Bidirectional power interconnection circuit

Abstract

To provide a bidirectional AC / DC power interconnection circuit through autonomous operation, which eliminates the need for automatic control by an electronic control unit.SOLUTION: A bidirectional power interconnection device that interconnects an AC power unit and a DC power unit in both directions includes: a first full-wave rectification unit having a plurality of first rectification elements capable of full-wave rectifying AC from the AC power unit and outputting the AC to the DC power unit; a second full-wave rectification unit having a plurality of second rectification elements capable of full-wave rectifying AC from the AC power unit and outputting the AC to a resistive element; and a switch unit including a plurality of switch elements respectively in parallel with the plurality of first rectification elements, the switch elements are respectively associated with the plurality of second rectification elements and switch to be off when the associated second rectification element is non-conducting and to be on when it is conducting.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a bidirectional power interconnection circuit that converts power bidirectionally between AC and DC. [Background technology]

[0002] There is known a bidirectional power grid-connected device that converts power between a commercial AC power grid and DC power facilities such as a power generation system and a storage battery. Patent Document 1 discloses a system in which a wind power generation system and a storage battery are connected to a power company grid via a grid-connected inverter.

[0003] In Patent Documents 2 and 3, although not bidirectional, the problem of high-frequency switching noise is solved by using a multi-phase transformer instead of an AC / DC converter when rectifying AC and converting it to DC. Furthermore, as a method of connecting the secondary terminals of the transformer, Patent Document 2 proposes a star connection, while Patent Document 3 proposes a modified connection based on a delta connection. These modified connections solve the problem of large transformers caused by providing independent windings for each phase of the multi-phase transformer. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-250227 [Patent Document 2] Japanese Patent Publication No. 2022-71713 [Patent Document 3] Japanese Patent Publication No. 2022-540927 Summary of the Invention [Problem to be solved by the invention]

[0005] Conventional AC / DC bidirectional interconnection technologies such as those described in Patent Document 1 require an electronic control unit such as a control IC for electronic control of the bidirectional converter, etc. Furthermore, the AC / DC interconnections using a multiphase transformer described in Patent Documents 2 and 3 convert the output of the multiphase transformer into DC by full-wave rectification, but bidirectional interconnection cannot be realized with a full-wave rectification circuit alone.

[0006] In view of the above, an object of the present invention is to provide a circuit that performs bidirectional AC / DC power interconnection by autonomous operation without the need for automatic control by an electronic control unit. [Means for solving the problem]

[0007] In order to achieve the above object, the present invention provides the following configuration. [1] A first aspect of the present invention is a bidirectional power circuit that bidirectionally connects an AC power section and a DC power section, a first full-wave rectification unit including a plurality of first rectification elements capable of full-wave rectifying the AC power from the AC power unit and outputting the full-wave rectified AC power to the DC power unit; a second full-wave rectification unit including a plurality of second rectification elements capable of full-wave rectifying the AC power from the AC power unit and outputting the full-wave rectified AC power to a resistance element; a switch section including a plurality of switch elements respectively in parallel with the plurality of first rectifying elements, each switch element being associated with a respective one of the plurality of second rectifying elements and being switched to be off when the associated second rectifying element is non-conductive and on when the associated second rectifying element is conductive; death, The plurality of first rectifying elements of the first full-wave rectifying unit a first positive-side rectifying element having an anode connected to a terminal of each phase of AC from the AC power unit and a cathode commonly connected to a positive terminal of the DC power unit; a first negative-side rectifying element having a cathode connected to a terminal of each phase of AC from the AC power unit and an anode commonly connected to a negative terminal of the DC power unit; The plurality of second rectifying elements of the second full-wave rectifying unit a second positive-side rectifying element having an anode connected to a terminal of each phase of the AC power from the AC power unit and a cathode commonly connected to one end of the resistor element; and second negative-side rectifying elements each having a cathode connected to a terminal of each phase of the AC power from the AC power unit and an anode commonly connected to the other end of the resistor element.

