KR101220910B1 - Zero voltage discharge circuit having active switching elements of parallel type - Google Patents

Abstract

The present invention relates to a zero voltage discharge circuit having a parallel active switching element, wherein four switching elements are arranged to be alternately turned on / off in a first switching means connected to a direct current power source, and also between a transformer and a secondary battery. A second switching means having four switching elements and a third switching means having four switching elements in parallel with the second switching means are arranged for turn-on / turn-off control, and also for turning on in parallel to 12 switching elements. It is possible to discharge the secondary battery sufficiently to 0V by installing a diode to form an electric closed circuit and by installing a diode in series with the switching elements of the second to third switching means to cut off the conduction path of the switching element when the switching element is turned off. It works. In addition, by sufficiently discharging a small amount of voltage (20% or less ~ 0%) remaining in the secondary battery, it is possible to perform accurate performance test during the performance test of the secondary battery, it is possible to improve the durability of the secondary battery.

Description

Zero voltage discharge circuit having active switching elements of parallel type

The present invention relates to a zero-voltage discharge circuit having a parallel active switching element, and in particular, the secondary side of the transformer to a full bridge circuit to discharge a small amount of voltage (20% ~ 0%) remaining in the secondary battery It relates to a discharge circuit of a secondary battery configured.

The definition of zero voltage discharge means that the battery operates in a constant current mode (CCM) with a constant current until the battery voltage reaches 0V.

As the need for zero voltage discharge, as shown in Table 3, the charger and discharger is used for general charging and discharging (formation) used in the manufacture of the secondary battery (secondary battery), and for more iterations for product design and research. It is classified as a cycler that repeats charging / discharging, and the cycler equipment has a voltage range of 0 to 4.5V and must be discharged by lowering it to a lower voltage. Implementing a discharge circuit is important.

Differences in Characteristics between Formation and Cycler in Chargers division For charging and discharging For Cycler Structure and main function Secondary Battery Production Equipment Secondary Battery R & D Equipment Voltage range 2.7 to 4.2 V 0 to 4.5 V Current range 50 mA to 60 A 50 mA to 500 A or more Control unit SET unit batch control Channel independent control Drive way Linear, Switching Linear, Switching

The reason why zero-voltage discharge is not realized in the existing circuits is that the charge / discharger has a long load wiring (approximately 6 to 10 m), and a voltage drop occurs when current flows to the load wiring (approximately 0.7 to 1 V), or the semiconductor inside the circuit The voltage drop caused by the conduction of the device (diode, MOSFET, etc.) occurs, so that the constant current discharge is not maintained in the region where the battery voltage is low due to the voltage drop components. For this reason, in the conventional charging / discharging circuits, the discharge cannot be maintained at a constant current when the battery voltage is 2V or less.

As described above, the conventional secondary battery charge / discharge circuit used for the test of the secondary battery can only discharge up to a predetermined voltage of the secondary battery (for example, a voltage of 20% of the rated voltage). I couldn't. Therefore, there was a problem in not fully testing the secondary battery.

In addition, the conventional secondary battery charging and discharging circuit has a problem in that it is not suitable for large-capacity charging and discharging in the circuit structure.

Accordingly, the present invention has been made to solve the above problems, and an object of the present invention is to implement a discharge only by switching operation in a state in which a separate auxiliary power source is not added, and a small amount of voltage remaining in the secondary battery (20% or less to 0) %) Also provides a zero voltage discharge circuit having a parallel active switching element capable of sufficiently discharging.

In addition, another object of the present invention is to provide a zero voltage discharge circuit having a parallel active switching element suitable for a large-capacity charger, since both the transformer primary side circuit and the secondary side circuit have a full bridge structure.

On the other hand, another object of the present invention is to solve the problem of transformer saturation because the polarity of the voltage across the transformer crosses within one period to provide a zero voltage discharge circuit having a parallel active switching element having a safe characteristic.

