JPH0746713A - Charging control circuit for battery for electric car - Google Patents

Abstract

PURPOSE:To obtain a charging control circuit for electric cars capable of prolonging the life of an inverter circuit, and applicable to either a single phase or three phase, by causing a circuit to constitute a voltage boosting and lowering circuit for boosting and lowering voltage, and minimizing the degree of deterioration per switching device. CONSTITUTION:The charging control circuit has a transformer 40 for stepping up AC voltage obtained by an AC generator 20A, an inverter circuit 1A for converting the DC voltage of a battery 12 to AC voltage and outputting it to a motor 14, and lowering the AC power obtained by the transformer 40, and a rectifier circuit 30 connected between the inverter circuit 1A and the battery 12 for converting the lowered voltage power obtained by the inverter circuit 1A into DC and outputting it to the battery.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charge control circuit for an electric vehicle battery used in an electric vehicle.

[0002]

2. Description of the Related Art FIGS. 3 and 4 are circuit diagrams showing a conventional electric vehicle battery charging control circuit disclosed in Japanese Utility Model Laid-Open No. 63-44643. In FIG. 3, reference numeral 12 denotes an electric vehicle battery (hereinafter, simply referred to as battery),
Reference numeral 14 denotes a three-phase AC motor (hereinafter, simply referred to as a motor) connected to a drive shaft (not shown) of the electric vehicle. The motor 14 includes a U-phase reactor 14a, a V-phase reactor 14b, and a W-phase reactor. 14c. Further, 20 is an AC generator for charging the battery 12 (hereinafter referred to as A
CG). And 1 is an inverter,
The inverter 1 has switching elements U1 and U2, V1 and V2, W1 and W2, respectively, which form a pair, and the center points of the inverters are in the U-phase, V-phase, and W-phase reactors 14a, 14b, and 14c of the motor 14, respectively. It is connected via a switch described later. Note that D1, D2, D3, D4, D
5 and D6 are switching elements U1, U2 and V, respectively.
Flywheel diodes provided at 1, V2, W1, and W2.

Further, in FIG. 3, 22, 24, 26,
28 is a changeover switch, and the changeover switch 22
Is a movable contact 22C connected between the switching elements V1 and V2, and a fixed contact 22B connected to the ACG 20.
Alternatively, it is connected to one of the fixed contacts 22A which is a connection point of the motor 14 to the V-phase reactor 14b. In the changeover switch 24, the movable contact 24C connected between the switching elements W1 and W2 is either the fixed contact 24B connected to the ACG 20 or the fixed contact 24A which is a connection point of the motor 14 to the W-phase reactor 14c. Connected to the crab. Further, in the changeover switch 26, the movable contact 26C connected to the output sides of the switching elements U2, V2, W2 is the fixed contact 26 connected to the battery 12.
It is connected to either A or the fixed contact 26B which is a connection point of the motor 14 to the V-phase reactor 14b. Then, the changeover switch 28 includes the switching element V1,
The movable contact 28C connected to the input side of W1 is the motor 1
Fixed contact 28 connected to the V phase reactor 14b of No. 4
B or a fixed contact 28A connected to the battery 12 is connected.

FIG. 4 is a circuit diagram showing a step-down charge control circuit for an electric vehicle battery. 3 that are the same as those shown in FIG. 3 are the same as those shown in FIG. 3, and description thereof is omitted here. Reference numeral 30 denotes a changeover switch. The changeover switch 30 has a movable contact 30C connected to the battery 12, a fixed contact 30B connected to the V-phase reactor 14b of the motor 14, or a switching element U1.
It is connected to one of the fixed contacts 30A connected to the input side of V1 and W1.

Next, the operation of the conventional charging control circuit for the electric vehicle battery will be described. In FIG. 3, when the electric vehicle travels, the changeover switches 22, 2
4, 26, 28 movable contacts 22C, 24C, 26C, 2
8C is connected to the fixed contacts 22A, 24A, 26A, 28A, and the electric power from the battery 12 is supplied to the motor 14 via the inverter circuit 1 to drive the motor 14. By driving the motor 14, the drive shaft of the electric vehicle rotates.

