JP5572838B2 - Bidirectional power conversion circuit - Google Patents

Description

  The present invention relates to a bidirectional power conversion circuit.

  Secondary battery technology for power storage, represented by electric vehicles, etc., continues to advance, and it has become possible to store large amounts of power with a small size. In addition, as the secondary battery technology advances, the charging technology continues to advance.

  However, secondary batteries vary in physical size, output voltage, etc., depending on the manufacturer and the product, and are not uniform when used as infrastructure. This is because each secondary battery is designed to be optimized for the intended use, and the charge / discharge circuit of the secondary battery is also designed to be optimized for each secondary battery. is the current situation.

  In addition, in order to save resources and energy, secondary batteries must be used flexibly and charged and discharged efficiently. From such a viewpoint, various charging / discharging circuits have been proposed for charging / discharging secondary batteries.

  For example, Patent Document 1 discloses a power regeneration device that functions as an AC / DC converter during charging and functions as a DC / AC converter during discharging. Further, Patent Document 2 discloses a circuit that can charge both a main secondary battery and an auxiliary secondary battery with a system power supply.

JP 2002-272121 A JP 2008-312395 A

  However, it is not always possible to secure an AC power supply when charging a secondary battery, and a charge / discharge circuit capable of charging a secondary battery with a secondary battery having a different standard voltage is desired. Further, since the circuits disclosed in Patent Documents 1 and 2 are complicated in configuration, a simpler circuit configuration is desired.

  The present invention has been made in view of the above circumstances, and can convert power bidirectionally from high voltage to low voltage or from low voltage to high voltage between different DC voltages, and has a simple configuration. An object is to provide a bidirectional power conversion circuit.

In order to achieve the above object, a bidirectional power conversion circuit of the present invention includes:
A first reactor connected in series with the first battery;
A second reactor,
A semiconductor switch connected in series with the second reactor and the second battery;
1st and 2nd AC terminal, 1st and 2nd DC terminal, 1st-4th diode, 1st-3rd self-extinguishing element, and capacitor, One of the anode of the first diode and the cathode of the second diode at the AC terminal, and one of the cathode of the first diode, the cathode of the third diode and the capacitor at the first DC terminal. The second DC terminal has the anode of the second diode, the anode of the fourth diode, and the other pole of the capacitor, and the second AC terminal has the third diode. An anode and a cathode of the fourth diode are connected, the first self-extinguishing element is connected to the first diode, and the second self-extinguishing element is connected to the second diode. Before 3 diodes A third self-extinguishing element is connected in parallel, and a series circuit of the first battery and the first reactor is connected between the first AC terminal and the second DC terminal, and the second A magnetic energy regenerative switch in which a series circuit of the second battery, the second reactor, and the semiconductor switch is connected between the AC terminal and the second DC terminal;
A control circuit for supplying a control signal to the semiconductor switch and the first to third self-extinguishing elements;
With
The control circuit includes:
When charging the second battery having a voltage higher than that of the first battery using the first battery, the second and third self-extinguishing elements are turned on at the same timing. Just repeat the switching off at the same timing,
Using the second battery, when charging the first battery having a voltage lower than that of the second battery, the semiconductor switch is held on and the first self-extinguishing element is switched. to repeat the,
It is characterized by that.

  For example, the control circuit has a function of controlling a duty ratio of the control signal.

  The semiconductor switch has, for example, a configuration in which a semiconductor element for switching and a diode are connected in parallel. Alternatively, the semiconductor switch may be constituted by, for example, a reverse conducting semiconductor element having no reverse blocking capability, or a circuit having a thyristor as an element.

  Further, a fourth self-extinguishing element connected in parallel to the fourth diode may be further provided.

  For example, each self-extinguishing element is a reverse conducting semiconductor switch, and each diode is a parasitic diode built in each self-extinguishing element connected in parallel.

  A filter for high frequency cut may be disposed between the fourth semiconductor switch and the second battery.

  With a circuit having a simple configuration, power can be converted bidirectionally from a high voltage to a low voltage or from a low voltage to a high voltage.