[0008] [2 In the above embodiment, The drive unit that switches the switch element on and off includes: a light-emitting element that is inserted and connected in series with the second rectifying element and emits light only when the second rectifying element is conductive, and a light-receiving element that receives light from the light-emitting element, The light receiving element outputs a drive signal that turns on the switch element when receiving light from the light emitting element and turns off the switch element when not receiving light. [ 3 In the above embodiment, the first rectifying element is a parasitic diode of a field effect transistor or a diode connected in parallel with the parasitic diode, The switch element is a current path between the drain and source of the field effect transistor, and the gate of the field effect transistor is driven by the drive signal of the drive unit. [ 4 In the above embodiment, the first rectifying element is an external diode for passing a current in a direction opposite to a current that flows when the IGBT or bipolar transistor is conductive, The switch element is a current path between the emitter and collector of the IGBT or the bipolar transistor, and the gate of the IGBT or the base of the bipolar transistor is driven by a drive signal from the drive unit. [Effects of the Invention]

[0009] According to the present invention, a circuit is realized that performs bidirectional AC / DC power interconnection through autonomous operation without the need for automatic control by an electronic control unit. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing a schematic diagram of the overall configuration including the bidirectional power interconnection device. [Figure 2] FIG. 2 shows an example of a specific configuration of the interconnection circuit unit of FIG. [Figure 3] FIG. 3 shows another example of the switch element of FIG. [Figure 4] 4(a) and 4(b) show an example of the operation of the interconnection circuit unit at point x of the waveform in FIG. 6(a). [Figure 5] 5(a) and 5(b) show an example of the operation of the interconnection circuit unit at point y of the waveform in FIG. 6(a). [Figure 6] FIG. 6(a) shows the voltage waveform of a 12-phase AC, and (b) shows the waveform obtained by full-wave rectifying the 12-phase AC voltage waveform shown in (a). [Figure 7] Figure 7(a) shows the relationship between the 12 terminals on the secondary side of a 12-phase transformer and the 12 line voltages, while (b) is a vector diagram showing the phase relationship of the line voltages. [Figure 8] FIG. 8 shows the waveform of a three-phase AC current observed on the primary side of a polyphase transformer when the storage batteries shown in FIGS. 4(b) and 5(b) are discharged. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of a bidirectional power grid-connection device according to the present invention will be described with reference to the drawings. In this specification, "three-phase AC" refers to symmetrical three-phase AC. Symmetrical three-phase AC consists of three sinusoidal waves with equal amplitude and frequency and a phase difference of 120 degrees.

[0012] (1) Configuration and operation of the interconnection circuit FIG. 1 is a diagram showing a schematic diagram of the overall configuration including a bidirectional power interconnection device. The bidirectional power interconnection device is a device for bidirectionally supplying and demanding power between an AC power section and a DC power section. The AC power section here is assumed to be grid power in which three-phase AC flows on lines R0, S0, and T0. The DC power section here is assumed to be a storage battery 5. A DC power generation facility such as a solar power generation system can also be connected to the storage battery 5. The bidirectional power interconnection device has a multi-phase transformer 1 and an interconnection circuit section 10.

[0013] The primary winding of multi-phase transformer 1 is connected to three-phase lines R0, S0, and T0 of the grid power. Multi-phase transformer 1 in Figure 1 converts the three-phase AC power from the primary side into 12-phase polyphase AC power, which is output from 12 secondary terminals R1...T4. Each of the 12-phase AC voltages is a line voltage output between a specific pair of terminals among the 12 secondary terminals R1...T4, and consists of four pairs of three-phase AC power. Figure 6(a) shows the waveform of the 12-phase AC voltage.

[0014] The interconnection circuit unit 10 is shown schematically in Fig. 1. The interconnection circuit unit 10 has the function of full-wave rectifying the output of the multi-phase transformer 1 and outputting the result to the storage battery 5, and the function of outputting power from the storage battery 5 to the secondary terminals of the multi-phase transformer 1. The interconnection circuit unit 10 has 12 positive-side circuits 11 and 12 negative-side circuits 12, each having the same configuration, that are connected to each of the secondary terminals R1 to T4 of the multi-phase transformer 1.