 In order to achieve the above object, a zero voltage discharge circuit including a parallel active switching device according to the present invention includes a first switching for converting a DC voltage output from a DC power supply into a pulse waveform according to a control signal output from a control means. Means, receiving a pulse waveform from the first switching means, transforming the transformer into an AC voltage having a magnitude smaller than the DC voltage, and receiving an AC voltage output from the transformer according to another control signal output from the control means. And a second switching means and a third switching means arranged in parallel with each other so as to be rectified by a DC waveform to be applied to the secondary battery or to discharge all of the voltage in the secondary battery. Switching means to form a pulse waveform for discharging the secondary battery Each is a full bridge switching circuit composed of four switching elements Q1, Q2, Q3 and Q4 (A1, A2, A3 and A4), and the switching elements Q1, Q2, Q3 and Q4 (A1, A2, A3, In A4), when the switching elements Q1, Q2, Q3, Q4 (A1, A2, A3, A4) are turned on, a current path is formed and the switching elements Q1, Q2, Q3, Q4 (A1, A2). When the A3 and A4 are turned off, the current guiding diodes D1, D2, D3, and D4 (D5, D6, D7, and D8) are connected in series to block current flow.

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The switching elements Q1, Q2, Q3, Q4 (A1, A2, A3, A4) and the switching elements S1, S2, S3, S4 of the first switching means are provided with the switching elements Q1, Q2, When the Q3 and Q4 (A1, A2, A3, A4) (S1, S2, S3, S4) are turned off, the internal diodes D31, D32, which turn on to form a current flow between the source and the drain of the switching element. D33, D34 (D41, D42, D43, D44) (D21, D22, D23, D24) may be connected in parallel, respectively.

On the other hand, the switching elements Q1, Q2, Q3, Q4 (A1, A2, A3, A4) (S1, S2, S3, S4) output control signals by the control means to actively turn on / turn off. It is an active switching element that can be controlled.

 According to the present invention configured as described above, by connecting the second switching means and the third switching means each consisting of four switching elements on the transformer secondary side in parallel with each other, the voltage of the secondary battery can be sufficiently discharged to 0V, Secondary batteries also have an effect that can be used for charge and discharge testing.

In addition, by sufficiently discharging a small amount of voltage (20% or less ~ 0%) remaining in the secondary battery, there is an effect that can be performed accurately performance test regardless of the voltage size of the secondary battery during the performance test of the secondary battery.

On the other hand, it is possible to simplify the configuration of the test apparatus by implementing the discharge only by the switching operation in the state without adding a separate auxiliary power source.

On the other hand, the zero-voltage discharge circuit having a parallel active switching element according to the present invention is a full bridge structure of the transformer primary side circuit and the secondary side circuit is suitable for switching a large capacity voltage, so There is an effect suitable for the discharger.

On the other hand, according to the zero-voltage discharge circuit having a parallel active switching element of the present invention, since the polarity of the voltage across the transformer crosses within one period, the transformer saturation problem is solved, thereby improving the safety of the test circuit.

1 is a block diagram of a zero voltage discharge circuit having a parallel active switching device according to an embodiment of the present invention,
2 is a gate waveform diagram during charging of a zero voltage discharge circuit having a parallel active switching device according to an embodiment of the present invention;
3 is a gate waveform diagram during discharge of a zero voltage discharge circuit having a parallel active switching device according to an embodiment of the present invention;
4 is a circuit diagram of FIG. 1 showing a current flow in MODE 1 during a charging mode;
FIG. 5 is a circuit diagram of FIG. 1 illustrating current flow in MODE 2 and MODE 4 during a charging mode; FIG.
6 is a circuit diagram of FIG. 1 showing the current flow in MODE 3 during charging mode;
7 is a circuit diagram of FIG. 1 showing a current flow in MODE 1 in a discharge mode;
8 is a circuit diagram of FIG. 1 showing a current flow in MODE 2 during discharge mode;
9 is a circuit diagram of FIG. 1 showing a current flow in MODE 2 during discharge mode;
10 is a circuit diagram of FIG. 1 showing a current flow in MODE 4 during discharge mode;
FIG. 11 is a control block diagram showing a connection state between a control means for switching switching elements and a switching signal generating means, according to an embodiment of the present invention; FIG.

 Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 and 10, the switching elements S1, S2, S3, S4 (Q1, Q2, Q3, Q4) (A1, A2) to be described later, in accordance with the control signal output from the control means 12. Switching signal generating means 14 switches each of the gates of the switching elements S1, S2, S3, S4 (Q1, Q2, Q3, Q4) A1, A2, A3, A4 to switch A3, A4. Is connected to.

