Power supply unit and energy storage system

Abstract

To provide a power unit and a power storage system which can suppress size increase and cost increase of the unit and cope with wrong wiring.SOLUTION: A power unit comprises: a first input terminal part in which first AC voltage is input; a second input terminal part in which second AC voltage lower than the first AC voltage is input; a first conversion part which converts the first AC voltage input in the first input terminal part into first DC voltage; a second conversion part which includes a voltage doubler rectifier circuit and converts the second AC voltage input in the second input terminal part into second DC voltage by using the voltage doubler rectifier circuit; and a wraparound prevention circuit which prevents wraparound current from flowing so that the first AC voltage is applied to an element constituting the voltage doubler rectifier circuit.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] This disclosure relates to power supply devices and energy storage systems. [Background technology]

[0002] The circuit shown in Figure 1 is known as a control power supply circuit used in an energy storage system that has an AC200V input for grid connection and an AC100V input from the standalone output of a PV (photovoltaic) power conditioner.

[0003] Referring to Figure 1, the first terminal IN1 and the second terminal IN2 are connected to an external power supply G1, and AC200V AC power is input from the external power supply G1 to the rectifier circuit 900 via these terminals. The third terminal IN3 and the fourth terminal IN4 are connected to an external power supply G2, and AC100V AC power is input from the external power supply G2 to the rectifier circuit 902 via these terminals. The AC power supplied from the external power supply G1 and the external power supply G2 is rectified by the rectifier circuits 900 and 902, respectively, and converted to a predetermined voltage by the transformer T1. The voltage converted to the predetermined voltage is then passed through a rectifier circuit consisting of diodes and capacitors to generate a DC voltage. The generated DC voltage is output as a control power supply from output terminals OUT1 and OUT2.

[0004] The AC200V from the external power supply G1 is rectified and smoothed by the rectifier circuit 900, resulting in 200 × 2V across the capacitor C91. 1 / 2 Approximately 282V appears. The AC100V from the external power supply G2 is rectified and smoothed by the rectifier circuit 902, resulting in 100 × 2V across capacitor C91. 1 / 2 Approximately 141V appears. Therefore, the operating voltage range of transformer T1, including the margin, becomes wide, ranging from DC100V to DC300V. This configuration can lead to decreased power supply efficiency and increased complexity in noise countermeasures.

[0005] As a countermeasure, a circuit like the one shown in Figure 2 is sometimes used. The circuit in Figure 2 is a circuit in which the rectifier circuit 902 in Figure 1 is replaced with a voltage doubler rectifier circuit 904.

[0006] Referring to Figure 2, the voltage doubler rectifier circuit 904 includes diode D91, diode D92, capacitor C92, and capacitor C93. By using the voltage doubler rectifier circuit 904 as a circuit that rectifies and smooths when AC100V is input from an external power supply G2, 200 × 2 is applied across the capacitor C91. 1 / 2 Approximately 282V appears. That is, whether AC200V is input by external power supply G1 or AC100V is input by external power supply G2, 282V appears across capacitor C91. This allows the operating voltage range of transformer T1 to be narrowed to approximately DC250V to DC300V, including a margin. As a result, the design optimization of transformer T1 becomes easier, and power supply efficiency improvements and noise countermeasures also become easier.

[0007] In the circuit shown in Figure 2, it is possible that the circuit inputs, namely the first terminal IN1, second terminal IN2, third terminal IN3, and fourth terminal IN4, may be incorrectly connected to the external power supply (hereinafter referred to as miswiring). In that case, a high voltage not anticipated in the design will be generated across capacitor C91, and a voltage exceeding the rating will be applied to the circuit components. In this case, the circuit components may be damaged. For example, in a battery storage system where the first AC input terminals (first terminal IN1 and second terminal IN2) are connected to the grid's single-phase three-wire 200V, and the second AC input terminals (third terminal IN3 and fourth terminal IN4) are connected to single-phase two-wire 100V, the correct connection should be the independent output of the PCS (Power Conditioning System) of the solar power generation device to the second AC input terminal. However, due to wiring errors during electrical work when installing the battery storage system, miswiring may occur where the grid's single-phase two-wire 100V is connected to the second AC input terminal. The circuit shown in Figure 2 can be miswired as shown in Figure 3.