[0015] Terminal R1 will be used as an example. The anode of the first positive-side rectifier element P1 and the anode of the second positive-side rectifier element P2 of the positive-side circuit 11 are connected to terminal R1. Furthermore, the cathode of the first negative-side rectifier element N1 and the cathode of the second negative-side rectifier element N2 of the negative-side circuit 12 are connected to terminal R1. An "anode" is a positive electrode into which current flows. A "cathode" is a negative electrode from which current flows. A "rectifier element" is typically a diode. However, the first positive-side rectifier element P1 and the first negative-side rectifier element N1 may be rectifier elements incorporated into other elements rather than being independent elements. Such a rectifier element may be, for example, a parasitic diode of a field-effect transistor (FET).

[0016] The cathode of the first positive-side rectifier element P 1 is connected to the positive electrode connection terminal 6 of the storage battery 5 , and the anode of the first negative-side rectifier element N 1 is connected to the negative electrode connection terminal 7 of the storage battery 5 .

[0017] The cathode of the second positive side rectifier element P2 is connected to one end of the resistor element 4, and the anode of the second negative side rectifier element N2 is connected to the other end of the resistor element 4. Photovoltaic photodiodes (described later) are inserted and connected in the forward direction between the cathode of the second positive side rectifier element P2 and one end of the resistor element 4, and between the anode of the second negative side rectifier element N2 and the other end of the resistor element 4. However, since this does not affect the functions of the second positive side rectifier element P2 and the second negative side rectifier element N2, even when they are indirectly connected to the resistor element 4, this is still referred to as being "connected."

[0018] Furthermore, the first positive-side rectifier element P1 and the first negative-side rectifier element N1 are each connected in parallel to a switch element SW. The term "switch element" as used herein includes an element that has a control end and a current path and can switch the current path between conductive and non-conductive states when the control end is driven. Such an element may be a semiconductor element such as an FET, a bipolar transistor, or an IGBT.

[0019] The switch element SW in parallel with the first positive-side rectifier element P1 switches off when the associated second positive-side rectifier element P2 is non-conducting and on when it is conducting. Similarly, the switch element SW in parallel with the first negative-side rectifier element N1 switches off when the associated second negative-side rectifier element N2 is non-conducting and on when it is conducting. Each switch element SW has a driver for driving its control terminal. In FIG. 1, part of the driver for each switch element SW is simply represented by a photodiode connected in series with the second positive-side rectifier element P2 and the second negative-side rectifier element N2, respectively. The operating mechanism of this switch element SW will be described in detail later.

[0020] Circuits having the same configuration as above are connected between each of the other secondary side terminals R2..T4 and the storage battery 5, and between the other secondary side terminals R2..T4 and the resistance element 4, respectively.

[0021] Generally speaking, the twelve first positive-side rectifier elements P1 have their anodes connected to the secondary-side terminals R1 to T4, respectively, and their cathodes connected in common to the positive electrode connection terminal 6 of the storage battery 5. The twelve first negative-side rectifier elements N1 have their cathodes connected to the secondary-side terminals R1 to T4, respectively, and their anodes connected in common to the negative electrode connection terminal 7 of the storage battery 5. Therefore, the twelve first positive-side rectifier elements P1 and the twelve first negative-side rectifier elements N1 constitute a first full-wave rectifier unit that full-wave rectifies the multi-phase AC on the secondary side of the multi-phase transformer 1 and outputs the full-wave rectified power to the storage battery 5.

[0022] Similarly, the twelve second positive-side rectifying elements P2 have their anodes connected to the secondary-side terminals R1 to T4, respectively, and their cathodes commonly connected to one end of the resistor element 4. The twelve second negative-side rectifying elements N2 have their cathodes connected to the secondary-side terminals R1 to T4, respectively, and their anodes commonly connected to the other end of the resistor element 4. Therefore, the twelve second positive-side rectifying elements P2 and the twelve second negative-side rectifying elements N2 constitute a second full-wave rectifying unit that full-wave rectifies the multi-phase AC on the secondary side of the multi-phase transformer 1 and outputs the full-wave rectified signal to the resistor element 4.

