JP3330714B2 - Battery charging / discharging device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery charging / discharging device, and more particularly to a device for regenerating a discharge output to a power supply.

[0002]

2. Description of the Related Art Conventionally, as a charging / discharging apparatus of this type, for example, as shown in Japanese Patent Application Laid-Open Nos. 2-261020 and 2-261221 shown in FIG. 3 phase converter 1 which is a rectifier circuit for charging
And a three-phase inverter 3 serving as a discharge rectifier circuit in parallel, and a storage battery 8 connected via a smoothing circuit composed of a reactor 5 and a capacitor 6 and a chopper circuit 7 composed of a diode bridge and a transistor. I am taking it. In these known devices, the converter 1 is controlled by the charging drive circuit 2, the chopper circuit 7 is controlled by the current flowing through the storage battery 8, and the discharge is performed by the voltage across the capacitor 6 of the smoothing circuit and the current of the inverter 3. The control circuit 4 controls the inverter 3. This is a principle configuration in which the discharge current is prevented from being wasted as heat when the storage battery 8 is discharged, and is regenerated to the power supply.

[0003]

When this apparatus is actually operated, the output of the three-phase converter 1 is stepped down by the chopper circuit 7 and supplied to the storage battery 8 to be supplied to the storage battery 8.
Is charged. At the time of discharging after charging, the output of the storage battery 8 is stepped down by the chopper circuit 7 and supplied to the three-phase inverter 3.

As a result, a voltage considerably lower than the output voltage of the three-phase converter 1 is applied to the input terminal of the three-phase inverter 3 at the time of discharging, and a regenerative output cannot be sent from the three-phase inverter 3 to the AC power supply. .

The present invention has been made in consideration of the above points, and has been made in consideration of the above-described circumstances, and has been made in consideration of the above-described circumstances. A discharge device is provided.

[0006]

In order to achieve the above object, according to the present invention, an alternating current from an alternating current power supply is converted by a converter and smoothed through a smoothing circuit. A storage battery discharging apparatus for repeatedly performing alternating current conversion from a storage battery through a chopper circuit by an inverter and performing regenerative discharge on an AC power supply, wherein the AC from the AC power supply is DC converted to a capacitor in the smoothing circuit. A rectifier circuit for charging the battery, a pair of first diodes each having one pole connected to each other and connected in the opposite direction to each other in an open state, and when charging and discharging the storage battery. A switching operation is performed, a first switch selectively connected to one of the other poles of the first diode, a controllable switching element, and a second diode. A series circuit of, and the second
A third diode in the opposite direction to the diode and connected in parallel with the series circuit, and a bidirectional current path connected in series between the first switch and one pole of the storage battery; It is switched at the same time as the first switch, and connects the switching element in the bidirectional current path with the second diode to the other pole of the storage battery when the storage battery is discharged, and opens when charging the storage battery. A storage battery charging / discharging device provided with a second switch.

[0007]

According to the first aspect of the present invention, when charging the storage battery, the converter converts AC into DC, smoothes it with the smoothing circuit, and supplies power to the storage battery while controlling the charging current with the chopper circuit. When discharging from the storage battery, the power from the storage battery is boosted and supplied to the inverter while controlling the discharge current by the chopper circuit, and the inverter converts the power into AC. At this time, the capacitor of the smoothing circuit provided between the chopper circuit and the inverter circuit is charged from the rectifier circuit and has a higher voltage than the voltage of the storage battery. Thereby, the boosting operation of the chopper at the time of discharging is stably performed.

According to the configuration of the second aspect, the charging and discharging current of the battery is controlled by the switching operation of the transistor as the controllable switching element.

[0009]

According to the first aspect of the present invention, the voltage between both ends of the capacitor of the smoothing circuit connected to the input terminal of the inverter at the time of discharging is kept high by the boosting operation of the chopper circuit. The voltage also increases, and the AC power is well regenerated.

According to the configuration of the second aspect, charging and discharging of the storage battery can be smoothly performed by controlling the opening and closing of the transistor of the chopper circuit.

[0011]

FIG. 1 shows an embodiment of the present invention. In the figure, TR is a transformer, which takes in AC power from its primary winding W1 to generate an output in a secondary winding W2 and a tertiary winding W3, and outputs the output of the secondary winding W2 to a converter CONV. The DC power is supplied to the storage battery BAT, and the output of the tertiary winding W3 is rectified by the rectifier RECT to charge the capacitor C1 in the smoothing circuit including the inductance L1 and the capacitor C1. On the other hand, the secondary winding W2 is connected to the inverter IN when discharging the storage battery BAT.
An output obtained by AC conversion by V is regenerated to an AC power supply.

When charging / discharging the storage battery BAT, a chopper CH composed of a transistor Q1, diodes D1-D5, a changeover switch SW and the like controls current. This current control is performed by the control circuit CONT3 in accordance with the inflow or outflow current of the storage battery BAT detected by the shunt SH to charge and discharge the storage battery BAT. The storage battery BAT has an inductance L2 and a capacitor C2.
Are connected.

The control of the converter CONV is performed by a control circuit CONT1 in accordance with the voltage across the capacitor C1 detected by the voltage divider VD, and the control of the inverter INV is controlled by the voltage across the capacitor C1 detected by the voltage divider VD. This is performed by the control circuit CONT2.

