Electronic pressure regulating voltage stabilizing device and control method thereof

Abstract

This application relates to the field of power voltage regulation and discloses an electronic voltage regulating device and its control method. It includes a bypass switch module, a bidirectional AC / AC power module, a control module, and a communication module. The bypass switch module includes an electronic bypass switch and a motorized bypass switch connected in parallel. The bidirectional AC / AC power module is connected in series with the motorized bypass switch and includes a first energy storage inductor and a single-stage three-arm topology, comprising a first arm, a second arm, and a third arm. During the positive half-cycle of AC, the first arm and the second arm are connected in series to form a first energy transfer path; during the negative half-cycle of AC, the first arm and the third arm are connected in series to form a second energy transfer path. The control module is connected to the bypass switch module and the bidirectional AC / AC power module respectively, and is used to control the bidirectional AC / AC power module to change and regulate voltage. The communication module is used for remote monitoring and operation. This application has a simple structure and can realize intelligent bidirectional voltage regulation.

Description

Technical Field

[0001] This application relates to the field of power voltage regulation, and in particular to an electronic voltage regulating device and its control method. Background Technology

[0002] With the deepening of my country's new power system construction and the acceleration of urbanization, the operating environment of low-voltage distribution areas, as a crucial link at the end of the power grid, has undergone significant changes. On the one hand, rural and remote areas have long been constrained by hardware conditions such as excessively long power supply radii and thin transmission line diameters. Seasonal and intermittent load fluctuations have led to persistent low-voltage problems at the end of the distribution lines, with some areas experiencing severe voltage deviations from national standards. This not only affects residential electricity consumption but also causes difficulties in starting motors, hindering regional economic development. On the other hand, with the high penetration of distributed photovoltaic power and the integration of new impact loads such as charging piles, the power flow in distribution areas has changed from unidirectional to bidirectional, making bidirectional voltage fluctuations, flicker, and exceeding limits increasingly prominent. The traditional "passive management" model can no longer meet the urgent needs of the new power system for high stability, dynamic response, and precise bidirectional control of end-point voltage quality.

[0003] Currently, traditional methods for addressing voltage issues in low-voltage distribution areas mainly include mechanical tap changers and reactive power compensation devices. Mechanical tap changers regulate voltage by altering transformer taps, but their drawbacks include slow response, low adjustment accuracy, and the risk of arcing due to frequent mechanical contact operation, posing a threat to the long-term reliability of the equipment. Reactive power compensation devices primarily rely on changing the distribution of reactive power to increase voltage. However, their effectiveness is limited for addressing active power voltage drops caused by excessively high resistive loads, and they also cannot handle bidirectional voltage fluctuations. These rigid methods are all insufficient for achieving continuous, bidirectional voltage regulation.

[0004] To overcome the shortcomings of traditional methods, electronic voltage regulators based on power electronics technology have been gradually introduced into existing technologies. However, existing electronic voltage regulators still face technical bottlenecks in practical engineering applications: Firstly, in terms of power conversion topology, most existing devices adopt a two-stage conversion architecture including a DC link (such as published patent documents CN106602888 A and CN 103683473 B), which not only increases energy conversion losses but also restricts the overall lifespan and power density of the equipment due to the introduction of large-capacity electrolytic capacitors on the DC side. Some topologies that use direct AC conversion face current imbalance or bias problems, requiring additional balancing circuits, leading to increased hardware costs and control complexity. Secondly, in terms of mode switching and redundant power supply, existing electronic voltage regulators generally suffer from an inherent contradiction between dynamic response speed and long-term operational reliability. Existing switching mechanisms either fail to meet the stringent requirements of sensitive loads for uninterrupted power supply or introduce additional conduction losses and thermal management pressures. How to reduce equipment thermal failure while ensuring power supply continuity is a systemic blind spot that urgently needs to be overcome in this type of device. Summary of the Invention

[0005] To address the aforementioned technical problems, this application provides an electronic voltage regulating and stabilizing device and its control method.