[0023] The rectification operations of the first and second full-wave rectifiers are basically the same, except for the output destination, which is either the storage battery 5 or the resistive element 4. In the rectification operation, full-wave rectified current can only flow between the two terminals that output the maximum voltage out of the 12 line voltages output from the secondary terminals R1..T4, i.e., between the secondary terminal with the highest potential and the secondary terminal with the lowest potential.

[0024] However, in the first full-wave rectifier, when the potential of the secondary terminal of the multi-phase transformer 1 is lower than the potential of the positive electrode connection terminal 6 of the storage battery 5, current cannot flow from the multi-phase transformer 1 to the storage battery 5. Furthermore, at this time, in the first full-wave rectifier, the positive side rectifier element P1 and the negative side rectifier element N1 are in the reverse direction, so current cannot flow from the storage battery 5 to the multi-phase transformer 1 either.

[0025] Therefore, in the present invention, the current flowing through the second full-wave rectifier is used as a trigger to turn on the switch element SW, thereby bypassing the rectifier elements P1 and N1 of the first full-wave rectifier and allowing current to flow from the storage battery 5 to the multi-phase transformer 1 through the switch element SW. The second full-wave rectifier is provided to operate the switch element SW. This mechanism achieves bidirectional interconnection between the AC power unit and the DC power unit. Furthermore, because this mechanism is realized autonomously by only the circuit elements of the interconnection circuit 10, automatic control by an electronic control unit is not required.

[0026] The main current for supplying and demanding power between the multi-phase transformer 1 and the storage battery 5 flows through the first full-wave rectifier circuit. The second full-wave rectifier circuit is a current detection circuit for driving each switch element SW of the switch section, so it is sufficient for a current sufficient for detection to flow through it. Therefore, the resistance value of the resistive element 4, which is the load of the second full-wave rectifier circuit, is set according to the current detection sensitivity.

[0027] Fig. 2 shows an example of a specific configuration of the interconnection circuit unit 10 in Fig. 1. Fig. 2 shows only a circuit connected between secondary side terminals R1 and S1 that outputs one line voltage V1r (see Fig. 6(a)).

[0028] The positive-side circuit 11r connected to the secondary-side terminal R1 will now be described. The switch element SWpr is an N-channel metal-oxide-semiconductor field-effect transistor (MOSFET). The drain of this MOSFET is connected to the positive electrode of the storage battery 5, and the source is connected to the terminal R1. The parasitic diode of the MOSFET corresponds to the positive-side rectifier element P1r in the first full-wave rectifier. Here, an external diode is connected in parallel with the parasitic diode, and this also plays the role of the positive-side rectifier element P1r. If the switch element is a MOSFET, this external diode is not essential.

[0029] Furthermore, the anode of the diode, which is the positive-side rectifier element P2r of the second full-wave rectifier, is connected to terminal R1, and the cathode is connected to one end of the input side of the photovoltaic device PVpr. The other end of the input side of the photovoltaic device PVpr is connected to one end of the resistor element 4. Therefore, the photodiode, which is the light-emitting element on the input side of the photovoltaic device PVpr, is connected in series with the positive-side rectifier element P2r and emits light when it detects a current flowing through the positive-side rectifier element P2r. The light-receiving diode on the output side of the photovoltaic device PVpr outputs a predetermined current to the outside when the input-side photodiode emits light. The output current of the photovoltaic device PVpr flows through resistor element 8, generating a gate drive voltage for the MOSFET switch element SWpr. In this way, when the positive-side rectifier element P2r is conductive, the photovoltaic device PVpr outputs a drive signal to the driver of the switch element SWpr.

[0030] The positive side circuit 11s connected to the secondary side terminal S1 has exactly the same configuration as the positive side circuit 11r described above.

