A bidirectional pressure regulating device

Abstract

This utility model discloses a bidirectional voltage regulating device, relating to the field of AC voltage regulation technology. It includes one or three voltage regulating units, each comprising a connection terminal group, a first filter circuit, a voltage regulating circuit, and a commutation circuit. The connection terminal group includes connection terminal U1 and connection terminal U2. The commutation circuit is used to implement input / output / voltage regulation direction switching functions. When implementing the input / output switching function, the commutation circuit switches the connection relationship between connection terminals U1 and U2 and the first filter circuit and the voltage regulating circuit. When implementing the voltage regulation direction switching function, the bidirectional voltage regulating device also includes a transformer. Connection terminal U2 outputs the sum of the input AC voltage input to connection terminal U1 and the corresponding primary winding voltage. The commutation circuit adjusts the direction of the corresponding primary winding voltage by switching the connection relationship between the voltage regulating circuit and the corresponding secondary winding, thereby switching the voltage regulation direction of the input AC voltage. This effectively improves the application flexibility of the voltage regulating device and reduces its power consumption.

Description

Technical Field

[0001] This utility model relates to the field of AC voltage regulation technology, and in particular to a bidirectional voltage regulation device. Background Technology

[0002] With continuous economic development, electricity consumption has increased year by year, especially among residential users. However, the upgrading and renovation of power distribution lines in factories, mines, residential areas, and shops have lagged behind, resulting in voltages at the end of the lines being lower than standard, large voltage fluctuations, and frequent grid overloads. This makes it difficult for some electrical appliances to operate normally and easily causes damage. In addition, newly added motors, compressors, and other equipment have high reactive power requirements, generating a large amount of high-order harmonic currents, leading to increased low-voltage line losses, a decrease in the power factor of the grid, and exacerbated voltage fluctuations.

[0003] To address the issues of low voltage and voltage fluctuations, a related technological solution is to add power supply equipment to the distribution network. Voltage stabilization circuit. The automatic voltage regulation circuit can adjust the supply voltage in real time to stabilize it at the standard value, directly provide reactive power to electrical equipment, improve the power distribution network transmission capacity, enhance the operational safety of the power supply transformer, and significantly improve abnormal conditions such as voltage flicker caused by lightning strikes and short circuits, thus protecting the safety of electrical equipment.

[0004] However, in the process of real-time adjustment of power supply through voltage automatic regulation circuits using related technologies, there are often problems. Impedance mismatch in circuits leads to ripple and noise, requiring manual rewiring, which is inconvenient. Furthermore, the voltage regulation circuit may have excessive power. No effective technical solutions have yet been proposed for these issues, and improvements are urgently needed. Utility Model Content

[0005] In response to the aforementioned problems and technical requirements, the applicant has proposed a bidirectional pressure regulating device.

[0006] The technical solution of this utility model is as follows: A bidirectional voltage regulating device includes one or three voltage regulating units. Each voltage regulating unit includes a connection terminal group, a first filter circuit, a voltage regulating circuit, and a commutation circuit. The connection terminal group includes a connection terminal U1 and a connection terminal U2. The first filter circuit is connected to the voltage regulating circuit. The commutation circuit is used to realize the input-output switching function or the voltage regulation direction switching function. When the commutation circuit is used to implement the input-output switching function, for each voltage regulation unit, the commutation circuit is connected between the connection terminal U1 and the connection terminal U2 and the first filter circuit and the voltage regulation circuit. The commutation circuit is used to switch the connection relationship between the connection terminal U1 and the connection terminal U2 and the first filter circuit and the voltage regulation circuit, so that the first filter circuit and the voltage regulation circuit can filter and regulate the AC voltage input to the connection terminal U1 and output it to the connection terminal U2, or so that the first filter circuit and the voltage regulation circuit can filter and regulate the AC voltage input to the connection terminal U2 and output it to the connection terminal U1. When the commutation circuit is used to realize the voltage regulation direction switching function, the bidirectional voltage regulation device also includes a transformer. The number of winding phases of the transformer is the same as the number of voltage regulation units. Each voltage regulation unit corresponds to one phase winding, and each phase winding includes a primary winding and a secondary winding. For each voltage regulation unit, the connection terminal U1 is connected to the connection terminal U2 through the corresponding primary winding. The connection terminal U2 is used to output the sum of the input AC voltage input to the connection terminal U1 and the voltage of the corresponding primary winding. The connection terminal U1 is connected to the first filter circuit. The commutation circuit is connected between the output terminal of the voltage regulation circuit and the corresponding secondary winding, and the commutation circuit is connected to the neutral line. The first filter circuit and the voltage regulation circuit are used to filter and regulate the input AC voltage input to the connection terminal U1, and then output it to the corresponding secondary winding through the commutation circuit. The commutation circuit is used to switch the connection relationship between the voltage regulation circuit and the corresponding secondary winding to adjust the direction of the voltage of the corresponding primary winding. The bidirectional voltage regulation device further includes an inverter circuit, which is connected to the first filter circuit or the voltage regulation circuit, and is used to regulate the DC voltage input to the inverter circuit, the input AC power, or the reactive current and harmonic current at the output of the voltage regulation circuit.

[0007] A further technical solution is that the commutation circuit includes a switch S1 and a switch S2, and both the switch S1 and the switch S2 include a common terminal, a first contact and a second contact. When the commutation circuit is used to implement the input-output switching function, the common terminal of switch S1 is connected to the connection terminal U1, the first contact of switch S1 is connected to the input terminal of the first filter circuit, and the second contact of switch S1 is connected to the output terminal of the voltage regulation circuit; the common terminal of switch S2 is connected to the connection terminal U2, the first contact of switch S2 is connected to the output terminal of the voltage regulation circuit, and the second contact of switch S2 is connected to the input terminal of the first filter circuit. When the commutation circuit is used to realize the voltage regulation direction switching function, the common terminal of the switch S1 is connected to the output terminal of the voltage regulation circuit, the first contact of the switch S1 is connected to the first end of the corresponding secondary winding, and the second contact of the switch S1 is connected to the second end of the corresponding secondary winding; the common terminal of the switch S2 is connected to the neutral line, the first contact of the switch S2 is connected to the second end of the corresponding secondary winding, and the second contact of the switch S2 is connected to the first end of the corresponding secondary winding.

[0008] A further technical solution is that the commutation circuit includes switches K1, K2, K3, and K4; When the commutation circuit is used to implement the input-output switching function, one end of switch K1 and switch K3 is connected to the connection terminal U1, and one end of switch K2 and switch K4 is connected to the connection terminal U2; the other end of switch K1 and switch K2 is connected to the output terminal of the voltage regulation circuit, and the other end of switch K3 and switch K4 is connected to the input terminal of the first filter circuit. When the commutation circuit is used to realize the voltage regulation direction switching function, one end of switch K1 and switch K3 is connected to the output terminal of the voltage regulation circuit, and one end of switch K2 and switch K4 is connected to the neutral line; the other end of switch K1 and switch K2 is connected to the first end of the corresponding secondary winding, and the other end of switch K3 and switch K4 is connected to the second end of the corresponding secondary winding.

[0009] A further technical solution is that the voltage regulating circuit includes a first switching device group and a second switching device group. The first switching device group and the second switching device group are connected in series to form a series circuit. The first terminal of the series circuit is connected to the output terminal of the first filter circuit, the second terminal of the series circuit is connected to the neutral line, and the midpoint of the series circuit serves as the output terminal of the voltage regulating circuit. The first switching device group includes a first transistor and a second transistor connected in reverse series, and the second switching device group includes a third transistor and a fourth transistor connected in reverse series.

