JP2001268718A - Power supply unit for electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a specific cell undecharged caused by variance in the terminal voltage of each cell when a plurality of capacitor cells are series connected, thereby preventing failure in all the cells. SOLUTION: An auxiliary power supply 3 with a few hundred capacitor cells C1 to Cn series-connected is so formed that terminal voltages of respective cells C1 to Cn may be monitored by a controller 10 serving as a failure determining means and, with the emitter and the collector of a transistor 31 connected between the terminals of the respective cells, application of base voltage from the controller 10 may cause short circuit between the terminals. If the terminal voltage of at least one capacitor cell is lower than that of any other capacitor cell by a prescribed value, the controller 10 determines the capacitor cell as abnormal and, as a short-circuiting means, applies voltage to the base part of the transistor 31 to short-circuit a section between the terminals of the capacitor cells determined as abnormal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply for an electric vehicle.

[0002]

2. Description of the Related Art Conventionally, electric vehicles and the like are provided with a power supply device called a capacitor (a power supply capable of charging and discharging small electric power in a short time by an electrolytic double layer capacitor or the like) in addition to a battery for driving a motor. I have. This power supply device is configured to accumulate energy regenerated by a motor at the time of deceleration of a vehicle or the like in a capacitor, and to discharge the energy at the time of acceleration or the like to supply power to the motor in an auxiliary manner.

As a prior art of this power supply device, Japanese Patent Application No. Hei.
In Japanese Patent Application Publication No. 0-201091, a plurality of capacitor cells are connected in series, a resistor is connected in parallel with one capacitor cell via a switch, and the resistor and the cell are connected when the capacitor cell is overcharged. A configuration for preventing charging is described.

Japanese Patent Application Laid-Open No. 9-322314 discloses that a battery and a power capacitor are connected in parallel, only a capacitor is connected to a load during energy regeneration or early discharge, and otherwise, a battery and a capacitor are connected. And a booster circuit for the power discharged from the capacitor.

Further, Japanese Patent Application Laid-Open Nos. 8-98313 and 8-98314, and a device that prohibits brake regeneration during ABS control (Japanese Patent Application Laid-Open No. 11-115743) have been proposed.

[0006]

However, since a plurality of capacitor cells are connected in series, the terminal voltage of each cell varies, and the charge stored in the cell having a relatively low terminal voltage is insufficient. As a result, there is a possibility that the whole cell fails due to the cell polarity being reversed.

The present invention has been made in view of the above circumstances, and an object of the present invention is to suppress a shortage of power storage in a specific cell caused by a variation in terminal voltage of each cell when a plurality of capacitor cells are connected in series. An object of the present invention is to provide a power supply device for an electric vehicle that can suppress the failure of the entire cell.

[0008]

Means for Solving the Problems To solve the above problems and achieve the object, a power supply device for an electric vehicle according to the present invention has the following arrangement. That is, a motor for driving the vehicle, regenerative means for regenerating the motor when the vehicle is decelerated, power supply means including a plurality of capacitor cells connected in series, and charging by supplying regenerative current by the regenerative means to the power supply means A power supply device for an electric vehicle, comprising: a charging unit that performs charging when a terminal voltage of at least one of the plurality of capacitor cells is lower than a terminal voltage of another capacitor cell by a predetermined value or more. An abnormality determining means for determining, and a short-circuit means for short-circuiting the capacitor cell determined to be abnormal by the abnormality determining means.

The power supply device for an electric vehicle according to the present invention has the following configuration. That is, a motor for driving the vehicle, regenerative means for regenerating the motor when the vehicle is decelerated, power supply means including a plurality of capacitor cells connected in series, and charging by supplying regenerative current by the regenerative means to the power supply means A power supply device for an electric vehicle, comprising: a charging unit that performs charging when a terminal voltage of at least one of the plurality of capacitor cells is lower than a terminal voltage of another capacitor cell by a predetermined value or more. Abnormality determining means for determining, and a return means for supplying at least a part of the electric charge of another capacitor cell to the capacitor cell determined to be abnormal and returning the capacitor cell when the abnormality determining means determines the abnormality. I do.

