 15 is a lead storage battery that stores electric power at a voltage of 12 V to 15 V, and supplies electric power to the instrument equipment 17 and the electric unit 18. The bi-directional DCDC converter 16 reduces the power of the high-power battery 11 and supplies it to the low-power battery 15 when the voltage of the low-power battery 15 decreases when the relay 12 is turned on. Sometimes, the power of the low-power battery 15 is boosted and supplied to the inverter 13.

  The instrument equipment 17 is a speed meter or a headlight. The electric unit 18 drives a power window or the like. The voltage sensor 19 detects the voltage across the high-power battery 11 and outputs voltage information to the control unit 20. The voltage sensor 19 a detects the voltage across the low-power battery 15 and outputs voltage information to the control unit 20.

  The control unit 20 inputs voltage information from the high-power battery 11 and turns off the relay 12 and controls the bidirectional DCDC converter 16 in the emergency evacuation mode for emergency evacuation of the vehicle based on the voltage information. The power of 15 is boosted and supplied to the inverter 13 to operate the inverter 13.

  The emergency evacuation switch 21 corresponds to the emergency evacuation operation unit of the present invention, performs an operation for entering the emergency evacuation mode, and outputs an operation signal to the control unit 20. Instead of the emergency evacuation switch 21, an operation signal may be output to the control unit 20 by an operation of pressing an emergency evacuation button. Alternatively, an operation signal may be output to the control unit 20 by touching a touch panel for emergency evacuation.

  When the operation signal from the emergency evacuation switch 21 is input, the control unit 20 displays on the emergency evacuation indicator 22 that the emergency evacuation switch 21 has been operated.

  Next, the operation in the emergency evacuation mode of the vehicle when the high-power battery 11 is over-discharged (electricity shortage) in the electric vehicle power supply device of the first embodiment configured as described above and the vehicle cannot run is performed. This will be described with reference to the flowchart shown in FIG.

  First, voltage information of the high-power battery 11 is input from the voltage sensor 19 to the control unit 20. When the high-power battery 11 is over-discharged (electric shortage), the control unit 20 determines over-discharge based on the voltage information of the high-power battery 11 from the voltage sensor 19 and stops the vehicle.

  When the vehicle stops, the driver turns on the emergency evacuation switch 21 in order to evacuate the vehicle (step S11). Then, the control unit 20 inputs a switch-on signal from the emergency evacuation switch 21, displays that the emergency evacuation switch 21 is turned on and blinks on the emergency evacuation indicator 22 (step S12), and then proceeds to the process of step S13. . Note that the process of step S11 may be advanced to the process of step S13 without displaying that the emergency evacuation switch 21 is turned on and blinking.

  Next, based on the voltage information of the high-power battery 11 from the voltage sensor 19, the control unit 20 determines whether the voltage of the high-power battery 11 is lower than the lower limit L or whether the high-power battery 11 is abnormal (step S13). The lower limit L is set to a value larger than the overdischarge voltage of the high-power battery 11.

  When the voltage of the high-power battery 11 is lower than the lower limit L or when the high-power battery 11 is abnormal, it is determined whether the relay 12 is off (step S14). If the relay 12 is not off, the control unit 20 turns off the relay 12 (step S15), and proceeds to the process of step SS16. When the relay 12 is off, the process proceeds to step S16.

  Next, the control unit 20 determines whether or not the voltage of the low-power battery 15 is equal to or higher than the lower limit L based on the voltage information from the voltage sensor 19a that detects the voltage across the low-power battery 15 (step S16). When the voltage of the low-power battery 15 is equal to or higher than the lower limit value L, the control unit 20 enters the emergency evacuation mode (step S17), turns on the emergency evacuation indicator 22, and turns on meter navigation (navigation) (step). S18).

  That is, the emergency evacuation indicator 22 displays that the emergency evacuation mode has been entered. Therefore, the driver can confirm that the emergency evacuation mode has been entered. In addition, you may progress to the process of step S19 from step S17, without performing the process of step S18.