It is a circuit diagram which shows the structure of the bidirectional | two-way power converter circuit of one Embodiment of this invention. (A) It is a figure which shows the function structure of a control circuit at the time of charging a high voltage battery with a low voltage battery in the bidirectional | two-way power converter circuit of FIG. (B) It is a figure which shows the gate signal which a control circuit outputs when charging a high voltage battery with a low voltage battery in the bidirectional | two-way power converter circuit of FIG. (A) It is a figure which shows the function structure of a control circuit at the time of charging a low voltage battery with a high voltage battery in the bidirectional | two-way power converter circuit of FIG. (B) It is a figure which shows the gate signal which a control circuit outputs when charging a low voltage battery with a high voltage battery in the bidirectional | two-way power converter circuit of FIG. FIG. 2 is a diagram for explaining an operation when charging a high voltage battery with a low voltage battery in the bidirectional power conversion circuit of FIG. 1. FIG. 2 is a diagram for explaining an operation when charging a high voltage battery with a low voltage battery in the bidirectional power conversion circuit of FIG. 1. FIG. 2 is a diagram for explaining an operation when charging a low voltage battery with a high voltage battery in the bidirectional power conversion circuit of FIG. 1. It is a figure which shows the modification of the bidirectional | two-way power converter circuit shown in FIG.

  Hereinafter, preferred bidirectional power conversion devices according to embodiments of the present invention will be described with reference to the drawings.

A bidirectional power conversion circuit 10 according to the present embodiment is a circuit for mutually charging a low voltage battery 11 and a high voltage battery 12, and as shown in FIG. 1, a reactor L1 for storing magnetic energy and L <b> 2, a smoothing reactor L <b> 3, a full-bridge type MERS 100, a reverse conducting semiconductor switch SW, a smoothing capacitor CC, and a control circuit 13 are provided.
The full-bridge MERS 100 includes four reverse conducting semiconductor switches SW1 to SW4, AC terminals AC1 and AC2, DC terminals DCP and DCN, and a capacitor CM.

The reverse-conducting semiconductor switches SW1 to SW4 of the full-bridge MERS 100 include diode units DSW1 to DSW4, switch units SSW1 to SSW4 connected in parallel to the diode units DSW1 to DSW4, and gates disposed in the switch units SSW1 to SSW4. GSW1 to GSW4.
The AC terminal AC1 has the anode of the diode part DSW1 and the cathode of the diode part DSW2, the DC terminal DCP has the cathode of the diode part DSW1, the cathode of the diode part DSW3, and the positive electrode of the capacitor CM, and the DC terminal DCN has the diode part. The anode of DSW2, the anode of diode part DSW4, and the negative electrode of capacitor CM are connected, and the anode of diode part DSW3 and the cathode of diode part DSW4 are connected to AC terminal AC2.
The switch parts SSW1 to SW4 of the reverse conducting semiconductor switches SW1 to SW4 are switched on / off by gate signals SG1 to SG4 input to the gates GSW1 to SW4.
When the switch units SSW1 to SSW4 are turned on, the diode units DSW1 to DSW4 are short-circuited, and the reverse conducting semiconductor switches SW1 to SW4 are turned on. When the switch units SSW1 to SSW4 are turned off, the diode units DSW1 to DSW4 function, and the reverse conducting semiconductor switches SW1 to SW4 are turned off.
The reverse conducting semiconductor switches SW1 to SW4 are, for example, N-channel silicon MOSFETs (MOSFETs: Metal-Oxide-Semiconductor Field-Effect Transistors).

The low voltage battery 11 is a secondary battery having a rating of 100V.
An equivalent circuit of the low voltage battery 11 is expressed by a series circuit of a DC voltage source 21 and an internal resistor R1. The low voltage battery 11 and the reactor L1 are connected in series, and this series circuit is connected between the AC terminal AC1 and the DC terminal DCN.

One end of the reactor L2 is connected to the AC terminal AC2.
The other end of the reactor L2 is connected to one end of the reverse conducting semiconductor switch SW. The reverse conducting semiconductor switch SW includes a switch unit SSW that is an IGBT (Insulated Gate Bipolar Transistor) and a diode unit DSW that is a diode. The collector of the switch unit SSW and the anode of the diode unit DSW are connected to become one end of the reverse conducting semiconductor switch SW, and the emitter of the switch unit SSW and the cathode of the diode unit DSW are connected to connect the other of the reverse conducting semiconductor switch SW. End. The switch unit SSW includes a gate GSW, and the on / off of the switch unit SSW is switched by a gate signal SG input to the gate GSW.
The reverse conduction type semiconductor switch SW is always turned on for the current from the low voltage battery 11 to the high voltage battery 12 and switched on / off for the current from the high voltage battery 12 to the low voltage battery 11.