As shown in FIG. 1, the charge / discharge circuit of the present invention includes a first switching means 4, a transformer 6, a second switching means 10 and a third switching means 11, and an inductor L. FIG. And a capacitor (C). The first switching means 4 is connected to the DC power supply 2 so as to switch the direction of the DC voltage output from the DC power supply 2.

The DC power supply 2 is a power source for easily charging the secondary battery, and has a DC voltage of 20V to 400V having a magnitude of about 10 to 80 times the voltage of the secondary battery (VB, 2V to 5V). This is a DC power supply prepared separately by the user to output the

The transformer 6 receives a large DC voltage output from the DC power supply as a pulsed AC voltage through the first switching means 4, and converts the DC voltage into a pulse size AC voltage. It is connected to the switching means 4. The transformer 6 has a winding ratio N1: N2 of the primary coil N1 and the secondary coil N2 to charge the large voltage of the DC power source according to the small capacity of the secondary battery. 5: a transformer with a size of 1 to 20: 1.

The second switching means 10 and the third switching means 11 receive an AC voltage output from the transformer according to another control signal output from the control means 12 and convert it into a DC voltage through a smoothing filter. In order to be applied to the secondary battery or to discharge all of the voltage in the secondary battery.

The first switching means 4 includes switching elements S1, S2, S3, S4 for switching the direction in which the voltage output from the DC power source is applied to the transformer 6, and the switching elements S1, S2, A turn connected in parallel with S3, S4 to form a current flow between the source and the drain of the switching elements S1, S2, S3, S4 when the switching elements S1, S2, S3, S4 are turned off. It consists of warm-up diodes D21, D22, D23, and D24. The switching elements S1, S2, S3, and S4 form a full bridge switching circuit in which the switching elements S1 and S2 and the switching elements S3 and S4 are alternately turned on and off.

The full bridge switching circuit refers to a circuit in which four active switching elements are arranged to be alternately switched by being connected in parallel to each other in a symmetrical form. Active switching means switching of the switching elements by the control means 12 in accordance with the period and timing desired by the user.

The switching elements S1, S2, S3 and S4 (Q1, Q2, Q3 and Q4) A1, A2, A3 and A4 output a control signal by the control means 12 to actively turn on / turn off. An active switching element capable of controlling of the active element is an FET (Field Effect Transistor), for example.

The turn-on diodes D21, D22, D23, and D24 are internal diodes installed in each of the switching elements S1, S2, S3, and S4, and currents when the switching elements S1, S2, S3, and S4 are turned off. The diode to guide the flow of.

The second switching means 10 and the third switching means 11 respectively comprise four switching elements Q1, Q2, Q3, and Q4 (A1, A2, A3) to form a pulse waveform for discharging the secondary battery. It is composed of a full bridge switching circuit composed of A4).

The switching elements Q1, Q2, Q3, Q4 (A1, A2, A3, A4) have a current path when the switching elements Q1, Q2, Q3, Q4 (A1, A2, A3, A4) are turned on. And the current guiding diodes D1, D2, D3, D4 (D5, D1) to block current flow when the switching elements Q1, Q2, Q3, Q4 (A1, A2, A3, A4) are turned off. D6, D7, and D8 may be connected in series, respectively.

Diodes D1, D2, D3, D4 connected in series with the switching elements Q1, Q2, Q3, Q4 of the second switching means 10, and the switching elements of the third switching means 11. The installation directions of the diodes D5, D6, D7, and D8 connected in series to the fields A1, A2, A3, and A4 are the respective switching elements Q1, Q2, Q3, and Q4 (A1, A2, A3, A4) prevents internal diodes D31, D32, D33, D34 (D41, D42, D43, D44) from forming paths when turned off (D41, D42, D43) It is installed opposite to the direction of D44).

Further, the switching elements S1, S2, S3, S4 (Q1, Q2, Q3, Q4) (A1, A2, A3, A4) include the switching elements S1, S2, S3, S4 (Q1, Q2). , Q3, Q4 (A1, A2, A3, A4) is turned off and the switching elements (S1, S2, S3, S4) (Q1, Q2, Q3, Q4) (A1, A2, A3, A4) Internal diodes D21, D22, D23, and D24 (D31, D32, D33, and D34) (D41, D42, D43, and D44) which form a current flow between the source and the drain of the C1 are connected in parallel.