  Next, the control unit 20 turns on the inverter 13 (step S19), turns on the bidirectional DCDC converter 16, and performs a boost operation (step S20). For this reason, the bidirectional DCDC converter 16 boosts the power of the low-power battery 15 and supplies the boosted power to the inverter 13. The inverter 13 supplies the boosted power to the traveling motor 14, so that the traveling motor 14 rotates. . When the driver operates the accelerator pedal (step S21), the control unit 20 causes the vehicle to retreat by an accelerator signal from the accelerator pedal (step S22).

  Next, the control unit 20 determines whether or not the voltage of the low-power battery 15 is equal to or lower than the lower limit value L based on the voltage information from the voltage sensor 19a (step S23). When the voltage of the low-power battery 15 is equal to or lower than the lower limit value L, the control unit 20 turns off the emergency evacuation indicator 22 and turns off meter navigation (navigation) (step S24).

  In addition, when the voltage of the low-power battery 15 becomes the lower limit L or less, it can be easily replaced with a new charged low-power battery 15.

  Thus, according to the electric vehicle power supply device of the first embodiment, the relay 12 can be turned off and the vehicle can be moved by the power of the low-power battery 15.

  Normally, an electric vehicle turns off the relay 12 by a VCM (vehicle control module) in order to protect the cells of the expensive high-power battery 11 during overdischarge or when the high-power battery 11 is abnormal. For this reason, the electric vehicle could not be urgently evacuated.

  On the other hand, in the electric vehicle power supply device according to the first embodiment, by providing the emergency evacuation mode, the low-voltage battery 15 is controlled by controlling the bidirectional DCDC converter 16 even when the relay 12 is turned off. The electric power is boosted and supplied to the inverter 13, and the driving motor 14 is driven, so that the vehicle can be moved somewhat from the road with a heavy traffic volume or from the intersection.

  Further, in the first embodiment, the emergency evacuation switch 21 is provided, and the emergency evacuation mode is entered by the driver pressing the emergency evacuation switch 21. It is possible to avoid unnecessarily consuming the power of the weak battery 15. Further, it is possible to prevent an error that the user does not notice unnecessary evacuation or emergency evacuation mode.

(Second Embodiment)
FIG. 3 is a block diagram showing the configuration of the electric vehicle power supply device according to the second embodiment of the present invention. The electric vehicle power supply device of the second embodiment shown in FIG. 3 is further provided with an accelerator pedal 23 and the operation of the accelerator pedal 23 with respect to the electric vehicle power supply device of the first embodiment shown in FIG. A counter 24 that counts the number of times is provided in the control unit 20a, and the control unit 20a determines that the high-power battery 11 is discharged based on the voltage information from the voltage sensor 19 and the vehicle cannot travel, and then the accelerator pedal 23 is operated a plurality of times. When it is determined that the driver has tried to run the vehicle a predetermined number of times (for example, more than 3 times) based on the count value of the counter 24 by the operation, the emergency evacuation mode is entered.

  Further, the control unit 20a displays on the instrument equipment 17 (corresponding to the notification unit of the present invention) whether or not to enter the emergency evacuation mode before entering the emergency evacuation mode. In addition, the control unit 20a enters the emergency evacuation mode when it is determined that the driver has further tried driving the vehicle after displaying whether the instrument equipment 17 enters the emergency evacuation mode. It is characterized by.

  Next, the operation in the emergency evacuation mode of the vehicle when the high-power battery 11 is over-discharged (power shortage) in the electric vehicle power supply device of the second embodiment configured as described above and the vehicle cannot run is performed. This will be described with reference to the flowchart shown in FIG.

  In FIG. 4, steps S <b> 25 to S <b> 30 are added to the flowchart shown in FIG. 2, so only this portion of the processing will be described.

  First, voltage information of the high-power battery 11 is input from the voltage sensor 19 to the control unit 20a. When the high-power battery 11 is over-discharged (electric shortage), the control unit 20a determines over-discharge based on the voltage information of the high-power battery 11 from the voltage sensor 19, and stops the vehicle.

  When the vehicle stops, the control unit 20a determines whether or not the emergency evacuation switch 21 is turned on (step S25). When the emergency evacuation switch 21 is turned on, the processing from step S12 to step S24 is performed.

