JPH06133564A - Battery charger - Google Patents

Abstract

PURPOSE:To obtain a light weight battery charger which can be built in an electric automobile. CONSTITUTION:In a battery charger to be bridged across battery voltage and equipped with a chopper circuit 2 for driving a motor 6, a series circuit of two diodes 31, 32 is connected across the battery voltage while a charging power supply 10 is connected between the joint of two diodes and one output terminal of the chopper circuit and charging control of the battery is performed through switching of the chopper circuit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery charging device in a device for driving an electric motor from a battery via a chopper circuit such as an electric vehicle.

[0002]

2. Description of the Related Art As a battery charging device for an electric vehicle, a battery charging device shown in FIG. 6 (Japanese Patent Laid-Open No. 59-123433) is known. The outline of this device will be described below.

AC power is supplied from a battery 1 to a motor 6 via a chopper bridge 2. Chopper bridge 2
Is a three-phase bridge composed of IGBTs 21 to 26, and the current detectors 3 and 5 detect the motor current. When the electric motor 6 is driven, the contactor 4 is closed, and when the accelerator is stepped on, the torque reference is input from the torque setting device 11 to the current reference circuit 13 via the switching device 12. A speed or position signal detected by a speed sensor (or a position sensor) 7 directly connected to the electric motor 6 is input to a current reference circuit 13 via a switch 14, and receives the torque reference, and the current reference circuit 13 is changed to an electric motor. Current reference Iu ^* , Iv ^* , Iw ^* Is output.

The current detectors 3 and 5 detect the U-phase and W-phase currents Iu and Iw, and the addition circuit 16 adds Iu and Iw to calculate the V-phase current Iv. Each current Iu,
Iv and Iw are current reference Iu ^* , Iv ^* , Iw ^* Is compared with a logic signal by the PWM circuit 15, and the IGBT of the chopper bridge is driven through the drive circuit 17 to control the motor current so as to match the current reference and generate the required torque.

Next, the case where the vehicle is put in the garage and the battery is charged will be described. With the contactor 4 in the open state, another power source 10 (generally a household power source of 100 V AC is considered) is connected, and a filter 9 (for the purpose of preventing radio noise and high-frequency current outflow) is used. One line of the U phase is connected to the other line of the W phase via the reactor 8.
The level detector 18 detects the zero-cross point of the separate power source 10 and inputs it to the current reference circuit 13 via the switcher 14.

On the other hand, when the battery voltage and the voltage reference 20 are compared and amplified by the amplifier 19 and used as the battery charging current reference and input to the current reference circuit 13 via the switching circuit 12, the current reference circuit 13 is separated from the zero cross point. The current reference Iu * with a power factor of 1 synchronized with the power supply 10 is output, and compared with the current Iu detected by the current detector 3 to the PWM circuit 15 and the drive circuit.
The IGBTs 21, 22, 25 and 26 are driven via 17, and a current having a power factor of 1 is made to flow from another power source 10 by the boosting chopper circuit composed of the reactor 8 to charge the battery.

[0007]

The battery voltage is 300.
To charge a V, 100 AH class battery in about 8 hours, it is necessary to flow about 40 to 50 A at 100 V AC. Therefore, the reactor 8 has a considerable size and weight.
Furthermore, the contactor 4 has a rating of about 200 A, and if the battery charging circuit is built into the vehicle, it will be heavy by 15 to 20 kg and fuel consumption will deteriorate. It is very important to reduce the mass to improve the efficiency of electric vehicles.

[0008] As described above, in the conventional system, since the built-in vehicle charging device is heavy and causes deterioration of fuel efficiency, it is desirable to install the battery charging device outside. However, in order to popularize the electric vehicle to the general public, a lightweight charging device built into the vehicle has been desired.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a battery charging device which can be incorporated in an electric vehicle by omitting a reactor to reduce the weight of the device. To do.

[0010]

(1) In a device provided with a chopper circuit for bridge driving between positive and negative battery voltages and controlling and driving an electric motor, two diodes connected in series between positive and negative battery voltages are connected in series. Circuit, a series connection point of the two diodes and one of the chopper circuit
A charging power source is provided between the two output terminals, and the charging of the battery is controlled by switching the chopper circuit.

(2) In addition to the configuration of the above item (1), a switch for opening a part of the chopper circuit is further provided, and the chopper circuit is used as a step-up chopper or a step-down chopper to control the charging of the battery.

[0012]

[Operation] (1) 1 of chopper circuit to which charging power source is connected
The chopper arm at one output end is made non-conductive, and the chopper arm at the other output end, the reactor component of the motor winding, and the two diodes constitute a chopper, and the chopper arm at the other output end is switching-controlled. Then, charge the battery from the charging power supply.

(2) A part of the chopper circuit is opened by a switch, and the chopper composed of the chopper arm at the other output end, the reactor component of the motor winding and the two diodes described above is either a boost chopper or a descent chopper. Make it work continuously.

[0014]

An embodiment of the present invention is shown in FIG. 1 and will be described below. In FIG. 1, the same parts as those in FIG. 6 are designated by the same reference numerals and the description thereof will be omitted.

A one-phase bridge composed of diodes 31 and 32 is connected between the DC power supplies of the chopper bridge 2, and one line is connected from another power supply 10 via the filter 9. The other one wire of the separate power source 10 is connected to the W-phase motor winding through the filter 9.