In the circuit shown in FIG. 1, when the changeover switch SW is turned to the charging side C, the chopper CH
Is charged to charge the storage battery BAT, and when the changeover switch SW is turned to the discharging side D, the chopper CH is connected so as to discharge from the storage battery BAT.

At the same time, the switching of the changeover switch SW causes the converter CONV and the inverter INV to operate.
Are selectively operated to charge the storage battery BAT or discharge from the storage battery BAT.

When the changeover switch SW is moved to the charging side C, a circuit configuration for supplying power to the storage battery BAT is obtained. That is, the control circuit CONT1 operates and the converter CO
NV is in operation state, and diode C
1. A step-down chopper is formed by the transistor Q1, the diodes D2 and D4, the inductance L2 of the smoothing circuit, and the capacitor C2. . The current supplied to the storage battery BAT is detected by the shunt SH, and the control circuit C
The signal is compared with the reference signal by the ONT3, and a signal corresponding to the comparison result is supplied to the transistor Q1. As a result, the on / off of the transistor Q1 is controlled, and the charging current to the storage battery BAT is controlled. At this time, the diodes D3, D
5 does not participate in the operation.

Next, when the changeover switch SW is moved to the discharging side D, the circuit configuration is such that the storage battery BAT is discharged.
That is, the control circuit CONT2 operates to operate the inverter I
The NV is in the operation state, and the path including the inductance L2, the diode D3, and the transistor Q1 is connected between both ends of the storage battery BAT in the chopper CH. And
When the transistor Q1 is on, the current from the storage battery BAT returns to the storage battery BAT through the inductance L2, the diode D3, and the transistor Q1. Thereby, energy is stored in the inductance L2. Next, when the transistor Q1 is turned off, the energy stored in the inductance L2 flows as current into the capacitor C1 via the diodes D3 and D5, and the energy stored in the inductance L2 transfers to the capacitor C1.

It should be noted here that the capacitor C1 is always connected to the rectifier circuit RECT, and the voltage across the both ends is kept higher than the charging voltage of the storage battery. Here, the chopper CH operates as a boost chopper, but if the terminal voltage of the capacitor C1 is
If the charge voltage is lower than the charging voltage of the AT, the changeover switch SW is moved to the discharging side, and at the same time, discharging starts through the inductance L2 and the diodes D3 and D5, so that a normal operation as a boost chopper cannot be performed. Since the voltage between both ends of the capacitor C1 is maintained higher than the charging voltage of the storage battery BAT, the chopper CH operates as a step-up chopper, and as a result, the inverter INV forms an output of a voltage sufficient to regenerate the AC power. It can be fed to the secondary winding of the transformer TR.

During this time, the control circuit CONT3 controls the on / off time of the transistor Q1 so that the discharge current of the storage battery BAT becomes constant. Further, the control circuit CONT2 controls the inverter INV so that the voltage between both ends of the capacitor C1 becomes constant.

FIG. 2 shows the diode D in the circuit of FIG.
1, another example of D5 and one of the switches SW is shown. That is, in FIG. 2A, a transistor Qc is connected in series with the diode D1, and a transistor Qd is connected in series with the diode D5. When the transistor Qc is on, a charging path is formed, and the transistor Qd is turned on. In some cases, a discharge path is formed. In FIG. 2B, the diodes D1 and D5 are connected in anti-series, and the transistors Qc and Qd are connected in parallel with the respective diodes to form a bridge circuit. The transistor Qd is turned on to form a discharge path.

As the switching element shown as a transistor, a self-extinguishing type element such as a bipolar transistor, a MOS transistor, a gate-controlled thyristor, or an IGBT may be appropriately selected and used.

[Brief description of the drawings]

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

FIG. 2 shows diodes D1 and D in the embodiment of FIG.
FIG. 5 is a diagram showing a circuit configuration replacing 5 and a switch SW.

FIG. 3 is a diagram showing a circuit configuration of a conventional battery charging / discharging device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 rectifier circuit for charging 2 driving circuit for charging 3 inverter 4 driving circuit for regeneration 5 reactor 6 capacitor 7 chopper 8 storage battery BAT storage battery CH chopper CONT control circuit CONV converter INV inverter Q transistor SH current divider SW switch TR transformer VD voltage divider

Claims (2)

(57) [Claims] A converter converts an alternating current from an alternating current power supply and converts the smoothed direct current through a smoothing circuit to a storage battery through a chopper circuit. After charging, the direct current passed through the chopper circuit from the storage battery is converted to an alternating current by an inverter. A rechargeable battery discharge device for repeatedly performing regenerative discharge on an AC power supply, wherein a rectifier circuit for converting AC from the AC power supply to DC and charging a capacitor in the smoothing circuit; A pair of first diodes connected to each other and connected in the opposite direction to each other in an open state, a switching operation is performed between charging and discharging of the storage battery, and the other diode of the first diode A first switch selectively connected to one of: a series circuit of a controllable switching element and a second diode; and a reverse of the second diode. A third diode oriented and connected in parallel to the series circuit;
A bidirectional current path connected in series between the first switch and one pole of the storage battery; and a switching element in the bidirectional current path that is switched at the same time as the first switch and discharges the storage battery. And a second switch that connects an interconnection point with the second diode to the other pole of the storage battery and that opens during charging. 2. The battery charging / discharging device according to claim 1, wherein the controllable switching element is a transistor.