Voltage regulating device for the end of a power distribution network

Abstract

This utility model relates to the field of power electronics technology and discloses a voltage regulating device for the end of a distribution network, installed between the distribution transformer and the load at the end of the distribution network. The device includes: a remote electromechanical switch, connected in series between the distribution transformer and the load; a bidirectional electronic switch, with its two ends connected to the two ends of the remote electromechanical switch via series circuit breakers; a bidirectional AC / AC module, composed of symmetrically arranged rectifier and inverter units, and connected in parallel with the bidirectional electronic switch; and a controller electrically connected to the remote electromechanical switch, the bidirectional electronic switch, the bidirectional AC / AC module, and a voltage sensor installed between the distribution transformer and the load. This utility model solves the problems of traditional methods relying on the power grid and having low accuracy.

Description

Technical Field

[0001] This utility model relates to the field of power electronics technology, specifically to a voltage regulating device for the end of a power distribution network. Background Technology

[0002] During power grid transmission, factors such as load changes (e.g., industrial equipment start-up and shutdown, peak residential electricity consumption), line impedance, and faults (short circuits, power outages) can easily cause voltage amplitude fluctuations (deviating from the rated value by ±10% or even higher). These fluctuations can damage sensitive equipment (e.g., precision instruments, computers), affect production efficiency (unstable motor speed), or cause safety accidents (overvoltage leading to insulation breakdown). Modern industry extensively uses electronic equipment such as frequency converters, servo motors, and PLC control systems, which typically require input voltage stability within a range of ±2% to ±5% for normal operation. Traditional mechanical voltage regulators (such as tap changer regulators) have slow response speeds and low adjustment accuracy, failing to meet high-precision requirements. Utility Model Content

[0003] This invention provides a voltage regulating device for the end of a power distribution network to solve the above-mentioned problems.

[0004] This utility model is achieved through the following technical solution: A voltage regulating device for the end of a distribution network, installed between the distribution transformer and the load at the end of the distribution network, includes: A remote electromechanical switch is connected in series between the distribution transformer and the load; A bidirectional electronic switch, wherein the two ends of the bidirectional electronic switch are respectively connected to the two ends of the remote electromechanical switch via a series circuit breaker; A bidirectional AC / AC module, wherein the bidirectional AC / AC module is composed of symmetrically arranged rectifier units and inverter units, and the bidirectional AC / AC module is connected in parallel with the bidirectional electronic switch; The controller is electrically connected to the remote electromechanical switch, the bidirectional electronic switch, the bidirectional AC / AC module, and the voltage sensor installed between the distribution transformer and the load.

[0005] As an optimization, the bidirectional electronic switch is composed of two bidirectional thyristors connected back-to-back in parallel. The two ends of the bidirectional thyristor are respectively connected to the two ends of the remote electromechanical switch through a series circuit breaker, and the gate of the bidirectional thyristor is electrically connected to the controller.

[0006] As an optimization, the rectifier unit and the inverter unit are T-type three-level circuits arranged symmetrically in series.

[0007] As an optimization, the rectifier unit includes a first filter inductor L1, a first filter capacitor C1, a second energy storage inductor L2, a second energy storage capacitor C2, a third energy storage capacitor C3, a first MOSFET Q1, a second MOSFET Q2, a third MOSFET Q3, and a fourth MOSFET Q4. The first filter inductor L1 and the second energy storage inductor L2 are connected in series. One end of the first filter capacitor C1 is connected to the common connection terminal of the first filter inductor L1 and the second energy storage inductor L2. The end of the second energy storage inductor L2 furthest from the first filter inductor L1 is connected to the source of the first MOSFET Q1, the drain of the second MOSFET Q2, and the source of the third MOSFET Q3. The drain of the first MOSFET Q1 and the source of the fourth MOSFET Q4 are connected to the two ends of the second energy storage capacitor C2. The drain of the first MOSFET Q1 is the positive terminal of the DC bus. The sources of the second MOSFET Q2 and the fourth MOSFET Q4 are respectively connected to the two ends of the third energy storage capacitor C3. The source of the second MOSFET Q2 is the negative terminal of the DC bus, and the source of the fourth MOSFET Q4 is the center point of the DC bus. The drain of the third MOSFET Q3 is connected to the drain of the fourth MOSFET Q4. The end of the first filter capacitor C1 away from the first filter inductor L1 is connected to the center point of the DC bus. The end of the first filter inductor L1 away from the second energy storage inductor L2 is connected to the output terminal of the distribution transformer through the circuit breaker. The gates of the first MOSFET Q1, the second MOSFET Q2, the third MOSFET Q3 and the fourth MOSFET Q4 are connected to the controller.

[0008] As an optimization, the inverter unit includes a third filter inductor L3, a fourth filter capacitor C4, a fourth energy storage inductor L4, a fifth energy storage capacitor C5, a sixth energy storage capacitor C6, a fifth MOSFET Q5, a sixth MOSFET Q6, a seventh MOSFET Q7, and an eighth MOSFET Q8. The third filter inductor L3 and the fourth energy storage inductor L4 are connected in series. One end of the fourth filter capacitor C4 is connected to the common connection terminal of the third filter inductor L3 and the fourth energy storage inductor L4. The other end of the fourth filter capacitor C4 is connected to the center point of the DC bus. The end of the fourth energy storage inductor L4 furthest from the third energy storage inductor L3 is connected to the source of the fifth MOSFET Q5, the drain of the sixth MOSFET Q6, and the source of the seventh MOSFET Q7. The drain of the fifth MOSFET Q5 and the source of the eighth MOSFET Q8 are connected to the fifth MOSFET Q5, the sixth MOSFET Q6, the seventh MOSFET Q7, and the eighth MOSFET Q8. The fifth energy storage capacitor C5 is connected to both ends, and the drain of the fifth MOSFET Q5 is connected to the positive terminal of the DC bus. The sources of the sixth MOSFET Q6 and the eighth MOSFET Q8 are respectively connected to both ends of the sixth energy storage capacitor C6. The source of the sixth MOSFET Q6 is connected to the negative terminal of the DC bus. The drain of the seventh MOSFET Q7 is connected to the drain of the eighth MOSFET Q8. The source of the eighth MOSFET Q8 is connected to the center point of the DC bus. The end of the fourth filter capacitor C4 away from the fourth energy storage inductor L4 is connected to the source of the eighth MOSFET Q8. The end of the third filter inductor L3 away from the fourth energy storage inductor L4 is connected to the load through the circuit breaker. The gates of the fifth MOSFET Q5, the sixth MOSFET Q6, the seventh MOSFET Q7 and the eighth MOSFET Q8 are connected to the controller.

[0009] As an optimization, the rectifier unit and inverter unit are symmetrically connected in series as a three-phase four-bridge-arm circuit.

[0010] As an optimization, the rectifier unit includes a rectifier-side filter inductor, a rectifier-side filter capacitor, a rectifier-side energy storage inductor, a rectifier-side IGBT switch group formed by two rectifier-side IGBT switches connected in series, and two bus capacitors connected in series, all based on the three-phase AC power. It also includes a rectifier-side IGBT switch group formed by two rectifier-side IGBT switches connected in series, based on the neutral line. The ends of the two bus capacitors that are far apart from each other are the positive and negative voltage ends of the bus, respectively. The IGBT switch groups corresponding to each phase of AC power and the neutral line are connected in parallel. Based on each phase of the three-phase AC power, the rectifier-side filter inductor... The rectifier-side energy storage inductor is connected in series with the midpoint of the rectifier-side IGBT switch group, and the neutral line is connected to the midpoint of the corresponding rectifier-side IGBT switch group. One end of the rectifier-side filter capacitor is connected to the common connection terminal of the rectifier-side energy storage inductor and the rectifier-side filter inductor, respectively. The other end of the rectifier-side filter capacitor is connected to the neutral line. The two ends of the four rectifier-side IGBT switch groups are connected to the positive voltage terminal and the negative voltage terminal of the bus, respectively. The end of the rectifier-side filter inductor furthest from the rectifier-side filter inductor is connected to the output terminal of the distribution transformer through the circuit breaker in series.