[0010] A further technical solution is that when the bidirectional voltage regulating device includes a voltage regulating unit, the inverter circuit includes two AC ports and two DC ports. The first AC port of the inverter circuit is coupled to the output terminal of the first filter circuit, or the output terminal of the voltage regulating circuit, or the input terminal of the first filter circuit, and the second AC port is connected to the neutral line. The inverter circuit includes an inverter bridge arm, two DC support capacitors, and a first inductor. The inverter bridge arm includes two transistors connected in series. The positive and negative terminals of the inverter bridge arm constitute the first DC port and the second DC port of the inverter circuit. The two DC support capacitors are connected in series, with their two endpoints coupled to the positive and negative terminals of the inverter bridge arm, respectively. One end of the first inductor is coupled to the midpoint of the inverter bridge arm, and the other end of the first inductor serves as the first AC port of the inverter circuit. The first inductor is used to filter out high-frequency pulsating current in the output current of the inverter circuit. The node between the two DC support capacitors serves as the second AC port of the inverter circuit, and the two DC support capacitors are used to stabilize the DC voltage of the inverter circuit. Alternatively, the inverter circuit may include two inverter bridge arms, a DC support capacitor, and a second inductor. Each inverter bridge arm consists of two transistors connected in series. The positive terminals of the two inverter bridge arms are coupled together to form the first DC port of the inverter circuit, and the negative terminals of the two inverter bridge arms are coupled together to form the second DC port of the inverter circuit. The DC support capacitor is connected in parallel with the two inverter bridge arms. One end of the second inductor is coupled to the midpoint of one inverter bridge arm, and the other end of the second inductor serves as the first AC port of the inverter circuit. The midpoint of the other inverter bridge arm serves as the second AC port of the inverter circuit.

[0011] A further technical solution is that when the bidirectional voltage regulating device includes three voltage regulating units, the inverter circuit includes three AC ports and two DC ports. The three AC ports of the inverter circuit are respectively coupled to the output terminals of the three first filter circuits, or the output terminals of the three voltage regulating circuits, or the input terminals of the three first filter circuits. The inverter circuit includes three inverter bridge arms, a DC support capacitor unit, and three inductors. Each inverter bridge arm consists of two transistors connected in series. The positive terminals of the three inverter bridge arms are coupled together to form the first DC port of the inverter circuit, and the negative terminals are coupled together to form the second DC port of the inverter circuit. The DC support capacitor unit is connected in parallel with the three inverter bridge arms. One end of each of the three inductors is coupled to one of the three midpoints of the three inverter bridge arms, and the other ends of each of the three inductors serve as the three AC ports of the inverter circuit. The DC support capacitor unit of the inverter circuit includes one or two capacitors. When the DC support capacitor unit includes one capacitor, the two ends of the capacitor are respectively coupled to the positive and negative terminals of the three inverter bridge arms. When the DC support capacitor unit includes two capacitors, the two capacitors are connected in series, and the two ends formed after the series connection are respectively coupled to the positive and negative terminals of the three inverter bridge arms. The node in the middle of the two capacitors serves as the connection port of the inverter circuit and is coupled to the neutral line of the input AC power.

[0012] A further technical solution is that the bidirectional voltage regulating device also includes a discharge circuit for discharging overvoltages and voltage spikes generated by the voltage regulating circuit; The discharge circuit includes two DC ports, a semiconductor switching device, a discharge resistor, and an energy storage capacitor. The semiconductor switching device and the discharge resistor are connected in series to form a series circuit. The two ends of the series circuit form the two DC ports of the discharge circuit. The two ends of the series circuit are connected to the two ends of the energy storage capacitor.

[0013] A further technical solution is that the bidirectional voltage regulating device further includes a freewheeling circuit, which is used to enable the voltage regulating circuit and the inverter circuit or the discharge circuit to form a freewheeling path and absorb the overvoltage and peak voltage generated by the voltage regulating circuit. When the bidirectional voltage regulating device includes a voltage regulating unit, the freewheeling circuit includes an input port, two DC ports and two diodes. The two diodes are connected in series in the same direction, and the two endpoints formed after the series connection serve as the two DC ports of the freewheeling circuit. The two DC ports are connected to the two DC ports of the inverter circuit or the discharge circuit respectively. The node in the middle of the two diodes serves as the input port of the freewheeling circuit and is coupled to the node in the middle of the first switching device group and the second switching device group in the voltage regulating circuit. Alternatively, the freewheeling circuit may include two input ports, two DC ports, and two diodes. The cathode of one diode forms the first DC port of the freewheeling circuit, and the anode forms the first input port of the freewheeling circuit. The anode of the other diode forms the second DC port of the freewheeling circuit, and the cathode forms the second input port of the freewheeling circuit. The two DC ports of the freewheeling circuit are connected to the two DC ports of the inverter circuit or the discharge circuit, respectively. The two input ports of the freewheeling circuit are connected to the intermediate nodes of the two transistors connected in series in the first switching device group and the intermediate nodes of the two transistors connected in series in the second switching device group.

[0014] A further technical solution is that, when the bidirectional voltage regulating device includes three voltage regulating units, the freewheeling circuit includes three input ports, two DC ports, and three sets of diodes connected in series in pairs. Each set of diodes connected in series in pairs forms two endpoints. The first endpoint of each set of diodes connected in series in pairs is coupled to serve as the first DC port of the freewheeling circuit, and the second endpoint of each set of diodes connected in series in pairs is coupled to serve as the second DC port of the freewheeling circuit. The two DC ports are connected to the two DC ports of the inverter circuit or the discharge circuit respectively. The three intermediate nodes of the three sets of diodes connected in series in pairs in pairs constitute the three input ports of the freewheeling circuit, and are respectively connected to the intermediate nodes of the first switching device group and the second switching device group of the three voltage regulating circuits in the three voltage regulating units. Alternatively, the freewheeling circuit may include six input ports, two DC ports, a first group of diodes, and a second group of diodes. The first group of diodes includes three diodes, wherein the cathodes of the three diodes are coupled to each other to form a first DC port, and the anodes of the three diodes constitute the three input ports of the freewheeling circuit, and are respectively coupled to the intermediate node of two transistors connected in series in the first or second switching device group of the three voltage regulating circuits in the three voltage regulating units. The second group of diodes includes three diodes, wherein the anodes of the three diodes are coupled to each other to form a second DC port, and two DC ports are connected to the two DC ports of the inverter circuit or the discharge circuit respectively. The cathodes of the three diodes constitute the other three input ports of the freewheeling circuit, and are respectively coupled to the intermediate node of the two transistors connected in series in the second switching device group or the first switching device group of the three voltage regulating circuits in the three voltage regulating units.

[0015] A further technical solution is that the first filter circuit includes a first capacitor or a third inductor and a second capacitor; when the first filter circuit includes a first capacitor, one end of the first capacitor serves as the input and output end of the first filter circuit, and the other end of the first capacitor serves as the common end of the first filter circuit and is connected to the neutral line. When the first filter circuit includes a third inductor and a second capacitor, one end of the third inductor serves as the input terminal of the first filter circuit, the other end of the third inductor is connected to one end of the second capacitor and serves as the output terminal of the first filter circuit, and the other end of the second capacitor serves as the common terminal of the first filter circuit and is connected to the neutral line. The voltage regulation unit further includes a second filter circuit. For each voltage regulation unit, the second filter circuit is connected between the output terminal of the voltage regulation unit and the commutation circuit. The second filter circuit includes a fourth inductor and a third capacitor. One end of the fourth inductor is coupled to the output terminal of the voltage regulation circuit, and the other end of the fourth inductor is coupled to one end of the third capacitor and serves as the output terminal of the second filter circuit connected to the commutation circuit. The other end of the third capacitor is coupled to the neutral line.

[0016] The beneficial technical effects of this utility model are: The bidirectional voltage regulating device provided by this utility model can realize input / output switching or voltage regulation direction switching functions using a commutation circuit. When using the commutation circuit to realize the input / output switching function, the input / output direction of the bidirectional voltage regulating device can be switched. Voltage regulation can be performed on the power grid or photovoltaic power generation equipment connected to the connection terminals U1 / U2, thereby improving the application flexibility of the voltage regulating device and avoiding complex line switching operations. When using the commutation circuit to realize the voltage regulation direction switching function, the voltage regulation direction is switched by changing the voltage direction of the primary side of the transformer through the commutation circuit, thereby realizing the step-up and step-down of the input voltage. This can reduce the current and power of the voltage regulating device. Although the voltage adjustment range is reduced by using a small power circuit to adjust a large power circuit, the application cost is significantly reduced. This application also includes an inverter circuit and a freewheeling circuit. The inverter circuit is used to regulate the reactive current and harmonic current in the circuit, as well as regulate the DC voltage of the input inverter circuit and suppress and absorb overvoltage. The freewheeling circuit organically connects the inverter circuit and the voltage regulating circuit, thereby realizing voltage regulation and stabilization more effectively. Attached Figure Description

[0017] Figure 1 This is a circuit block diagram of one embodiment of the bidirectional voltage regulation device provided in this application for a single-phase application scenario where the commutation circuit is used to realize the input-output switching function.