[0006] Firstly, the electronic voltage regulating and stabilizing device provided in this application adopts the following technical solution: An electronic voltage regulator is configured in series between the grid side and the load side, comprising: a bypass switch module, a bidirectional AC / AC power module, a control module, and a communication module. The bypass switch module includes an electronic bypass switch S2 and a motorized bypass switch S3 connected in parallel. The bidirectional AC / AC power module is connected in series with the motorized bypass switch S3 and includes a first energy storage inductor L1 and a single-stage three-arm topology, comprising a first arm, a second arm, and a third arm. The first energy storage inductor L1 is connected in series between the grid side and the midpoint of the first arm. During the positive half-cycle of AC, the first arm and the second arm are connected in series to form a first energy transfer path; during the negative half-cycle of AC, the first arm and the third arm are connected in series to form a second energy transfer path. The control module... The system is connected to the bypass switch module and the bidirectional AC / AC power module respectively, for real-time acquisition of grid voltage and grid current, and control of the bidirectional AC / AC power module for voltage regulation. When the grid voltage is detected to be within a preset normal voltage range, the system controls the electronic bypass switch S2 to close and the electric bypass switch S3 to open, putting the bidirectional AC / AC power module in standby mode, with the load powered by the grid. When the grid voltage is detected to be lower than a preset lower voltage limit or higher than a preset upper voltage limit, the system controls the electronic bypass switch S2 to open and the electric bypass switch S3 to close, using the bidirectional AC / AC power module for voltage boosting or bucking to stabilize the load-side voltage at a preset target value. The communication module is connected to the control module for remote monitoring and operation.

[0007] By adopting the above technical solutions, the device is connected to the power distribution line in series without modifying the original power distribution line, making it suitable for on-site installation and renovation scenarios in low-voltage distribution areas. The timing coordination of the electronic bypass switch and the electric bypass can achieve zero-interruption switching of the power supply circuit, improving the power supply reliability of sensitive loads. The use of a single-stage bidirectional AC / AC power module without DC links can reduce the energy conversion levels, which is beneficial to reducing conversion losses and improving the power density and service life of the equipment. Based on the three-arm topology, bidirectional power flow and buck-boost regulation are realized, which can be compatible with distributed photovoltaic access and bidirectional power flow scenarios, and can simultaneously address low voltage and overvoltage issues. The control module automatically switches between bypass and voltage regulation modes based on real-time collected voltage and current signals, forming an active voltage management mechanism, improving the response lag and repeated voltage limit exceedance problems caused by traditional passive management. With the communication module, remote monitoring and operation can be realized, which is beneficial to improving the intelligence level of distribution area operation and maintenance and supporting the autonomous operation of the end of the new power system.

[0008] Optionally, the bypass switch module further includes a manual bypass switch S1, which is connected in parallel with the electric bypass switch S3. When the electronic voltage regulator fails or is under maintenance, the manual bypass switch S1 is closed to bypass the device.

[0009] By adopting the above technical solutions, the manual bypass, electric bypass and electronic bypass switches form a triple redundancy structure, which can improve the continuity of power supply and the safety of operation of the device; the manual bypass can directly bypass the whole machine in the event of device failure or maintenance, without affecting the user's normal power supply and improving the convenience of on-site operation and maintenance.

[0010] Optionally, during the positive half-cycle of AC, the switch of the second bridge arm remains on and the switch of the third bridge arm remains off; during the negative half-cycle of AC, the switch of the second bridge arm remains off and the switch of the third bridge arm remains on; throughout the entire AC cycle, the upper and lower bridge arm switches of the first bridge arm are driven in a high-frequency complementary manner, so that the first energy storage inductor L1 alternately stores and releases energy during the high-frequency switching cycle to perform boost or buck regulation.

[0011] By adopting the above technical solution, the topology control logic can be simplified and switching losses can be reduced by configuring the fixed on / off states of the second and third bridge arms respectively in the positive and negative half-cycles of AC. The first bridge arm adopts high-frequency complementary drive, which enables the first energy storage inductor to stably store and release energy in the high-frequency cycle, which is conducive to achieving smooth and continuous buck-boost regulation. This driving method does not require additional current sharing or bias suppression circuits, which helps to reduce control complexity and hardware cost.