[0031] Next, the negative-side circuit 12r connected to the secondary-side terminal R1 will be described. The switch element SWnr is an N-channel MOSFET. The drain of this MOSFET is connected to the terminal R1, and the source is connected to the positive electrode of the storage battery 5. The parasitic diode of the MOSFET corresponds to the negative-side rectifier element N1r in the first full-wave rectifier. Here, an external diode is connected in parallel with the parasitic diode, and this also plays the role of the negative-side rectifier element N1r. However, this external diode is not essential.

[0032] Furthermore, the anode of the diode, which is the negative-side rectifier element N2r of the second full-wave rectifier, is connected to one end of the input side of the photovoltaic PVnr, and the cathode is connected to terminal R1. The other end of the input side of the photovoltaic PVnr is connected to the other end of the resistor element 4. Therefore, the photodiode, which is the light-emitting element on the input side of the photovoltaic PVnr, is connected in series with the negative-side rectifier element N2r and emits light when it detects current flowing through the negative-side rectifier element N2r. The light-receiving diode on the output side of the photovoltaic PVnr outputs a predetermined current to the outside when the input-side photodiode emits light. The output current of the photovoltaic PVnr flows through resistor element 8, generating a gate drive voltage for the MOSFET switch element SWnr. In this way, when the negative-side rectifier element N2r is conductive, the photovoltaic PVnr outputs a drive signal to the driver of the switch element SWnr.

[0033] The negative side circuit 12s connected to the secondary side terminal S1 has exactly the same configuration as the negative side circuit 12r described above.

[0034] Figure 3 shows another example of the switch elements SWpr, SWnr, SWps, and SWns in Figure 2. When the switch elements are IGBTs or bipolar transistors, external diodes are required to allow a current to flow in the opposite direction to the current that flows when the switch elements are conductive. The external diodes function as the positive-side rectifier elements P1r and P1s or the negative-side rectifier elements N1r and N1s of the first full-wave rectifier section.

[0035] 4(a) and 4(b) show the operation of the interconnection circuit unit 10 at time x of the waveform in Fig. 6(a). At time x, the line voltage V1r between the R1 terminal and the S1 terminal is at its maximum (the R1 terminal is at a high potential, and the S1 terminal is at a low potential), and therefore the R1 terminal has the highest potential among the 12 secondary side terminals.

[0036] FIG. 4(a) shows the case where the potential of the R1 terminal is higher than the potential of the positive electrode of the storage battery 5. Current I1 flows through the first full-wave rectifier circuit via the thick-line path, and current I2 flows through the second full-wave rectifier circuit via the thin-line path through the resistor element 4. Current I2 flows through the positive-side rectifier element P2r and the negative-side rectifier element N2s, turning on the switch elements SWpr and SWns. In this case, the positive-side rectifier element P1r and the negative-side rectifier element N1s are forward-directed with respect to current I1. Therefore, regardless of whether switch elements SWpr and SWns are on or off, current I1, which charges the storage battery 5, can flow from terminal R1 to the positive electrode of the storage battery 5 and from the negative electrode of the storage battery 5 to terminal S1.

[0037] FIG. 4(b) shows the case where the potential of the positive electrode of the storage battery 5 is higher than the potential of the R1 terminal. The positive-side rectifier element P1r and the negative-side rectifier element N1s are opposite to the current I1 flowing from the storage battery 5 to the terminal R1. Meanwhile, in the second full-wave rectifier circuit, current I2 flows in the same direction as in FIG. 4(a) through the resistor element 4. The current I2 flows through the positive-side rectifier element P2r and the negative-side rectifier element N2s, turning on the switch elements SWpr and SWns. As a result, current I1 can flow through the switch elements SWpr and SWns. In other words, the positive-side rectifier element P1r and the negative-side rectifier element N1s are bypassed by the switch elements SWpr and SWns.

[0038] 5(a) and 5(b) show an example of the operation of the interconnection circuit unit 10 at time y of the waveform in Fig. 6(a). At time y, the line voltage V1r between the R1 terminal and the S1 terminal is at a maximum (the S1 terminal is at a high potential, and the R1 terminal is at a low potential), and therefore the S1 terminal has the highest potential among the 12 secondary side terminals.