Next, when charging the battery 12 for an electric vehicle, the movable contacts 22C, 24C, 26C, 28C of the switches 22, 24, 26, 28 are replaced with the fixed contacts 22B, 24B, 26B, 28B as shown in the figure. Connecting. ACG2
The electric power supplied from 0 goes through the switches 22 and 24 to flywheel diodes D3 and D4 and D5 and D.
6 and the motor 1 through the switch 28.
4 is input. And the V-phase reactor 1 of the motor 14
4b, boosted by the U-phase reactor 14a and the switching element U2, and supplied to the battery 12 via the flywheel diode D1 to charge the battery 12. The charge control circuit shown in FIG. 3 has the same configuration as the boost chopper circuit shown in FIG.

Further, in FIG. 4, when charging the battery 12, the movable contacts 2 of the switches 22, 24 and 30 are set.
2C, 24C and 30C are fixed contacts 22B and 2C as shown.
Connect to 4B and 30B. Then, the power supplied from the ACG 20 is rectified by the flywheel diodes D3 and D4 and D5 and D6 via the switches 22 and 24,
The voltage is stepped down by the switching element U1 inside the inverter circuit 1 and the V-phase reactors 14b and 14a inside the motor, and further supplied to the battery 12 via the switch 30 to charge the battery 12. In this case, the charge control circuit shown in FIG. 4 is equivalent to the step-down chopper circuit shown in FIG.

[0008]

The conventional charging control circuit for the electric vehicle battery is constructed as described above, and the number of batteries (battery voltage) mounted on the vehicle and the AC
Depending on the relationship with the voltage of G, it is determined whether the charging circuit should be a step-up charging control circuit or a step-down charging control circuit, and there is a problem that either one has to be selected and mounted on the vehicle. Further, in the conventional electric vehicle battery charge control circuit, when the inverter circuit operates as a chopper circuit at the time of charging, one switching element inside the inverter circuit is operated both at the time of traveling and at the time of charging, and both of these switching elements are operated. There is a problem that the life is shorter than that of other switching elements that are not operated together. Further, the circuits shown in FIGS. 3 and 4 have a problem that only a single-phase alternating current can be used as a charging power source.

The present invention has been made in order to solve the above-mentioned problems, and simplifies the circuit configuration, such as configuring a step-up / step-down voltage step-up / down circuit with a single circuit. In addition to being able to minimize the degree of deterioration per switching element, it prolongs the life of the inverter circuit, and can control the charging of the electric vehicle battery that can be used in either single-phase or three-phase. The purpose is to get the circuit.

[0010]

An electric vehicle battery charging control circuit according to claim 1 of the present invention drives an AC motor by a battery and charges the battery by an AC generator. An inverter circuit for converting the DC voltage of the battery into an AC voltage and outputting the AC voltage to the AC motor, and for stepping down the AC voltage obtained from the AC generator; the inverter circuit; Connected between batteries,
A rectifier circuit that converts the step-down voltage obtained by the inverter circuit into a direct current and outputs the direct current to the battery.

According to a second aspect of the present invention, there is provided a charge control circuit for a battery for an electric vehicle, wherein an AC motor is driven by the battery and the battery for the electric vehicle is charged by an AC generator. In the control circuit, a transformer for boosting the AC voltage obtained by the AC generator, and the DC voltage of the battery is converted to an AC voltage and output to the AC motor, while the AC voltage obtained by the transformer. And a rectifier circuit that is connected between the inverter circuit and the battery and that converts the stepped-down voltage obtained by the inverter circuit into direct current and outputs the direct current to the battery.

[0012]

According to the charge control circuit for an electric vehicle battery according to claim 1 of the present invention, the inverter circuit converts the DC voltage of the battery into an AC voltage and outputs the AC voltage to the AC motor, while the AC voltage changes. The AC voltage obtained from the generator is stepped down. The rectifier circuit converts the step-down voltage obtained by the inverter circuit into direct current and outputs the direct current to the battery to charge the battery.

According to a second aspect of the present invention, there is provided a charge control circuit for an electric vehicle battery, wherein:
The AC voltage obtained by the AC generator is boosted. The inverter circuit converts the DC voltage of the battery into an AC voltage and outputs the AC voltage to the AC motor, while stepping down the AC voltage obtained from the transformer. The rectifier circuit is connected between the inverter circuit and the battery, converts the step-down voltage obtained by the inverter circuit into direct current and outputs the direct current to the battery to charge the battery.