[0018] Figure 2 This is a circuit block diagram of one embodiment of the bidirectional voltage regulation device provided in this application, where the commutation circuit is used to realize the voltage regulation direction switching function in a single-phase application scenario.

[0019] Figure 3 This is a circuit diagram of one embodiment of the bidirectional voltage regulation device for the first type of commutation circuit in the single-phase application scenario provided in this application, used to realize the input-output switching function.

[0020] Figure 4 This is a circuit diagram of an embodiment of a bidirectional voltage regulation device when the first type of commutation circuit provided in this application is used to realize the voltage regulation direction switching function in a single-phase application scenario.

[0021] Figure 5 This is a circuit diagram of one embodiment of the bidirectional voltage regulation device for the second type of commutation circuit in the single-phase application scenario provided in this application, used to realize the input-output switching function.

[0022] Figure 6 This is a circuit diagram of an embodiment of a bidirectional voltage regulation device used in a single-phase application scenario where the second type of commutation circuit provided in this application is used to realize the voltage regulation direction switching function.

[0023] Figure 7 This is the circuit schematic diagram of the second type of inverter circuit in the single-phase application scenario provided in this application.

[0024] Figure 8 This is a circuit schematic diagram of one embodiment of the discharge circuit provided in this application.

[0025] Figure 9 This is a circuit diagram of one embodiment of the bidirectional voltage regulation device when applying the second type of freewheeling circuit in a single-phase application scenario provided in this application.

[0026] Figure 10 This is a circuit diagram of one embodiment of the bidirectional voltage regulation device for single-phase application scenarios provided in this application, which has a first type of commutation circuit and a second filter circuit for realizing input-output switching function.

[0027] Figure 11 This is a circuit diagram of one embodiment of the bidirectional voltage regulating device for single-phase application scenarios provided in this application, which has a first type of commutation circuit and a second filter circuit for realizing the voltage regulation direction switching function.

[0028] Figure 12 This is a circuit block diagram of one embodiment of the bidirectional voltage regulation device for a three-phase application scenario where the commutation circuit is used to realize the input-output switching function.

[0029] Figure 13 This is a circuit block diagram of one embodiment of the bidirectional voltage regulation device provided in this application, which uses the commutation circuit in a three-phase application scenario to realize the voltage regulation direction switching function.

[0030] Figure 14 This is the circuit diagram of the first type of inverter circuit in the three-phase application scenario provided in this application.

[0031] Figure 15 This is the circuit diagram of the second type of inverter circuit in the three-phase application scenario provided in this application.

[0032] Figure 16 This is the circuit schematic diagram of the first type of freewheeling circuit in the three-phase application scenario provided in this application.

[0033] Figure 17 This is the circuit schematic diagram of the second type of freewheeling circuit in the three-phase application scenario provided in this application. Detailed Implementation

[0034] The specific embodiments of this utility model will be further described below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of this disclosure.

[0035] This utility model discloses a bidirectional voltage regulating device, including one or three voltage regulating units. Each voltage regulating unit includes a connection terminal group, a first filter circuit 1, a voltage regulating circuit 2, and a commutation circuit 5. The connection terminal group includes a connection terminal U1 and a connection terminal U2. The first filter circuit 1 is connected to the voltage regulating circuit 2. The commutation circuit 5 is used to realize the input-output switching function or the voltage regulation direction switching function. like Figure 1 As shown, when the commutation circuit 5 is used to implement the input / output switching function, for each voltage regulation unit, the commutation circuit 5 is connected between the connection terminals U1 and U2 and the first filter circuit and the voltage regulation circuit. The commutation circuit 5 is used to switch the connection relationship between the connection terminals U1 and U2 and the first filter circuit 1 and the voltage regulation circuit 2 to achieve input / output switching. When the commutation circuit 5 is used to implement the input / output switching function, "bidirectional" specifically means that the input / output direction of the circuit is bidirectional. The commutation circuit 5 can be used to make the connection terminal U1 the input terminal and the connection terminal U2 the output terminal, or vice versa. When terminal U1 is used as the input terminal and terminal U2 is used as the output terminal, the first filter circuit 1 and the voltage regulation circuit 2 filter and regulate the AC voltage input to terminal U1 before outputting it to terminal U2. When terminal U2 is used as the input terminal and terminal U1 is used as the output terminal, the first filter circuit 1 and the voltage regulation circuit 2 filter and regulate the AC voltage input to terminal U2 before outputting it to terminal U1. This avoids complex manual line changing operations in practical applications, and allows adjustment of the voltage connected to terminal U1 / terminal U2 according to application needs.

[0036] like Figure 2As shown, when the commutation circuit 5 is used to realize the voltage regulation direction switching function, the bidirectional voltage regulation device also includes a transformer 6. The number of winding phases of the transformer 6 is the same as the number of voltage regulation units. Each voltage regulation unit corresponds to one phase winding, and each phase winding includes a primary winding and a secondary winding. For each voltage regulation unit, the connection terminal U1 is connected to the connection terminal U2 through the corresponding primary winding. The connection terminal U2 is used to output the sum of the input AC voltage to the connection terminal U1 and the voltage of the corresponding primary winding. The connection terminal U1 is connected to the first filter circuit 1. The commutation circuit 5 is connected between the output terminal of the voltage regulation circuit 2 and the corresponding secondary winding, and the commutation circuit 5 is connected to the neutral line. When the commutation circuit 5 is used to implement the voltage regulation direction switching function, the bidirectional nature specifically refers to the circuit's ability to regulate the input AC voltage in both directions, allowing for both boost and buck regulation. The first filter circuit 1 and the voltage regulation circuit 2 filter and regulate the input AC voltage to the connection terminal U1, and then output it to the corresponding secondary winding through the commutation circuit 5. The commutation circuit 5 adjusts the direction of the voltage in the corresponding primary winding by switching the connection relationship between the voltage regulation circuit 2 and the corresponding secondary winding, thereby switching the voltage regulation direction of the input AC voltage. Using the commutation circuit to implement the voltage regulation direction switching function reduces the current and power of the voltage regulation circuit. While using a low-power circuit to regulate a high-power circuit reduces the voltage regulation amplitude, the application cost is significantly reduced.

[0037] The bidirectional voltage regulation device also includes an inverter circuit 3, which is connected to the first filter circuit 1 or the voltage regulation circuit 2. The inverter circuit 3 is used to regulate the DC voltage input to the inverter circuit 3, the input AC voltage, or the reactive current and harmonic current at the output of the voltage regulation circuit. The specific principles of the commutation circuit 5 in implementing the input / output switching function or the voltage regulation direction switching function, as well as its specific connection relationships with the connection terminal group, the first filter circuit 1, the voltage regulation circuit 2, or the transformer 6, and the specific structure and working principle of the first filter circuit 1, the voltage regulation circuit 2, and the inverter circuit 3, can be found in the following description.

[0038] Furthermore, the application scenarios of the bidirectional voltage regulating device include both three-phase and single-phase. Three-phase applications are mostly found in factories and similar settings, while single-phase applications are mostly found in residential power consumption scenarios. In single-phase applications, the bidirectional voltage regulating device includes only one voltage regulating unit, while in three-phase applications, it includes three voltage regulating units. When the commutation circuit 5 is used to implement the voltage regulation direction switching function, in single-phase applications, the transformer 6 in the bidirectional voltage regulating device is a single-phase transformer, and in three-phase applications, the transformer 6 in the bidirectional voltage regulating device is a three-phase transformer.

[0039] For the commutation circuit 5, this application provides two forms. In the first form, the commutation circuit includes a switch S1 and a switch S2. Both the switch S1 and the switch S2 include a common terminal, a first contact, and a second contact. Figure 3 The circuit diagram of the first form of the commutation circuit 5 used to implement the input-output switching function is shown, as follows: Figure 3 As shown, when the commutation circuit is used to implement the input-output switching function, the common terminal of switch S1 is connected to the connection terminal U1, the first contact of switch S1 is connected to the input terminal 11 of the first filter circuit 1, and the second contact of switch S1 is connected to the output terminal 23 of the voltage regulation circuit; the common terminal of switch S2 is connected to the connection terminal U2, the first contact of switch S2 is connected to the output terminal 23 of the voltage regulation circuit, and the second contact of switch S2 is connected to the input terminal 11 of the first filter circuit.