[0039] FIG. 5(a) shows the case where the potential of the S1 terminal is higher than the potential of the positive electrode of the storage battery 5. A current I1 flows through the first full-wave rectifier circuit via the path indicated by the thick line, and a current I2 flows through the second full-wave rectifier circuit via the path indicated by the thin line, passing through the resistor element 4. The current I2 flows through the positive-side rectifier element P2s and the negative-side rectifier element N2r, turning on the switch elements SWps and SWnr. In this case, the positive-side rectifier element P1s and the negative-side rectifier element N1r are forward-directed with respect to the current I1. Therefore, regardless of whether the switch elements SWps and SWnr are on or off, the current I1 that charges the storage battery 5 can flow from the terminal S1 to the positive electrode of the storage battery 5 and from the negative electrode of the storage battery 5 to the terminal R1.

[0040] FIG. 5(b) shows the case where the potential of the positive electrode of the storage battery 5 is higher than the potential of the S1 terminal. The positive-side rectifier element P1s and the negative-side rectifier element N1r flow in the opposite direction to the current I1 flowing from the storage battery 5 to the terminal S1. Meanwhile, in the second full-wave rectifier circuit, current I2 flows in the same direction as in FIG. 5(a) through the resistor element 4. The current I2 flows through the positive-side rectifier element P2s and the negative-side rectifier element N2r, turning on the switch elements SWps and SWnr. As a result, current I1 can flow through the switch elements SWps and SWnr. In other words, the positive-side rectifier element P1s and the negative-side rectifier element N1r are bypassed by the switch elements SWps and SWnr.

[0041] Figure 6(b) shows the waveform obtained by full-wave rectifying the 12-phase AC voltage waveform shown in Figure 6(a). This is the voltage waveform across the storage battery 5 when the storage battery 5 is being charged as shown in Figures 4(a) and 5(a). The 12 line voltages V1r to V4t output from the secondary terminals R1 to T4 of the 12-phase transformer alternate maximum voltages every 15 degrees of phase, and current flows from the terminal with the highest potential to the terminal with the lowest potential through the first full-wave rectifier circuit. The more phases in the multi-phase transformer, the smaller the ripple of the rectified waveform becomes, approaching pure DC.

[0042] Figure 7(a) is a diagram showing the correspondence between the 12 terminals R1 to T4 on the secondary side of a 12-phase transformer and the 12 line voltages Vr1 to Vt4. (b) is a vector diagram showing the phase relationship of the 12 line voltages Vr1 to Vt4 (clockwise is the leading direction). The 12 line voltages Vr1 to Vt4 consist of four sets of three-phase AC, numbered 1 to 4, as follows: The numbers in parentheses indicate which terminals the line voltages are between. First three-phase AC: V1r (between R1 and S1), V1s (between S1 and T1), V1t (between T1 and R1) Second three-phase AC: V2r (between R1 and R3), V2s (between S1 and S3), V2t (between T1 and T3) Third three-phase AC: V3r (between R1 and R2), V3s (between S1 and S2), V3t (between T1 and T2) Fourth three-phase AC: V4r (between R1 and R4), V4s (between S1 and S4), V4t (between T1 and T4)

[0043] The second three-phase AC, the third three-phase AC, and the fourth three-phase AC are delayed in phase with respect to the first three-phase AC by 15 degrees, 30 degrees, and 45 degrees, respectively.

[0044] 8 shows the measured waveform of the three-phase AC power output to the primary side of the multi-phase transformer 1 when discharging from the storage battery 5 to the multi-phase transformer 1 as shown in FIGS. 4(b) and 5(b). According to the bidirectional power interconnection device of the present invention, a stable three-phase AC waveform can be generated from the DC power section through the autonomous operation of the interconnection circuit section itself, without automatic control by an electronic control unit, and power can be supplied to the grid. This reduces adverse effects on the grid.

