JPH0739014A - Charging device for vehicle - Google Patents

Abstract

PURPOSE:To make a charging current definite by a method wherein, when a battery is charged by an inverter generating a three-phase alternating current, the secondary side of a transformer for a single-phase alternating current is connected to two arms for the inverter and remaining arms are connected to the battery via a DC inductance. CONSTITUTION:When a battery 1 is discharged, individual switching elements T1 to T6 for a three-phase inverter 7 are turned sequentially on and off by a signal from a gate circuit 13 via a contactor 4, the signal is converted into 3 three-phase VVVF, a contactor 11 is connected as shown in the figure, and an induction motor 12 is turned. When the battery 1 is charged, an AC single- phase power supply 14 is transformed by a transformer 16, a voltage which is lower than the voltage of the battery 1 is generated, the contactor 11 is changed over, the voltage is applied to two out of the arms T3 to T6 for the inverter 7 via two contacts, the voltage is rectified, and a capacitor 6 and the battery 1 are charged. The remaining arms T1, T2 are connected to the battery 1 via the contactor 11 and a DC inductance 20. Thereby, the battery is charged by a definite current.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to charging in an electric vehicle having a three-phase AC motor, an inverter and a battery, and more particularly to a charging device which makes an input current proportional to an input voltage and makes a charging current to a battery constant.

[0002]

2. Description of the Related Art As a conventional technique, there is JP-A-59-61402. In this method, a three-phase AC power source is used as an input to an electric vehicle having a three-phase AC motor, an inverter, and a battery.

If a three-phase AC power supply is used as input, charging can be performed with the charging current kept substantially constant. However, when a single-phase AC power supply is used as input, the charging current fluctuates considerably.

Therefore, there is a problem that a large current can flow to the battery.

The single-phase AC power supply is used as a general household power supply, and it can be charged with a power supply plug-in set to prevent a situation where the vehicle cannot run due to battery discharge.

[0006]

SUMMARY OF THE INVENTION In a charging device using a single-phase AC power source, the input current is proportional to the input voltage, that is, close to a power factor of 1, and the battery charging current is constant.

[0007]

The peak value of the secondary voltage of the transformer is set to a winding ratio which is lower than the nominal voltage of the battery. The impedance of the secondary winding of the transformer is 0.1m
It is assumed that the inductor has an inductance of H 2 to several mH. The operating frequency of the inverter that short-circuits the secondary winding of the transformer is set to several tens Khz.

The on-time (that is, the conduction ratio) of the inverter is controlled so that the output signal of the current sensor for detecting the current flowing through the secondary winding of the transformer becomes the same as the sine wave of the primary winding of the transformer. .

During the off-time of the inverter, the secondary winding of the transformer is short-circuited, the energy stored in the inductance and the voltage of the secondary winding of the transformer are added, and a capacitor (generally an electrolytic capacitor of several thousand micro F) is added. store.

An IGBT in which the charge stored in this capacitor is connected to the (+) side of one arm of a DC reactor DCL inverter is connected to the (-) side for switching.
A step-down switching regulator is constructed using the IGBT as a diode.

[0011]

Since the peak value of the secondary voltage of the transformer is kept lower than the nominal voltage of the battery, the rectified current by the diode of the inverter composed of the IGBT does not flow even if the alternating current (AC) single-phase power supply is connected. IGB connected to the (-) side
When T is turned on, a short-circuit current flows, but the on-time is shortened (the impedance value of the secondary winding and the operating frequency are set to appropriate values) to prevent a steep rise of the current.

When the inverter is turned off, a voltage is generated in the inductance, which tends to keep the current flowing, and this voltage is added to the voltage of the secondary winding of the transformer to charge the capacitor.

The electric charge charged in the capacitor causes a constant current to flow through the step-down switching regulator.

That is, the input power is stored in the capacitor (when the input power is larger than the power value obtained by multiplying the charging current by the voltage of the battery) and released (at a higher value than the power value obtained by multiplying the charging current by the voltage of the battery). When the input power is small), a constant charging current is passed.

[0015]

The present invention will be described below with reference to the drawings.