[0040] Figure 4 The circuit diagram of the first form of the commutation circuit 5 used to implement the voltage regulation direction switching function is shown, as follows: Figure 4 As shown, when the commutation circuit is used to implement the voltage regulation direction switching function, the common terminal of switch S1 is connected to the output terminal 23 of the voltage regulation circuit, the first contact of switch S1 is connected to the first end of the corresponding secondary winding, and the second contact of switch S1 is connected to the second end of the corresponding secondary winding; the common terminal of switch S2 is connected to the neutral line, the first contact of switch S2 is connected to the second end of the corresponding secondary winding, and the second contact of switch S2 is connected to the first end of the corresponding secondary winding. When the first type of commutation circuit 5 is working, the common terminal of switch S1 and switch S2 is simultaneously connected to the first contact or the second contact. When the commutation circuit 5 is used to implement the input-output switching function, for each voltage regulation unit, when the common terminal of switch S1 and switch S2 is simultaneously connected to the first contact, the first filter circuit 1 and voltage regulation circuit 2 filter and regulate the AC voltage input to the connection terminal U1 and output it to the connection terminal U2. When the common terminal of switch S1 and switch S2 is simultaneously connected to the second contact, the first filter circuit 1 and voltage regulation circuit 2 filter and regulate the AC voltage input to the connection terminal U2 and output it to the connection terminal U1.

[0041] When the commutation circuit 5 is used to realize the voltage regulation direction switching function, for each voltage regulation unit, when the common terminal of the switches S1 and S2 is simultaneously connected to the first contact, the output voltage value output by the connection terminal U2 is the sum of the input AC voltage value and the corresponding primary winding voltage value. If the turns ratio of the primary winding to the secondary winding of the transformer 6 is 1:N, then the output voltage value Vout = Vin + Vo / N, where Vin is the input AC voltage value and Vo is the output voltage value of the voltage regulation circuit 2, that is, the voltage value of the corresponding secondary winding. When the common terminal of the switches S1 and S2 is simultaneously connected to the second contact, the output voltage value output by the connection terminal U2 is the input AC voltage value minus the corresponding primary winding voltage value, that is, the output voltage value Vout = Vin - Vo / N.

[0042] In the second form of the commutation circuit 5 provided in this application, the commutation circuit 5 includes switches K1, K2, K3, and K4; as shown... Figure 5 As shown, when the commutation circuit 5 is used to implement the input-output switching function, one end of the switch K1 and switch K3 is connected to the connection terminal U1, and one end of the switch K2 and switch K4 is connected to the connection terminal U2; the other end of the switch K1 and switch K2 is connected to the output terminal 23 of the voltage regulation circuit, and the other end of the switch K3 and switch K4 is connected to the input terminal 11 of the first filter circuit. like Figure 6 As shown, when the commutation circuit 5 is used to realize the voltage regulation direction switching function, one end of the switch K1 and switch K3 is connected to the output terminal 23 of the voltage regulation circuit, and one end of the switch K2 and switch K4 is connected to the neutral line; the other end of the switch K1 and switch K2 is connected to the first end of the corresponding secondary winding, and the other end of the switch K3 and switch K4 is connected to the second end of the corresponding secondary winding. When the second type of commutation circuit 5 is working, switches K1 and K4 are closed simultaneously, or switches K2 and K3 are closed simultaneously. When the commutation circuit 5 is used to implement the input-output switching function, for each voltage regulation unit, when switches K2 and K3 are closed simultaneously, the first filter circuit 1 and the voltage regulation circuit 2 filter and regulate the AC voltage input to the connection terminal U1 and output it to the connection terminal U2. When switches K1 and K4 are closed simultaneously, the first filter circuit 1 and the voltage regulation circuit 2 filter and regulate the AC voltage input to the connection terminal U2 and output it to the connection terminal U1.

[0043] When the commutation circuit is used to implement the voltage regulation direction switching function, for each voltage regulation unit, when switches K1 and K4 are closed simultaneously, the output voltage value output from connection terminal U2 is the sum of the input AC voltage value and the corresponding primary winding voltage value, i.e., the output voltage value Vout = Vin + Vo / N; when switches K2 and K3 are closed simultaneously, the output voltage value output from connection terminal U2 is the input AC voltage value minus the corresponding primary winding voltage value, i.e., the output voltage value Vout = Vin - Vo / N. In specific implementation, the specific form of the commutation circuit 1 can be selected from the above two forms according to the actual situation.

[0044] Furthermore, Figure 3-6 An exemplary circuit schematic of voltage regulation circuit 2 is shown, such as... Figure 3-6As shown, the voltage regulating circuit 2 includes a first switching device group 7 and a second switching device group 8. The first switching device group 7 and the second switching device group 8 are connected in series to form a series circuit. The first terminal 21 of the series circuit is connected to the output terminal 12 of the first filter circuit 1, and the second terminal 22 of the series circuit is connected to the neutral line. The midpoint of the series circuit serves as the output terminal 23 of the voltage regulating circuit. The first switching device group 7 includes a first transistor M1 and a second transistor M2 connected in reverse series. The second switching device group 8 includes a third transistor M3 and a fourth transistor M4 connected in reverse series. One end of the first switching device group 7 is the first terminal 21 of the series circuit, and the other end of the first switching device group 7 is coupled to one end of the second switching device group 8, forming the midpoint of the series circuit and serving as the output terminal 23 of the voltage regulating circuit 2. The other end of the second switching device group 8 is the second terminal 22 of the series circuit. It should be noted that in practical applications, the number of transistors in the first switching device group 7 and the second switching device group 8 can be adaptively adjusted. For example, each transistor (the first to fourth transistors) can be simultaneously replaced by a parallel structure of two or more transistors. Furthermore, the transistors in the voltage regulation circuit 2 can be one or more power semiconductors such as IGBTs and MOSFETs.

[0045] When the voltage regulating circuit 2 is working, it modulates the operating states of the switching devices in the first switching device group 7 and the second switching device group 8 through the peripheral circuit to regulate the AC voltage input to the voltage regulating circuit 2. Specifically, it achieves PWM modulation by controlling the conduction or cutoff of the transistors, thereby realizing the functions of AC voltage regulation and bidirectional energy transfer. The complex peripheral circuit of the voltage regulating circuit 2 is not shown in the example provided in this application. The specific form of the peripheral circuit and the specific method of modulation of the switching devices can be consistent with the prior art. For example, those skilled in the art can realize forward conduction and reverse conduction through transistors, and connect a freewheeling diode in parallel with each transistor for the purpose of protecting the transistors, providing a freewheeling path for the current when the transistors are turned off, and reasonably set the corresponding drive circuit to receive control signals from the outside (e.g., PWM signals), control the conduction or cutoff of the transistors according to the control signals, and set filter inductors according to the requirements of different application scenarios to filter out high-frequency harmonics and make the voltage output smoother.

[0046] When the commutation circuit 5 is used to implement the input / output switching function, the voltage regulating circuit 2 can modulate the input AC voltage to the voltage regulating circuit 2 to the corresponding preset voltage through different modulation states according to different settings of the input / output terminals. For example, when the connection terminal U1 is connected to the input terminal 11 of the filter circuit and the connection terminal U2 is connected to the output terminal 23 of the voltage regulating circuit, the AC voltage input to the connection terminal U1 is regulated to the first preset voltage and then output to the connection terminal U2 through the modulation voltage regulating circuit 2; when the connection terminal U1 is connected to the output terminal 23 of the voltage regulating circuit and the connection terminal U2 is connected to the input terminal 11 of the filter circuit, the AC voltage input to the connection terminal U2 is regulated to the second preset voltage and then output to the connection terminal U1. When the commutation circuit 5 is used to implement the voltage regulation direction switching function, the voltage regulating circuit 2 can modulate the input AC voltage according to the magnitude of the voltage to be adjusted and the turns ratio of the secondary winding to the primary winding of the transformer 6.

[0047] Furthermore, the bidirectional voltage regulating device also includes a freewheeling circuit 4. In some embodiments, the inverter circuit 3 can be replaced by a discharge circuit 9. The freewheeling circuit 4 is configured to form a freewheeling path between the voltage regulating circuit 2 and the inverter circuit 3 or the discharge circuit 9, absorbing the overvoltage and voltage spikes generated by the voltage regulating circuit. The discharge circuit 9 is used to discharge the overvoltage and voltage spikes generated by the voltage regulating circuit 2.