One end of the reactor L3 is connected to the other end of the reverse conducting semiconductor switch SW.
One end of the capacitor CC is connected to a connection node between the other end of the reverse conducting semiconductor switch SW and one end of the reactor L3. Reactor L3 and capacitor CC function as a low-pass filter that suppresses high-frequency components.

The high voltage battery 12 is a secondary battery having a rating of 1500 V, for example.
An equivalent circuit of the high voltage battery 12 is expressed by a series circuit of a DC voltage source 22 and an internal resistance R2 of the battery, and the high voltage battery 12 is connected in series with the reactor L3.

  The cathodes of the low voltage battery 11 and the high voltage battery 12, the DC terminal DCN of the full bridge MERS 100, the other end of the capacitor CM, and the other end of the capacitor CC are connected to each other by a reference voltage line (for example, a ground line). .

  The control circuit 13 performs on / off control of the reverse conducting semiconductor switches SW1 to SW4 and SW, thereby charging the low voltage battery 11 to the high voltage battery 12 and from the high voltage battery 12 to the low voltage battery 11. Control charging.

  When charging the high voltage battery 12 from the low voltage battery 11, the control circuit 13, as shown in FIGS. 2A and 2B, sets the switch portions SSW 2 and SSW 3 of the reverse conducting semiconductor switches SW 2 and SW 3. Gate signals SG2 and SG3 having a predetermined frequency, for example, 2 kHz, and a duty ratio of 0.9 are output to the gates GSW2 and GSW3, and the switch units SSW2 and SSW3 are turned on / off at the same timing. On the other hand, the control circuit 13 always outputs low-level gate signals SG, SG1, and SG4 to the gates GSW, GSW1, and GSW4 of the switch units SSW, SSW1, and SSW4 of the reverse conducting semiconductor switches SW, SW1, and SW4. The units SSW, SSW1, and SSW4 are always turned off.

  On the other hand, when charging the low voltage battery 11 from the high voltage battery 12, the control circuit 13 switches the switch parts SSW2, SSW3 of the switches SW2, SW3, SW4 as shown in FIGS. 3 (a) and 3 (b). The low-level gate signals SG2, SG3, and SG4 are output to the gates GSW2, GSW3, and GSW4 of the SSW4, and the switch units SSW2, SSW3, and SSW4 are always turned off. On the other hand, the control circuit 13 outputs a gate signal SG1 having a duty ratio of 0.1 at 1 kHz to the gate GSW1 of the switch unit SSW1 of the reverse conducting semiconductor switch SW1, and controls the switch unit SSW1 to be turned off / off. . In addition, the control circuit 13 outputs a high-level gate signal SGW to the gate of the switch unit SSW of the switch SW, and always turns on the switch unit SSW.

Next, the operation of the bidirectional power conversion circuit 10 having the above configuration will be described.
First, the operation of charging the high voltage battery 12 using the power of the low voltage battery 11 will be described.
In this case, as described above, the control unit 13 outputs an alternating signal having a duty ratio of 0.9 at a predetermined frequency, for example, 2 kHz, to the gates of the switch units SSW2 and SSW3.
When the gate signal SG2 becomes high level, the switch unit SSW2 is turned on. Then, as shown in FIG. 4, with the low-voltage battery 11 as a power source, a current I1 flows through the reactor L1 and the reverse conducting semiconductor switch SW2, and magnetic energy is stored in the reactor L1.

  Subsequently, when the gate signal SG2 becomes a low level, the switch unit SSW2 is turned off and the flow path of the current I1 is interrupted. Therefore, as shown in FIG. 5, due to the magnetic energy accumulated in the reactor L1, the reactor L1 becomes a boost power source, and the current I3 is passed through the diode portion DSW1 and the capacitor CM of the reverse conducting semiconductor switch SW1. Flow and charge capacitor CM. The charging voltage at this time is determined by the duty ratio of the gate signal SG2, and in this example reaches 1500V or more.