Referring to the installation direction of the diodes (D21, D22, D23, D24) (D31, D32, D33, D34) (D41, D42, D43, D44), the switching elements (S1, S2, S3, S4) When (Q1, Q2, Q3, Q4) (A1, A2, A3, A4) is turned off, the switching elements S1, S2, S3, S4 (Q1, Q2, Q3, Q4) (A1, A2, A3) , Anodes of the diodes D21, D22, D23, and D24 (D31, D32, D33, and D34) (D41, D42, D43, and D44) in an order consistent with the current direction formed between the source and the drain of A4. And cathode are connected to the switching elements S1, S2, S3, S4 (Q1, Q2, Q3, Q4) (A1, A2, A3, A4).

In FIG. 1, the capacitor C is a voltage stabilizing capacitor for stabilizing the waveform of the voltage charged in the secondary battery 8.

The inductor L receives and smoothes a pulse-type voltage output from the transformer during charging to transfer the DC voltage to the secondary battery 8, and boosts the energy discharged from the secondary battery 8 during discharge to increase the transformer 6. It is installed between the second switching means 10 and the third switching means 11 and the secondary battery 8 so as to transfer the discharge energy to the DC power supply 2 through.

The operation of the zero-voltage discharge circuit having a parallel active switching element of the present invention configured as described above will be described with reference to the waveform diagrams of FIGS. 2 and 3, the description of Tables 1 and 2, and the circuit diagrams of FIGS. 4 to 10. It demonstrates with reference.

First, the charging operation will be described.

Description of the charging mode according to the switching operation of the circuit of the present invention division Primary side Secondary MODE 1 S1, S4 ON S2, S3 OFF Q1, Q2, Q3, Q4 OFF A1, A2, A3, A4 ON MODE 2 S1, S4 OFF S2, S3 OFF Q1, Q2, Q3, Q4 OFF A1, A2, A3, A4 ON MODE 3 S1, S4 OFF S2, S3 ON Q1, Q2, Q3, Q4 OFF A1, A2, A3, A4 ON MODE 4 S1, S4 OFF S2, S3 OFF Q1, Q2, Q3, Q4 OFF A1, A2, A3, A4 ON

As shown in Figs. 2 and 4 to 7, the switching elements A1, A2, A3, and A4 of the third switching means 11 are all turned on at the secondary side of the transformer in MODE1 to MODE4 in the charging mode. The switching elements Q1, Q2, Q3, Q4 of the second switching means 10 are all turned off. Therefore, in the charging mode, the current path is formed only through the second switching means 10.

The switching elements S1, S4, S2, S3 of the first switching means 4 alternately switch.

On the primary side of the transformer 6, the switching elements S1, S4, S2, S3 of the first switching means 4 perform a switching operation at a duty ratio of 0.5 or less, whereby a square wave (+ VS, 0, -VS, 0) Generate the voltage.

On the secondary side of the transformer 6, the switching elements A1, A2, A3, A4 of the second switching means 10 are kept on, thereby alternating through the diodes D5, D6, D7, D8. The voltage waveform is rectified and output as a square wave DC waveform, and at the same time, an emission path of energy stored in the inductor L is formed.

Referring to the operation of the charging mode sequentially, first, as shown in FIG. 4, the switching control signal corresponding to the charging mode of FIG. 2 is transferred from the control unit 12 of FIG. 11 to the switching signal generating unit 14. Is output. At the initial time of the mode 1 of FIG. 2, a turn-on signal is output from the switching signal generating means 14 to the gates of the switching elements S1 and S4 (A1, A2, A3, and A4) and the switching element ( The turn-off signal is output to S2, S3 (Q1, Q2, Q3, Q4). Then, the switching elements S1 and S4 (A1, A2, A3 and A4) are turned on and the switching elements S2 and S3 (Q1, Q2, Q3 and Q4) are turned off.