[0048] Specifically, the inverter circuit 3 can supplement the reactive power of the input AC power or the output terminal 23 of the voltage regulator circuit. Specifically, the output reactive current can be controlled by adjusting the switching operation of the transistors in the inverter circuit 3 using PWM. Furthermore, adjusting the inverter circuit 3 can suppress harmonic currents, further ensuring voltage stability. The inverter circuit 3 can also adjust the DC voltage input to the inverter circuit 3. Additionally, when the voltage output by the voltage regulator circuit 2 exceeds a preset voltage value (preset stable voltage value), the inverter circuit 3 can also act as an absorption circuit, absorbing the excess voltage. The specific adjustment method of the inverter circuit 3 can be consistent with existing technologies.

[0049] The inverter circuit 3 and freewheeling circuit 4 take different forms in single-phase and three-phase application scenarios. In single-phase application scenarios (i.e., when the bidirectional voltage regulation device includes a voltage regulation unit), the inverter circuit 3 includes two AC ports (AC1, AC2) and two DC ports (DC+, DC-). The first AC port (AC1) of the inverter circuit 3 is coupled to the output terminal 12 of the first filter circuit, or the output terminal 23 of the voltage regulation circuit, or the input terminal 11 of the first filter circuit. The second AC port (AC2) is connected to the neutral wire. If the first AC port (AC1) is coupled to the output terminal 12 or the input terminal 11 of the first filter circuit, the reactive current and harmonic current of the input AC power are adjusted. If the first AC port (AC1) is coupled to the output terminal 23 of the voltage regulation circuit, the reactive current and harmonic current of the output terminal 23 of the voltage regulation circuit are adjusted.

[0050] This application provides two types of inverter circuits for single-phase applications. Figure 3-6 The inverter circuits 3 shown are all of the first type, such as... Figure 3-6 As shown, in the first embodiment, the inverter circuit 3 includes an inverter bridge arm, two DC-coupled capacitors (Cs), and a first inductor (L1). The inverter bridge arm is composed of two transistors (M5, M6) connected in series. The positive and negative terminals (the two ends of the inverter bridge arm) constitute the first DC port (DC+) and the second DC port (DC-) of the inverter circuit 3. The two DC-coupled capacitors (Cs) are connected in series, and their two endpoints are coupled to the positive and negative terminals of the inverter bridge arm, respectively. The two DC-coupled capacitors (Cs) are used to stabilize the DC voltage of the inverter circuit. One end of the first inductor (L1) is coupled to the midpoint of the inverter bridge arm, and the other end of the first inductor (L1) serves as the first AC port (AC1) of the inverter circuit. The node between the two DC-coupled capacitors (Cs) serves as the second AC port (AC2) of the inverter circuit 3. The first inductor (L1) is used to filter out high-frequency pulsating current in the output current of the inverter circuit 3.

[0051] like Figure 7As shown, the second type of inverter circuit 3 in a single-phase application scenario includes two inverter bridge arms, a DC support capacitor (Cs), and a second inductor (L2). Each inverter bridge arm consists of two transistors connected in series. Specifically, transistors M7 and M8 form one inverter bridge arm, and transistors M9 and M10 form another inverter bridge arm. The positive terminals of the two inverter bridge arms are coupled together to form the first DC port (DC+) of the inverter circuit, and the negative terminals of the two inverter bridge arms are coupled together to form the second DC port (DC-) of the inverter circuit. The DC support capacitor is connected in parallel with the two inverter bridge arms. One end of the second inductor is coupled to the midpoint of one inverter bridge arm, and the other end of the second inductor serves as the first AC port (AC1) of the inverter circuit 3. The midpoint of the other inverter bridge arm serves as the second AC port (AC2) of the inverter circuit.

[0052] It should be noted that, Figure 3-6 Inverter circuit 3 in the diagram is a half-bridge inverter structure with low power consumption. Figure 7 Inverter circuit 3 in the diagram is a full-bridge inverter structure with high power, but all of its functions can be achieved by controlling the transistors within it. In practical applications, the specific inverter circuit 3 structure can be selected based on the actual power requirements.

[0053] like Figure 8 As shown, the discharge circuit 9 includes two DC ports, a semiconductor switching device, a discharge resistor, and an energy storage capacitor. The semiconductor switching device and the discharge resistor are connected in series to form a series circuit. The two ends of the series circuit form the two DC ports of the discharge circuit. One end of the discharge resistor forms the first DC port (DC+), and one end of the semiconductor switching device forms the second DC port (DC-). The two ends of the series circuit are connected to the two ends of the energy storage capacitor. When the voltage across the energy storage capacitor exceeds the preset voltage value of the capacitor, the semiconductor switching device is turned on, allowing the electrical energy stored in the energy storage capacitor to discharge through the discharge resistor. The switching device in the discharge circuit 9 can be one of the power semiconductors such as IGBT, MOSFET, or IGCT. The preset voltage value of the capacitor and the resistance value of the discharge resistor can be set according to the actual application requirements.

[0054] In single-phase application scenarios (i.e., when the bidirectional voltage regulating device includes a voltage regulating unit), this application provides two forms of freewheeling circuit 4. Figure 3-6 The freewheeling circuits 4 shown are all of the first type, such as... Figure 3-6As shown, in the first embodiment, the freewheeling circuit 4 includes two input ports 41, two DC ports, and two diodes (D1, D2). The cathode of one diode (D1) forms the first DC port of the freewheeling circuit 4, and the anode forms the first input port. The anode of the other diode (D2) forms the second DC port of the freewheeling circuit 4, and the cathode forms the second input port. The two DC ports of the freewheeling circuit 4 are connected to the two DC ports of the inverter circuit 3 or the discharge circuit 9, respectively. Specifically, the first DC port of the freewheeling circuit 4 is connected to the first DC port (DC+) of the inverter circuit 3, and the second DC port is connected to the second DC port (DC-) of the inverter circuit 3; or the first DC port of the freewheeling circuit 4 is connected to the first DC port (DC+) of the discharge circuit 9, and the second DC port is connected to the second DC port (DC-) of the discharge circuit 9. The two input ports of the freewheeling circuit 4 are respectively connected to the intermediate nodes of the two transistors connected in series in the first switching device group 7 and the intermediate nodes of the two transistors connected in series in the second switching device group 8.

[0055] Figure 9 The diagram illustrates a second type of freewheeling circuit 4 for single-phase applications, such as... Figure 9 As shown, in the second form, the freewheeling circuit 4 includes an input port 41, two DC ports, and two diodes (D3 and D4). The two diodes are connected in series in the same direction, that is, the anode of diode D3 is connected to the cathode of diode D4. The two endpoints formed by the series connection serve as the two DC ports of the freewheeling circuit 4, that is, the cathode of diode D3 forms the first DC port, and the anode of diode D4 forms the second DC port. The two DC ports are connected to the two DC ports of the inverter circuit 3 or the discharge circuit 9 respectively. That is, the first DC port of the freewheeling circuit 4 is connected to the first DC port (DC+) of the inverter circuit 3, and the second DC port of the freewheeling circuit 4 is connected to the second DC port (DC-) of the inverter circuit 3, or the first DC port of the freewheeling circuit 4 is connected to the first DC port (DC+) of the discharge circuit 9, and the second DC port of the freewheeling circuit 4 is connected to the second DC port (DC-) of the discharge circuit 9. The node between the two diodes serves as the input port 41 of the freewheeling circuit 4 and is coupled to the node between the first switching device group 7 and the second switching device group 8 of the voltage regulating circuit 2.

[0056] Furthermore, this application provides two forms of the first filter circuit 1, such as... Figure 3-6 As shown, in the first embodiment, the first filter circuit 1 includes a first capacitor C1. One end of the first capacitor C1 serves as the input terminal 11 and the output terminal 12 of the first filter circuit 1, and the other end of the first capacitor C1 serves as the common terminal 13 of the first filter circuit 1, connected to the neutral wire. Figure 9As shown, in the second form, the first filter circuit 1 includes a third inductor L3 and a second capacitor C2. One end of the third inductor L3 serves as the input terminal 11 of the first filter circuit 1, and the other end of the third inductor L3 is connected to one end of the second capacitor C2 and serves as the output terminal 12 of the first filter circuit 1. The other end of the second capacitor C2 serves as the common terminal 13 of the first filter circuit 1 and is connected to the neutral line.