From the (+) power supply line 2 of the battery BAT1 to the (+) electric wire 5 via the contactor CONTA4 (electrolysis)
The capacitor CO6 is connected to a three-phase inverter 7 composed of IGBTs, T1 to T6, and the other terminal is (-).
Connect to power line 3.

The output of the three-phase inverter 7 is connected to the AC motor 12 via the current detecting current sensor (A) 8, the current sensor (B) 9, and the current sensor (C) 10 and the contactor CONTB11 for switching charging.

IGBT of the three-phase inverter 7, T1 to T
The gate circuit 13 applies a conduction signal to the gate of 6 to control the rotation of the AC motor 12.

Next, the charging circuit will be described.

From the alternating current (AC) single-phase power supply 14 to the fuse F
U15 and the primary winding 17 of the transformer 16 are connected.

The secondary winding 18 is connected to the contactor CONTB11 via the contactor CONTC19. In addition, the DC inductance DCL20 and the contactor CONTD21 are connected in series from the remaining contact of the contactor CONTB11 from the three-phase inverter 7 to the (+) power supply line 2.

FIG. 2 is a rewrite of FIG. 1 mainly for charging. The symbols shown in FIG. 1 are the same. Also IGB
A diode is used when T is used only as a diode. The gate circuit 13 includes a primary voltage value / phase detection circuit 22, a current control circuit 23, and a gate trigger circuit 2.
4, a voltage detection circuit 25, a trigger and a constant current control circuit 26.

The primary voltage value / phase detection circuit 22 detects the peak voltage of the alternating current (AC) single-phase power supply 14 and determines that it is lower than the battery voltage VB, and turns on the contactor CONTC14. If it is determined that the voltage is higher than the battery voltage VB, the contactor CONTC14 is not turned on and the capacitor CO is charged via the resistor R0. The phase detection is to determine the rising edge when the control current is made a sine wave.

The current control circuit 23 feeds back the signal of the current sensor to make the current sine wave.
The ON time of T is adjusted.

The gate trigger circuit 24 turns on the IGBT.
Turn off.

The voltage detecting circuit 25 has a voltage higher than the battery voltage, and the voltage detection circuit 25 does not exceed the withstand voltage of the circuit components.
This is to adjust the on-time of BT.

The trigger and constant current control circuit 26 controls the charging current to be constant while feeding back the signal of the current sensor (C) 10.

FIG. 3 shows the operation of FIG.

(A) shows the relationship between the secondary voltage of the transformer and the battery voltage VB.

Contact at battery voltage VB1 CONT
Turn on C19, and contact when battery voltage is VB2 CONT
Charging without charging C19 causes the battery voltage to rise and VB3
Then, the voltage of the capacitor CO is also increased.

(B) shows the voltage waveform of the capacitor CO at that time. Therefore, the charging current can be made constant.

FIG. 4 shows a charging circuit according to another method of the present invention.

A full-wave rectifier circuit (A) 28 consisting of a diode, a transistor TR1, and a DC inductance DCL (A) 29 are connected in series from an AC single-phase power supply 14 to (electrolytic) capacitors C0, 6.

A high frequency transformer 30 is provided at the output of the inverter 7.
The primary winding 30-1 is connected, the full-wave rectifier circuit (B) 31 and the DC inductance DCL 20 are connected from the secondary winding, and the battery 1 is connected. The diode D1 is a freewheel diode that circulates the current energy stored in the DC inductance DCL20. Capacitor C1
Is for noise absorption.

From the full-wave rectifier circuit (A) 28, the transistor TR2 and the DC inductance DCL (B) 32 are connected in series and connected to the capacitor C2 to be used as the power source of the DC-DC converter transformer 33. The diode D2 is a freewheeling diode for circulation.

The diodes D3 and D4 are for rectification and are used to charge the auxiliary battery (generally 12V) 34.

FIG. 5 is an explanatory diagram of the operation of FIG.

When the voltage of the rectified waveform is up to V1, the transistor TR2 is turned on / off, and when it is V1 or higher, the transistor TR1 is turned on / off to charge the high-voltage battery 1.