[0011] As an optimization, the rectifier unit includes a rectifier-side A-phase energy storage inductor L4, a rectifier-side A-phase filter inductor L1, a rectifier-side A-phase filter capacitor C1, a rectifier-side A-phase IGBT switch Q7, and a rectifier-side A-phase IGBT switch Q8, all configured based on phase A. The two ends of the rectifier-side A-phase filter capacitor C1 are connected to the neutral line and the common connection terminal of the rectifier-side A-phase energy storage inductor L4 and the rectifier-side A-phase filter inductor L1, respectively. The bases of the rectifier-side A-phase IGBT switch Q7 and the rectifier-side A-phase IGBT switch Q8 are connected to the controller. The rectifier-side A-phase... The emitter of IGBT switch Q7 is connected to the collector of rectifier-side A-phase IGBT switch Q8. The collector of rectifier-side A-phase IGBT switch Q7 is connected to the positive voltage terminal of the bus. The emitter of rectifier-side A-phase IGBT switch Q8 is connected to the negative voltage terminal of the bus. Rectifier-side A-phase filter inductor L1 is connected to the emitter of rectifier-side A-phase IGBT switch Q7 through series connection with rectifier-side A-phase energy storage inductor L4. The end of rectifier-side A-phase filter inductor L1 away from rectifier-side energy storage inductor L4 is connected to the output terminal of the distribution transformer through the circuit breaker. The rectifier unit further includes a rectifier-side B-phase energy storage inductor L5, a rectifier-side B-phase filter inductor L2, a rectifier-side B-phase filter capacitor C2, a rectifier-side B-phase IGBT switch Q5, and a rectifier-side B-phase IGBT switch Q6, all configured based on phase B. The two ends of the rectifier-side B-phase filter capacitor C2 are connected to the neutral line and the common connection terminal of the rectifier-side B-phase energy storage inductor L5 and the rectifier-side B-phase filter inductor L2, respectively. The bases of the rectifier-side B-phase IGBT switches Q5 and Q6 are connected to the controller, respectively. The emitter of BT switch Q5 is connected to the collector of the rectifier-side B-phase IGBT switch Q6. The collector of the rectifier-side B-phase IGBT switch Q5 is connected to the positive voltage terminal of the bus. The emitter of the rectifier-side B-phase IGBT switch Q6 is connected to the negative voltage terminal of the bus. The rectifier-side B-phase filter inductor L2 is connected to the emitter of the rectifier-side B-phase IGBT switch Q5 through series connection with the rectifier-side B-phase energy storage inductor L5. The end of the rectifier-side B-phase filter inductor L2 away from the rectifier-side energy storage inductor L5 is connected to the output terminal of the distribution transformer through the circuit breaker. The rectifier unit further includes a rectifier-side C-phase energy storage inductor L6, a rectifier-side C-phase filter inductor L3, a rectifier-side C-phase filter capacitor C3, a rectifier-side C-phase IGBT switch Q3, and a rectifier-side C-phase IGBT switch Q4, all configured based on the C-phase. The two ends of the rectifier-side C-phase filter capacitor C3 are connected to the neutral line and the common connection terminal of the rectifier-side C-phase energy storage inductor L6 and the rectifier-side C-phase filter inductor L3, respectively. The bases of the rectifier-side C-phase IGBT switch Q3 and the rectifier-side C-phase IGBT switch Q4 are connected to the controller. The rectifier-side C-phase IGBT... The emitter of BT switch Q3 is connected to the collector of the rectifier-side C-phase IGBT switch Q4. The collector of the rectifier-side C-phase IGBT switch Q3 is connected to the positive voltage terminal of the bus. The emitter of the rectifier-side C-phase IGBT switch Q4 is connected to the negative voltage terminal of the bus. The rectifier-side C-phase filter inductor L3 is connected to the emitter of the rectifier-side C-phase IGBT switch Q3 through series connection with the rectifier-side C-phase energy storage inductor L6. The end of the rectifier-side C-phase filter inductor L3 away from the rectifier-side energy storage inductor L6 is connected to the output terminal of the distribution transformer through the circuit breaker. The rectifier-side IGBT switch group corresponding to the neutral line includes a rectifier-side neutral line IGBT switch Q1 and a rectifier-side neutral line IGBT switch Q2. The bases of the rectifier-side neutral line IGBT switch Q1 and Q2 are respectively connected to the controller. The emitter of the rectifier-side neutral line IGBT switch Q1 is connected to the collector of the rectifier-side neutral line IGBT switch Q2. The collector of the rectifier-side neutral line IGBT switch Q1 is connected to the positive voltage terminal of the bus. The emitter of the rectifier-side neutral line IGBT switch Q2 is connected to the negative voltage terminal of the bus. The neutral line is connected to the emitter of the rectifier-side neutral line IGBT switch Q1.

[0012] As an optimization, the inverter unit includes an inverter-side filter inductor, an inverter-side filter capacitor, an inverter-side energy storage inductor, an inverter-side IGBT switch group formed by two inverter-side IGBT switches connected in series, and two bus capacitors connected in series, all based on the three-phase AC power. It also includes an inverter-side IGBT switch group formed by two inverter-side IGBT switches connected in series, based on the neutral line. The ends of the two bus capacitors that are far apart from each other are the positive and negative voltage ends of the bus, respectively. The IGBT switch groups corresponding to each phase of AC power and the neutral line are connected in parallel. Based on each phase of the three-phase AC power, the inverter-side filter inductor... The inverter-side energy storage inductor is connected in series with the midpoint of the inverter-side IGBT switch group, and the neutral line is connected to the midpoint of the corresponding inverter-side IGBT switch group. One end of the inverter-side filter capacitor is connected to the common connection terminal of the inverter-side energy storage inductor and the inverter-side filter inductor, respectively. The other end of the inverter-side filter capacitor is connected to the neutral line. The two ends of the four inverter-side IGBT switch groups are connected to the positive voltage terminal and the negative voltage terminal of the bus, respectively. The end of the inverter-side filter inductor furthest from the inverter-side filter inductor is connected to the output terminal of the distribution transformer through the circuit breaker in series.

[0013] As an optimization, the inverter unit includes an inverter-side A-phase energy storage inductor L7, an inverter-side A-phase filter inductor L10, an inverter-side A-phase filter capacitor C8, an inverter-side A-phase IGBT switch Q9, and an inverter-side A-phase IGBT switch Q10, all configured based on phase A. The two ends of the inverter-side A-phase filter capacitor C8 are connected to the neutral line and the common connection terminal of the inverter-side A-phase energy storage inductor L7 and the inverter-side A-phase filter inductor L10, respectively. The bases of the inverter-side A-phase IGBT switches Q9 and Q10 are connected to the controller. The emitter of the inverter-side A-phase IGBT switch Q9 is connected to the collector of the inverter-side A-phase IGBT switch Q10. The collector of the inverter-side A-phase IGBT switch Q9 is connected to the positive voltage terminal of the bus. The emitter of the inverter-side A-phase IGBT switch Q10 is connected to the negative voltage terminal of the bus. The inverter-side A-phase filter inductor L10 is connected to the emitter of the inverter-side A-phase IGBT switch Q9 through series connection with the inverter-side A-phase energy storage inductor L7. The end of the inverter-side A-phase filter inductor L10 away from the inverter-side energy storage inductor L7 is connected to the load through the circuit breaker. The inverter unit further includes an inverter-side B-phase energy storage inductor L8, an inverter-side B-phase filter inductor L11, an inverter-side B-phase filter capacitor C9, an inverter-side B-phase IGBT switch Q11, and an inverter-side B-phase IGBT switch Q12, all configured based on phase B. The two ends of the inverter-side B-phase filter capacitor C9 are connected to the neutral line and the common connection terminal of the inverter-side B-phase energy storage inductor L8 and the inverter-side B-phase filter inductor L11, respectively. The bases of the inverter-side B-phase IGBT switches Q11 and Q12 are connected to the controller, respectively. The emitter of phase B IGBT switch Q11 is connected to the collector of inverter-side phase B IGBT switch Q12. The collector of inverter-side phase B IGBT switch Q11 is connected to the positive voltage terminal of the bus. The emitter of inverter-side phase B IGBT switch Q12 is connected to the negative voltage terminal of the bus. The inverter-side phase B filter inductor L11 is connected to the emitter of inverter-side phase B IGBT switch Q11 through series connection with inverter-side phase B energy storage inductor L8. The end of inverter-side phase B filter inductor L11 away from inverter-side energy storage inductor L8 is connected to the load through the circuit breaker. The inverter unit further includes an inverter-side C-phase energy storage inductor L9, an inverter-side C-phase filter inductor L12, an inverter-side C-phase filter capacitor C10, an inverter-side C-phase IGBT switch Q13, and an inverter-side C-phase IGBT switch Q14, all configured based on the C-phase. The two ends of the inverter-side C-phase filter capacitor C10 are connected to the neutral line and the common connection terminal of the inverter-side C-phase energy storage inductor L9 and the inverter-side C-phase filter inductor L12, respectively. The bases of the inverter-side C-phase IGBT switches Q13 and Q14 are connected to the controller. The emitter of the C-phase IGBT switch Q13 is connected to the collector of the inverter-side C-phase IGBT switch Q14. The collector of the inverter-side C-phase IGBT switch Q13 is connected to the positive voltage terminal of the bus. The emitter of the inverter-side C-phase IGBT switch Q14 is connected to the negative voltage terminal of the bus. The inverter-side C-phase filter inductor L12 is connected to the emitter of the inverter-side C-phase IGBT switch Q13 through series connection with the inverter-side C-phase energy storage inductor L9. The end of the inverter-side C-phase filter inductor L12 away from the inverter-side energy storage inductor L9 is connected to the load through the circuit breaker. The inverter-side IGBT switch group corresponding to the neutral line includes an inverter-side neutral line IGBT switch Q15 and an inverter-side neutral line IGBT switch Q16. The bases of the inverter-side neutral line IGBT switch Q15 and Q16 are respectively connected to the controller. The emitter of the inverter-side neutral line IGBT switch Q15 is connected to the collector of the inverter-side neutral line IGBT switch Q16. The collector of the inverter-side neutral line IGBT switch Q15 is connected to the positive voltage terminal of the bus. The emitter of the inverter-side neutral line IGBT switch Q16 is connected to the negative voltage terminal of the bus. The neutral line is connected to the emitter of the inverter-side neutral line IGBT switch Q15.

