JP2000278806A - Power supply system for electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain reduction in size and weight and high efficiency. SOLUTION: This system is provided with a main storage device supplying power to a traveling motor 6, three battery blocks 10, 11, 12 constituted of electric double-layer capacitor cells 100, 110, 120 in the main storage device, and a block connection switching circuit 13 switching the number of the battery blocks 10, 11, 12 connected in series according to a voltage change by the charging or discharging of the electric double-layer capacitor cells 100, 110, 120 so that the voltage Vc of the main storage device 4 may be a prescribed value V1 or higher.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a power supply system of an electric vehicle using an electric double layer capacitor cell as a main power storage device.

[0002]

2. Description of the Related Art A main power storage device mounted on an electric vehicle or the like repeatedly discharges and charges when braking and accelerating the vehicle at a constant speed, and the number of times of operation reaches tens of thousands of times. Chemical batteries have a short charge-discharge cycle life,
In addition, due to poor efficiency at the time of high-power operation, in recent years, an electric double-layer capacitor cell has attracted attention as a main power storage device.

FIG. 12 shows a known basic configuration example of an electric system in which an electric double layer capacitor cell is applied to a main power storage device mounted on a series hybrid vehicle. Engine 1
Drives the generator 2, and the electric power generated by the generator 2 is supplied to the main power storage device 4 via the rectifier 3 and to the traveling motor 6 via the inverter 5. Wheels (not shown) are driven by a traveling motor 6. In the figure, 8 is an auxiliary power storage device composed of a chemical battery, 7 is a DC-DC converter for charging the auxiliary power storage device 8, and 9 is an auxiliary machine.

The main power storage device 4 is a system in which a number of electric double layer capacitor cells 41, 42, 43,... Are connected in series, and a conventional chemical secondary battery is replaced with an electric double layer capacitor cell.

During acceleration or running at a constant speed, part or all of the electric power generated by generator 2 is charged in main power storage device 4, and the power generated by generator 2 and the power of main power storage device 4 pass through inverter 5. The motor is supplied to the traveling motor 6 through the motor. At the time of braking, the braking power generated in the traveling motor 6 is regenerated to the main power storage device 4 via the inverter 5.

[0006]

The electric storage energy of the electric double layer capacitor cells 41, 42, 43,... Is proportional to the square of the voltage of the capacitor cells 41, 42, 43,. In other words, when used as a DC power supply,
Capacitor cells 41 and 4 respond to an increase in discharge energy.
The voltages of 2, 43, ... decrease. 75% of energy
Is discharged, the voltage drops by half.

A method is employed in which a chopper circuit 44 is inserted between the main power storage device 4 and the inverter 5 to keep the input voltage of the inverter 5 constant. However, the chopper circuit 44 requires a current smoothing reactor. Since this reactor current is inversely proportional to the voltage of main power storage device 4, when the voltage of main power storage device 4 is reduced by half, the reactor current is doubled. For this reason, when the voltage of main power storage device 4 fluctuates greatly, chopper circuit 44 becomes large and there is a problem that the efficiency is reduced.

A power supply device using an electric double layer capacitor cell has been proposed in Japanese Patent Application Laid-Open No. Hei 8-168182.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to reduce the size and weight of a power supply system for an electric vehicle and increase the efficiency thereof.

[0010]

A first aspect of the present invention is applied to a power supply system of an electric vehicle including a main power storage device for supplying electric power to a traveling motor, wherein the main power storage device includes a plurality of electric double layer capacitor cells. I do.

A plurality of battery blocks, each of which includes an electric double layer capacitor cell in the main power storage device, and a voltage change caused by charging / discharging of the electric double layer capacitor cell so that the voltage of the main power storage device becomes a specified value or more. And a block connection switching circuit for switching the number of battery blocks connected in series.

In a second aspect based on the first aspect, the power stored in each battery block is gradually changed such that the voltage of the main power storage device becomes equal to or lower than a specified value.

[0013] In a third aspect based on the first or second aspect, the block connection switching circuit is constituted by a bidirectional flow semiconductor switch.

According to a fourth aspect of the present invention, in the third aspect, the two-way conduction type semiconductor switch is constituted by a pair of thyristors connected in antiparallel to each other.

According to a fifth aspect of the present invention, in the third aspect, the two-way conduction type semiconductor switch is constituted by a pair of reverse blocking GTO thyristors connected in anti-parallel to each other.

In a sixth aspect based on the third aspect, the two-way conduction type semiconductor switch comprises a pair of transistors connected in series with opposite polarities and a diode connected in antiparallel to each transistor. To do.