  When the emergency evacuation switch 21 is not turned on, the control unit 20a sets n to an initial value “0” (step S26). Next, the control unit 20a determines whether or not the accelerator pedal 23 has been operated a predetermined number of times after the high-power battery 11 is discharged and the vehicle cannot travel based on the voltage information from the voltage sensor 19 (step S27). . That is, the control unit 20a determines whether or not the driver has tried to drive the vehicle a predetermined number of times based on the count value of the counter 24 by the operation of the accelerator pedal 23.

  The controller 20a increments n by “1” when the driver tries to drive the vehicle a predetermined number of times (step S28), and n becomes “1”. Next, the control unit 20a determines whether n is “2” (step S29). When n is not “2”, the control unit 20a determines whether or not to display whether or not to enter the emergency evacuation mode on the instrumentation equipment 17 (step S30).

  If the control unit 20a does not display on the instrumentation device 17 whether the emergency evacuation mode is entered, the process proceeds to step S13. That is, when the vehicle cannot travel due to overdischarge of the high-power battery 11, and the driver tries to travel the vehicle a predetermined number of times, the process immediately enters step S13.

  On the other hand, in step S30, when the control unit 20a displays on the instrumentation equipment 17 whether the emergency evacuation mode is entered, the driver confirms the display content, and further, the driver travels the vehicle. Try. That is, returning to step S27, the control unit 20a determines whether or not the accelerator pedal 23 has been operated a predetermined number of times.

  Next, when n is incremented by “1” (step S28), since n becomes “2” (step S29), the process proceeds to step S13. In other words, the vehicle cannot travel due to overdischarge of the high-power battery 11, the driver tries to travel the vehicle a predetermined number of times, and displays whether the vehicle enters the emergency evacuation mode. If the number of times is tried, the process enters step S13.

  As described above, according to the electric vehicle power supply device of the second embodiment, the accelerator pedal 23 is provided, and the control unit 20a discharges the high-power battery 11 based on the voltage information from the voltage sensor 19 so that the vehicle cannot travel. After that, when the driver tries to travel the vehicle a predetermined number of times based on the count value from the counter 24, the emergency evacuation mode is entered. It is possible to avoid unnecessarily consuming the power of the battery 15 and to enter the emergency evacuation mode even if the user is panicked and is unaware of pressing the emergency evacuation switch 21.

  In addition, the control unit 20a can enter the emergency evacuation mode when the driver further tries to drive the vehicle after displaying whether the instrument equipment 17 enters the emergency evacuation mode. Therefore, it can be avoided that the emergency retraction mode is entered when the power is not necessary and the power of the low-power battery 15 is unnecessarily consumed.

(Third embodiment)
FIG. 5 is a block diagram showing the configuration of the electric vehicle power supply device according to the third embodiment of the present invention.

  In the electric vehicle power supply device of the third embodiment shown in FIG. 5, the inverter 13a uses the minimum current that the vehicle can travel and travel based on the output of the bidirectional DCDC converter 16 in the emergency evacuation mode. Control is performed so as to flow through the motor 14.

  As shown in FIG. 6, the output Vap of a general inverter increases with the passage of time in accordance with the output from the accelerator pedal 23 (the amount of depression of the accelerator pedal).

  However, if the output from the accelerator pedal 23 is increased, the speed can be increased or the vehicle can start suddenly. However, in the emergency retreat mode, the travel distance is shortened.

  In addition, the electric power obtained by boosting the low-power battery 15 cannot supply a large amount of power to the traveling motor 14, panics and suddenly accelerates the vehicle, causing a large current to flow through the traveling motor 14 at a time. If this happens, the mileage will be shortened.

  Therefore, in the emergency evacuation mode, the inverter 13a determines a limit value Vpc indicated by a solid line in FIG. 6 based on the output of the bidirectional DCDC converter 16, and the inverter output is peak cut at the limit value Vpc. The limit value Vpc is set to a minimum current that allows the vehicle to travel and move. Further, the upper limit value of the limit value Vpc is obtained by adding α (a slight value) to the current when the traveling motor 14 starts to rotate.