[0008] Referring to Figure 3, transformer T2 outputs AC200V through output terminals L1 and L2, and AC100V from center tap N. The first terminal IN1 and the second terminal IN2 are correctly connected to output terminals L1 and L2, respectively. However, the third terminal IN3 and the fourth terminal IN4 are not connected to an external power source other than the external power source G1 (the independent output of the PCS of the solar power generation system), but are incorrectly connected to the center tap N and output terminal L2 of transformer T2, respectively. Note that in Figure 3, a full-wave rectifier circuit 906 is shown as a specific example of the rectifier circuit 900.

[0009] The miswiring shown in Figure 3 creates a path through which a diverting current flows, as shown in Figure 4. Specifically, the AC200V supplied from output terminals L1 and L2 causes a diverting current, shown by the solid and dashed lines, to flow through the diodes constituting the full-wave rectifier circuit 906. Since AC200V is applied to the voltage doubler rectifier circuit 904, 200 × 2V flows through capacitor C92 with respect to the interconnection node of capacitors C92 and C93. 1 / 2 Approximately 282V is applied, and -200 × 2 is applied to capacitor C93. 1 / 2 Approximately -282V is applied. As a result, the same voltage as the voltage across both ends of the interconnected capacitors C92 and C93 is applied to capacitor C91, which has a voltage of 2 × 200 × 2 1 / 2 Approximately 564V is applied. In this way, capacitors C91, C92, C93, and switching element Q91 are subjected to a voltage exceeding their voltage rating, which could cause them to be damaged.

[0010] As a countermeasure to this problem, Patent Document 1 discloses a circuit equipped with a relay, or a relay and a photocoupler, to prevent AC power from being input to both the full-wave rectifier circuit and the voltage doubler rectifier circuit simultaneously. [Prior art documents] [Patent Documents]

[0011] [Patent Document 1] Japanese Patent Publication No. 2016-96613 [Overview of the initiative] [Problems that the invention aims to solve]

[0012] In the circuit disclosed in Patent Document 1, the circuit composed of the added components spans both the circuit for the first AC input terminal and the circuit for the second AC input terminal, thus requiring a considerable amount of installation space. Therefore, the technology disclosed in Patent Document 1 has the problem of making the device larger and unsuitable for miniaturization. The added relays and photocouplers are products with limited lifespans, and the addition of these components also results in an increase in the number of components. Considering that the aforementioned miswiring is a rare occurrence such as wiring errors during the installation of a battery storage system and can be detected during commissioning when the battery storage system is installed, the addition of such components can be considered an excessive measure. Therefore, the technology disclosed in Patent Document 1 also has the problem of leading to higher costs.

[0013] Therefore, the purpose of this disclosure is to provide a power supply and energy storage system that can suppress the increase in size and cost of the device and can accommodate miswiring. [Means for solving the problem]

[0014] A power supply device according to a certain aspect of the present disclosure includes a first input terminal section into which a first AC voltage is input, a second input terminal section into which a second AC voltage lower than the first AC voltage is input, a first conversion section that converts the first AC voltage input to the first input terminal section into a first DC voltage, a second conversion section that includes a voltage doubling rectifier circuit and converts the second AC voltage input to the second input terminal section into a second DC voltage using the voltage doubling rectifier circuit, and a feedback prevention circuit that prevents feedback current from flowing so that the first AC voltage is applied to the elements constituting the voltage doubling rectifier circuit. [Effects of the Invention]

[0015] According to this disclosure, it is possible to suppress the increase in size and cost of the equipment and to provide a power supply unit and energy storage system that can handle miswiring. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] [Figure 1] FIG. 1 is a circuit diagram showing the configuration of a power supply device having two inputs. [Figure 2] FIG. 2 is a circuit diagram showing the configuration of a power supply device using a voltage doubler rectifier circuit. [Figure 3] FIG. 3 is a circuit diagram showing a state where the input of the power supply device shown in FIG. 2 is incorrectly wired to an external power supply. [Figure 4] FIG. 4 is a circuit diagram showing a sneak current flowing in the circuit shown in FIG. 3. [Figure 5] FIG. 5 is a circuit diagram showing the configuration of a power supply device according to an embodiment of the present disclosure. [Figure 6] FIG. 6 is a circuit diagram showing a state where the input of the power supply device shown in FIG. 5 is incorrectly wired. [Figure 7] FIG. 7 is a block diagram showing the configuration of a power storage system including the power supply device shown in FIG. 5. MODE FOR CARRYING OUT THE INVENTION

[0017] Description of Embodiments of the Present Disclosure The contents of the embodiments of the present disclosure are listed and described below. At least a part of the embodiments described below may be arbitrarily combined.