In the embodiment of the present invention, the duty ratio of the switching elements S1, S2, S3, S4 is limited to within 50% to reset the transformer in one period TS of pulses. The duty ratio means the ratio of the time that the pulse is ON for one period of the arbitrary pulse.

4, in the first switching means 4, the lower terminal switching element of the primary coil N1 of the primary terminal transformer of the primary coil N1 of the + terminal switching element S1 transformer of the DC power supply. (S4) As the closed circuit flowing to the negative terminal of the DC power is formed, current flows in the transformer (6).

Then, a low voltage is generated in the secondary coil N2 of the transformer 6 according to the winding ratio N1: N2. This voltage is a falling voltage (lowing voltage) in which the voltage of the pulse waveform of 20 to 400V is lowered to the voltage of the pulse waveform of 10 to 20V. Then, the + terminal of the upper terminal switching element (A1) of the secondary coil (N2) of the transformer (6) diode (D5) inductor (L) of the secondary battery (8) and the capacitor (C) of the secondary battery (8) The closed circuit is formed by the lower terminal of the secondary coil N2 of the terminal diode D8 switching element A4 transformer to charge the secondary battery 8. At the same time, electrical energy is accumulated in the inductor L.

Next, a turn-off signal is continuously output from the switching signal generating means 14 to the gates of the switching elements Q1, Q2, Q3, and Q4 at an initial time point of the mode 2 of the charging mode of FIG. The turn-off signal is output to the gates of S1, S4, S2, and S3. At the same time, the turn-on signal is continuously output to the gates of the switching elements A1, A2, A3, and A4.

Then, the switching elements S1, S4, S2, and S3 and the switching elements Q1, Q2, Q3, and Q4 are all turned off.

Then, as shown in FIG. 5, the + terminal of the inductor (L) secondary battery 8 and the capacitor (C)-terminal diode (D7) and diode (D8) switching elements (A3, A4) of the secondary battery (8). The closed circuit is formed in the direction of the switching elements A1 and A2 diode D5 and diode D6 inductor L. Then, the power energy stored in the inductor L is supplied to the secondary battery 8, thereby charging the secondary battery 8.

Next, as shown in FIG. 6, in the mode 3 of the charging mode, the switching elements S2 and S3 are turned on and the switching elements S1 and S4 are turned off. Then, the + terminal switching element (S2) of the DC power supply (2), the lower terminal of the transformer primary coil (N1), the upper terminal switching element (S3) of the primary coil (N1) of the transformer, and the current in the negative terminal direction of the DC power supply (2). Flow is formed.

Then, a current flows in the secondary coil N2 of the transformer 6, so that the + terminal of the lower terminal switching element A2 diode D6 inductor L secondary battery 8 of the transformer secondary coil N2. And a current flows in the direction of the upper terminal of the -terminal diode D7 of the capacitor C secondary battery 8, the switching element A3, and the transformer secondary coil N2. Then, the pulse-shaped voltage output from the secondary coil N2 of the transformer 6 is rectified by the diodes D6 and D7 to charge the secondary battery 8 with a DC voltage and at the same time, power energy in the inductor L. Accumulates.

Next, as the mode 4 of the charging mode in FIG. 2, all of the switching elements S1, S2, S3, and S4 of the first switching means 4 are turned off, and the power energy stored in the inductor L of the transformer secondary side is accumulated. The process of charging the secondary battery 8 is performed. MODE 4 of this charging mode is the same as the operation in MODE 2 of the charging mode shown in FIG. 5 of the charging mode, and thus repeated description is omitted.

Next, the discharge operation of the present invention will be described.

Description of Discharge Mode According to Switching Operation of the Invention Circuit division Primary side Secondary MODE 1 S1, S4 ON S2, S3 OFF Q1, Q4 OFF Q2, Q3 ON A1, A2, A3, A4 OFF MODE 2 S1, S4 OFF S2, S3 OFF Q1, Q4 ON Q2, Q3 OFF A1, A2, A3, A4 OFF MODE 3 S1, S4 OFF S2, S3 ON Q1, Q4 ON Q2, Q3 OFF A1, A2, A3, A4 OFF MODE 4 S1, S4 OFF S2, S3 OFF Q1, Q4 OFF Q2, Q3 ON A1, A2, A3, A4 OFF

In the discharge mode, on the primary side of the transformer 6, the secondary battery (in the discharge boost section (sector for storing energy in the inductor L)) by alternating operations of the switching elements S1 and S4 and the switching elements S2 and S3. Equivalently to adding an auxiliary power supply in series to 8), the constant current can be maintained in a region where the voltage of the secondary battery 8 is low (from 2V or less to 0V), resulting in zero voltage discharge. .