Preferably, the abnormality determining means includes:
Among the plurality of capacitor cells, a terminal voltage of a part of the entire capacitor cell group is detected, and when the terminal voltage is lower than a terminal voltage of another capacitor cell group by a predetermined value or more, the part of the capacitor cell group is detected. It is determined that there is an abnormality, and the short-circuiting means short-circuits the terminals of the capacitor cell group at least during charging.

[0011]

As described above, according to the first aspect of the present invention, when the terminal voltage of at least one of the plurality of capacitor cells is lower than the terminal voltage of the other capacitor cells by a predetermined value or more, The capacitor cells are determined to be abnormal, and the capacitor cells determined to be abnormal are short-circuited, so that a plurality of capacitor cells are connected in series, so that the terminal voltage of each cell varies, and an overvoltage occurs between the terminals. It is possible to prevent the entire cell from failing due to, for example, inversion of the polarity of the cell due to shortage of the electric charge applied or accumulated by the low voltage.

According to the second aspect of the invention, when the terminal voltage of at least one of the plurality of capacitor cells is lower than the terminal voltage of the other capacitor cell by a predetermined value or more, the capacitor cell is determined to be abnormal. At the time of abnormality determination, by supplying at least a part of the electric charge of another capacitor cell to the capacitor cell determined to be abnormal and restoring the capacitor cell, the cell determined to be abnormal is temporarily used due to a short circuit or the like. The cell whose terminal voltage has temporarily dropped can be restored by preventing the cell from becoming impossible.

According to the third aspect of the present invention, the terminal voltage of a part of the plurality of capacitor cells among the plurality of capacitor cells is detected, and the terminal voltage is higher than the terminal voltage of the other capacitor cells by a predetermined value or more. When it is low, some of the capacitor cell groups are determined to be abnormal, and at least the terminals of the capacitor cell group are short-circuited at the time of charging, whereby the configuration can be simplified without monitoring all the cells.

[0014]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. [Overall Configuration of Power Supply Device] FIG. 1 is a block diagram showing a power supply device for an electric vehicle according to this embodiment.

As shown in FIG. 1, the electric vehicle according to the present embodiment is an electric vehicle using a motor 1 as a driving source.

The power supply device of the present embodiment comprises left and right wheels 7, 8
, A main power source 2 including a battery or a fuel cell, an auxiliary power source 3 including a plurality of capacitor cells connected in parallel to the main power source 2, and a voltage converter connected in series with the auxiliary power source 3. A main power supply 2 and an auxiliary power supply 3 connected in parallel are connected to the motor 1 via an inverter 5.

The voltage conversion circuit 4 is controlled by the controller 10 and converts a voltage output from the auxiliary power supply 3 to an appropriate value and outputs the converted value.

The inverter 5 is controlled by the controller 10 and receives a signal from the motor 1 from the main power supply 2 and / or the auxiliary power supply 3.
And the frequency of the current supplied to the main power supply 2 or the auxiliary power supply 3 is adjusted.

A switch 6 is connected between the main power supply 2 and the inverter 5, and the on / off of the switch 6 is controlled by a controller 10.

The controller 10 includes a CPU, ROM, RA
M, an interface circuit, and the like. The power is supplied from the main power supply 2 to the motor 1 when the vehicle is running at a low load and the power is supplied from the main power supply 2 and the auxiliary power supply 3 to the motor 1 when the vehicle is accelerating at a high load. When the motor 1 is regenerated at the time of deceleration, the motor 1 is regenerated as regenerative means, and the regenerative current is controlled as a charging means by controlling the voltage conversion circuit 4, the inverter 5 and the switch 6 so as to charge the main power supply 2 and the auxiliary power supply 3. 1 to control the output torque, rotation speed, and the like. [Detailed Configuration of Auxiliary Power Supply] <First Embodiment> FIG. 2 is a circuit diagram showing a detailed configuration of the auxiliary power supply of the first embodiment.