[0018] (1) A power supply device according to a first aspect of the present disclosure includes: a first input terminal portion to which a first AC voltage is input; a second input terminal portion to which a second AC voltage lower than the first AC voltage is input; a first conversion portion that converts the first AC voltage input to the first input terminal portion into a first DC voltage; a second conversion portion that includes a voltage doubler rectifier circuit and converts the second AC voltage input to the second input terminal portion into a second DC voltage using the voltage doubler rectifier circuit; and a sneak current prevention circuit that prevents a sneak current from flowing such that the first AC voltage is applied to elements configuring the voltage doubler rectifier circuit. This makes it possible to suppress an increase in size and cost of the device and realize a power supply device compatible with incorrect wiring.

[0019] (2) In (1) above, the feedback prevention circuit may include a first diode and a second diode, and the first diode and the second diode may be arranged to prevent feedback current. This prevents high voltage from being applied to the circuit components of the power supply when the input terminal of the power supply and the external power supply are miswired.

[0020] (3) In (2) above, the first conversion unit may include a full-wave rectifier circuit, and the magnitude of the second AC voltage may be half the magnitude of the first AC voltage. This allows the first and second rectifier circuits to generate DC voltages of roughly the same magnitude. Therefore, the design of a transformer for converting and outputting the voltages generated by the first and second rectifier circuits becomes easier.

[0021] (4) In (2) or (3) above, the voltage doubler rectifier circuit may include a third diode and a fourth diode connected in series to form a first interconnection node, and a first capacitor and a second capacitor connected in series to form a second interconnection node, and the two uninterconnected terminals of the third diode and the fourth diode and the two uninterconnected terminals of the first capacitor and the second capacitor may be connected one-to-one to form a first node and a second node, and the first interconnection node and the second interconnection node may be connected to the second input terminal section, and the anode of the first diode may be connected to the first node, and the cathode of the second diode may be connected to the second node. This prevents the generation of rift current when the input terminal of the power supply and the external power supply are miswired, and reliably prevents high voltage from being applied to the circuit components of the power supply.

[0022] (5) The energy storage system relating to the second aspect of this disclosure includes a power supply device as described in any one of (1) to (4) above, a storage battery, a power conversion circuit having the function of converting AC power to DC power to charge the storage battery and the function of converting the discharge power of the storage battery to AC power for output, and a control unit that controls the power conversion circuit, wherein the power supply device supplies power to the control unit. This makes it possible to suppress the increase in size and cost of the device and to realize an energy storage system including a power supply device that can handle miswiring.

[0023] [Details of the embodiments of this disclosure] In the following embodiments, identical parts are assigned the same reference numeral. Their names and functions are also identical. Therefore, detailed descriptions of them will not be repeated.

[0024] Referring to Figure 5, the power supply unit 100 according to the embodiment of the present disclosure includes a first conversion unit 101, a second conversion unit 103, a feedback prevention circuit 106, a first input terminal unit 108, and a second input terminal unit 110. The first conversion unit 101 includes a first rectifier circuit 102. The first rectifier circuit 102 includes a first input / output terminal 120, a second input / output terminal 122, an output terminal 124, and an input terminal 126. The first rectifier circuit 102 is, for example, a full-wave rectifier circuit. The first input terminal unit 108 includes a first terminal IN1 and a second terminal IN2. The first input / output terminal 120 is connected to the first terminal IN1, and the second input / output terminal 122 is connected to the second terminal IN2. The first terminal IN1 and the second terminal IN2 are connected to an external power supply G1, and AC power supplied from the external power supply G1, for example AC200V, is supplied to the first input / output terminal 120 and the second input / output terminal 122 of the first rectifier circuit 102. The first rectifier circuit 102 rectifies the AC current supplied to the first input / output terminal 120 and the second input / output terminal 122 and outputs it from the output terminal 124.