[0014] Compared with the prior art, this utility model has the following advantages and beneficial effects: Response speed and regulation accuracy: The bidirectional AC / AC module adopts a T-type three-level or three-phase four-arm topology, paired with a bidirectional electronic switch, achieving a response time of milliseconds, far exceeding the traditional second-level response; it precisely controls the output voltage with high regulation accuracy, solving the problems of traditional reliance on the power grid and low precision.

[0015] Power quality management: The rectifier and inverter units use SICMOS transistors for high-frequency modulation to achieve bidirectional power flow, manage low / high voltage at the end, eliminate PV (photovoltaic power generation) high voltage, improve the power supply quality of the grid, adapt to unbalanced loads, and ensure stable power supply.

[0016] Operational reliability and maintainability: The combination of remote electromechanical switches and bidirectional electronic switches enables millisecond-level switching. During equipment maintenance, the load automatically switches to a fault-safe bypass, balancing reliability and ease of maintenance, and creating a high-quality power environment for end users. Attached Figure Description

[0017] The accompanying drawings, which are included to provide a further understanding of the embodiments of the present invention and form part of this application, do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the structure of a voltage regulating device for the end of a power distribution network according to the present invention; Figure 2 This is a current flow diagram of a voltage regulating device for the end of a power distribution network as described in this utility model, within the normal voltage range. Figure 3 This is a current flow diagram of a voltage regulating device for the end of a power distribution network as described in this utility model when the AC output port voltage is low. Figure 4 This invention provides a current flow diagram for a voltage regulating device at the end of a power distribution network, in case of voltage regulation device failure or maintenance. Figure 5 This is a circuit diagram of a T-type three-level topology bidirectional AC / AC module. Figure 6 This is a circuit diagram of a bidirectional AC / AC module with a three-phase four-bridge-arm topology. Figure 7 for Figure 6 A magnified schematic diagram of the intermediate rectifier unit circuit; Figure 8 for Figure 6 A magnified schematic diagram of the intermediate inverter unit. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of this utility model are only used to explain this utility model and are not intended to limit this utility model.

[0019] This embodiment 1 provides a voltage regulating device for the end of a distribution network, installed between the distribution transformer and the load at the end of the distribution network, such as... Figure 1 As shown, it includes a remote electromechanical switch, a two-way electronic switch, a two-way AC / AC module, and a controller.

[0020] Specifically, a remote electromechanical switch is connected in series between the distribution transformer and the load. The two ends of the bidirectional electronic switch are connected to the two ends of the remote electromechanical switch via series circuit breakers; that is, two circuit breakers are provided, each located at one end of the bidirectional electronic switch. The output end of the distribution transformer is connected to one end of the bidirectional electronic switch via a series circuit breaker, and the load is connected to the other end of the bidirectional electronic switch via a circuit breaker. The bidirectional AC / AC module is composed of symmetrically arranged rectifier and inverter units, and the bidirectional AC / AC module is connected in parallel with the bidirectional electronic switch; in other words, it can be understood that the output end of the distribution transformer is connected to one end of the bidirectional AC / AC module via a series circuit breaker, and the load is connected to the other end of the bidirectional AC / AC module via a circuit breaker.

[0021] The controller is electrically connected to the remote electromechanical switch, the bidirectional electronic switch, the bidirectional AC / AC module, and the voltage sensor installed between the distribution transformer and the load.

[0022] In this technical solution, a voltage sensor is installed at the output end of the distribution transformer. The controller collects the voltage value of the voltage sensor and controls the opening or closing of the bidirectional AC / AC module and the bidirectional electronic switch based on the voltage value transmitted from the voltage sensor.

[0023] Specifically, the bidirectional AC / AC module is used to transform the voltage when the output voltage of the distribution network (i.e., the voltage at the output terminal of the distribution transformer) is in an abnormal range, thereby outputting a stable voltage value. A bidirectional electronic switch is used to close when the output voltage of the distribution network is within the normal range, thereby transmitting the output voltage of the distribution network to the load; The remote electromechanical switch is used to close during maintenance of the bidirectional AC / AC module, thereby transmitting the voltage output from the distribution network to the load. At this time, the circuit breaker is manually disconnected. When the bidirectional AC / AC module requires maintenance or repair, the remote electromechanical switch is triggered by a closing signal from the controller.

[0024] Its working principle is as follows: 1) When the AC output port grid voltage (i.e., the output voltage of the distribution transformer) is within the normal voltage range (220Vac±10%), the S5 bidirectional electronic switch is closed, the S1 remote electromechanical switch is open, and the S4 bidirectional AC / AC module is in operation but has no output. Power is supplied to the load through the S2 circuit breaker, the S5 bidirectional electronic switch, and the S3 circuit breaker. Figure 2 The power flow is shown in red; 2) When the AC output port voltage is low or fluctuates (below 198Vac), the S5 bidirectional electronic switch quickly disconnects (the bidirectional electronic switch consists of two back-to-back parallel thyristors, and its switching action is rapid), and the S4 bidirectional AC / AC module outputs a stable 220Vac voltage (the AC / AC module's switching transistor generates a high-frequency PWM wave, and the output voltage value is a feedback quantity; the controller adjusts it to the output setpoint through PI regulation, forming a closed-loop control; this is existing technology and does not involve any improvement to the computer program), continuously providing the rated voltage to the load. Figure 3 The power flow is shown in red; 3) When the AC output port voltage returns to the normal voltage range (220Vac±10%), the S5 bidirectional electronic switch changes from open to closed, and the S4 bidirectional AC / AC module is in a running but no-output state. The load is then powered through the S2 circuit breaker, the S5 bidirectional electronic switch, and the S3 circuit breaker. Figure 2 The power flow is shown in red; 4) In the event of a voltage regulator malfunction or maintenance, the load current will automatically transfer to the fault-safe bypass, disconnecting the S5 bidirectional electronic switch. The S4 bidirectional AC / AC module will be in the off state, meaning the current will directly supply power to the load through the S1 remote electromechanical switch. Figure 4 The power flow is shown in red.

[0025] It should be noted that the controller controls the opening or closing of the corresponding switch by collecting the voltage value from the voltage sensor, which is existing technology and does not involve the improvement of the computer program. For example, in the controller integrated circuit of utility model patent CN208314052U, it is disclosed that "the controller integrated circuit controls the switching operation of the primary switch based on the feedback voltage indicating the output voltage of the power supply".

[0026] In some embodiments, the remote electromechanical switch may be a relay or a contactor.

[0027] In some embodiments, the bidirectional electronic switch comprises a bidirectional thyristor consisting of two unidirectional thyristors connected back-to-back in parallel. The two ends of the bidirectional thyristor are respectively connected to the two ends of the remote electromechanical switch via a series circuit breaker, and the gate of the bidirectional thyristor is electrically connected to the controller. The bidirectional thyristor is modularly packaged, internally encapsulating two back-to-back silicon controlled thyristors.

[0028] Next, we will introduce the structure of the bidirectional AC / AC module in detail.

[0029] In some embodiments, the rectifier unit and the inverter unit are T-type three-level circuits arranged symmetrically in series.