[0057] Furthermore, the voltage regulating unit also includes a second filter circuit 10. For each voltage regulating unit, the second filter circuit 10 is connected between the output terminal 23 of the voltage regulating unit and the commutation circuit 5. The second filter circuit 10 includes a fourth inductor L4 and a third capacitor C3. One end of the fourth inductor L4 is coupled to the output terminal 23 of the voltage regulating circuit 2, and the other end of the fourth inductor L4 is coupled to one end of the third capacitor C3, serving as the output terminal of the second filter circuit 10 connected to the commutation circuit 5. The other end of the third capacitor C3 is coupled to the neutral line. The specific way the output terminal of the second filter circuit 10 is connected to the commutation circuit 5 depends on the function of the commutation circuit 5 in the bidirectional voltage regulating device and the specific form of the commutation circuit 5. Specifically, when the commutation circuit 5 is used to implement the input / output switching function and is in the first form, such as... Figure 10 As shown, the output terminal of the second filter circuit 10 is connected to the second contact of switch S1 and the first contact of switch S2; when the commutation circuit 5 is used to realize the voltage regulation direction switching function and is in the first form, such as... Figure 11 As shown, the output terminal of the second filter circuit 10 is connected to the common terminal of switch S1; when the commutation circuit 5 is used to implement the input-output switching function and is in the second form, the output terminal of the commutation circuit 5 is connected to the other end of switch K1 and switch K2; when the commutation circuit 5 is used to implement the voltage regulation direction switching function and is in the second form, the output terminal of the commutation circuit 5 is connected to one end of switch K1 and switch K3.

[0058] Figure 12 and Figure 13 The diagrams show the circuit block diagrams of the bidirectional voltage regulation device in a three-phase application scenario, where the commutation circuit 5 is used to implement input / output switching and voltage regulation direction switching. In the three-phase application scenario, when the commutation circuit 5 is used to implement the input / output switching function, the commutation circuit 5 in each voltage regulation unit is connected to two terminals in a connection terminal group. For ease of distinction, [further details are provided]. Figure 12The three sets of connection terminals are shown as A1, A2, B1, B2, C1, C2 respectively. Connection terminals A1-C1 are equivalent to connection terminals U1 in the circuit description when the commutation circuit 5 is used to realize the input-output switching function. That is, the connection relationship between connection terminals A1-C1 and the corresponding commutation circuit 5 is consistent with the connection relationship between connection terminals U1 and the commutation circuit 5. Connection terminals A2-C2 are equivalent to connection terminals U2 in the above description. That is, the connection relationship between connection terminals A2-C2 and the corresponding commutation circuit 5 is consistent with the connection relationship between connection terminals U2 and the commutation circuit 5.

[0059] When commutation circuit 5 is used to implement the voltage regulation direction switching function, the two ends of the three primary windings are respectively connected to two connection terminals in a connection terminal group. For easy differentiation, Figure 13 The three sets of connection terminals are respectively represented by Ai, Ao, Bi, Bo, Ci, and Co. Connection terminal Ai-Ci is equivalent to connection terminal U1 in the circuit description above when the commutation circuit 5 is used to realize the voltage regulation direction switching function. Connection terminal Ao-Co is equivalent to connection terminal U2 in the above description. That is, the connection terminals Ai / Bi / Ci are respectively connected to the connection terminals Ao / Bo / Co through a primary winding.

[0060] In three-phase applications, when the commutation circuit 5 is used to implement the input-output switching function, the commutation circuit 5 in each voltage regulation unit can be adjusted so that the bidirectional voltage regulation device can adjust the input AC power at connection terminals A1-C1 and output it to A2-C2, or adjust the input AC power at connection terminals A2-C2 and output it to A1-C1. When the commutation circuit 5 is used to implement the voltage regulation direction switching function, the commutation circuit 5 in each voltage regulation unit can be adjusted to boost or buck the input AC power at connection terminals Ai-Ci by superimposing the corresponding primary winding voltage on the input AC power. In some embodiments, the voltage regulation unit 2 may also be provided with a second filter circuit 10. In three-phase applications, the specific forms and working principles of the commutation circuit 5, voltage regulation circuit 2, first filter circuit 1, and second filter circuit 10 in each voltage regulation unit are the same as described above, and can be referred to the above description, and will not be repeated here.

[0061] In three-phase applications, the bidirectional voltage regulator may also include an inverter circuit 3 and a freewheeling circuit 4, or a discharge circuit 9 may replace the inverter circuit 3. The functions and working principles of the inverter circuit 3, freewheeling circuit 4, and discharge circuit 9 remain the same as described above and will not be repeated here. The form of the discharge circuit 9 can remain the same in both single-phase and three-phase applications. The forms of the inverter circuit 3 and freewheeling circuit 4 differ between single-phase and three-phase applications. The specific structure of the inverter circuit 3 and freewheeling circuit 4 in three-phase applications will be described in detail below: In a three-phase application scenario (i.e., when the bidirectional voltage regulating device includes three voltage regulating units), the inverter circuit 3 includes three AC ports (AC1, AC2, AC3) and two DC ports (DC+, DC-). The three AC ports of the inverter circuit 3 are respectively coupled to the output terminals 12 of the three first filter circuits 1, or the output terminals 23 of the three voltage regulating circuits, or the input terminals 11 of the three first filter circuits. For three-phase applications, this application provides two forms of inverter circuit 3. In the first form, the inverter circuit 3 includes three inverter bridge arms, a DC support capacitor unit, and three inductors (L5, L6, L7), wherein the DC support capacitor unit includes one capacitor. Figure 14 As shown, each inverter bridge arm consists of two transistors connected in series. Specifically, transistors M5' and M6' are connected in series to form the first inverter bridge arm, transistors M7' and M8' are connected in series to form the second inverter bridge arm, and transistors M9' and M10' are connected in series to form the third inverter bridge arm. The positive terminals of the three inverter bridge arms are coupled together to form the first DC port (DC+) of the inverter circuit, and the negative terminals of the three inverter bridge arms are coupled together to form the second DC port (DC-) of the inverter circuit. The capacitor in the DC support capacitor unit is connected in parallel with the three inverter bridge arms, that is, the two ends of the capacitor are respectively connected to... The positive and negative terminals of the three inverter bridge arms are coupled together; one end of each of the three inductors is coupled to one of the three midpoints of the three inverter bridge arms respectively, and the other end of each of the three inductors serves as one of the three AC ports of the inverter circuit. Specifically, one end of inductor L5 is coupled to the midpoint X of the first inverter bridge arm, and the other end of inductor L5 forms the first AC port AC1; one end of inductor L6 is coupled to the midpoint Y of the second inverter bridge arm, and the other end of inductor L6 forms the second AC port AC2; one end of inductor L7 is coupled to the midpoint Z of the third inverter bridge arm, and the other end of inductor L7 forms the third AC port AC3.

[0062] For three-phase applications, the difference between the second type of inverter circuit 3 provided in this application and the first type is that the DC support capacitor unit of the inverter circuit 3 includes two capacitors, such as... Figure 15 As shown, the two capacitors (C4 and C5) are connected in series, and the two terminals formed by the series connection are respectively coupled to the positive and negative terminals of the three inverter bridge arms. The node T in the middle of the two capacitors serves as the connection port (AC4) of the inverter circuit 3 and is coupled to the neutral line of the input AC power.

[0063] For three-phase applications, this application provides two forms of freewheeling circuit 4. In the first form, the freewheeling circuit 4 includes three input ports 41, two DC ports, and three sets of diodes connected in series in pairs. Each set of diodes connected in series in pairs forms two endpoints. The first endpoint of each set of diodes connected in series in pairs is coupled to serve as the first DC port of the freewheeling circuit 4, and the second endpoint of each set of diodes connected in series in pairs is coupled to serve as the second DC port of the freewheeling circuit 4. The two DC ports are connected to the two DC ports of the inverter circuit 3 or the discharge circuit 9. The three intermediate nodes of the three sets of diodes connected in series in pairs in pairs form the three input ports of the freewheeling circuit, and are respectively connected to the intermediate nodes of the first switching device group 7 and the second switching device group 8 of the three voltage regulating circuits 2 in the three voltage regulating units.