[0025] Between the output terminal 124 and the input terminal 126, the primary coil and switching element Q1 of the transformer T1, which are connected in series, and the capacitor C1 are connected in parallel. The switching element Q1 is, for example, a transistor, and its on / off state is controlled by the control unit (e.g., a microcontroller) of the system (e.g., an energy storage system) including the power supply unit 100. The switching element Q1 may also be an FET (Field Effect Transistor). When AC 200V is supplied to the first rectifier circuit 102 from the external power supply G1, 200 × 2V is supplied to both terminals of the capacitor C1. 1 / 2 Approximately 282V is generated.

[0026] Transformer T1, together with its surrounding circuitry (i.e., switching element Q1, diode D1, and capacitor C2), constitutes a flyback DC / DC converter. The current output from the first rectifier circuit 102 flows to the primary coil of transformer T1 through the on / off control of switching element Q1, and power is transmitted to the secondary coil of transformer T1. The current flowing through the secondary coil of transformer T1 is rectified by diode D1 and capacitor C2 and output from output terminals OUT1 and OUT2.

[0027] Furthermore, the primary coil of the transformer T3 and the switching element Q2 are connected in series between the output terminal 124 and the input terminal 126. The switching element Q2, like the switching element Q1, is, for example, a transistor, and its on / off state is controlled by the control unit of the system, which includes the power supply unit 100. The switching element Q2 may also be an FET.

[0028] Transformer T3, together with its surrounding circuitry (i.e., switching element Q2, diode D2, and capacitor C3), constitutes a flyback DC / DC converter. The current output from the first rectifier circuit 102 flows to the primary coil of transformer T3 through the on / off control of the switching element Q2, and power is transmitted to the secondary coil of transformer T3. The current flowing through the secondary coil of transformer T3 is rectified by the diode D2 and capacitor C3 and output from output terminals OUT3 and OUT4. When the power supply unit 100 is installed in an energy storage system, the output power from output terminals OUT3 and OUT4 is supplied to a control unit for controlling a power conversion circuit (DC / DC converter, inverter, etc.).

[0029] The second conversion unit 103 includes a second rectifier circuit 104. The second rectifier circuit 104 includes a third diode 140, a fourth diode 142, a first capacitor 144, and a second capacitor 146, and constitutes a voltage doubler rectifier circuit. Specifically, the third diode 140 and the fourth diode 142 are connected in series with each other (i.e., the anode of the third diode 140 is connected to the cathode of the fourth diode 142), forming a first interconnection node 150. The first capacitor 144 and the second capacitor 146 are connected in series with each other, forming a second interconnection node 152. Both terminals of the third diode 140 and the fourth diode 142, which are connected in series with each other, and both terminals of the first capacitor 144 and the second capacitor 146, which are connected in series with each other, are connected one-to-one, forming the first node 154 and the second node 156. Specifically, the first node 154 corresponds to the cathode of the third diode 140, and the second node 156 corresponds to the anode of the fourth diode 142. The first interconnection node 150 and the second interconnection node 152 of the second rectifier circuit 104 are connected to the third terminal IN3 and the fourth terminal IN4, respectively. An external power supply G2 is connected to the third terminal IN3 and the fourth terminal IN4. The external power supply G2 is, for example, the standalone output of the PCS of a solar power generation system. The AC power supplied from the external power supply G2, for example AC100V, is supplied to the first interconnection node 150 and the second interconnection node 152 via the third terminal IN3 and the fourth terminal IN4.