[0030] In some embodiments, the rectifier unit includes a first filter inductor L1, a first filter capacitor C1, a second energy storage inductor L2, a second energy storage capacitor C2, a third energy storage capacitor C3, a first MOSFET Q1, a second MOSFET Q2, a third MOSFET Q3, and a fourth MOSFET Q4. The first filter inductor L1 and the second energy storage inductor L2 are connected in series. One end of the first filter capacitor C1 is connected to the common connection terminal of the first filter inductor L1 and the second energy storage inductor L2. The end of the second energy storage inductor L2 furthest from the first filter inductor L1 is connected to the source of the first MOSFET Q1, the drain of the second MOSFET Q2, and the source of the third MOSFET Q3. The drain of the first MOSFET Q1 and the source of the fourth MOSFET Q4 are connected to the two ends of the second energy storage capacitor C2. The drain of the first MOSFET Q1 is the positive terminal of the DC bus. The sources of the second MOSFET Q2 and the fourth MOSFET Q4 are respectively connected to the two ends of the third energy storage capacitor C3. The source of the second MOSFET Q2 is the negative terminal of the DC bus, and the source of the fourth MOSFET Q4 is the center point of the DC bus. The drain of the third MOSFET Q3 is connected to the drain of the fourth MOSFET Q4. The end of the first filter capacitor C1 away from the first filter inductor L1 is connected to the center point of the DC bus. The end of the first filter inductor L1 away from the second energy storage inductor L2 is connected to the output terminal of the distribution transformer through the circuit breaker. The gates of the first MOSFET Q1, the second MOSFET Q2, the third MOSFET Q3, and the fourth MOSFET Q4 are connected to the controller.

[0031] In some embodiments, the inverter unit includes a third filter inductor L3, a fourth filter capacitor C4, a fourth energy storage inductor L4, a fifth energy storage capacitor C5, a sixth energy storage capacitor C6, a fifth MOSFET Q5, a sixth MOSFET Q6, a seventh MOSFET Q7, and an eighth MOSFET Q8. The third filter inductor L3 and the fourth energy storage inductor L4 are connected in series. One end of the fourth filter capacitor C4 is connected to the common connection terminal of the third filter inductor L3 and the fourth energy storage inductor L4. The other end of the fourth filter capacitor C4 is connected to the center point of the DC bus. The end of the fourth energy storage inductor L4 furthest from the third energy storage inductor L3 is connected to the source of the fifth MOSFET Q5, the drain of the sixth MOSFET Q6, and the source of the seventh MOSFET Q7. The drain of the fifth MOSFET Q5 and the source of the eighth MOSFET Q8 are connected to the... The fifth energy storage capacitor C5 is connected to both ends, and the drain of the fifth MOSFET Q5 is connected to the positive terminal of the DC bus. The sources of the sixth MOSFET Q6 and the eighth MOSFET Q8 are respectively connected to both ends of the sixth energy storage capacitor C6. The source of the sixth MOSFET Q6 is connected to the negative terminal of the DC bus. The drain of the seventh MOSFET Q7 is connected to the drain of the eighth MOSFET Q8. The source of the eighth MOSFET Q8 is connected to the center point of the DC bus. The end of the fourth filter capacitor C4 away from the fourth energy storage inductor L4 is connected to the source of the eighth MOSFET Q8. The end of the third filter inductor L3 away from the fourth energy storage inductor L4 is connected to the load through the circuit breaker. The gates of the fifth MOSFET Q5, the sixth MOSFET Q6, the seventh MOSFET Q7, and the eighth MOSFET Q8 are connected to the controller.

[0032] Traditional mechanical voltage regulators (such as tap changer regulators) suffer from slow response speed (seconds) and low regulation accuracy (±5%~±10%), failing to meet high-precision requirements. They are also dependent on grid strength, have low efficiency and relative stability, and are prone to equipment damage and grid faults if voltage or current is unstable. Furthermore, they cannot address the issue of managing high and low voltage in the grid. In this embodiment, the voltage regulator design utilizes the same T-type three-level topology for both the rectifier and inverter units in the bidirectional AC / AC module. These units are connected back-to-back in series to achieve bidirectional operation. This is achieved through full control... The device utilizes third-generation SICMOS transistors for high-frequency pulse width modulation, enabling bidirectional power flow. The rectifier unit inputs a three-phase four-wire system, boosting the voltage to 750V DC via AC / DC conversion. The inverter unit then converts this back to stable and reliable AC via DC / AC conversion, connecting it in series to the end of the power grid line to manage the voltage at the end. With an extremely fast response time (milliseconds), it achieves precise control, enabling high-quality and highly stable power output. This addresses low voltage at the user's end and eliminates high voltage from PV at the end, improving the power grid voltage quality at the device's end and providing a better power environment for users at the end of the line.

[0033] like Figure 5 As shown, the advantages of using a T-type three-level topology as a rectifier (rectifier unit) are as follows: For example, in the rectifier unit, all power devices use SICMOS transistors. Using SICMOS transistors for synchronous rectification can achieve the rectification effect, improve efficiency, and control Q1, Q2, Q3, and Q4 to generate PMW modulation waves.

[0034] Figure 5 In the PFC circuit, the AC input is connected to L1, which is the grid-side filter inductor (i.e., the first filter inductor), C1 is the grid-side filter capacitor (i.e., the first filter capacitor), L2 is the inductor-side energy storage inductor (i.e., the second energy storage inductor), Q1 / Q2 are SICMOS transistors using synchronous rectification, Q3 / Q4 are main power SICMOS transistors, and C2 / C3 are DC bus energy storage capacitors.

[0035] During the positive half-cycle of AC, Q4 is turned on and Q1 / Q2 / Q3 are turned off, storing energy in L2 with the voltage direction being positive on the left and negative on the right. When Q4 is turned off, L2 releases energy with the voltage direction being negative on the left and positive on the right. This energy, along with the AC mains power, is rectified by Q1 to charge C2. During the negative half-cycle of AC, transistor Q3 is turned on, while transistors Q1 / Q2 / Q4 are turned off, storing energy in L2 with the voltage direction being negative on the left and positive on the right. When transistor Q3 is turned off, L2 releases energy with the voltage direction being positive on the left and negative on the right. This energy, along with the AC mains power, is rectified by transistor Q2 to charge C3.

[0036] For example, in the inverter unit, all power devices use SICMOS transistors, and Q5, Q6, Q7, and Q8 are controlled to generate PMW modulation waves.

[0037] Figure 5 In the circuit, the DC bus input is fed into the INV circuit. L3 is the grid-side filter inductor (i.e., the third filter inductor), C4 is the grid-side filter capacitor (i.e., the fourth filter capacitor), L4 is the inductor-side filter inductor (i.e., the fourth filter inductor), Q5 / Q6 are the main inverter tubes, Q7 / Q8 are the auxiliary inverter tubes, and C5 / C6 are the DC bus energy storage capacitors.

[0038] During the positive half-cycle, transistors Q5 / Q7 are turned on, and transistors Q6 / Q8 are turned off. BUS+ (the positive terminal of the DC bus) flows through transistor Q5, turning the midpoint of the bridge arm to a positive level (same as the BUS+ potential), and then flows back to N (the midpoint of the DC bus) through L4 and C4. When Q5 is turned off, since the current in L4 cannot change abruptly, the current continues to flow through C4 to N, through the body diode of Q6, and then through transistor Q7 for freewheeling, turning the midpoint of the bridge arm to a 0 level (same as the N potential). During the negative half-cycle, transistors Q6 / Q8 are turned on, and transistors Q5 / Q7 are turned off. N (the midpoint of the DC bus) flows through C4, L4, and Q6 to BUS-, turning the midpoint of the bridge arm to a negative level (the same as the BUS- potential). When Q6 is turned off, since the current in L4 cannot change abruptly, the current flows through the body diode of transistor Q7, through transistor Q8 to N, then through C4, and back to L4 for freewheeling. The bidirectional AC / AC module in this device mainly uses two T-type three-level topologies connected back-to-back to convert AC power to DC power through a rectifier. Then, the inverter converts the DC power back to AC power. The device is connected in series to the end-user side of the power grid. If the voltage at the end-user side of the power grid is lower than 220Vac, this device can regulate the voltage at the end to 220Vac to supply the user side, ensuring the stability of the power supply at the user side. That is, the voltage at the end of the power grid is effectively managed. With the bidirectional electronic switch, a millisecond-level switching response can be achieved. With the remote electromechanical switch, the reliability of the device operation and the maintainability of the equipment are improved.

[0039] Example 2: Unlike Embodiment 1, in the bidirectional AC / AC module, the rectifier unit and inverter unit are symmetrically connected in series as a three-phase four-bridge-arm circuit.

[0040] The reason for setting the rectifier unit and inverter unit as a three-phase four-bridge-arm circuit is that when using other topologies for power conversion, there are often situations such as uneven three-phase current and bus voltage bias during the power conversion process. It is often necessary to add a balancing circuit to suppress the bias and uneven current, which increases the complexity and cost of the system.

[0041] A three-phase four-bridge-arm topology is adopted as the main power topology, and the two are used in series back-to-back to achieve bidirectional operation. By using high-frequency pulse width modulation on the fully controllable third-generation semiconductor IGBT, the response speed is extremely fast (millisecond level), which can achieve precise control, reduce the harmonic content of the input current, improve the system power factor, and achieve high-quality and high-stability power output. It can also manage low voltage at the user end and eliminate high voltage caused by PV at the end, improve the grid voltage supply quality at the end of the device, and bring a good power environment to users at the end of the line.