[0012] Optionally, the electric bypass switch S3 includes a first set of contactor switches and a second set of contactor switches; when the grid voltage is boosted, the control module controls the first set of contactor switches to close and controls the second set of contactor switches to open, so that the bidirectional AC / AC power module is connected to the main power supply circuit in a forward manner; when the grid voltage is bucked, the control module controls the second set of contactor switches to close and the first set of contactor switches to open, so that the bidirectional AC / AC power module is connected to the main power supply circuit in a reverse manner.

[0013] By adopting the above technical solution, and utilizing different closing combinations of the contactors inside the same set of electric bypass switches, flexible switching between forward and reverse access of bidirectional AC / AC power modules to the main circuit can be achieved without the need to add additional reversing switches or modify hardware wiring. This design enables the device to perform both boost and buck bidirectional regulation functions on a single unit, adapting to the governance needs of bidirectional power flow fluctuations in high-penetration distributed photovoltaic areas, and reducing equipment hardware costs and control complexity.

[0014] Optionally, the bidirectional AC / AC power module further includes a second energy storage inductor L2, and the single-stage three-arm topology further includes a fourth arm, which is connected in parallel with the first arm, and the second energy storage inductor L2 is connected in series between the grid side and the midpoint of the fourth arm.

[0015] By adopting the above technical solution, parallel branches are added to the basic three-bridge topology, which can multiply the power capacity without changing the main control logic. The dual-branch parallel structure disperses the current stress of a single set of switching transistors and energy storage inductors, reduces the heat generation level of the devices and the difficulty of thermal management, and provides an expansion path for the device to evolve to a larger power level.

[0016] Optionally, the PWM drive signal of the fourth bridge arm is 180° out of phase with the PWM drive signal of the first bridge arm, forming an interleaved parallel working mode.

[0017] By adopting the above technical solution, the two bridge arms are driven by an interleaved phase difference of 180°, which can make the high-frequency ripple of the two inductor currents cancel each other out when they are superimposed. The reduction of current ripple helps to reduce the stress of filter devices and improve the quality of output voltage waveform. The interleaved working mode can also improve the current sharing characteristics of the device, reduce EMI interference and improve the overall conversion efficiency.

[0018] Optionally, the control module integrates an adaptive closed-loop current sharing control architecture, which includes: an interval decoupling unit, a dynamic reference generation unit, a symmetric deviation adjustment unit, and a cooperative modulation unit. The interval decoupling unit is used to separate and independently store the branch currents of the first energy storage inductor L1 and the second energy storage inductor L2 according to the positive and negative half-cycles of the power frequency based on the zero-crossing signal of the grid voltage. The dynamic reference generation unit is used to calculate the average current of all parallel branches in each half-cycle and generate independent positive half-cycle current sharing references and negative half-cycle current sharing references. The symmetric deviation adjustment unit is used to calculate the deviation value between the instantaneous current of each branch and the corresponding half-cycle current sharing reference and generate a duty cycle compensation command. The cooperative modulation unit is used to receive the duty cycle compensation command to maintain the basic interleaved phase, and to issue a duty cycle correction amount first when the branch current is unbalanced. When the correction amount reaches the preset boundary, it outputs a phase fine-tuning signal for cooperative compensation.

[0019] By adopting the above technical solutions, the zero-crossing adjustment distortion problem is improved by using positive and negative half-cycle separate references to address the characteristics of direct AC / AC topology bidirectional AC conversion; the masterless peer-to-peer architecture reduces the risk of single-point failure caused by a fault in the main branch in traditional master-slave control, thus improving the system's fault tolerance and redundancy capability; the coordinated adjustment of phase and duty cycle with dual degrees of freedom improves the technical contradiction between current sharing accuracy and interleaved ripple suppression, achieving full-cycle dynamic current sharing while ensuring low ripple output.