[0030] The backflow prevention circuit 106 includes a first diode 130 and a second diode 132. An anode of the first diode 130 is connected to a first node 154 of the second rectifier circuit 104, and a cathode of the first diode 130 is connected to an output terminal 124 of the first rectifier circuit 102. A cathode of the second diode 132 is connected to a second node 156 of the second rectifier circuit 104, and an anode of the second diode 132 is connected to an input terminal 126 of the first rectifier circuit 102. Accordingly, between the first node 154 and the second node 156 of the second rectifier circuit 104, that is, across both terminals of the capacitor C1, a voltage twice the alternating voltage input from the external power supply G2 is generated. When 100V AC is output from the external power supply G2, 200×2 1 / 2 ≒282V is generated across both terminals of the capacitor C1. Accordingly, similarly to the case where alternating-current power is supplied from the external power supply G1, the current output from the first node 154 flows through the primary coil of the transformer T1 by the on-off control of the switching element Q1, and power is transmitted to the secondary coil of the transformer T1. The current flowing through the secondary coil of the transformer T1 is rectified by the diode D1 and the capacitor C2, and output from the output terminal OUT1 and the output terminal OUT2. Further, the current output from the first node 154 also flows through the primary coil of the transformer T3 by the on-off control of the switching element Q2. Accordingly, as described above, power is also transmitted to the secondary coil of the transformer T3, and the current flowing through the secondary coil is rectified by the diode D2 and the capacitor C3, and output from the output terminal OUT3 and the output terminal OUT4.

[0031] As described above, in both the case where 200V AC is supplied from the external power supply G1 to the first rectifier circuit 102 and the case where 100V AC is supplied from the external power supply G2 to the second rectifier circuit 104, 200×2 of direct-current voltage having the same magnitude is applied across both terminals of the capacitor C1 1 / 2 ≒282V is generated. Note that "the same magnitude" includes a case where there is a difference equal to or less than a predetermined value. Therefore, the operating voltage range of the transformer T1 can be narrowed to approximately 250V DC to 300V DC including a margin, which facilitates design optimization, and also facilitates improvement of power supply efficiency and noise countermeasures.

[0032] Figure 6 shows the power supply unit 100 shown in Figure 5, but with the first input terminal 108 and the second input terminal 110 incorrectly connected to an external power supply. For convenience, part of the configuration shown in Figure 5 (i.e., the circuit portion for outputting power from output terminals OUT3 and OUT4 via transformer T3) is not shown in Figure 6. Transformer T2 has a center tap N and outputs AC200V through output terminals L1 and L2, and AC100V from center tap N. In Figure 6, the connections between the first terminal IN1, second terminal IN2, third terminal IN3, and fourth terminal IN4 and transformer T2 are the same as in Figure 3. That is, the first terminal IN1 and second terminal IN2 are correctly connected to output terminals L1 and L2, respectively. However, the third terminal IN3 and fourth terminal IN4 are incorrectly connected to the center tap N and output terminal L2 of transformer T2, respectively, instead of being connected to an external power supply other than external power supply G1. Figure 6 shows a full-wave rectifier circuit as a specific example of the first rectifier circuit 102.

[0033] When current is supplied from the output terminal L1 of transformer T2, a current path indicated by the solid arrow is formed by the output terminal 124 of the first rectifier circuit 102, capacitor C1, second diode 132, second capacitor 146, second interconnection node 152, fourth terminal IN4, second terminal IN2, and output terminal L2. When current is supplied from the output terminal L2 of transformer T2, a path indicated by the dashed arrow is formed by the second terminal IN2, fourth terminal IN4, second interconnection node 152, first capacitor 144, first diode 130, capacitor C1, input terminal 126 of the first rectifier circuit 102, first terminal IN1, and output terminal L1. The current supplied from the output terminal L1 of transformer T2 does not flow to the first capacitor 144 due to the first diode 130, and the current loop path indicated by the solid arrow in Figure 4 is not formed. Furthermore, the current supplied from the output terminal L2 of transformer T2 does not flow from the second capacitor 146 to the input terminal 126 due to the second diode 132, and the current loop path shown by the dashed arrow in Figure 4 is not formed. Therefore, the circuit components constituting the power supply unit 100, namely the first capacitor 144, the second capacitor 146, capacitor C1, and switching element Q1, are not subjected to high voltages exceeding their ratings, as shown in Figure 4.

[0034] AC power (i.e., 100V AC) supplied from the center tap N and output terminal L2 causes current to flow through the third diode 140 and the first capacitor 144, as indicated by the arc-shaped solid arrows, and through the fourth diode 142 and the second capacitor 146, as indicated by the arc-shaped dashed arrows. Depending on the polarity reversal of the center tap N and output terminal L2, the currents indicated by the arc-shaped solid and dashed arrows occur alternately. Therefore, 100 × 2 current flows through each of the first capacitor 144 and the second capacitor 146. 1 / 2 Approximately 141V is generated. Furthermore, as AC power (i.e., AC 200V) is supplied from output terminals L1 and L2, the voltage across capacitor C1 is the sum of the voltage from full-wave rectification by the first rectifier circuit 102 and the voltage from half-wave rectification by the first capacitor 144 or the second capacitor 146, resulting in 200 × 21 / 2 +100 x 2 1 / 2 =300×2 1 / 2 Approximately 423V is generated.