[0042] The voltage regulating device composed of the bidirectional AC / AC module in Example 2 is installed at the end of the line. The voltage regulating device is connected in series in the power grid, which is convenient to install, has low modification cost, and high reliability. It also has functions such as harmonic control, reactive power compensation, and three-phase imbalance control, and is applicable to most application scenarios.

[0043] In some embodiments, the rectifier unit includes a rectifier-side filter inductor, a rectifier-side filter capacitor, a rectifier-side energy storage inductor, a rectifier-side IGBT switch group formed by two rectifier-side IGBT switches connected in series, and two bus capacitors connected in series, all based on the three-phase AC power. It also includes a rectifier-side IGBT switch group formed by two rectifier-side IGBT switches connected in series, based on the neutral line. The ends of the two bus capacitors that are far apart from each other are the positive and negative voltage ends of the bus, respectively. The IGBT switch groups corresponding to each phase of AC power and the neutral line are connected in parallel. Based on each phase of the three-phase AC power, the rectifier-side filter inductor... The inductor is connected in series with the rectifier-side energy storage inductor and the midpoint of the rectifier-side IGBT switch group, and the neutral line is connected to the midpoint of the corresponding rectifier-side IGBT switch group. One end of the rectifier-side filter capacitor is connected to the common connection terminal of the rectifier-side energy storage inductor and the rectifier-side filter inductor, and the other end of the rectifier-side filter capacitor is connected to the neutral line. The two ends of the four rectifier-side IGBT switch groups are connected to the positive voltage terminal and the negative voltage terminal of the bus, respectively. The end of the rectifier-side filter inductor furthest from the rectifier-side filter inductor is connected to the output terminal of the distribution transformer in series with the circuit breaker.

[0044] More specifically, the rectifier unit includes a rectifier-side A-phase energy storage inductor L4, a rectifier-side A-phase filter inductor L1, a rectifier-side A-phase filter capacitor C1, a rectifier-side A-phase IGBT switch Q7, and a rectifier-side A-phase IGBT switch Q8, all configured based on phase A. The two ends of the rectifier-side A-phase filter capacitor C1 are connected to the neutral line and the common connection terminal of the rectifier-side A-phase energy storage inductor L4 and the rectifier-side A-phase filter inductor L1, respectively. The bases of the rectifier-side A-phase IGBT switch Q7 and the rectifier-side A-phase IGBT switch Q8 are connected to the controller. The emitter of phase A IGBT switch Q7 is connected to the collector of phase A IGBT switch Q8 on the rectifier side. The collector of phase A IGBT switch Q7 on the rectifier side is connected to the positive voltage terminal of the bus. The emitter of phase A IGBT switch Q8 on the rectifier side is connected to the negative voltage terminal of the bus. Phase A filter inductor L1 on the rectifier side is connected to the emitter of phase A IGBT switch Q7 on the rectifier side through series connection with phase A energy storage inductor L4 on the rectifier side. The end of phase A filter inductor L1 on the rectifier side away from the energy storage inductor L4 is connected to the output terminal of the distribution transformer through the circuit breaker. The rectifier unit further includes a rectifier-side B-phase energy storage inductor L5, a rectifier-side B-phase filter inductor L2, a rectifier-side B-phase filter capacitor C2, a rectifier-side B-phase IGBT switch Q5, and a rectifier-side B-phase IGBT switch Q6, all configured based on phase B. The two ends of the rectifier-side B-phase filter capacitor C2 are connected to the neutral line and the common connection terminal of the rectifier-side B-phase energy storage inductor L5 and the rectifier-side B-phase filter inductor L2, respectively. The bases of the rectifier-side B-phase IGBT switches Q5 and Q6 are connected to the controller, respectively. The emitter of BT switch Q5 is connected to the collector of the rectifier-side B-phase IGBT switch Q6. The collector of the rectifier-side B-phase IGBT switch Q5 is connected to the positive voltage terminal of the bus. The emitter of the rectifier-side B-phase IGBT switch Q6 is connected to the negative voltage terminal of the bus. The rectifier-side B-phase filter inductor L2 is connected to the emitter of the rectifier-side B-phase IGBT switch Q5 through series connection with the rectifier-side B-phase energy storage inductor L5. The end of the rectifier-side B-phase filter inductor L2 away from the rectifier-side energy storage inductor L5 is connected to the output terminal of the distribution transformer through the circuit breaker. The rectifier unit further includes a rectifier-side C-phase energy storage inductor L6, a rectifier-side C-phase filter inductor L3, a rectifier-side C-phase filter capacitor C3, a rectifier-side C-phase IGBT switch Q3, and a rectifier-side C-phase IGBT switch Q4, all configured based on the C-phase. The two ends of the rectifier-side C-phase filter capacitor C3 are connected to the neutral line and the common connection terminal of the rectifier-side C-phase energy storage inductor L6 and the rectifier-side C-phase filter inductor L3, respectively. The bases of the rectifier-side C-phase IGBT switch Q3 and the rectifier-side C-phase IGBT switch Q4 are connected to the controller. The rectifier-side C-phase IGBT... The emitter of BT switch Q3 is connected to the collector of the rectifier-side C-phase IGBT switch Q4. The collector of the rectifier-side C-phase IGBT switch Q3 is connected to the positive voltage terminal of the bus. The emitter of the rectifier-side C-phase IGBT switch Q4 is connected to the negative voltage terminal of the bus. The rectifier-side C-phase filter inductor L3 is connected to the emitter of the rectifier-side C-phase IGBT switch Q3 through series connection with the rectifier-side C-phase energy storage inductor L6. The end of the rectifier-side C-phase filter inductor L3 away from the rectifier-side energy storage inductor L6 is connected to the output terminal of the distribution transformer through the circuit breaker. The rectifier-side IGBT switch group corresponding to the neutral line includes a rectifier-side neutral line IGBT switch Q1 and a rectifier-side neutral line IGBT switch Q2. The bases of the rectifier-side neutral line IGBT switch Q1 and Q2 are respectively connected to the controller. The emitter of the rectifier-side neutral line IGBT switch Q1 is connected to the collector of the rectifier-side neutral line IGBT switch Q2. The collector of the rectifier-side neutral line IGBT switch Q1 is connected to the positive voltage terminal of the bus. The emitter of the rectifier-side neutral line IGBT switch Q2 is connected to the negative voltage terminal of the bus. The neutral line is connected to the emitter of the rectifier-side neutral line IGBT switch Q1.

[0045] In some embodiments, the inverter unit includes an inverter-side filter inductor, an inverter-side filter capacitor, an inverter-side energy storage inductor, an inverter-side IGBT switch group formed by two inverter-side IGBT switches connected in series, and two bus capacitors connected in series, all configured based on the three-phase AC power. It also includes an inverter-side IGBT switch group formed by two inverter-side IGBT switches connected in series, configured based on the neutral line. The ends of the two bus capacitors that are far apart from each other are respectively the positive and negative voltage ends of the bus. The IGBT switch groups corresponding to each phase of AC power and the neutral line are connected in parallel. Based on each phase of the three-phase AC power, the inverter-side filter inductor... The inverter-side energy storage inductor is connected in series with the midpoint of the inverter-side IGBT switch group, and the neutral line is connected to the midpoint of the corresponding inverter-side IGBT switch group. One end of the inverter-side filter capacitor is connected to the common connection terminal of the inverter-side energy storage inductor and the inverter-side filter inductor, and the other end of the inverter-side filter capacitor is connected to the neutral line. The two ends of the four inverter-side IGBT switch groups are connected to the positive voltage terminal and the negative voltage terminal of the bus, respectively. The end of the inverter-side filter inductor furthest from the inverter-side filter inductor is connected to the output terminal of the distribution transformer in series with the circuit breaker.