[0064] Please refer to the details. Figure 16 In the first group of diodes, the anode of diode D1' is connected to the cathode of diode D2'; in the second group of diodes, the anode of diode D3' is connected to the cathode of diode D4'; and in the third group of diodes, the anode of diode D5 is connected to the cathode of diode D6. The cathodes of diodes D1', D3', and D5, when connected, form the first DC port of the freewheeling circuit 4. The anodes of diodes D2', D4', and D6, when connected, form the second DC port of the freewheeling circuit 4. The first and second DC ports of the freewheeling circuit 4 are connected to the first and second DC ports of the inverter circuit 3 or the discharge circuit 9. The intermediate node O of the first group of diodes, the intermediate node P of the second group of diodes, and the intermediate node Q of the third group of diodes are respectively connected to the intermediate nodes of the first switching device group 7 and the second switching device group 8 of the three voltage regulating circuits 2 in the three voltage regulating units.

[0065] For three-phase applications, the second type of freewheeling circuit 4 provided in this application includes six input ports 41, two DC ports, a first set of diodes, and a second set of diodes, such as... Figure 17As shown, the first group of diodes includes three diodes, wherein the cathodes of the three diodes (D1'', D2'', D3'') are coupled to each other to form a first DC port, and the anodes of the three diodes (D1'', D2'', D3'') constitute the three input ports 41 of the freewheeling circuit, and are respectively coupled to the intermediate node of the two transistors connected in series in the first switching device group 7 or the second switching device group 8 of the three voltage regulating circuits in the three voltage regulating units; the second group of diodes includes three diodes, wherein the anodes of the three diodes (D4'', D5', D6') are coupled to each other to form a second DC port, and the two DC ports are connected to the two DC ports of the inverter circuit or the discharge circuit, that is, the first DC port and the second DC port of the freewheeling circuit 4 are connected to the first DC port and the second DC port of the inverter circuit 3 or the discharge circuit 9. The cathodes of the three diodes (D4'', D5', D6') constitute the other three input ports 41 of the freewheeling circuit, and are respectively coupled to the intermediate nodes of the two transistors connected in series in the second switching device group 8 or the first switching device group 7 of the three voltage regulating circuits 2 in the three voltage regulating units.

[0066] In summary, the bidirectional voltage regulator provided in this application can achieve input / output switching or voltage regulation direction switching using the commutation circuit 5. When using the commutation circuit 5 to achieve input / output switching, the input / output direction of the bidirectional voltage regulator can be switched, and the voltage connected to both terminals can be adjusted, thereby improving the flexibility of the voltage regulator application and avoiding complex wiring operations. When using the commutation circuit 2 to achieve voltage regulation direction switching, the voltage regulation direction is switched by changing the primary voltage direction of the transformer 6, thereby achieving step-up and step-down of the input voltage. This reduces the current and power of the voltage regulator, allowing a low-power circuit to adjust a high-power circuit, significantly reducing application costs. This application also includes an inverter circuit 3 and a freewheeling circuit 4. The inverter circuit 3 regulates the reactive current and harmonic current in the circuit, as well as the DC voltage input to the inverter circuit 3 and suppresses and absorbs overvoltage. The freewheeling circuit 4 organically connects the inverter circuit and the voltage regulator circuit 2, achieving more effective voltage regulation and stabilization.

[0067] It should be noted that in the description of this application, the reference to terms such as "one embodiment / mode," "some embodiments / modes," "example," "specific example," or "some examples," etc., means that a specific feature, structure, material, or characteristic described in connection with that embodiment / mode or example is included in at least one embodiment / mode or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment / mode or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments / modes or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments / modes or examples and the features of different embodiments / modes or examples described in this specification. Where the terms "first" and "second" appear, they are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature.

[0068] The above descriptions are merely preferred embodiments of the present invention, and the present invention is not limited to the above embodiments. It is understood that other improvements and variations that can be directly derived or conceived by those skilled in the art without departing from the spirit and concept of the present invention should be considered to be included within the protection scope of the present invention.

Claims

1. A bidirectional voltage regulating device, characterized in that, It includes one or three voltage regulating units. Each voltage regulating unit includes a connection terminal group, a first filter circuit, a voltage regulating circuit, and a commutation circuit. The connection terminal group includes a connection terminal U1 and a connection terminal U2. The first filter circuit is connected to the voltage regulating circuit. The commutation circuit is used to realize the input-output switching function or the voltage regulation direction switching function. When the commutation circuit is used to implement the input-output switching function, for each voltage regulation unit, the commutation circuit is connected between the connection terminal U1 and the connection terminal U2 and the first filter circuit and the voltage regulation circuit. The commutation circuit is used to switch the connection relationship between the connection terminal U1 and the connection terminal U2 and the first filter circuit and the voltage regulation circuit, so that the first filter circuit and the voltage regulation circuit can filter and regulate the AC voltage input to the connection terminal U1 and output it to the connection terminal U2, or so that the first filter circuit and the voltage regulation circuit can filter and regulate the AC voltage input to the connection terminal U2 and output it to the connection terminal U1. When the commutation circuit is used to realize the voltage regulation direction switching function, the bidirectional voltage regulation device also includes a transformer. The number of winding phases of the transformer is the same as the number of voltage regulation units. Each voltage regulation unit corresponds to one phase winding, and each phase winding includes a primary winding and a secondary winding. For each voltage regulation unit, the connection terminal U1 is connected to the connection terminal U2 through the corresponding primary winding. The connection terminal U2 is used to output the sum of the input AC voltage input to the connection terminal U1 and the voltage of the corresponding primary winding. The connection terminal U1 is connected to the first filter circuit. The commutation circuit is connected between the output terminal of the voltage regulation circuit and the corresponding secondary winding, and the commutation circuit is connected to the neutral line. The first filter circuit and the voltage regulation circuit are used to filter and regulate the input AC voltage input to the connection terminal U1, and then output it to the corresponding secondary winding through the commutation circuit. The commutation circuit is used to switch the connection relationship between the voltage regulation circuit and the corresponding secondary winding to adjust the direction of the voltage of the corresponding primary winding. The bidirectional voltage regulation device further includes an inverter circuit, which is connected to the first filter circuit or the voltage regulation circuit, and is used to regulate the DC voltage input to the inverter circuit, the input AC power, or the reactive current and harmonic current at the output of the voltage regulation circuit.

2. The bidirectional voltage regulating device according to claim 1, characterized in that, The commutation circuit includes switch S1 and switch S2, and both switch S1 and switch S2 include a common terminal, a first contact and a second contact. When the commutation circuit is used to implement the input-output switching function, the common terminal of switch S1 is connected to the connection terminal U1, the first contact of switch S1 is connected to the input terminal of the first filter circuit, and the second contact of switch S1 is connected to the output terminal of the voltage regulation circuit; the common terminal of switch S2 is connected to the connection terminal U2, the first contact of switch S2 is connected to the output terminal of the voltage regulation circuit, and the second contact of switch S2 is connected to the input terminal of the first filter circuit. When the commutation circuit is used to realize the voltage regulation direction switching function, the common terminal of the switch S1 is connected to the output terminal of the voltage regulation circuit, the first contact of the switch S1 is connected to the first end of the corresponding secondary winding, and the second contact of the switch S1 is connected to the second end of the corresponding secondary winding; the common terminal of the switch S2 is connected to the neutral line, the first contact of the switch S2 is connected to the second end of the corresponding secondary winding, and the second contact of the switch S2 is connected to the first end of the corresponding secondary winding.

3. The bidirectional voltage regulating device according to claim 1, characterized in that, The commutation circuit includes switches K1, K2, K3, and K4; When the commutation circuit is used to implement the input-output switching function, one end of switch K1 and switch K3 is connected to the connection terminal U1, and one end of switch K2 and switch K4 is connected to the connection terminal U2; the other end of switch K1 and switch K2 is connected to the output terminal of the voltage regulation circuit, and the other end of switch K3 and switch K4 is connected to the input terminal of the first filter circuit. When the commutation circuit is used to realize the voltage regulation direction switching function, one end of switch K1 and switch K3 is connected to the output terminal of the voltage regulation circuit, and one end of switch K2 and switch K4 is connected to the neutral line; the other end of switch K1 and switch K2 is connected to the first end of the corresponding secondary winding, and the other end of switch K3 and switch K4 is connected to the second end of the corresponding secondary winding.