[0035] As described above, transformer T1, together with its surrounding circuitry, constitutes a flyback DC / DC converter. The source-drain voltage VDS of the power supply IC (Integrated Circuit) used in switching element Q1 is assumed to be used by rectifying AC200V, and its rated voltage is generally around DC800V to DC900V. The source-drain voltage VDS of switching element Q1 must not exceed the rated voltage, including surge voltage and flyback voltage. As described above, the voltage generated across capacitor C1 is approximately 423V, so even considering surge voltage and flyback voltage, it will not exceed the rated voltage of switching element Q1.

[0036] In contrast, in Figure 4, capacitors C92 and C93 have a 200 × 2 1 / 2 Approximately 282V is generated, and capacitor C91 has 2 × 200 × 2 1 / 2 Approximately 564V is generated. When approximately 564V is generated across capacitor C91, considering the surge voltage and flyback voltage, the source-drain voltage VDS of switching element Q91 (see Figure 4) exceeds the rated voltage, and a general-purpose power supply IC cannot be used for switching element Q91. Using a high-voltage power supply IC would increase costs. Furthermore, high-voltage power supply ICs have high losses and are inefficient (i.e., generate more heat).

[0037] In the power supply unit 100 shown in Figure 5, even if there is a wiring error as shown in Figure 6, the voltage applied to the first capacitor 144 and the second capacitor 146 constituting the second rectifier circuit 104 can be reduced to half of that in Figure 4, and the voltage applied to capacitor C1 can be reduced to three-quarters of that in Figure 4. Therefore, damage to the circuit components constituting the power supply unit 100 due to the application of a voltage exceeding its rating can be prevented, and wiring errors can be accommodated. A general-purpose power supply IC can be used for the switching element Q1, eliminating the need for a high-voltage power supply IC. Therefore, cost increases can be suppressed.

[0038] Furthermore, when the power supply unit 100 is incorporated into a system (for example, an energy storage system), the system's control unit determines whether the input voltage of the power supply unit 100 is normal. Therefore, even if a wiring error occurs during the installation of the power supply unit 100, as shown in Figure 6, power will be supplied from the power supply unit 100 to the control unit, and the control unit will detect that the input voltage of the power supply unit 100 is not normal. When it is detected that the input voltage of the power supply unit 100 is not normal, the system will display a warning (for example, sound, text, etc.), allowing the operator to correct the wiring error. To supply power from the power supply unit 100 to the control unit to operate the control unit, a flyback type DC / DC converter (i.e., transformer T3, switching element Q2, diode D2, and capacitor C3) can be provided on both terminals of the capacitor C1, as shown in Figure 5.

[0039] Furthermore, in the power supply unit 100, there is no need to use relays, photocouplers, etc., as circuit components to address miswiring, thus suppressing the increase in size and cost of the power supply unit. In the power supply unit 100, only the first diode 130 and the second diode 132 that constitute the feedback prevention circuit 106 need to be added as circuit components to address miswiring. Therefore, the increase in the number of components to address miswiring can be suppressed.

[0040] As described above, the first diode 130 and the second diode 132 that constitute the feedback prevention circuit 106 are arranged to prevent feedback current. This prevents high voltage from being applied to the circuit components of the power supply unit 100 when the input terminals of the power supply unit 100 and the external power supply are miswired.

[0041] As described above, the magnitude of the AC voltage supplied from the external power supply G2 (e.g., AC100V) is half the magnitude of the AC voltage supplied from the external power supply G1 (e.g., AC200V), the first rectifier circuit 102 is a full-wave rectifier circuit, and the second rectifier circuit 104 is a voltage doubler rectifier circuit. As a result, the first rectifier circuit 102 and the second rectifier circuit 104 can generate DC voltages of roughly the same magnitude. Therefore, the design of the transformer T1 for converting and outputting the voltages generated by the first rectifier circuit 102 and the second rectifier circuit 104 becomes easier.