[0046] More specifically, the inverter unit includes an inverter-side A-phase energy storage inductor L7, an inverter-side A-phase filter inductor L10, an inverter-side A-phase filter capacitor C8, an inverter-side A-phase IGBT switch Q9, and an inverter-side A-phase IGBT switch Q10, all configured based on phase A. The two ends of the inverter-side A-phase filter capacitor C8 are connected to the neutral line and the common connection terminal of the inverter-side A-phase energy storage inductor L7 and the inverter-side A-phase filter inductor L10, respectively. The bases of the inverter-side A-phase IGBT switches Q9 and Q10 are connected to the controller. The emitter of the inverter-side A-phase IGBT switch Q9 is connected to the collector of the inverter-side A-phase IGBT switch Q10. The collector of the inverter-side A-phase IGBT switch Q9 is connected to the positive voltage terminal of the bus. The emitter of the inverter-side A-phase IGBT switch Q10 is connected to the negative voltage terminal of the bus. The inverter-side A-phase filter inductor L10 is connected to the emitter of the inverter-side A-phase IGBT switch Q9 through series connection with the inverter-side A-phase energy storage inductor L7. The end of the inverter-side A-phase filter inductor L10 away from the inverter-side energy storage inductor L7 is connected to the load through the circuit breaker. The inverter unit further includes an inverter-side B-phase energy storage inductor L8, an inverter-side B-phase filter inductor L11, an inverter-side B-phase filter capacitor C9, an inverter-side B-phase IGBT switch Q11, and an inverter-side B-phase IGBT switch Q12, all configured based on phase B. The two ends of the inverter-side B-phase filter capacitor C9 are connected to the neutral line and the common connection terminal of the inverter-side B-phase energy storage inductor L8 and the inverter-side B-phase filter inductor L11, respectively. The bases of the inverter-side B-phase IGBT switches Q11 and Q12 are connected to the controller, respectively. The emitter of phase B IGBT switch Q11 is connected to the collector of inverter-side phase B IGBT switch Q12. The collector of inverter-side phase B IGBT switch Q11 is connected to the positive voltage terminal of the bus. The emitter of inverter-side phase B IGBT switch Q12 is connected to the negative voltage terminal of the bus. The inverter-side phase B filter inductor L11 is connected to the emitter of inverter-side phase B IGBT switch Q11 through series connection with inverter-side phase B energy storage inductor L8. The end of inverter-side phase B filter inductor L11 away from inverter-side energy storage inductor L8 is connected to the load through the circuit breaker. The inverter unit further includes an inverter-side C-phase energy storage inductor L9, an inverter-side C-phase filter inductor L12, an inverter-side C-phase filter capacitor C10, an inverter-side C-phase IGBT switch Q13, and an inverter-side C-phase IGBT switch Q14, all configured based on the C-phase. The two ends of the inverter-side C-phase filter capacitor C10 are connected to the neutral line and the common connection terminal of the inverter-side C-phase energy storage inductor L9 and the inverter-side C-phase filter inductor L12, respectively. The bases of the inverter-side C-phase IGBT switches Q13 and Q14 are connected to the controller. The emitter of the C-phase IGBT switch Q13 is connected to the collector of the inverter-side C-phase IGBT switch Q14. The collector of the inverter-side C-phase IGBT switch Q13 is connected to the positive voltage terminal of the bus. The emitter of the inverter-side C-phase IGBT switch Q14 is connected to the negative voltage terminal of the bus. The inverter-side C-phase filter inductor L12 is connected to the emitter of the inverter-side C-phase IGBT switch Q13 through series connection with the inverter-side C-phase energy storage inductor L9. The end of the inverter-side C-phase filter inductor L12 away from the inverter-side energy storage inductor L9 is connected to the load through the circuit breaker. The inverter-side IGBT switch group corresponding to the neutral line includes an inverter-side neutral line IGBT switch Q15 and an inverter-side neutral line IGBT switch Q16. The bases of the inverter-side neutral line IGBT switch Q15 and Q16 are respectively connected to the controller. The emitter of the inverter-side neutral line IGBT switch Q15 is connected to the collector of the inverter-side neutral line IGBT switch Q16. The collector of the inverter-side neutral line IGBT switch Q15 is connected to the positive voltage terminal of the bus. The emitter of the inverter-side neutral line IGBT switch Q16 is connected to the negative voltage terminal of the bus. The neutral line is connected to the emitter of the inverter-side neutral line IGBT switch Q15.

[0047] Traditional mechanical voltage regulators (such as tap changer regulators) suffer from slow response speed (seconds) and low regulation accuracy (±5%~±10%), failing to meet high-precision requirements. They are also dependent on grid strength, have low efficiency and relative stability, and are prone to equipment damage and grid failures if the voltage or current is unstable. Furthermore, they cannot address the issue of managing high and low voltage in the grid. In this embodiment, the voltage regulator device is designed with a bidirectional AC / AC module that uses a two-stage three-phase four-bridge-arm topology connected back-to-back. The power transistors are IGBTs, enabling bidirectional power flow. The rectifier unit receives a three-phase four-wire input, boosts it to 750V DC via AC / DC conversion, and then the inverter unit converts it to stable and reliable AC via DC / AC conversion. This AC is then connected in series to the end of the grid line to manage the voltage at the end.

[0048] like Figure 6-8 As shown, the advantages of using a three-phase four-arm topology as a rectifier (rectifier unit) are as follows: All power devices use SICMOS transistors. Using SICMOS transistors for synchronous rectification can achieve rectification effect, improve efficiency, and control Q1~Q8 to generate PMW modulation waves.

[0049] In the rectifier section, C4 / C5 are the bus capacitors, BUS+ / BUS- are the positive and negative bus voltages, Q1~Q8 are SICMOS transistors, L1 / L2 / L3 are the input grid-side inductors, L4 / L5 / L6 are the input PFC inductors, C1 / C2 / C3 are the input AC filter capacitors, and A_IN / B_IN / C_IN are the AC mains input. The rectifier section consists of multiple SICMOS transistors, with two power transistors on each of the four bridge arms (A / B / C / N). Connecting the midpoint divides the section into upper and lower bridge arms. The SICMOS transistors used are 1200V / 17mΩ transistors for AC / DC power conversion. After rectification, the DC bus voltage is 750V. Multiple 450V / 820uF electrolytic capacitors are used for bus capacitors C4 / C5 to stabilize the voltage and ensure bus stability. A 260uH ferrite inductor is used for PFC, and a 20uF 440VAC film capacitor is used for filter capacitor. The switching frequency of the semiconductor power transistor is 32kHz.

[0050] Taking phase A as an example, its working principle is explained as follows: During the positive half-cycle of AC, the timing of Q4 / Q6 / Q7 is controlled, while the other transistors are turned off. The current flows through L1 and L4, then through Q7 to charge the bus capacitors C4 / C5, and then through Q4 / Q5, L2 / L3 / L5 / L6 to return to phases B and C respectively. During the negative half-cycle of AC, the timing of Q3 / Q5 / Q8 is controlled, while the other transistors are turned off. The current in phases B and C flows through L2 / L3 / L5 / L6, then through Q3 / Q5 to charge the bus capacitors C4 / C5, and then through Q8, L1 / L4 to return to phase A respectively.

[0051] For example, in the inverter unit, all power devices use SICMOS transistors to improve efficiency, and control Q9~Q16 to generate PMW modulation waves.

[0052] In the inverter unit, C6 / C7 are the bus capacitors, BUS+ / BUS- are the positive and negative bus voltages, Q9~Q16 are SICMOS transistors, L7 / L8 / L9 are the output AC filter inductors, L10 / L11 / L12 are the output grid-side inductors, C8 / C9 / C10 are the output AC filter capacitors, and A_OUT / B_OUT / C_OUT are the inverter AC outputs. The inverter section also consists of multiple SICMOS transistors, with two power transistors on each of the four bridge arms A / B / C / N. Connecting the midpoint divides the unit into upper and lower bridge arms. 1200V / 17mΩ SICMOS transistors are used for power conversion, i.e., DC / AC. The AC phase voltage after inversion is 220V. Multiple 450V / 820uF electrolytic capacitors are used for bus capacitors C6 / C7 to stabilize the voltage and ensure power output. A 260uH ferrite inductor is used for the inverter filter, and a 20uF 440VAC film capacitor is used for the filter capacitor. The switching frequency of the semiconductor power transistor is 32kHz. The three-phase four-arm inverter adds a neutral current path to unbalanced loads, increases the fourth arm, and increases the degree of freedom, allowing the three-phase four-arm inverter power supply to generate three independent voltages, thus enabling it to maintain symmetrical three-phase output voltages under unbalanced and nonlinear loads.

[0053] Taking phase A as an example, its working principle is explained as follows: Controlling the conduction sequence and time of Q9 / Q12 / Q14, while turning off the other transistors, the current passes through Q9, L7, and C8 for filtering, then through L10 to the load, and then through phases B and C, L8 / L9 / L11 / L12, and finally through transistors Q12 / Q14 to BUS- to form a circuit, thereby generating a 220V sine wave in phase A.

[0054] The bidirectional AC / AC module in this device mainly uses two three-phase four-arm topologies connected back-to-back to convert AC power to DC power through a rectifier. Then, the inverter converts the DC power back to AC power. The device is connected in series to the end-user side of the power grid. If the voltage at the end-user side of the power grid is lower than 220Vac, this device can regulate the voltage at the end to 220Vac to supply the user side, ensuring the stability of the power supply at the user side. That is, the voltage at the end of the power grid is effectively managed. With the bidirectional electronic switch, a millisecond-level switching response can be achieved. With the remote electromechanical switch, the reliability of the device operation and the maintainability of the equipment are improved.