  As described above, according to the electric vehicle power supply device of the third embodiment, the inverter 13a travels the minimum current that the vehicle can travel and move based on the output of the bidirectional DCDC converter 16 in the emergency evacuation mode. Since the control is performed so as to flow to the motor 14, the distance that the vehicle can move can be extended by efficiently using the small electric power of the low-power battery 15.

  In addition, this invention is not limited to the power supply device for electric vehicles of 1st Embodiment thru | or 3rd Embodiment. In the electric vehicle power supply device of the second embodiment, the emergency evacuation switch 21 and the counter 24 for counting the number of operations of the accelerator pedal 23 are provided. For example, the accelerator pedal 23 is not provided without providing the emergency evacuation switch 21. 4 may be provided, and after the processing from step S26 to step S30 shown in FIG. 4 is performed, the processing from switch S13 to step S24 may be performed.

  In the second embodiment, the display indicating whether or not to enter the emergency evacuation mode is displayed. However, a voice indicating whether or not the emergency evacuation mode is to be entered may be given by a speaker or the like.

  Further, another relay may be provided between the relay 12 and the inverter 13 and between the relay 12 and the bidirectional DCDC converter 16. In this case, by turning on the relay 12 and turning off another relay, the power of the low-power battery 15 can be boosted by the bidirectional DCDC converter 16 and supplied to the high-power battery 11. That is, since another relay is turned off, the power from the bidirectional DCDC converter 16 is not supplied to the inverter 13.

  Further, when the relay 12 and another relay are turned on, the power from the high voltage battery 11 can be supplied to the traveling motor 14 via the inverter 13. When the relay 12 is turned off and another relay is turned on, the emergency evacuation mode is entered, and the electric power of the low-power battery 15 is boosted by the bidirectional DCDC converter 16 and supplied to the traveling motor 14 via the inverter 13. can do.

11 Strong battery
12 Relay 13, 13a Inverter
DESCRIPTION OF SYMBOLS 14 Driving motor 15 Weak electric battery 16 Bidirectional DCDC converter 17 Instrument equipment 18 Electric unit 19, 19a Voltage sensor 20, 20a, 20b Control part 21 Emergency evacuation switch 22 Emergency evacuation indicator 23 Accelerator pedal 24 Counter

Claims (5)

A high-power battery (11) and a low-power battery (15);
An inverter (13) connected to the high-power battery (11) via a relay (12), and driving the vehicle by rotating a driving motor (14) with electric power from the high-power battery (11);
A bi-directional DCDC converter (16) that steps down the power of the high-power battery (11) and supplies it to the low-power battery (15), and boosts the power of the light-power battery (15) and supplies it to the inverter (13). When,
In the emergency evacuation mode, the relay (12) is turned off and the bidirectional DCDC converter (16) is controlled to boost the power of the low-power battery (15) and supply it to the inverter (13). A control unit (20) for operating (13);
An electric vehicle power supply device comprising:   The power supply apparatus for an electric vehicle according to claim 1, further comprising an emergency retreat operation unit (21) that performs an operation for entering the emergency retreat mode and outputs an operation signal to the control unit (20). A voltage sensor (19) for detecting the voltage of the high-power battery (11);
The control unit (20) includes a counter (24) for counting the number of times the accelerator pedal (23) is operated, and the high-power battery (11) is discharged based on the voltage from the voltage sensor (19), so that the vehicle travels. The emergency evacuation mode is entered when it is determined that the driver has tried to run the vehicle a predetermined number of times based on the count value of the counter (24) after determining that the vehicle is impossible. The electric vehicle power supply device according to claim 1 or 2. Before entering the emergency evacuation mode, comprising a notification unit (17) for notifying whether to enter the emergency evacuation mode,
When the control unit (20) further determines that the driver has tried to travel the vehicle after the notification unit (17) notifies whether or not the emergency evacuation mode is entered, the emergency unit (20) 4. The electric vehicle power supply device according to claim 3, wherein the power supply device enters the retreat mode.   In the emergency evacuation mode, the inverter (13) causes a minimum current that the vehicle can travel and move to flow to the travel motor (14) based on the output of the bidirectional DCDC converter (16). The power supply device for an electric vehicle according to any one of claims 1 to 4, wherein the power supply device is controlled.

Images