[0014]

EXAMPLES Example 1. An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, the same reference numerals as those in FIG. 3 or FIG. 4 indicate the same or equivalent parts as those shown in FIG. 3 or FIG. In FIG. 1, 20A is a three-phase AC generator (hereinafter simply referred to as ACG), 30 is a rectifier circuit that changes three-phase AC into DC, and this rectifier circuit 30 has three input terminals 30a to which three-phase AC is input. , 30b, 30c, and two output terminals 30d, 30e for outputting direct current
Have. Reference numeral 40 is a transformer that boosts the three-phase alternating current output from the ACG 20A and outputs the boosted three-phase alternating current to the inverter circuit 1.
This transformer has three input terminals 40a, 40b, 40c connected to the ACG 20A and three output terminals 40d, 40e, 40f connected to the inverter circuit 1A.

The switch 52 in the inverter circuit 1A
Is a movable contact 52C connected to the midpoint of the flywheel diodes D1 and D2, a fixed contact 52A connected to the midpoint of the switching elements U1 and U2, or the transformer 40.
To one of the fixed contacts 52B connected to one of the output terminals 40f. Also, the switch 54 in the inverter circuit 1A is a movable contact 54C connected to the intermediate point of the flywheel diodes D3 and D4, a fixed contact 54A connected to the intermediate point of the switching elements V1 and V2, or one output terminal of the transformer 40. It connects to either of the fixed contacts 54B connected to 40e. Further, the switch 56 in the inverter circuit 1A has a movable contact 56C connected to the midpoints of the flywheel diodes D5 and D6, a fixed contact 56A connected to the midpoints of the switching elements W1 and W2, or one output of the transformer 40. Terminal 40d
To one of the fixed contacts 56B connected to.

Numerals 58 and 59 are switches interlocking with each other, and the movable contacts 58C and 59C are fixed contacts 58A and 59A or fixed contacts 58B and 59, respectively.
Connect to either B. Fixed contact 58 of switch 58
A is three switching elements U of the inverter circuit 1A
It is connected to the input side of 1, V1, and W1. Fixed contact 5
8B is connected to the output terminal 30d of the rectifier circuit 30. Further, the fixed contact 59A of the switch 59 is connected to the output sides of the three switching elements U2, V2, W2 of the inverter circuit 1A. The fixed contact 59B is connected to the other output terminal 30e of the rectifier circuit 30.

Further, reference numeral 60 denotes three interlocking switches, and these switches 60 are the fixed contacts 52 described above.
Moving contacts 60 connected to A, 54A and 56A, respectively
Fixed contacts 6 in which C-1 to 60C-3 are connected to U-phase, V-phase, and W-phase reactors 14a, 14b, and 14c, respectively.
0A-1 to 60A-3, or fixed contacts 60B- connected to the input terminals 30a, 30b, 30c of the rectifier circuit 30.
Connect to any of 1 to 60B-3.

Next, the operation of the first embodiment will be described.
First, when the electric vehicle powers, the switches 52, 5
Movable contacts 52C, 54 of 4, 56, 58, 59, 60
C, 56C, 58C, 59C, 60C-1 to 60C-3
Fixed contacts 52A, 54A, 56A, 58A,
59A, 60A-1 to 60A-3. Since the circuit operation in this case has been described with reference to FIG. 3, description thereof is omitted here.

Next, when the battery 12 is being charged, the movable contacts 52 of the switches 52, 54, 56, 58, 59 and 60.
C, 54C, 56C, 58C, 59C, 60C-1 to 6
0C-3 are fixed contacts 52B, 54B, 56B,
58B, 59B, 60B-1 to 60B-3.
The electric power supplied from the ACG 20A as the electric power supply source is boosted by the transformer 40 and the switches 52, 5
Flywheel diodes D1, D2,
It is rectified by D3, D4, D5, D6, and then converted into alternating current again by the switching elements U1, U2, V1, V2, W1, W2. At this time, the inverter circuit 1
It is stepped down by the PWM frequency that controls A. The reduced voltage is rectified by the rectifier circuit 30 and charges the battery 12 of the electric vehicle through the switches 58 and 59.