[0042] As shown in Figure 5, the second rectifier circuit 104 includes a third diode 140, a fourth diode 142, a first capacitor 144, and a second capacitor 146. The first diode 130 has its anode connected to the first node 154 and its cathode connected to the output terminal 124 of the first rectifier circuit 102. The second diode 132 has its cathode connected to the second node 156 and its anode connected to the input terminal 126 of the first rectifier circuit 102. This prevents the generation of rift current when the input terminal of the power supply unit 100 and the external power supply are miswired, and reliably prevents high voltage from being applied to the circuit components of the power supply unit 100.

[0043] In the above, Figure 6 was shown as illustrating the state in which the power supply unit 100 shown in Figure 5 is miswired to an external power supply. However, the power supply unit 100 may also be used with a non-isolated transformer T2 connected, as shown in Figure 6. Even in that case, as described above, a voltage exceeding the rating will not be applied to the circuit components of the power supply unit 100.

[0044] The above describes the case where AC200V is supplied to the first terminal IN1 and the second terminal IN2, and half of that, AC100V, is supplied to the third terminal IN3 and the fourth terminal IN4, but it is not limited to this case. The AC voltage supplied to the third terminal IN3 and the fourth terminal IN4 should be close to half the AC voltage supplied to the first terminal IN1 and the second terminal IN2. In other words, the voltage difference generated across capacitor C1 between the case where AC power is supplied to the first terminal IN1 and the second terminal IN2 and the case where AC power is supplied to the third terminal IN3 and the fourth terminal IN4 should be such that the design of transformer T1 does not become difficult.

[0045] (Energy storage system) The power supply unit 100 shown in Figure 5 can be used in an energy storage system. Referring to Figure 7, the energy storage system 200 according to the embodiment includes a battery 202, a bidirectional DC / DC converter 204, a bidirectional inverter 206, a switch unit 208, a control unit 210, and the power supply unit 100. The battery 202 is a rechargeable battery such as a lithium-ion secondary battery. The bidirectional DC / DC converter 204 and the bidirectional inverter 206 constitute a power conversion circuit. The bidirectional DC / DC converter 204, under the control of the control unit 210, boosts the DC voltage output from the battery 202 and outputs it to the bidirectional inverter 206. The bidirectional inverter 206, under the control of the control unit 210, converts the DC voltage from the bidirectional DC / DC converter 204 into an AC voltage and outputs it. The switch unit 208 includes a plurality of switches (relays, etc.) and, under the control of the control unit 210, interconnects the bidirectional inverter 206, load 212, grid 214, photovoltaic power generation device 216, and power supply unit 100. Load 212 is an electrical appliance or similar device installed in a home or similar location. The switch unit 208, under the control of the control unit 210, connects the bidirectional inverter 206 to the load 212, thereby supplying the output power of the bidirectional inverter 206 to the load 212.

[0046] System 214 corresponds to the external power supply G1 shown in Figure 5. The photovoltaic power generation device 216 corresponds to the external power supply G2 shown in Figure 5. AC power is also supplied to the load 212 from system 214. In the event of a power outage in system 214, the switch unit 208 is controlled by the control unit 210 to connect the load 212 and the photovoltaic power generation device 216, thereby supplying AC power from the independent output of the PCS of the photovoltaic power generation device 216 to the load 212.

[0047] Furthermore, the switch unit 208 can be controlled by the control unit 210 to connect the bidirectional inverter 206 to the grid 214 or the solar power generation device 216. In this case, the AC power supplied from the grid 214 or the solar power generation device 216 is converted to DC power by the bidirectional inverter 206 and the bidirectional DC / DC converter 204 and supplied to the storage battery 202. As a result, the storage battery 202 is charged.

[0048] The power supply unit 100 has output terminals OUT1 and OUT2 connected to the battery 202, first terminal IN1 and second terminal IN2 connected to the grid 214, and third terminal IN3 and fourth terminal IN4 connected to the standalone output of the PCS of the solar power generation device 216. Output terminals OUT3 and OUT4 of the power supply unit 100 are connected to the control unit 210. As a result, the power supply unit 100 generates DC power of a predetermined voltage from the power supplied from the battery 202, grid 214, or solar power generation device 216, as described above, and supplies it to the control unit 210.