This system is characterized in that the transformer can be downsized.

A charging circuit using a three-phase AC power source, which can reduce the size of the transformer, will be described below.

FIG. 6 shows terminals R, S, T, of the three-phase AC power supply.
U, V, W and E of the inverter 7 are connected to E of FIG.
The symbols and numbers used here are the same as those described above. The additional circuit 36 is shown in FIG.

Rectifier circuits R1, 37, rectifier circuits S1, 3
8. Rectifier circuits T1, 39 rectify the voltage between the lines.
From the secondary windings of the insulating transformers R and 40 having two primary windings, the insulating transformer S41, and the insulating transformers T and 42, rectifying circuits R2 and 43, rectifying circuits S2 and 44, and rectifying circuits T2 and 45, respectively. Connect.

From the output of each rectifying circuit, the DC inductances DCL (R), DCL (S) DCL (T), the diode D11, the diode D12 and the diode D13 are connected in series and connected to the contactor CONTD.

Transistor TR11, transistor TR
12. The transistor TR13 is turned on when the output voltage of the isolation transformer is small, and then turned off to allow a charging current to flow.

This operation is shown in FIG.

[0046]

The input current is proportional to the input voltage, that is, close to the power factor of 1, and the battery charging current can be kept constant.

[Brief description of drawings]

FIG. 1 is a main circuit diagram of a vehicle charging control according to the present invention.

FIG. 2 is a connection diagram during charging of FIG.

FIG. 3 is an operation explanatory diagram of FIG. 2;

FIG. 4 is another vehicle charging control circuit diagram according to the present invention.

5 is an operation explanatory diagram of FIG. 4;

FIG. 6 is a vehicle charging control circuit diagram of a three-phase power supply according to the present invention.

FIG. 7 is a circuit diagram of a charging unit in FIG.

FIG. 8 is an operation explanatory diagram of FIG. 7;

[Explanation of symbols]

1 ... Battery BAT, 2 ... (+) power supply line, 3 ... (-) power supply line, 4 ... Contactor CONTA, 5 ... (+) electric wire, 6
... Capacitor CO, 7 ... Three-phase inverter, 8 ... Current sensor (A), 9 ... Current sensor (B), 10 ... Current sensor (C), 11 ... Contactor CONTB, 12 ... AC electric motor, 13 ... Gate circuit, 14 … AC (AC) single-phase power supply, 1
5 ... Fuse FU, 16 ... Transformer, 17 ... Primary winding, 1
8 ... Secondary winding, 19 ... Contactor CONTC, 20 ... DC inductance DCL, 21 ... Contactor CONT
D, 22 ... Primary voltage value / phase detection circuit, 23 ... Current control circuit, 24 ... Gate trigger circuit, 25 ... Voltage detection circuit,
26 ... Trigger and constant current control circuit, 28 ... Full wave rectification circuit
(A), 29 ... DC inductance DCL (A), 30 ... High frequency transformer, 31 ... Full wave rectification circuit (B), 32 ... DC inductance DCL (B), 33 ... Transformer, 34 ... Auxiliary battery, 36 ... Additional circuit .

Claims (1)

[Claims] 1. A battery, a three-phase motor, an inverter composed of an IGBT, and a battery to an inverter (+).
Consists of a (electrolytic) capacitor connected to the (-) electrode, a contactor that connects the output of the inverter to the (three-phase) AC motor, a contactor that inputs and shuts off the charging power supply, and a gate circuit that drives the inverter. In the electric vehicle, the secondary winding of the single-phase transformer is connected to the contactor for inputting or cutting off the charging power source, and the above-mentioned IGBT is connected.
Connected to two arms of an inverter composed of T, turning on / off the IGBT on the (-) electrode side of the inverter, charging the (electrolytic) capacitor connected to the (+) (-) electrode of the inverter, and charging the inverter. The DC inductance DCL and the contactor are connected in series to the battery from the third arm other than the two arms, and the IGBT on the (+) electrode side of the third arm is turned on / off to make the charging current of the battery constant. Characteristic vehicle charging device.