As shown in FIG. 2, the auxiliary power supply 3 is configured such that several hundred capacitor cells C1 to Cn are connected in series, and the controller 10 monitors terminal voltages of the cells C1 to Cn as abnormality determining means. It is configured.

An emitter section and a collector section of the transistor 31 are connected between the terminals of each cell.
When a base voltage is applied from the terminals, the terminals are short-circuited. The terminal voltage is maintained at a constant voltage (for example, about 2 to 3 V) by a large-capacity zener diode 32 disposed between the emitter and the collector of the transistor 31.

When the terminal voltage of at least one capacitor cell is lower than the terminal voltage of another capacitor cell by a predetermined value or more, the controller 10 determines that the capacitor cell is abnormal and applies a voltage to the base of the transistor 31 as short-circuit means. To short-circuit the terminals of the capacitor cells determined to be abnormal.

According to the first embodiment, since a plurality of capacitor cells are connected in series, the terminal voltage of each cell varies, and an overvoltage is applied between the terminals.
It is possible to prevent the entire cell from failing due to a shortage of charge accumulated due to the low voltage and inversion of the cell polarity.

Further, by increasing the capacity of the Zener diode 32, it is possible to prevent the current discharged from the capacitor cells other than the abnormal cell from bypassing the abnormal cell during the discharge and failing the entire cell. <Second Embodiment> FIG. 3 is a circuit diagram showing a detailed configuration of an auxiliary power supply according to a second embodiment. FIG. 4 is a detailed circuit diagram of the induction circuit of FIG.

As shown in FIG. 3, each capacitor cell C1
To the terminal voltage of the controller 1 as abnormality determination means.
0 is configured to monitor.

A voltage exchange circuit 41 is connected between the terminals of each cell as a return means, and the transformer 42 is configured so that the variation of the terminal voltage of each cell can be made uniform.

The transformer 42, when the terminal voltage of each cell varies, a voltage exchange circuit 41 having a high terminal voltage.
Thus, an induced electromotive force is generated in the voltage exchange circuit 41 having a low terminal voltage.

As shown in FIG. 4, the voltage exchange circuit 41
A transistor 43 and an oscillation circuit 45 are provided on the positive terminal side of the cell.
Are arranged in series, and a transistor 44 and a rectifier circuit 46 are arranged in parallel with each other to form a closed circuit. The positive terminal of the capacitor cell is connected to the transistor 4.
The oscillating circuit 45 and the rectifying circuit 46 are connected between the collector of the third cell and the emitter of the transistor 44, and are connected to the voltage exchange circuits of other cells.

The bases of the transistors 43 and 44 are insulated by insulating circuits 48 and 49, and a voltage is applied from the controller 10.

When a base voltage is applied from the controller 10 to the transistor 43, the electric charge in the cell moves, and a current flows through the transistor 43 and the oscillation circuit 45, and the oscillation circuit 4
In step 5, it is converted to AC and output to the voltage exchange circuit of another cell. Further, when a base voltage is applied from the controller 10 to the transistor 44, a current flows from the oscillation circuit of another voltage exchange circuit to the rectifier circuit 46, is converted into a direct current by the rectifier circuit 46, and is transferred from the transistor 44 to the positive terminal of the cell. Flow, and the cell charge is accumulated.

According to the above configuration, when there is a cell having a low terminal voltage, an induced electromotive force is generated in a cell having a high terminal voltage and a cell having a low terminal voltage is accumulated. it can.

When the terminal voltage of at least one capacitor cell is lower than the terminal voltage of another capacitor cell by a predetermined value or more, the controller 10 determines that the capacitor cell is abnormal and, at the same time, resets the gate portion of the transistor 43 or 44 as recovery means. To supply at least a part of the electric charge of the other capacitor cell to the capacitor cell determined to be abnormal to restore it.