[0020] Optionally, the control module also integrates a hierarchical adaptive overcurrent protection mechanism, which includes: a first-level early warning and current limiting logic, triggered when the current of the first energy storage inductor L1 is detected to be slowly rising and the duration exceeds a preset time. The control module clamps the output current within the rated range by dynamically fine-tuning the PWM duty cycle of the first bridge arm without interrupting the voltage regulation process; a second-level stepped power reduction logic, triggered when the overload condition is detected to be continuously aggravated or the current reaches a preset threshold higher than the first level. The control module gradually reduces the output voltage and power using a stepped strategy; when the overload fault is cleared, the control module restores the rated output by gradually increasing the PWM duty cycle of the first bridge arm; and a third-level hard shutdown protection logic, triggered when the current amplitude is detected to exceed a preset limit value and the current change rate meets the sudden increase characteristic. The control module blocks the PWM drive signals of all bridge arms in the bidirectional AC / AC power module and simultaneously controls the electronic bypass switch S2 to close, switching the power supply circuit to bypass state.

[0021] By adopting the above technical solutions, a graded and differentiated response is implemented for overcurrent conditions of varying severity: the first-level current limiting ensures uninterrupted voltage regulation during minor overloads; the second-level stepped power reduction prevents power outages caused by direct shutdowns, and the soft-start recovery mechanism prevents secondary impacts; the third-level hard shutdown, combined with the millisecond-level response of the electronic bypass switch, enables rapid bypassing on the load side under extreme short-circuit faults, constructing a three-dimensional protection system that ensures uninterrupted power supply during minor faults, stress reduction during heavy loads, and power supply protection during severe faults, thereby improving the device's survivability and power supply reliability under complex operating conditions.

[0022] Secondly, the control method for the electronic voltage regulating and stabilizing device provided in this application adopts the following technical solution: A control method for an electronic voltage regulator, applied to the electronic voltage regulator as described in any one of the first aspects, includes the following steps: S1, real-time acquisition of voltage and current signals from the power grid side; S2, determination of whether the voltage signal is within a preset normal voltage range; if so, control the electronic bypass switch S2 to remain closed and control the electric bypass switch S3 to remain open, so that the bidirectional AC / AC power module is in standby mode and the power grid supplies power to the load; S3, if it is determined that the voltage signal is lower than a preset lower voltage limit or higher than a preset upper voltage limit, control the electronic bypass switch S2 to open and control the electric bypass switch S3 to close, and start... The bidirectional AC / AC power module is activated to boost or buck the grid voltage to stabilize the load-side voltage at a preset target value; S4, during the operation of the bidirectional AC / AC power module, the bridge arm channel is switched according to the AC cycle: during the positive half-cycle of AC, the switch of the second bridge arm is kept on and the switch of the third bridge arm is kept off; during the negative half-cycle of AC, the switch of the second bridge arm is kept off and the switch of the third bridge arm is kept on; throughout the entire AC cycle, the upper and lower bridge arm switches of the first bridge arm are driven in a high-frequency complementary manner, so that the first energy storage inductor L1 alternately stores and releases energy.

[0023] By adopting the above technical solutions, closed-loop control based on real-time electrical quantity acquisition can achieve rapid identification and timely response to voltage over-limits; automatic switching between bypass and voltage regulation states helps to reduce device energy consumption while ensuring voltage quality; switching of bridge arm channels according to AC cycles and high-frequency complementary drive make the voltage regulation process smooth and continuous, which can reduce fluctuations on the load side.

[0024] Optionally, when starting the bidirectional AC / AC power module in step S3, a soft-start step is also included: setting the initial duty cycle of the first bridge arm to a preset initial value, and gradually increasing the duty cycle according to a preset slope function; during the increase of the duty cycle, if the current of the first energy storage inductor L1 is detected to exceed a preset current limit value, the increase of the duty cycle is paused; during the soft start, the electronic bypass switch S2 is kept closed until the output voltage stabilizes and reaches a preset target value, after which the electronic bypass switch S2 is opened.