On the other hand, on the secondary side of the transformer 6, the switching elements A1, A2, A3, and A4 of the third switching means 11 maintain the turn-off state, so that the current path is not formed in the third switching means 11. The switching elements Q1 and Q4 and Q2 and Q3 of the second switching means 10 alternately overlap and turn on / off to form a current path through the second switching means 10. In this case, the switching elements Q1 and Q4 of the second switching means 10, Q2 and Q3 operate at a fixed duty ratio to form a path of current, and the switching elements of the first switching means 4 The duty ratios of S1 and S4 (S2 and S3) are variable to operate as a boost converter.

The operation of the discharge mode will be described sequentially.

As shown in the waveform diagram of FIG. 3 and the circuit diagram of FIG. 7, in the mode 1 of the discharge mode, while the switching elements S1 and S4 of the first switching means 4 are turned on, the switching elements S2 and S3 Is turned off. In the second switching means 10, the switching elements Q2 and Q3 are turned on, and the switching elements Q1 and Q2 are turned off. The switching elements A1, A2, A3 and A4 of the third switching means 11 remain in a turn off state.

Then, on the primary side of the transformer 6, the + terminal switching element S1 of the DC power supply (S1) of the upper terminal of the transformer primary coil N1 and the negative terminal of the lower terminal switching element S4 of the transformer primary coil N1 of the DC power supply. As a closed circuit is formed, current flows in the primary coil N1 of the transformer 6. Then, a low voltage is induced from the secondary coil N2 of the transformer 6 according to the turns ratio N1 / N2 of the primary coil N1 and the secondary coil N2 of the transformer 6.

Then, at the secondary side of the transformer 6, the terminal of the upper terminal switching element Q3 of the secondary coil N2 of the transformer 6, the diode D3 of the secondary battery 8, and the capacitor C of the secondary battery 8. The closed circuit is configured in the direction of the lower terminal of the + terminal inductor (L) diode (D2) switching element (Q3) transformer (6) of the secondary coil (N2) of the (), and the voltage of the secondary battery (8) is discharged. At the same time, electrical energy is accumulated in the inductor L connected in series with the secondary battery 8 by the voltage discharged from the secondary battery 8.

Next, in the mode 2 of the discharge mode, as shown in FIG. 8, the switching elements S1, S2, S3, and S4 of the first switching means 4 are all turned off.

At the same time, the switching elements Q1, Q4 of the second switching means 10 are turned on, and the other switching elements Q2, Q3 and the switching elements A1, A2, A3, A4 of the third switching means 11 are turned on. Is turned off.

Then, the sum of the voltage accumulated in the inductor L and the voltage remaining in the secondary battery 8 is applied to the secondary coil N2 of the transformer 6 to open the primary coil N1 of the transformer 6. It flows into the DC power supply 2 through.

That is, the inductor (L) diode (D1) switching element (Q1) the upper terminal of the transformer secondary coil (N2) the lower terminal switching element (Q4) of the transformer secondary coil (N2) diode (D4) secondary battery (8) The current flows in the negative terminal and capacitor (C) of the secondary battery 8 toward the + terminal inductor (L).

Conversely, this current causes current flow in the transformer primary coil N1. Then, the current flows in the direction of the lower terminal of the + terminal DC power supply 2 of the + terminal DC power supply 2 of the upper terminal diode D21 of the transformer primary coil N1 to the lower terminal of the transformer primary coil N1. By flow, energy of the discharged voltage flows into the direct current power source 8.

Next, in the mode 3 of the discharge mode, the switching elements S2 and S3 of the first switching means 4 are turned on, and in the second switching means 10, the switching elements Q1 and Q4 are turned on. Then, the voltage of -VS (N2 / N1) is induced in the secondary coil N2 of the transformer 6. The induced voltage serves as a supplementary power supply to compensate for the magnitude of the secondary battery's voltage (VB). Save it.