  When the gate signal SG2 becomes high level again, the switch unit SSW2 is turned on, the current I1 flows, and magnetic energy is accumulated in the reactor L1. Subsequently, when the gate signal SG2 becomes low level, the switch unit SSW2 is turned off, the current I3 flows, and the capacitor CM is charged.

  When the charging voltage of the capacitor CM becomes higher than the voltage of the high voltage battery 12, when the gate signal SG3 becomes high level and the switch section SSW3 of the reverse conducting semiconductor switch SW3 is turned on, as shown in FIG. Using the capacitor CM as a power source, a current I2 flows through the reverse conducting semiconductor switch SW3, the reactor L2, the diode portion DSW of the reverse conducting semiconductor switch SW, and the reactor L3, and the high voltage battery 12 is charged. At this time, the high-frequency noise is cut by a low-pass filter including the reactor L3 and the capacitor CC.

Subsequently, when the gate signal SG3 becomes low level and the switch section SSW3 of the switch SW3 is turned off, the current I2 is cut off.
When the magnetic energy remains in the reactor L2 when the current I2 is interrupted, the current I4 is converted into the diode part DSW of the reverse conducting semiconductor switch SW as shown in FIG. 5 by the magnetic energy accumulated in the reactor L2. , Reactor L3, high voltage battery 12, and diode part DSW4 of switch SW4 to charge high voltage battery 12. At this time, the high frequency noise is cut by a low pass filter constituted by the reactor L3 and the capacitor CC.
When no magnetic energy remains in reactor L2, current I4 does not flow.

  Thereafter, the same operation is repeated according to ON / OFF of the reverse conducting semiconductor switches SW2 and SW3, and the high voltage battery 12 is charged from the capacitor CM. The voltage of the capacitor CM and the voltage of the high voltage battery 12 are almost equal. At this point, charging of the high voltage battery 12 is completed.

Next, the operation of charging the low voltage battery 11 using the power of the high voltage battery 12 will be described.
In this case, as described above, the control unit 13 outputs a high level gate signal SGW to the gate GSW of the switch unit SSW of the reverse conducting semiconductor switch SW, and outputs a predetermined frequency, for example, to the gate GSW1 of the switch unit SSW1. A 1 kHz gate signal is output at a duty ratio of 0.1, and low level gate signals SG2, SG3, SG4 are output to the gates GSW2, GSW3, GSW4 of the switch sections SSW2, SSW3, SSW4.

As a result, the reverse conducting semiconductor switch SW is always turned on, and the diode of the reactor L3, the reverse conducting semiconductor switch SW, the reactor L2, the reverse conducting semiconductor switch SW3 from the anode of the high voltage battery 12 as shown in FIG. The current I5 flows through the capacitor CM via the unit DSW3, and the capacitor CM is charged.
On the other hand, since the switch section SSW1 of the reverse conducting semiconductor switch SW1 is repeatedly turned on and off, a current I6 flows through the reactor L1 and the low voltage battery 11 with the capacitor CM as a power source. At this time, the current is suppressed by the on / off of the reverse conducting semiconductor switch SW1 and the action of the reactor L1, and the reduced voltage is applied to the low voltage battery 11. In other words, the low voltage battery 11 is charged by stepping down the charging voltage of the capacitor CM by a chopper operation performed by the reverse conducting semiconductor switch SW1 and applying it to the low voltage battery 11.

  Thus, according to the bidirectional power conversion circuit having the configuration shown in FIG. 1, the high-voltage battery 12 is charged using the power stored in the low-voltage battery 11, and the power stored in the high-voltage battery 12 is used. It can be used to charge the low voltage battery 11. In addition, batteries of various voltages can be charged with each other without changing the circuit configuration. In addition, charging / discharging can be performed with a combination of batteries of any voltage simply by adjusting the duty ratio of the gate signal.

In addition, this invention is not limited to the said embodiment, A various deformation | transformation and application are possible.
For example, the polarity of the circuit of FIG. 1 can be changed as shown in FIG. Also in this case, the gate signal supplied to the gate of each switch unit by the control circuit 13 is the same as the gate signal shown in FIGS.