[0017]

According to the first aspect of the present invention, since the stored energy of each capacitor battery block is proportional to the square of the voltage of the capacitor cell, the voltage of the capacitor block greatly fluctuates due to the change of the stored energy due to charging and discharging. The block connection switching circuit connects a required number of these in series according to the charging and discharging of each capacitor battery block, so that the fluctuation of the voltage of the main power storage device can be suppressed. For this reason, the chopper circuit for making the voltage of the main power storage device substantially constant can be reduced in size and weight and improved in efficiency, and a power supply system for a long-life electric vehicle can be realized.

In the second invention, the power stored in each battery block is gradually changed so that the voltage of the main power storage device is set to a specified value or less, so that the voltage of the main power storage device becomes excessive when the battery block is connected. Is suppressed. For this reason, the chopper circuit for making the voltage of the main power storage device substantially constant can be reduced in size and weight and improved in efficiency, and a power supply system for a long-life electric vehicle can be realized.

In the third invention, the bidirectional current-carrying type semiconductor switch automatically flows according to the direction of the discharging or charging current of the main power storage device.

According to the fourth aspect of the present invention, the on / off signal is supplied to both of the thyristors connected in anti-parallel irrespective of the direction of the current, so that the thyristors are automatically connected to the direction of the current for discharging or charging the main power storage device. Flow through.

According to the fifth aspect of the present invention, by providing on / off signals to both of the reverse blocking GTO thyristors connected in anti-parallel irrespective of the direction of the current, it is possible to respond to the direction of the current of discharging or charging of the main power storage device. Flow automatically.

According to the sixth aspect of the present invention, the on / off signal is given to both of the transistors connected in series with opposite polarities irrespective of the direction of the current, so that the on / off signal is automatically adjusted according to the direction of the current of discharging or charging of the main power storage device. Flow through.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an electric system in which the present invention is applied to a main power storage device mounted on a series hybrid vehicle will be described below with reference to the accompanying drawings.

As shown in FIG. 1, an engine 1 includes a generator 2
And the power generated by the generator 2 is supplied to the main power storage device 4 via the rectifier 3 and to the traveling motor 6 via the inverter 5. A step-up / step-down chopper circuit 44 is interposed between the main power storage device 4 and the inverter 5,
The input voltage of the inverter 5 is made constant. Wheels (not shown) are driven by a traveling motor 6. In the figure, reference numeral 8 denotes an auxiliary power storage device constituted by a chemical battery, 7 denotes a DC-DC converter for charging the auxiliary power storage device 8, and 9 denotes an auxiliary machine.

The main power storage device 4 includes three capacitor battery blocks 10, 11, 12 and a block connection switching circuit 13.
It is composed of The number of capacitor battery blocks is 2
More than one.

Each of the capacitor battery blocks 10, 11, 1
2 is a plurality of electric double layer capacitor cells 10
0, 110, and 120 are connected in series and parallel. The voltage polarity of the capacitor battery blocks 10, 11, and 12 is the same.

As shown in FIG. 2, the block connection switching circuit 13 includes switches 130, 131, and 132, and when these switches are turned on and off, each of the capacitor battery blocks 1 is switched.
0, 11, and 12 are connected in series by a required number. Each of the switches 130, 131 and 132 is constituted by a bidirectional flow type semiconductor switch. In FIG. 2, each battery block 10,
The display of the capacitor cells 11 and 12 is omitted.

As shown in FIG. 3, the switches 130 of the block connection switching circuit 13 are thyristors 130a and 130b.
Are connected in antiparallel. When the switch 130 is turned on and off according to the operation mode, the thyristors 130a and 130b connected in anti-parallel regardless of the direction of the current
By supplying an ON or OFF signal to both of them, the current automatically flows according to the direction of the current of discharging or charging of main power storage device 4. Since the switches 131 and 132 have the same configuration, the description is omitted.

The block connection switching circuit 13 responds to a voltage change due to charging and discharging of the electric double layer capacitor cells 100, 110, and 120 so that the voltage of the main power storage device 4 becomes equal to or higher than the specified value V1. , 12 are switched. FIG. 4 shows the behavior of voltage Vc of main power storage device 4 in the case of a discharging operation in the circuit configuration of FIG. FIG. 5 shows an equivalent circuit of FIG. 2 corresponding to the operation mode of FIG.

In the mode I, the switch 130 is turned on and the switches 131 and 132 are turned off. The voltage of the main power storage device 4 becomes the voltage of the battery block 10, and the current of the capacitor cell becomes the circuit shown in FIG. 5A. It decreases as shown in mode I. Main power storage device 4
When the voltage Vc reaches the specified value V1, the switch 131 is turned on and the switch 130 is turned off. As a result, the main power storage device 4 is connected in series with the capacitor battery blocks 10 and 11, and forms the circuit of FIG. Voltage Vc of main power storage device 4 is the sum voltage V2 of capacitor battery blocks 10 and 11. The operation in this circuit is mode II in FIG. The voltage of the capacitor battery block 11 is selected so that V2 becomes substantially equal to V0.