As shown in FIG. 9, as the primary side path of the transformer 6, the primary coil N1 of the lower terminal transformer of the primary coil N1 of the + terminal switching element S2 transformer of the DC power supply 2 is used. The current flows through the path of the negative terminal of the upper terminal switching element S3 of the DC power supply 2.

As the secondary side path of the transformer 6, the terminal of the lower terminal switching element Q4 of the transformer secondary coil N2, the diode D4 of the secondary battery 8, and the + of the secondary battery 8 of the capacitor C. Terminal Inductor (L) Diode (D1) Switching Element (Q1) Current flows in the direction of the upper terminal of the transformer secondary coil N2.

Next, in the mode 4 of the discharge mode, the voltage accumulated in the inductor L and the voltage VB remaining in the secondary battery 8 are added in series to flow into the DC power supply 2 through the transformer 6. do.

Specifically, all of the switching elements S1, S2, S3, S4 of the first switching means 4 are turned off at the initial time of the mode 4 of FIG. At the same time, the switching elements Q1, Q4 of the second switching means 10 and the switching elements A1, A2, A3, A4 of the third switching means are turned off and the other switching elements of the second switching means 10 are turned off. (Q2, Q3) is turned on.

Then, as shown in FIG. 10, at the secondary side of the transformer 6, the inductor (L) diode (D2) switching element (Q2) the lower terminal of the transformer secondary coil (N2) the secondary coil (N2) of the transformer. The upper terminal switching element (Q3) of the diode (D3) of the secondary battery (8)-terminal and capacitor (C) the current flows in the + terminal inductor (L) direction of the secondary battery (8), the transformer secondary coil Current flows in (N2). Then, a reverse voltage of a voltage obtained by adding the voltage accumulated in the inductor L and the voltage VB remaining in the secondary battery 8 is applied to the transformer secondary coil N2.

Then, the current is directed toward the upper terminal of the + terminal DC power supply 2 of the + terminal DC power supply 2 of the lower terminal diode D22 of the transformer primary coil N1 of the transformer primary coil N1. As a result, the energy stored in the inductor L and the electric power remaining in the secondary battery 8 flow into the DC power supply 2. By repeating this operation, the voltage VB of the secondary battery 8 is discharged to zero voltage which is zero potential.

As described above, the present invention is provided by configuring two switching means 10 and 11 consisting of a full bridge switching circuit on the secondary side of the transformer 6 in parallel with each other, thereby merely controlling the switching operation without using a separate power supply. The voltage of the secondary battery 8 can be sufficiently discharged to 0V.

2: DC power supply, 4: first switching means
6: transformer, 8: secondary battery
10 second switching means 11 third switching means
12 control means 14 switching signal generating means
L: Inductor
S1, S2, S3, S4, Q1, Q2, Q3, Q4, A1, A2, A3, A4: switching element
D1, D2, D3, D4, D5, D6, D7, D8, D21, D22, D23, D24, D31, D32, D33, D34, D41, D42, D43, D44: Diode

Claims (4)

First switching means for converting the DC voltage output from the DC power supply into a pulse waveform in accordance with the control signal output from the control means;
A transformer for receiving a pulse waveform from the first switching means and transforming the voltage into an AC voltage having a magnitude smaller than the DC voltage;
According to another control signal output from the control means, the AC voltage output from the transformer is received and rectified in a DC waveform to be applied to the secondary battery or arranged in parallel with each other to switch operation to discharge all the voltage in the secondary battery. A second switching means and a third switching means,
The second switching means and the third switching means are each composed of four switching elements Q1, Q2, Q3, Q4 (A1, A2, A3, A4) to form a pulse waveform for discharging the secondary battery. Bridge switching circuit,
The switching elements Q1, Q2, Q3, Q4 (A1, A2, A3, A4) have a current path when the switching elements Q1, Q2, Q3, Q4 (A1, A2, A3, A4) are turned on. And the current guiding diodes D1, D2, D3, D4 (D5, D1) to block current flow when the switching elements Q1, Q2, Q3, Q4 (A1, A2, A3, A4) are turned off. A zero voltage discharge circuit having parallel active switching elements, wherein D6, D7, and D8 are connected in series.

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