FIG. 2 shows each of the switches 52,
1 is a circuit diagram equivalently showing a circuit at the time of charging configured by switching 54, 56, 58, 59, 60.
The same reference numerals are given to the same items.

Example 2. In the first embodiment described above, the example in which the transformer 40 is provided to sufficiently charge the battery 12 by boosting the voltage even when the voltage obtained from the ACG 20A is low has been described. When the voltage obtained from the ACG 20A is high enough to sufficiently charge the battery 12, the output of the ACG 20A is directly connected to the switches 52, 54, 56 of the inverter circuit 1A without providing the transformer 40.
The same effect as that of the first embodiment can be obtained by connecting to.

[0022]

According to the charge control circuit for a battery for an electric vehicle according to claim 1 of the present invention, the battery for an electric vehicle is configured such that the battery drives the AC motor and the AC generator charges the battery. In the charging control circuit of the above, while converting the DC voltage of the battery into an AC voltage and outputting the AC voltage to the AC motor, an inverter circuit that steps down the AC voltage obtained from the AC generator, and between the inverter circuit and the battery Connected to the rectifier circuit for converting the step-down voltage obtained by the inverter circuit into a direct current and outputting it to the battery, the circuit configuration is simplified and the degree of deterioration per switching element of the inverter circuit is increased. Can be kept to a minimum, and the life of the inverter circuit can be lengthened, and single-phase and three-phase An effect that can be used in displacement.

According to the second aspect of the present invention, there is provided the electric vehicle battery charge control circuit, wherein the battery drives the AC motor and the AC generator charges the battery. In the charge control circuit of, a transformer for boosting the AC voltage obtained by the AC generator, and the DC voltage of the battery is converted into an AC voltage and output to the AC motor, while being obtained by the transformer. An inverter circuit that steps down the AC voltage,
Since the rectifier circuit is connected between the inverter circuit and the battery and converts the step-down voltage obtained by the inverter circuit to direct current and outputs the direct current to the battery, a step-up / step-down circuit for step-up and step-down is provided as one. Since it can be configured with a circuit, the circuit configuration can be simplified, the deterioration degree per switching element of the inverter circuit can be minimized, and thus the life of the inverter circuit can be extended and the single phase There is an effect that any of the three phases can be used.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a first embodiment.

FIG. 2 is an equivalent circuit diagram of the circuit of FIG. 1 during charging.

FIG. 3 is a circuit diagram showing a conventional charge control circuit for an electric vehicle battery.

FIG. 4 is a circuit diagram showing a conventional charge control circuit for a battery for an electric vehicle.

FIG. 5 is a circuit diagram showing a boost chopper circuit.

FIG. 6 is a circuit diagram showing a step-down chopper circuit.

[Explanation of Codes] 1A Inverter circuit 12 Battery for electric vehicle 14 Motor 20A ACG 30 Rectifier circuit 40 Transformer

Claims (2)

[Claims] 1. A charging control circuit for a battery for an electric vehicle, wherein an AC motor is driven by a battery and the battery is charged by an AC generator, and a DC voltage of the battery is converted into an AC voltage to convert the AC voltage. An inverter circuit for stepping down the AC voltage obtained from the AC generator while outputting to the motor, and connected between the inverter circuit and the battery, and converting the stepped-down voltage obtained by the inverter circuit into DC, A charge control circuit for an electric vehicle battery, comprising: a rectifier circuit that outputs to a battery. 2. A charging control circuit for an electric vehicle battery, wherein an AC motor is driven by a battery and the battery is charged by an AC generator, and a transformer for boosting the AC voltage obtained by the AC generator. A converter, which converts the DC voltage of the battery into an AC voltage and outputs the AC voltage to the AC motor, and an inverter circuit which steps down the AC voltage obtained from the transformer, and is connected between the inverter circuit and the battery, A charge control circuit for a battery for an electric vehicle, comprising: a rectifier circuit that converts a step-down voltage obtained by the inverter circuit into a direct current and outputs the direct current to the battery.