[0055] It should be noted that the controller is connected to the base of the IGBT switch and the gate of the MOSFET to control the opening and closing of the IGBT switch and the MOSFET. The controller can be a PLC controller, a 51 microcontroller, or any existing controller model on the market, such as a DSP (Digital Signal Processor). Its pin connections are set according to the actual model. This is existing technology, and you can refer to the technical manual of the corresponding controller. It will not be elaborated here.

[0056] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of this utility model. It should be understood that the above description is only a specific embodiment of this utility model and is not intended to limit the scope of protection of this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. A voltage regulating device for the end of a power distribution network, installed between a power distribution transformer and a load at the end of the power distribution network, characterized in that, include: A remote electromechanical switch is connected in series between the distribution transformer and the load; A bidirectional electronic switch, wherein the two ends of the bidirectional electronic switch are respectively connected to the two ends of the remote electromechanical switch via a series circuit breaker; A bidirectional AC / AC module, comprising a symmetrically arranged rectifier unit and an inverter unit, wherein the bidirectional AC / AC module is connected in parallel with the bidirectional electronic switch; The controller is electrically connected to the remote electromechanical switch, the bidirectional electronic switch, the bidirectional AC / AC module, and the voltage sensor installed between the distribution transformer and the load.

2. A voltage regulating device for the end of a power distribution network according to claim 1, characterised in that, The bidirectional electronic switch is composed of two unidirectional thyristors connected back-to-back in parallel. The two ends of the bidirectional thyristor are respectively connected to the two ends of the remote electromechanical switch through a series circuit breaker. The gate of the bidirectional thyristor is electrically connected to the controller.

3. A voltage regulating device for the end of a power distribution network according to claim 1, characterized in that, The rectifier unit and inverter unit are T-type three-level circuits arranged symmetrically in series.

4. A voltage regulating device for the end of a power distribution network according to claim 3, characterized in that, The rectifier unit includes a first filter inductor L1, a first filter capacitor C1, a second energy storage inductor L2, a second energy storage capacitor C2, a third energy storage capacitor C3, a first MOSFET Q1, a second MOSFET Q2, a third MOSFET Q3, and a fourth MOSFET Q4. The first filter inductor L1 and the second energy storage inductor L2 are connected in series. One end of the first filter capacitor C1 is connected to the common connection terminal of the first filter inductor L1 and the second energy storage inductor L2. The end of the second energy storage inductor L2 furthest from the first filter inductor L1 is connected to the source of the first MOSFET Q1, the drain of the second MOSFET Q2, and the source of the third MOSFET Q3. The drain of the first MOSFET Q1 and the source of the fourth MOSFET Q4 are connected to the two ends of the second energy storage capacitor C2. The drain of MOSFET Q1 is the positive terminal of the DC bus. The sources of the second MOSFET Q2 and the fourth MOSFET Q4 are respectively connected to the two ends of the third energy storage capacitor C3. The source of the second MOSFET Q2 is the negative terminal of the DC bus, and the source of the fourth MOSFET Q4 is the center point of the DC bus. The drain of the third MOSFET Q3 is connected to the drain of the fourth MOSFET Q4. The end of the first filter capacitor C1 away from the first filter inductor L1 is connected to the center point of the DC bus. The end of the first filter inductor L1 away from the second energy storage inductor L2 is connected to the output terminal of the distribution transformer through the circuit breaker. The gates of the first MOSFET Q1, the second MOSFET Q2, the third MOSFET Q3 and the fourth MOSFET Q4 are connected to the controller.

5. A voltage regulating device for the end of a distribution network according to claim 4, characterized in that, The inverter unit includes a third filter inductor L3, a fourth filter capacitor C4, a fourth energy storage inductor L4, a fifth energy storage capacitor C5, a sixth energy storage capacitor C6, a fifth MOSFET Q5, a sixth MOSFET Q6, a seventh MOSFET Q7, and an eighth MOSFET Q8. The third filter inductor L3 and the fourth energy storage inductor L4 are connected in series. One end of the fourth filter capacitor C4 is connected to the common connection terminal of the third filter inductor L3 and the fourth energy storage inductor L4. The other end of the fourth filter capacitor C4 is connected to the center point of the DC bus. The end of the fourth energy storage inductor L4 furthest from the third filter inductor L3 is connected to the source of the fifth MOSFET Q5, the drain of the sixth MOSFET Q6, and the source of the seventh MOSFET Q7. The drain of the fifth MOSFET Q5 and the source of the eighth MOSFET Q8 are connected to the fifth energy storage inductor L3. The terminals of capacitor C5 are connected, and the drain of the fifth MOSFET Q5 is connected to the positive terminal of the DC bus. The sources of the sixth MOSFET Q6 and the eighth MOSFET Q8 are respectively connected to the terminals of the sixth energy storage capacitor C6. The source of the sixth MOSFET Q6 is connected to the negative terminal of the DC bus. The drain of the seventh MOSFET Q7 is connected to the drain of the eighth MOSFET Q8. The source of the eighth MOSFET Q8 is connected to the center point of the DC bus. The end of the fourth filter capacitor C4 away from the fourth energy storage inductor L4 is connected to the source of the eighth MOSFET Q8. The end of the third filter inductor L3 away from the fourth energy storage inductor L4 is connected to the load through the circuit breaker. The gates of the fifth MOSFET Q5, the sixth MOSFET Q6, the seventh MOSFET Q7, and the eighth MOSFET Q8 are connected to the controller.

6. A voltage regulating device for the end of a power distribution network according to claim 1, characterized in that, The rectifier unit and inverter unit are a three-phase four-bridge-arm circuit arranged symmetrically in series.

7. A voltage regulating device for the end of a power distribution network according to claim 6, characterized in that, The rectifier unit includes a rectifier-side filter inductor, a rectifier-side filter capacitor, a rectifier-side energy storage inductor, a rectifier-side IGBT switch group formed by two rectifier-side IGBT switches connected in series, and two bus capacitors connected in series, all based on the three-phase AC power. It also includes a rectifier-side IGBT switch group formed by two rectifier-side IGBT switches connected in series, based on the neutral line. The ends of the two bus capacitors that are far apart from each other are the positive and negative voltage ends of the bus, respectively. The IGBT switch groups corresponding to each phase of AC power and the neutral line are connected in parallel. Based on each phase of the three-phase AC power, the rectifier-side filter inductor is connected in series with... The rectifier-side energy storage inductor is connected to the midpoint of the rectifier-side IGBT switch group, and the neutral line is connected to the midpoint of the corresponding rectifier-side IGBT switch group. One end of the rectifier-side filter capacitor is connected to the common connection terminal of the rectifier-side energy storage inductor and the rectifier-side filter inductor, respectively. The other end of the rectifier-side filter capacitor is connected to the neutral line. The two ends of the four rectifier-side IGBT switch groups are connected to the positive voltage terminal and the negative voltage terminal of the bus, respectively. The end of the rectifier-side filter inductor furthest from the rectifier-side filter inductor is connected to the output terminal of the distribution transformer through the circuit breaker in series.