4. The bidirectional voltage regulating device according to claim 1, characterized in that, The voltage regulating circuit includes a first switching device group and a second switching device group. The first switching device group and the second switching device group are connected in series to form a series circuit. The first terminal of the series circuit is connected to the output terminal of the first filter circuit, the second terminal of the series circuit is connected to the neutral line, and the midpoint of the series circuit serves as the output terminal of the voltage regulating circuit. The first switching device group includes a first transistor and a second transistor connected in reverse series, and the second switching device group includes a third transistor and a fourth transistor connected in reverse series.

5. The bidirectional voltage regulating device according to claim 4, characterized in that, When the bidirectional voltage regulating device includes a voltage regulating unit, the inverter circuit includes two AC ports and two DC ports. The first AC port of the inverter circuit is coupled to the output terminal of the first filter circuit, or the output terminal of the voltage regulating circuit, or the input terminal of the first filter circuit, and the second AC port is connected to the neutral wire. The inverter circuit includes an inverter bridge arm, two DC support capacitors, and a first inductor. The inverter bridge arm includes two transistors connected in series. The positive and negative terminals of the inverter bridge arm constitute the first DC port and the second DC port of the inverter circuit. The two DC support capacitors are connected in series, with their two endpoints coupled to the positive and negative terminals of the inverter bridge arm, respectively. One end of the first inductor is coupled to the midpoint of the inverter bridge arm, and the other end of the first inductor serves as the first AC port of the inverter circuit. The first inductor is used to filter out high-frequency pulsating current in the output current of the inverter circuit. The node between the two DC support capacitors serves as the second AC port of the inverter circuit, and the two DC support capacitors are used to stabilize the DC voltage of the inverter circuit. Alternatively, the inverter circuit may include two inverter bridge arms, a DC support capacitor, and a second inductor. Each inverter bridge arm consists of two transistors connected in series. The positive terminals of the two inverter bridge arms are coupled together to form the first DC port of the inverter circuit, and the negative terminals of the two inverter bridge arms are coupled together to form the second DC port of the inverter circuit. The DC support capacitor is connected in parallel with the two inverter bridge arms. One end of the second inductor is coupled to the midpoint of one inverter bridge arm, and the other end of the second inductor serves as the first AC port of the inverter circuit. The midpoint of the other inverter bridge arm serves as the second AC port of the inverter circuit.

6. The bidirectional voltage regulating device according to claim 5, characterized in that, When the bidirectional voltage regulating device includes three voltage regulating units, the inverter circuit includes three AC ports and two DC ports. The three AC ports of the inverter circuit are respectively coupled to the output terminals of the three first filter circuits, or the output terminals of the three voltage regulating circuits, or the input terminals of the three first filter circuits. The inverter circuit includes three inverter bridge arms, a DC support capacitor unit, and three inductors. Each inverter bridge arm consists of two transistors connected in series. The positive terminals of the three inverter bridge arms are coupled together to form the first DC port of the inverter circuit, and the negative terminals are coupled together to form the second DC port of the inverter circuit. The DC support capacitor unit is connected in parallel with the three inverter bridge arms. One end of each of the three inductors is coupled to one of the three midpoints of the three inverter bridge arms, and the other ends of each of the three inductors serve as the three AC ports of the inverter circuit. The DC support capacitor unit of the inverter circuit includes one or two capacitors. When the DC support capacitor unit includes one capacitor, the two ends of the capacitor are respectively coupled to the positive and negative terminals of the three inverter bridge arms. When the DC support capacitor unit includes two capacitors, the two capacitors are connected in series, and the two ends formed after the series connection are respectively coupled to the positive and negative terminals of the three inverter bridge arms. The node in the middle of the two capacitors serves as the connection port of the inverter circuit and is coupled to the neutral line of the input AC power.

7. The bidirectional voltage regulating device according to claim 4, characterized in that, The bidirectional voltage regulating device also includes a discharge circuit for discharging overvoltages and voltage spikes generated by the voltage regulating circuit. The discharge circuit includes two DC ports, a semiconductor switching device, a discharge resistor, and an energy storage capacitor. The semiconductor switching device and the discharge resistor are connected in series to form a series circuit. The two ends of the series circuit form the two DC ports of the discharge circuit. The two ends of the series circuit are connected to the two ends of the energy storage capacitor.

8. The bidirectional voltage regulating device according to claim 6 or 7, characterized in that, The bidirectional voltage regulating device further includes a freewheeling circuit, which is used to enable the voltage regulating circuit and the inverter circuit or the discharge circuit to form a freewheeling path and absorb the overvoltage and peak voltage generated by the voltage regulating circuit. When the bidirectional voltage regulating device includes a voltage regulating unit, the freewheeling circuit includes an input port, two DC ports and two diodes. The two diodes are connected in series in the same direction, and the two endpoints formed after the series connection serve as the two DC ports of the freewheeling circuit. The two DC ports are connected to the two DC ports of the inverter circuit or the discharge circuit respectively. The node in the middle of the two diodes serves as the input port of the freewheeling circuit and is coupled to the node in the middle of the first switching device group and the second switching device group in the voltage regulating circuit. Alternatively, the freewheeling circuit may include two input ports, two DC ports, and two diodes. The cathode of one diode forms the first DC port of the freewheeling circuit, and the anode forms the first input port of the freewheeling circuit. The anode of the other diode forms the second DC port of the freewheeling circuit, and the cathode forms the second input port of the freewheeling circuit. The two DC ports of the freewheeling circuit are connected to the two DC ports of the inverter circuit or the discharge circuit, respectively. The two input ports of the freewheeling circuit are connected to the intermediate nodes of the two transistors connected in series in the first switching device group and the intermediate nodes of the two transistors connected in series in the second switching device group.

9. The bidirectional voltage regulating device according to claim 8, characterized in that, When the bidirectional voltage regulating device includes three voltage regulating units, the freewheeling circuit includes three input ports, two DC ports, and three sets of diodes connected in series in pairs. Each set of diodes connected in series in pairs forms two endpoints. The first endpoint of each set of diodes connected in series in pairs is coupled to serve as the first DC port of the freewheeling circuit, and the second endpoint of each set of diodes connected in series in pairs is coupled to serve as the second DC port of the freewheeling circuit. The two DC ports are connected to the two DC ports of the inverter circuit or the discharge circuit respectively. The three intermediate nodes of the three sets of diodes connected in series in pairs in pairs form the three input ports of the freewheeling circuit, and are respectively connected to the intermediate nodes of the first switching device group and the second switching device group of the three voltage regulating circuits in the three voltage regulating units. Alternatively, the freewheeling circuit may include six input ports, two DC ports, a first group of diodes, and a second group of diodes. The first group of diodes includes three diodes, wherein the cathodes of the three diodes are coupled to each other to form a first DC port, and the anodes of the three diodes constitute the three input ports of the freewheeling circuit, and are respectively coupled to the intermediate node of two transistors connected in series in the first or second switching device group of the three voltage regulating circuits in the three voltage regulating units. The second group of diodes includes three diodes, wherein the anodes of the three diodes are coupled to each other to form a second DC port, and two DC ports are connected to the two DC ports of the inverter circuit or the discharge circuit respectively. The cathodes of the three diodes constitute the other three input ports of the freewheeling circuit, and are respectively coupled to the intermediate node of the two transistors connected in series in the second switching device group or the first switching device group of the three voltage regulating circuits in the three voltage regulating units.

10. The bidirectional voltage regulating device according to claim 1, characterized in that, The first filter circuit includes a first capacitor or a third inductor and a second capacitor; when the first filter circuit includes a first capacitor, one end of the first capacitor serves as the input and output terminal of the first filter circuit, and the other end of the first capacitor serves as the common terminal of the first filter circuit and is connected to the neutral line. When the first filter circuit includes a third inductor and a second capacitor, one end of the third inductor serves as the input terminal of the first filter circuit, the other end of the third inductor is connected to one end of the second capacitor and serves as the output terminal of the first filter circuit, and the other end of the second capacitor serves as the common terminal of the first filter circuit and is connected to the neutral line. The voltage regulation unit further includes a second filter circuit. For each voltage regulation unit, the second filter circuit is connected between the output terminal of the voltage regulation unit and the commutation circuit. The second filter circuit includes a fourth inductor and a third capacitor. One end of the fourth inductor is coupled to the output terminal of the voltage regulation circuit, and the other end of the fourth inductor is coupled to one end of the third capacitor and serves as the output terminal of the second filter circuit connected to the commutation circuit. The other end of the third capacitor is coupled to the neutral line.

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