[0045] In principle, multi-phase transformer 1 is not limited to 12-phase, 9-phase, or 6-phase transformers, and includes those that convert three-phase AC to 3n-phase polyphase AC. When n = 4, it becomes a 12-phase transformer, when n = 3, it becomes a 9-phase transformer, and when n = 2, it becomes a 6-phase transformer. The secondary-side terminals consist of first to third main terminals that output the first three-phase AC and fourth to third sub-terminals. The secondary-side line voltages are the first three-phase AC Vr1, Vs1, and Vst, and the second to n-th three-phase ACs, which are phase-delayed by 60 / n degrees, 2 × (60 / n) degrees, and (n-1) × (60 / n) degrees from each phase of the first three-phase AC, respectively.

[0046] As n increases, the ripple in the full-wave rectified waveform shown in Figure 6(b) decreases, and the waveform approaches DC. However, as n increases, the configuration of the multi-phase transformer and interconnection circuit becomes more complex and the number of components increases.

[0047] Although the embodiments of the present invention have been described above with reference to exemplary configurations, the present invention is not limited to these specific configurations. Various modifications are also within the scope of the present invention as long as they comply with the principles of the present invention. [Explanation of symbols]

[0048] 1. Polyphase transformer 10 Grid connection circuit section 11 Positive circuit 12 Negative side circuit 4 Resistive elements 5. Storage battery 6, 7 DC connection terminals P1 First positive rectifier P2 Second positive-side rectifier N1 First negative rectifier N2 Second negative side rectifier SW switch R0, S0, T0 Three-phase AC lines R1, S1, T1 main terminals R2, R3, R4, S2, S3, S4, T2, T3, T4 sub terminals V1r, V1s, V1t First three-phase AC (line voltage) V2r, V2s, V2t Second three-phase AC (line voltage) V3r, V3s, V3t Third three-phase AC (line voltage) V4r, V4s, V4t Fourth three-phase AC (line voltage)

Claims

1. A bidirectional power interconnection circuit that interconnects an AC power unit and a DC power unit in both directions, a first full-wave rectification unit including a plurality of first rectification elements capable of full-wave rectifying the AC power from the AC power unit and outputting the full-wave rectified AC power to the DC power unit; a second full-wave rectification unit including a plurality of second rectification elements capable of full-wave rectifying the AC power from the AC power unit and outputting the full-wave rectified AC power to a resistance element; a switch section configured to switch off when the associated second rectifying element is non-conducting and on when the associated second rectifying element is conducting, and The plurality of first rectifying elements of the first full-wave rectifying unit a first positive-side rectifying element having an anode connected to a terminal of each phase of AC from the AC power unit and a cathode commonly connected to a positive terminal of the DC power unit; a first negative-side rectifying element having a cathode connected to a terminal of each phase of AC from the AC power unit and an anode commonly connected to a negative terminal of the DC power unit; The plurality of second rectifying elements of the second full-wave rectifying unit a second positive-side rectifying element having an anode connected to a terminal of each phase of the AC power from the AC power unit and a cathode commonly connected to one end of the resistor element; a second negative-side rectifying element having a cathode connected to a terminal of each phase of the AC power from the AC power unit and an anode commonly connected to the other end of the resistor element.

2. The drive unit that switches the switch element on and off includes: a light-emitting element that is connected in series with the second rectifying element and emits light only when the second rectifying element is conductive; and a light-receiving element that receives light from the light-emitting element, 2. The bidirectional power interconnection circuit according to claim 1, wherein the light receiving element outputs a drive signal that turns the switch element on when receiving light from the light emitting element and turns the switch element off when not receiving light.

3. the first rectifying element is a parasitic diode of a field effect transistor or a diode connected in parallel with the parasitic diode, 3. The bidirectional power interconnection circuit according to claim 2, wherein the switch element is a current path between the drain and source of the field effect transistor, and the gate of the field effect transistor is driven by the drive signal of the drive unit.

4. the first rectifying element is an external diode for passing a current in a direction opposite to a current that flows when the IGBT or bipolar transistor is conductive, 3. The bidirectional power interconnection circuit according to claim 2, wherein the switch element is a current path between the emitter and collector of the IGBT or the bipolar transistor, and a gate of the IGBT or a base of the bipolar transistor is driven by a drive signal from the drive unit.

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