[0025] By adopting the above technical solution, the dual soft-start mechanism, which combines duty cycle ramp control with current closed-loop limiting, suppresses the current inrush and voltage resonance overshoot generated at the moment the power module is put into operation, reducing the electrical impact on the power switch and load; during the soft start period, the electronic bypass switch is kept closed to form parallel power supply, ensuring zero interruption throughout the entire process of switching from bypass mode to voltage regulation mode, and achieving a smooth and seamless transition.

[0026] In summary, this application includes at least one of the following beneficial technical effects: 1. Using a single-stage, DC-free, three-bridge bidirectional AC / AC topology, bidirectional power flow and continuous step-up / step-down are achieved. It eliminates the need for electrolytic capacitors, resulting in lower losses and longer lifespan. It is suitable for low-voltage distributed photovoltaic and bidirectional power flow scenarios, overcoming the inherent defects of traditional two-stage converters and mechanical voltage regulation from the topology level. 2. By automatically switching between the bypass switch module and the power module, proactive real-time management of voltage over-limit is achieved. Combined with the remote communication module, it forms the autonomous capability of the distribution area. The installation and modification are simple, and it takes into account both power supply reliability and intelligent operation and maintenance. 3. By relying on the interleaved parallel extension structure and bidirectional filter branch, the power capacity of the device is increased while the current ripple and harmonic output are reduced. With the standardization of voltage threshold and parameter configuration, the voltage regulation accuracy is higher, the operation is more stable, and the engineering applicability is stronger. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the electronic voltage regulating and stabilizing device provided in the embodiments of this application; Figure 2 Is with Figure 1 The corresponding circuit structure diagram; Figure 3 This is a circuit structure diagram of the bidirectional AC / AC power module provided in the embodiments of this application; Figure 4 This is a PWM timing diagram of each power transistor in the bidirectional AC / AC power module provided in the embodiments of this application; Figure 5 This is a circuit structure diagram of another bidirectional AC / AC power module provided in the embodiments of this application; Figure 6 This is a schematic diagram of the adaptive closed-loop current sharing control architecture provided in the embodiments of this application; Figure 7 This is a flowchart of the control method for the electronic voltage regulating and stabilizing device provided in the embodiments of this application; Figure 8 This is a schematic diagram of the control architecture of the electronic voltage regulating and stabilizing device provided in the embodiments of this application; Figure 9 This is a detailed logic flowchart of the graded protection and control of the electronic voltage regulating and stabilizing device provided in the embodiments of this application.

[0028] Explanation of reference numerals in the attached figures: 10. Electronic voltage regulator; 11. Bypass switch module; 12. Bidirectional AC / AC power module; 13. Control module; 14. Communication module; 20. Power grid; 30. Load. Detailed Implementation

[0029] The following is in conjunction with the appendix Figure 1-9 This application will be described in further detail.

[0030] It should be noted that, in the description of this application, "grid side" refers to the end of the electronic voltage regulator connected to the power distribution network, i.e., the input end of the device, corresponding to the "IN" side in the circuit diagram; "load side" refers to the end of the electronic voltage regulator connected to the user load, i.e., the output end of the device, corresponding to the "OUT" side in the circuit diagram. "Port 1" and "Port 2" refer to the first and second physical connection ends of the bidirectional AC / AC power module itself. "AC positive half-cycle" refers to half a power frequency cycle in which the instantaneous value of the AC voltage is greater than zero; "AC negative half-cycle" refers to half a power frequency cycle in which the instantaneous value of the AC voltage is less than zero. "High-frequency complementary drive" means that the upper and lower transistors in the same bridge arm alternately turn on and off at the switching frequency, and their drive signals are complementary, i.e., when the upper transistor is on, the lower transistor is off, and when the upper transistor is off, the lower transistor is on (excluding dead time). "Series setting" means that the power circuit of the device is connected in series in the power supply line from the grid side to the load side, and the device performs voltage superposition or compensation on the current flowing through it. "Bypass" refers to disconnecting the power conversion stage of the device from the main power supply circuit, allowing the power grid to supply power directly to the load.