  Further, the reverse conducting semiconductor switch SW4 does not perform switching. For this reason, the switch unit SSW4 may not be provided. For the same reason, the reverse conducting semiconductor switch SW4 may be changed to a diode.

  For example, the reverse conducting semiconductor switch is not limited to an N-channel MOSFET. For example, the reverse conducting semiconductor switch may have a configuration in which a normal bipolar transistor and a diode are connected in antiparallel. Moreover, you may comprise a reverse conduction type semiconductor switch from FET (Field Effect Transistor). Furthermore, you may comprise from a thyristor. In addition, any switching semiconductor element and freewheeling diode connected in antiparallel, for example, a reverse conduction type semiconductor element having no reverse blocking capability, such as a power MOSFET having a parasitic diode built in at the time of manufacture What has been configured can be used as a reverse conducting semiconductor switch.

It is also possible to connect a load in place of the battery to which power is supplied.
Moreover, it is not necessary to provide all the configurations described in the embodiment, and a combination of some configurations may be used as long as the intended purpose can be achieved.

DESCRIPTION OF SYMBOLS 10 Bidirectional power converter circuit 11 Low voltage battery 12 High voltage battery 13 Control circuit L1, L2, L3 Reactor CC, CM Capacitor SW Semiconductor switch SW, SW1, SW3, SW2, SW4 Reverse conduction type semiconductor switch SSW, SSW1, SSW3, SSW2, SSW4 Switch part SG, SG1, SG3, SG2, SG4 Gate signal DSW, DSW1, DSW3, DSW2, DSW4 Diode part R1, R2 Internal resistance AC1, AC2 AC terminal DCP, DCN DC terminal

Claims (6)

A first reactor connected in series with the first battery;
A second reactor,
A semiconductor switch connected in series to the second reactor and the second battery;
1st and 2nd AC terminal, 1st and 2nd DC terminal, 1st-4th diode, 1st-3rd self-extinguishing element, and capacitor, One of the anode of the first diode and the cathode of the second diode at the AC terminal, and one of the cathode of the first diode, the cathode of the third diode and the capacitor at the first DC terminal. The second DC terminal has the anode of the second diode, the anode of the fourth diode, and the other pole of the capacitor, and the second AC terminal has the third diode. An anode and a cathode of the fourth diode are connected, the first self-extinguishing element is connected to the first diode, and the second self-extinguishing element is connected to the second diode. Before 3 diodes A third self-extinguishing element is connected in parallel, and a series circuit of the first battery and the first reactor is connected between the first AC terminal and the second DC terminal, and the second A magnetic energy regenerative switch in which a series circuit of the second battery, the second reactor, and the semiconductor switch is connected between the AC terminal and the second DC terminal;
A control circuit for supplying a control signal to the semiconductor switch and the first to third self-extinguishing elements;
With
The control circuit includes:
When charging the second battery having a voltage higher than that of the first battery using the first battery, the second and third self-extinguishing elements are turned on at the same timing. Repeated switching off at the same timing ,
Using the second battery, when charging the first battery having a voltage lower than that of the second battery, the semiconductor switch is held on and the first self-extinguishing element is switched. to repeat the,
A bidirectional power conversion circuit characterized by that. The control circuit has a function of controlling a duty ratio of the control signal.
The bidirectional power converter circuit according to claim 1. The semiconductor switch has a configuration in which a semiconductor element for switching and a diode are connected in parallel.
The bidirectional power converter circuit according to claim 1, wherein the bidirectional power converter circuit is provided. The semiconductor switch is a reverse conductive semiconductor element having no reverse blocking capability, or a circuit having a thyristor as an element.
The bidirectional power conversion circuit according to claim 1, wherein the bidirectional power conversion circuit is provided. A fourth self-extinguishing element connected in parallel to the fourth diode;
The bidirectional power conversion circuit according to claim 1, wherein the bidirectional power conversion circuit is provided. Each self-extinguishing element is a reverse conducting semiconductor switch, and each diode is a parasitic diode built in each self-extinguishing element connected in parallel.
The bidirectional power conversion circuit according to claim 1, wherein the bidirectional power conversion circuit is provided.

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