8. A voltage regulating device for the end of a power distribution network according to claim 7, characterised in that, The rectifier unit includes a rectifier-side A-phase energy storage inductor L4, a rectifier-side A-phase filter inductor L1, a rectifier-side A-phase filter capacitor C1, a rectifier-side A-phase IGBT switch Q7, and a rectifier-side A-phase IGBT switch Q8, all configured based on phase A. The two ends of the rectifier-side A-phase filter capacitor C1 are connected to the neutral line and the common connection terminal of the rectifier-side A-phase energy storage inductor L4 and the rectifier-side A-phase filter inductor L1, respectively. The bases of the rectifier-side A-phase IGBT switches Q7 and Q8 are connected to the controller. The rectifier-side A-phase IGBT... The emitter of BT switch Q7 is connected to the collector of the rectifier-side A-phase IGBT switch Q8. The collector of the rectifier-side A-phase IGBT switch Q7 is connected to the positive voltage terminal of the bus. The emitter of the rectifier-side A-phase IGBT switch Q8 is connected to the negative voltage terminal of the bus. The rectifier-side A-phase filter inductor L1 is connected to the emitter of the rectifier-side A-phase IGBT switch Q7 through series connection with the rectifier-side A-phase energy storage inductor L4. The end of the rectifier-side A-phase filter inductor L1 away from the rectifier-side energy storage inductor L4 is connected to the output terminal of the distribution transformer through the circuit breaker. The rectifier unit further includes a rectifier-side B-phase energy storage inductor L5, a rectifier-side B-phase filter inductor L2, a rectifier-side B-phase filter capacitor C2, a rectifier-side B-phase IGBT switch Q5, and a rectifier-side B-phase IGBT switch Q6, all configured based on phase B. The two ends of the rectifier-side B-phase filter capacitor C2 are connected to the neutral line and the common connection terminal of the rectifier-side B-phase energy storage inductor L5 and the rectifier-side B-phase filter inductor L2, respectively. The bases of the rectifier-side B-phase IGBT switches Q5 and Q6 are connected to the controller, respectively. The emitter of BT switch Q5 is connected to the collector of the rectifier-side B-phase IGBT switch Q6. The collector of the rectifier-side B-phase IGBT switch Q5 is connected to the positive voltage terminal of the bus. The emitter of the rectifier-side B-phase IGBT switch Q6 is connected to the negative voltage terminal of the bus. The rectifier-side B-phase filter inductor L2 is connected to the emitter of the rectifier-side B-phase IGBT switch Q5 through series connection with the rectifier-side B-phase energy storage inductor L5. The end of the rectifier-side B-phase filter inductor L2 away from the rectifier-side energy storage inductor L5 is connected to the output terminal of the distribution transformer through the circuit breaker. The rectifier unit further includes a rectifier-side C-phase energy storage inductor L6, a rectifier-side C-phase filter inductor L3, a rectifier-side C-phase filter capacitor C3, a rectifier-side C-phase IGBT switch Q3, and a rectifier-side C-phase IGBT switch Q4, all configured based on the C-phase. The two ends of the rectifier-side C-phase filter capacitor C3 are connected to the neutral line and the common connection terminal of the rectifier-side C-phase energy storage inductor L6 and the rectifier-side C-phase filter inductor L3, respectively. The bases of the rectifier-side C-phase IGBT switch Q3 and the rectifier-side C-phase IGBT switch Q4 are connected to the controller. The rectifier-side C-phase IGBT... The emitter of BT switch Q3 is connected to the collector of the rectifier-side C-phase IGBT switch Q4. The collector of the rectifier-side C-phase IGBT switch Q3 is connected to the positive voltage terminal of the bus. The emitter of the rectifier-side C-phase IGBT switch Q4 is connected to the negative voltage terminal of the bus. The rectifier-side C-phase filter inductor L3 is connected to the emitter of the rectifier-side C-phase IGBT switch Q3 through series connection with the rectifier-side C-phase energy storage inductor L6. The end of the rectifier-side C-phase filter inductor L3 away from the rectifier-side energy storage inductor L6 is connected to the output terminal of the distribution transformer through the circuit breaker. The rectifier-side IGBT switch group corresponding to the neutral line includes a rectifier-side neutral line IGBT switch Q1 and a rectifier-side neutral line IGBT switch Q2. The bases of the rectifier-side neutral line IGBT switch Q1 and Q2 are respectively connected to the controller. The emitter of the rectifier-side neutral line IGBT switch Q1 is connected to the collector of the rectifier-side neutral line IGBT switch Q2. The collector of the rectifier-side neutral line IGBT switch Q1 is connected to the positive voltage terminal of the bus. The emitter of the rectifier-side neutral line IGBT switch Q2 is connected to the negative voltage terminal of the bus. The neutral line is connected to the emitter of the rectifier-side neutral line IGBT switch Q1.

9. A voltage regulating device for the end of a power distribution network according to claim 6, wherein, The inverter unit includes inverter-side filter inductors, inverter-side filter capacitors, inverter-side energy storage inductors, inverter-side IGBT switch groups formed by two inverter-side IGBT switches connected in series, and two bus capacitors connected in series, all based on the three-phase AC power. It also includes an inverter-side IGBT switch group formed by two inverter-side IGBT switches connected in series, based on the neutral line. The ends of the two bus capacitors that are far apart from each other are the positive and negative voltage ends of the bus, respectively. The IGBT switch groups corresponding to each phase of AC power and the neutral line are connected in parallel. Based on each phase of the three-phase AC power, the inverter-side filter inductor is connected in series with... The inverter-side energy storage inductor is connected to the midpoint of the inverter-side IGBT switch group, and the neutral line is connected to the midpoint of the corresponding inverter-side IGBT switch group. One end of the inverter-side filter capacitor is connected to the common connection terminal of the inverter-side energy storage inductor and the inverter-side filter inductor, respectively. The other end of the inverter-side filter capacitor is connected to the neutral line. The two ends of the four inverter-side IGBT switch groups are connected to the positive voltage terminal and the negative voltage terminal of the bus, respectively. The end of the inverter-side filter inductor furthest from the inverter-side filter inductor is connected to the output terminal of the distribution transformer through the circuit breaker in series.

10. A voltage regulating device for the end of a power distribution network according to claim 9, wherein, The inverter unit includes an inverter-side A-phase energy storage inductor L7, an inverter-side A-phase filter inductor L10, an inverter-side A-phase filter capacitor C8, an inverter-side A-phase IGBT switch Q9, and an inverter-side A-phase IGBT switch Q10, all configured based on phase A. The two ends of the inverter-side A-phase filter capacitor C8 are connected to the neutral line and the common connection terminal of the inverter-side A-phase energy storage inductor L7 and the inverter-side A-phase filter inductor L10, respectively. The bases of the inverter-side A-phase IGBT switches Q9 and Q10 are connected to the controller. The emitter of phase A IGBT switch Q9 is connected to the collector of inverter-side phase A IGBT switch Q10. The collector of inverter-side phase A IGBT switch Q9 is connected to the positive voltage terminal of the bus. The emitter of inverter-side phase A IGBT switch Q10 is connected to the negative voltage terminal of the bus. The inverter-side phase A filter inductor L10 is connected to the emitter of inverter-side phase A IGBT switch Q9 through series connection with inverter-side phase A energy storage inductor L7. The end of inverter-side phase A filter inductor L10 away from inverter-side energy storage inductor L7 is connected to the load through the circuit breaker. The inverter unit further includes an inverter-side B-phase energy storage inductor L8, an inverter-side B-phase filter inductor L11, an inverter-side B-phase filter capacitor C9, an inverter-side B-phase IGBT switch Q11, and an inverter-side B-phase IGBT switch Q12, all configured based on phase B. The two ends of the inverter-side B-phase filter capacitor C9 are connected to the neutral line and the common connection terminal of the inverter-side B-phase energy storage inductor L8 and the inverter-side B-phase filter inductor L11, respectively. The bases of the inverter-side B-phase IGBT switches Q11 and Q12 are connected to the controller, respectively. The emitter of phase B IGBT switch Q11 is connected to the collector of inverter-side phase B IGBT switch Q12. The collector of inverter-side phase B IGBT switch Q11 is connected to the positive voltage terminal of the bus. The emitter of inverter-side phase B IGBT switch Q12 is connected to the negative voltage terminal of the bus. The inverter-side phase B filter inductor L11 is connected to the emitter of inverter-side phase B IGBT switch Q11 through series connection with inverter-side phase B energy storage inductor L8. The end of inverter-side phase B filter inductor L11 away from inverter-side energy storage inductor L8 is connected to the load through the circuit breaker. The inverter unit further includes an inverter-side C-phase energy storage inductor L9, an inverter-side C-phase filter inductor L12, an inverter-side C-phase filter capacitor C10, an inverter-side C-phase IGBT switch Q13, and an inverter-side C-phase IGBT switch Q14, all configured based on the C-phase. The two ends of the inverter-side C-phase filter capacitor C10 are connected to the neutral line and the common connection terminal of the inverter-side C-phase energy storage inductor L9 and the inverter-side C-phase filter inductor L12, respectively. The bases of the inverter-side C-phase IGBT switches Q13 and Q14 are connected to the controller. The emitter of the C-phase IGBT switch Q13 is connected to the collector of the inverter-side C-phase IGBT switch Q14. The collector of the inverter-side C-phase IGBT switch Q13 is connected to the positive voltage terminal of the bus. The emitter of the inverter-side C-phase IGBT switch Q14 is connected to the negative voltage terminal of the bus. The inverter-side C-phase filter inductor L12 is connected to the emitter of the inverter-side C-phase IGBT switch Q13 through series connection with the inverter-side C-phase energy storage inductor L9. The end of the inverter-side C-phase filter inductor L12 away from the inverter-side energy storage inductor L9 is connected to the load through the circuit breaker. The inverter-side IGBT switch group corresponding to the neutral line includes an inverter-side neutral line IGBT switch Q15 and an inverter-side neutral line IGBT switch Q16. The bases of the inverter-side neutral line IGBT switch Q15 and Q16 are respectively connected to the controller. The emitter of the inverter-side neutral line IGBT switch Q15 is connected to the collector of the inverter-side neutral line IGBT switch Q16. The collector of the inverter-side neutral line IGBT switch Q15 is connected to the positive voltage terminal of the bus. The emitter of the inverter-side neutral line IGBT switch Q16 is connected to the negative voltage terminal of the bus. The neutral line is connected to the emitter of the inverter-side neutral line IGBT switch Q15.

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