According to the second embodiment, it is possible to prevent a cell determined to be abnormal from being temporarily unusable due to a short circuit or the like, and to recover a cell whose terminal voltage has temporarily dropped. <Third Embodiment> FIG. 5 is a circuit diagram showing a detailed configuration of an auxiliary power supply according to a third embodiment.

As shown in FIG. 5, each capacitor cell C1
To the terminal voltage of the controller 1 as abnormality determination means.
0 is configured to monitor.

A switching circuit 51 is connected between the terminals of each cell as return means.

As shown in FIG. 5, the switching circuit 51
Is a MOSFE having a source and a drain connected between terminals of each cell via a coil 52 and a gate connected via a series resistor R and a high voltage driver D.
T53 is provided. The gate voltage is maintained at a constant voltage by a Zener diode 54 disposed between the source and the drain. Further, a diode 55 is provided between the source and the drain.

When a gate voltage is applied from the controller 10 to the MOSFET 53, the charge moves from a cell having a high terminal voltage to a cell having a low terminal voltage, and the switching operation is performed by the coil 52 as a constant current source so that the terminal voltage becomes uniform. It is configured.

According to the above configuration, when there is a cell having a low terminal voltage, by applying a rectangular wave gate voltage to the MOSFET 53 of the normal cell, the electric charge moves from the normal cell to accumulate the electric charge. .

When the terminal voltage of at least one capacitor cell is lower than the terminal voltage of another capacitor cell by a predetermined value or more, the controller 10 judges that the capacitor cell is abnormal and switches the MOSFET 53 as a return means by a rectangular wave. Then, at least a part of the electric charge of the other capacitor cell is supplied to the capacitor cell determined to be abnormal and is restored.

According to the third embodiment, it is possible to prevent a cell determined to be abnormal from being temporarily unusable due to a short circuit or the like, and to recover a cell whose terminal voltage has temporarily dropped.

In addition, an insulating circuit is not required, the driving can be performed with high efficiency by switching, and the voltages of all cells can be made uniform. <Modification> In the above embodiment, the terminal voltage is detected for each capacitor cell. However, a plurality of aggregates including a plurality of capacitor cells are formed, and the terminal voltage of each aggregate is detected. When the terminal voltage is lower than the terminal voltage of another aggregate by a predetermined value or more, one of the aggregates is determined to be abnormal, and at least the terminal voltage of the aggregate determined to be abnormal at the time of charging is short-circuited, May be moved to return. Thus, the configuration of the power supply device can be simplified without monitoring all the cells. <Other Embodiments> When the main power supply 2 fails or malfunctions, the output characteristics of the auxiliary power supply 3 are constant. Therefore, (i) the acceleration performance deteriorates as the output of the main power supply 2 decreases, (ii)
When the output of the main power supply stops, the amount of power stored in the auxiliary power supply 3 decreases, and there is a problem that the vehicle cannot be driven immediately.

As means for solving the above problems, the following control may be performed. That is, (I) the malfunction of the main power supply 2 is detected, and there is no possibility that the main power supply 2 is stopped. However, when the output decreases, the output of the auxiliary power supply 3 is increased from the normal state.

(II) If the malfunction of the main power supply 2 is detected and the power can still be output, but it must be stopped after that (for example, after several tens of seconds), the auxiliary power supply 3 is controlled while the output is suppressed.
Is fully charged, and after the main power supply is stopped, the vehicle is driven with the amount of power stored in the auxiliary power supply 3 (to a repair shop or a safe area).

(III) When a malfunction of the main power supply 2 is detected and the output must be quickly suppressed and stopped immediately, the output is suppressed and the charge and output of the auxiliary power supply 3 are stopped to store the amount of stored power. After the main power supply 2 is stopped, the vehicle is driven with the amount of power stored in the auxiliary power supply 3 (to a repair shop or a safe area). <Other Embodiments> If the auxiliary power supply 3 is fully charged in preparation for acceleration, there is a problem that regenerative power cannot be received during downhill traveling or sudden braking.

As a means for solving the above problems, the following control may be performed. That is, (I) the charging amount of the auxiliary power supply is adjusted by predicting the traveling route using the map information of the car navigation system.