When the discharge proceeds further in mode II, when the capacitor battery blocks 10 and 11 discharge and the voltage Vc decreases to V1, the switch 132 is turned on and the switch 13 is turned on.
Turn off 0,131. As a result, the main power storage device 4 is connected in series with the capacitor battery blocks 10, 11, and 12, and the circuit shown in FIG. The sum voltage of the capacitor battery blocks 10, 11, 12 becomes the output voltage V3. The voltage V3 of the capacitor battery block 12 is selected so as to be substantially equal to V0. The operation in this circuit is the operation mode III in FIG.

In mode III, when the voltage V3 decreases as the discharge proceeds and reaches the specified voltage value V1, the discharging operation of each of the capacitor battery blocks 10, 11, and 12 ends.

The electric power stored in each of the battery blocks 10, 11, and 12 is set to gradually decrease so that the maximum values of the voltages V1, V2, and V3 become substantially equal. This allows
The voltage when the battery blocks 11 and 12 are connected to the battery block 10 can be suppressed to a specified value or less.

When the main power storage device 4 is charged, the operation is the reverse of the above-described operation when the main power storage device 4 is discharged.

FIG. 6 shows a circuit configuration of the chopper circuit 44. In the figure, reference numerals 441 and 442 denote semiconductor switches.
The figure shows the case of a transistor. 443, 4
44 is a diode and a semiconductor switch 44 as shown in the figure.
1, 442 are connected in anti-parallel. 445 is a current smoothing reactor, and 446 and 447 are filter capacitors.

During acceleration and constant speed traveling, the voltage Vc of the main power storage device 4 becomes lower than the input voltage of the inverter 5, and the chopper circuit 44 is operated as a step-up chopper as shown in FIG. In this case, the semiconductor switch 441 is switched, and the semiconductor switch 442 is turned off.

During regenerative braking, the chopper circuit 44 operates as a step-down chopper as shown in FIG. in this case,
The semiconductor switch 442 is switched, and the semiconductor switch 441 is turned off.

FIG. 9 is a diagram for explaining the operation of the chopper circuit 44 of FIG. Mode I is the mode for acceleration
II indicates a meandering operation, and Mode III indicates a braking operation. acceleration,
During traveling at a constant speed, the main power storage device 4 discharges and the battery voltage Vc decreases, but the input voltage Vi of the inverter 5 is kept constant by the boosting operation of the chopper circuit 44. The current Ic of the chopper circuit 44 (the current of the reactor in FIG. 6) increases as the voltage of the main power storage device 4 decreases. In the regenerative braking in mode III, the step-down chopper operation of the chopper circuit 44 keeps the input voltage of the chopper circuit 44 constant,
The regenerative power is charged in the main power storage device 4. Chopper circuit 44
Current Ic decreases as voltage Vc of main power storage device 4 increases.

Each of the capacitor battery blocks 10, 11, 1
2 is proportional to the square of each voltage, the respective voltages greatly fluctuate due to the change in the stored energy due to charging and discharging. However, the block connection switching circuit 13 causes the charging of each of the capacitor battery blocks 10, 11, 12 to be performed. By connecting a required number of them in series according to the discharge, the fluctuation of voltage Vc of main power storage device 4 can be suppressed. The chopper circuit 44 includes a current smoothing reactor 445, and the reactor current is inversely proportional to the voltage Vc of the main power storage device 4.
Since the fluctuation of the voltage Vc of the main power storage device 4 is suppressed, the chopper circuit 44 can be reduced in size, weight, and efficiency, and a power supply system for a long-life electric vehicle can be realized.

The semiconductor switch 130 of the block connection switching circuit 13 performs a switching operation only at the time of circuit switching.
Since there is only one semiconductor switch that does not perform switching in a steady state and flows, a highly efficient power supply system can be realized.

FIG. 10 shows a second embodiment of the switch 130 of the capacitor battery switching circuit 13. The switch 130 is a reverse blocking GTO thyristor 130c, 130d.
Are connected in antiparallel. When the switch 130 is turned on and off by the operation mode, the reverse blocking GTO thyristor 13 connected in anti-parallel regardless of the direction of the current
By giving an ON or OFF signal to both 0c and 130d, the current automatically flows according to the direction of the current of discharging or charging of main power storage device 4. Since the switches 131 and 132 have the same configuration, the description is omitted.