In the above structure, the control for driving the electric motor 6 is exactly the same as that shown in FIG. Figure 2 shows the current reference in this case.
It shows in (a). When charging the battery 1, the position of the changeover switch 12 is the position shown in FIG. IGBT21,22
Only the switching is performed and all the other IGBTs are turned off. An equivalent circuit in this state is shown in FIG.

The potential on one side is connected to the W-phase terminal of the electric motor 6 from the separate power source 10 through the filter 9, the winding between the U-phase and the W-phase of the electric motor is used as the inductance L, and the current detector is connected from the U-phase terminal. The current is detected by 3 and the IGBTs 21, 22 and the diodes 31, 32 constitute a step-up chopper. The other terminal out of the filter 9 is connected to the AC terminals (serial connection points) of the diodes 31 and 32.

FIG. 2 shows the relationship between voltage and current in this state.
It shows in (b). The level detector 18 detects the zero-cross phase of the voltage V10 of the separate power source 10 and the current reference Iu synchronized with V10.
^* Is output and the current Iu is Iu ^* The IGBTs 21 and 22 are driven by PWM control so as to match with, and the boost chopper operation is performed. The filter 9 is for removing high frequency components contained in Iu. According to this embodiment, only the diodes 31 and 32 are attached and the 200 A class contactor 4 and the reactor N8 which have been conventionally used can be omitted.

The diodes 31 and 32 are modularized, and
Weight of only 180g including 2 pieces of A rating. On the other hand, the omitted reactor is about 15 to 20 kg, and the contactor is 1
Since the weight is about kg, the size and weight can be remarkably reduced, and a highly efficient battery charger which leads to an improvement in fuel consumption can be constructed. Moreover, since the charging circuit is installed in the car, it can be charged simply by inserting the plug from the AC power supply at home.

It is needless to say that in FIG. 1, another inductance can be added between the motor and another power source when the inductance of the motor is insufficient.

In the apparatus shown in FIG. 1, the boost chopper can charge the battery only when the voltage of the battery is higher than that of the separate power source. However, the separate power source is AC200V,
When the battery voltage is 250 V, a system that can respond to changes in the battery voltage and changes in the voltage of another power supply, and that can use a buck-boost chopper to charge batteries that are lower than or higher than another power supply is available. is necessary. This is realized by the second embodiment shown in FIG. 5 (a). Compared to the embodiment of FIG. 1, a contactor 4 for opening a part of a DC bus is provided, diodes 33 and 34 are added to form a single-phase full-wave rectifier circuit, and its AC terminal is connected via a filter 9. Connect to another power supply 10. In the above configuration, when driving the electric motor 6, the contactor 4 is closed. When charging the battery 1, the contactor 4 is opened and only the IGBT22 and the IGBT25 are switched. This equivalent circuit is shown in FIG. When charging as a step-up chopper, the IGBT 25 keeps the ON signal and switches the IGBT 22 by PWM control to control the input current. When charging as a step-down chopper, the IGBT 22 keeps the off signal, and the IGBT 25 performs chopping to charge the battery. The step-up / step-down chopper can continuously control step-up and step-down by a PWM signal comparing two sets of triangular waves and a control signal as shown in FIG. Further, in the case of a DC motor as the electric motor, the present invention can be similarly applied only by using a chopper circuit as a single-phase bridge. In the above description, the case where the separate power source 10 is an alternating current has been described, but it goes without saying that it can also be used for a direct current power source such as a solar cell.

[0022]

As described above, according to the present invention, the reactor which has a large volume and mass in the charging device can be omitted by utilizing the inductance component of the motor winding, so that the size and weight can be reduced. Since the contactor can be omitted by designing the battery voltage higher than the separate power source, it is possible to realize a compact, lightweight, economical, reliable, fuel-efficient, built-in battery charger.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram showing an embodiment of the present invention.

FIG. 2 is an operation explanatory diagram of the above embodiment.

FIG. 3 is an equivalent circuit during operation of the above embodiment.

FIG. 4 is a PWM control waveform diagram showing a control method according to a second embodiment of the present invention.

5A is a second embodiment of the present invention, FIG.
(B) is its equivalent circuit

FIG. 6 is a circuit configuration diagram of a conventional battery charger.

[Explanation of symbols]

1 ... Battery, 2 ... Chopper bridge, 21-26 ... IGB
T, 3, 5 ... Current detector, 6 ... Electric motor, 7 ... Speed sensor, 8 ... Reactor, 9 ... Filter, 10 ... Separate power supply, 11 ...
Torque setter, 12 ... Switching circuit, 13 ... Current reference circuit, 14 ...
Switching circuit, 15 ... PWM circuit, 16 ... Addition circuit, 17 ... Driving circuit, 18 ... Level detection circuit, 19 ... Amplifier, 20 ... Voltage reference,
31-34 ... Diode.

Claims (2)

[Claims] 1. A device including a chopper circuit bridge-connected between positive and negative of a battery voltage to control and drive an electric motor, wherein a series circuit of two diodes connected between the positive and negative of the battery voltage and the two A battery charging device, wherein a charging power source is provided between a series connection point of diodes and one output terminal of the chopper circuit, and charging control of a battery is performed by switching of the chopper circuit. 2. The battery charging device according to claim 1, wherein a switch for opening a part of the chopper circuit is provided, and battery charging control is performed by using the chopper circuit as a step-up chopper or a step-down chopper. Charging device.