(II) The driving pattern of the driver is learned, and the amount of charge is adjusted to be optimal for the driving pattern.

(III) The charge amount of the auxiliary power supply can be set at the driver's own discretion. <Other Embodiments> Since the internal resistance of the main power supply 2 and the auxiliary power supply 3 changes due to environmental conditions and the like, (i) the efficiency deteriorates, and (ii) one of the main power supply 2 and the auxiliary power supply 3 malfunctions. In such a case, there is a problem that the output becomes insufficient.

As a means for solving the above problems, the following control may be performed. That is, (I) the output ratio at which the efficiency becomes maximum is calculated and controlled based on the voltage, temperature, and internal resistance of the main power supply 2 and the auxiliary power supply 3. This output ratio may be mapped according to the required output, temperature, voltage, and the like.

It should be noted that the present invention can be applied to a modification or modification of the above embodiment without departing from the spirit thereof.

For example, the present invention can be applied to motor control in a hybrid vehicle that runs using both a motor and an engine.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a power supply device of an electric vehicle according to an embodiment.

FIG. 2 is a circuit diagram illustrating a detailed configuration of an auxiliary power supply according to the first embodiment.

FIG. 3 is a circuit diagram illustrating a detailed configuration of an auxiliary power supply according to a second embodiment.

FIG. 4 is a detailed circuit diagram of the induction circuit of FIG. 3;

FIG. 5 is a circuit diagram showing a detailed configuration of an auxiliary power supply according to a third embodiment.

[Explanation of symbols]

 Reference Signs List 1 motor 2 main power supply 3 auxiliary power supply 4 voltage conversion circuit 5 inverter 10 controller

Continued on the front page (72) Inventor Hideo Katsuta 3-1 Fuchu-cho, Shinchu, Aki-gun, Hiroshima Mazda Co., Ltd. (72) Inventor Seiji Sadahira 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda ) Inventor Akira Takemoto 3-1 Fuchu-cho, Shinchu, Aki-gun, Hiroshima Prefecture Inside Mazda Co., Ltd. (72) Inventor Hideaki Akahoshi 3-1 Shinchi, Fuchu-cho, Aki County, Hiroshima Prefecture Inside Mazda Co., Ltd. 3-1, Fuchu-cho, Aki-gun, Mazda F-term (reference) in Mazda Co., Ltd.

Claims (3)

[Claims] 1. A motor for driving a vehicle, a regenerative means for regenerating the motor when the vehicle is decelerated, a power supply means comprising a plurality of capacitor cells connected in series, and a regenerative current supplied by the regenerative means is supplied to the power supply means. And a charging means for charging when the terminal voltage of at least one of the plurality of capacitor cells is lower than the terminal voltage of another capacitor cell by a predetermined value or more. And a short-circuiting means for short-circuiting the capacitor cell determined to be abnormal by the abnormality determining means. 2. A motor for driving a vehicle, regenerative means for regenerating the motor when the vehicle is decelerated, power supply means comprising a plurality of capacitor cells connected in series, and a regenerative current supplied by the regenerative means is supplied to the power supply means. And a charging means for charging when the terminal voltage of at least one of the plurality of capacitor cells is lower than the terminal voltage of another capacitor cell by a predetermined value or more. Abnormality determination means for determining that an abnormality has occurred, and a return means for supplying at least a part of the electric charge of another capacitor cell to the capacitor cell determined to be abnormal when the abnormality determination means determines the abnormality, thereby restoring the capacitor cell. A power supply device for an electric vehicle, comprising: 3. The abnormality determining means detects a terminal voltage of a part of the plurality of capacitor cells among the plurality of capacitor cells, and the terminal voltage is higher than a terminal voltage of another capacitor cell by a predetermined value or more. The power supply for the electric vehicle according to claim 1, wherein when the battery is low, the part of the capacitor cell set is determined to be abnormal, and the short-circuiting means short-circuits a terminal of the capacitor cell set at least during charging. apparatus.