FIG. 11 shows a third embodiment of the switch 130 of the capacitor battery switching circuit 13. The switch 130 connects the transistors 130e and 130f in series with opposite polarities, and similarly connects the diodes 130g and 130h to the transistor 130e. , 130f connected in anti-parallel. When the switch 130 is turned on and off according to the operation mode, the on or off signal is applied to both the transistors 130 e and 130 f connected in series with opposite polarities irrespective of the direction of the current, thereby discharging or charging the main power storage device 4. It flows automatically according to the direction of. Since the switches 131 and 132 have the same configuration, the description is omitted.

Although the above description has been made in connection with the series hybrid electric vehicle, the present invention relates to other electric vehicles such as a parallel hybrid electric vehicle, an electric vehicle without a generator, and an electric vehicle powered by a fuel cell. Of the power supply system.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a power supply system of an electric vehicle according to an embodiment of the present invention.

FIG. 2 is a circuit diagram of the same block connection switching circuit.

FIG. 3 is a circuit diagram of the same switch.

FIG. 4 is an explanatory diagram of the operation.

FIG. 5 is an operation explanatory view of the same.

FIG. 6 is a circuit diagram of the chopper circuit.

FIG. 7 is an explanatory diagram of the operation of the chopper circuit.

FIG. 8 is an operation explanatory diagram of the chopper circuit.

FIG. 9 is an explanatory diagram of the operation.

FIG. 10 is a circuit diagram of a switch according to another embodiment.

FIG. 11 is a circuit diagram of a switch showing still another embodiment.

FIG. 12 is a configuration diagram of a power supply system of an electric vehicle showing a conventional example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 engine 2 generator 3 rectifier 4 main power storage device 5 inverter 6 running motor 10 battery block 11 battery block 12 battery block 13 block connection switching circuit 100 electric double layer capacitor cell 110 electric double layer capacitor cell 120 electric double layer capacitor cell 130 Bidirectional conduction switch 130a Thyristor 130b Thyristor 130c Reverse blocking GTO thyristor 130d Reverse blocking GTO thyristor 130e Transistor 130f Transistor 130g Diode 130h Diode 131 Bidirectional conduction switch 132 Bidirectional conduction switch

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H02J 7/14 H02J 7/14 H // B60K 6/02 B60K 9/00 C (71) Applicant 000005234 Fuji Electric Co., Ltd. 1-1-1, Tanabe-Nitta, Kawasaki-ku, Kawasaki-ku, Kanagawa-ken (72) Inventor Yoshito Watanabe Ichi-cho, Ichi-cho, Ageo-shi, Saitama Pref. Niisan Diesel Industry Co., Ltd. (72) Inventor Dio Okamura 2-19-6 Minamiota, Minami-ku, Yokohama, Kanagawa Prefecture Okamura Research Institute Co., Ltd. (72) Inventor Masaaki Yamagishi Yokohama, Kanagawa Prefecture 1-1-1 Fukuura, Kanazawa-ku, Yokohama Yokohama Kanazawa High-tech Center Techno Core 3F Inside Power System Co., Ltd. (72) Inventor Shigenori Kinoshita Tokyo First place in Fuji-cho, Hino-shi F-term in Fuji Electric Co., Ltd. (reference) RB19 SE06 TI05 TI06 TO13 TR19 TU06

Claims (6)

[Claims] 1. A power supply system for an electric vehicle, comprising: a main power storage device for supplying electric power to a traveling motor; wherein the main power storage device includes a plurality of electric double layer capacitor cells; A plurality of battery blocks configured by capacitor cells; and the battery blocks connected in series corresponding to a voltage change due to charging and discharging of the electric double layer capacitor cell such that a voltage of the main power storage device is equal to or higher than a specified value. A power supply system for an electric vehicle, comprising: 2. A power supply system for an electric vehicle according to claim 1, wherein electric power stored in each of said battery blocks is gradually changed such that a voltage of said main power storage device becomes a specified value or less. 3. A power supply system for an electric vehicle according to claim 1, wherein said block connection switching circuit is constituted by a bidirectional flow semiconductor switch. 4. A power supply system for an electric vehicle according to claim 3, wherein said two-way semiconductor switches are constituted by a pair of thyristors connected in antiparallel to each other. 5. The power supply system for an electric vehicle according to claim 3, wherein said two-way conduction type semiconductor switches are constituted by a pair of reverse blocking GTO thyristors connected in anti-parallel to each other. 6. The semiconductor switch according to claim 1, wherein said semiconductor switch comprises a pair of transistors connected in series with opposite polarities to each other and a diode connected in antiparallel to each of said transistors. 4. The power supply system for an electric vehicle according to 3.