[0049] In the energy storage system 200, the power supply unit 100 shown in Figure 5 is used to prevent damage to circuit components due to the application of voltages exceeding their rated voltage, and to address miswiring. A general-purpose power supply IC can be used for the switching element Q1 shown in Figure 5, eliminating the need for a high-voltage power supply IC. Therefore, cost increases can be suppressed.

[0050] In the above description, the case in which the independent output of the PCS of the photovoltaic power generation device 216 is connected to the third terminal IN3 and fourth terminal IN4 of the power supply device 100 shown in Figure 5 was described, but it is not limited to this. A power source other than the photovoltaic power generation device 216 may be connected to the third terminal IN3 and fourth terminal IN4, for example, AC100V may be supplied to the power supply device 100.

[0051] The present disclosure has been described above by describing embodiments, but the embodiments described above are illustrative and the present disclosure is not limited to the embodiments described above. The scope of the present disclosure is given by the claims, with reference to the detailed description of the invention, and includes all modifications within the meaning and scope equivalent to the wording contained herein. [Explanation of symbols]

[0052] 100 Power supply 101 First Conversion Unit 102 1st rectifier circuit 103 Second Conversion Unit 104 Second rectifier circuit 106 Anti-backflow circuit 108 First Input Terminal Section 110 Second input terminal section 120 1st input / output terminal 122 2nd input / output terminal Output terminals: 124, L1, L2, OUT1, OUT2, OUT3, OUT4 126 Input terminals 130 First Diode 132 Second Diode 140 Third Diode 142 Fourth Diode 144 First Capacitor 146 Second Capacitor 150 First interconnection node 152 Second Interconnection Node 154 Node 1 156 2nd Node 200 Energy Storage Systems 202 Battery 204 Bidirectional DC / DC Converter 206 Bidirectional Inverter 208 Switch section 210 Control Unit 212 load 214 line 216 Solar power generation equipment 900, 902 rectifier circuit 904x voltage rectifier circuit 906 Full wave rectifier circuit C1, C2, C3, C91, C92, C93 Capacitors D1, D2, D91, D92 diodes G1, G2 External power supply IN1 Terminal 1 IN2 Second terminal IN3 Third Terminal IN4 4th terminal N Center Tap Q1, Q2, Q91 switching elements T1, T2, T3 transformers

Claims

1. A first input terminal section into which a first AC voltage is input, A second input terminal section to which a second AC voltage lower than the first AC voltage is input, A first conversion unit that converts the first AC voltage input to the first input terminal into a first DC voltage, A second conversion unit that includes a voltage doubler rectifier circuit and converts the second AC voltage input to the second input terminal into a second DC voltage using the voltage doubler rectifier circuit, The system includes a feedback prevention circuit that prevents feedback current from flowing so that the first AC voltage is applied to the elements constituting the voltage doubler rectifier circuit, The aforementioned feedback prevention circuit includes a first diode and a second diode, A power supply device in which the first diode and the second diode are arranged to prevent the leakage current.

2. The first conversion unit includes a full-wave rectifier circuit, The power supply device according to claim 1, wherein the magnitude of the second AC voltage is half the magnitude of the first AC voltage.

3. The voltage doubler rectifier circuit described above is A third diode and a fourth diode are connected in series to each other to form a first interconnection node, It includes a first capacitor and a second capacitor that are connected in series with each other to form a second interconnection node, The two unconnected terminals of the third diode and the fourth diode, and the two unconnected terminals of the first capacitor and the second capacitor, are connected one-to-one to form the first node and the second node. The first interconnection node and the second interconnection node are connected to the second input terminal section. The first diode has an anode connected to the first node, The power supply device according to claim 1 or claim 2, wherein the cathode of the second diode is connected to the second node.

4. A power supply device according to claim 1 or claim 2, Storage batteries and A power conversion circuit having the function of converting AC power to DC power to charge the storage battery, and the function of converting the discharge power of the storage battery to AC power and outputting it, Includes a control unit that controls the power conversion circuit, The power supply unit is an energy storage system that supplies power to the control unit.

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