[0031] This application provides an electronic voltage regulating device and its control method, which realizes direct conversion of AC voltage through a single-stage bidirectional AC / AC power module without DC link, and achieves continuous, bidirectional and efficient voltage regulation by combining the multiple redundant bypass structure and automatic control strategy in the bypass switch module.

[0032] Reference Figure 1 , Figure 1 This diagram illustrates a module schematic of an electronic voltage regulator 10 provided in an embodiment of this application. The electronic voltage regulator 10 is connected in series between the power grid 20 and the load 30, and includes a bypass switch module 11, a bidirectional AC / AC power module 12, a control module 13, and a communication module 14.

[0033] Specifically, the electronic voltage regulator includes the following components: The bypass switch module 11 is connected between the grid side and the load side, and is used to provide a direct power supply path to the load when the device does not require voltage regulation, and to ensure continuous power supply to the load when the device fails or is under maintenance. The bypass switch module 11 includes an electronic bypass switch S2 and a motorized bypass switch S3 connected in parallel.

[0034] Specifically, the electronic bypass switch S2 is a fast switch based on semiconductor devices, such as a thyristor module connected in anti-parallel or an integrated solid-state relay module. It utilizes the inherent high-speed switching characteristics of semiconductor devices—no mechanical contacts—to achieve millisecond-level on / off response speeds. The electronic bypass switch S2 remains closed when the mains voltage is normal, providing a direct power supply path to the load; it opens when switching to voltage regulation mode is required, switching the power supply circuit to the bidirectional AC / AC power module 12.

[0035] Electric bypass switch S3 is an electromechanical switch, see reference. Figure 2 The electric bypass switch S3 internally includes two sets of contactor switches K1 / K2 and K3 / K4, as well as a current transformer CT2. K1 / K2 and K3 / K4 form two independent access paths, used to control the bidirectional AC / AC power module 12 to connect to the main power supply circuit in a forward or reverse manner. When the electric bypass switch S3 is closed, depending on the different closing combinations of K1 / K2 or K3 / K4, the bidirectional AC / AC power module 12 is connected in series between the grid side and the load side with different wiring directions, thereby realizing forward boost regulation or reverse buck regulation.

[0036] Understandably, the electronic bypass switch S2 and the electric bypass switch S3 serve different functional roles: When the grid voltage is normal, the electronic bypass switch S2 acts as the primary bypass path, utilizing the fast response characteristics of semiconductor devices to quickly switch the power supply circuit during mode switching, preventing power interruption to the load; the electric bypass switch S3 acts as the access path for the power module in voltage regulation mode, utilizing the low on-resistance characteristics of mechanical contacts to carry the entire load current during voltage regulation operation, reducing steady-state conduction losses. The timing coordination between the two enables smooth switching between bypass mode and voltage regulation mode.

[0037] The bidirectional AC / AC power module 12 is connected in series with the electric bypass switch S3. That is, the bidirectional AC / AC power module 12 is connected to the main power supply circuit through K1 / K2 or K3 / K4 inside the electric bypass switch S3. The bidirectional AC / AC power module 12 adopts a single-stage three-bridge topology to achieve direct AC conversion, eliminating the need for intermediate DC links and large-capacity electrolytic capacitors. During operation, this module performs boost or buck compensation on the AC voltage flowing through it, stabilizing the load-side voltage at a preset target value.

[0038] Reference Figure 2 The input terminal of the bidirectional AC / AC power module 12 is connected to the power grid side via internal switch K5, and the output terminal is connected to the electric bypass switch S3 via internal switch K6. K5 and K6 are internal isolating switches of the power module, used to completely isolate the power module from the main circuit when it is in standby or faulty, thereby improving system safety.

[0039] Control module 13 is connected to bypass switch module 11 and bidirectional AC / AC power module 12, respectively. (Refer to...) Figure 2 Preferably, the control module 13 uses a digital signal processor (DSP) as the main control chip. Executable control code runs within the DSP, which collects the grid voltage and current in real time through a data acquisition circuit and outputs PWM drive signals to each switch via a real-time control interface. The control module 13 automatically controls the switching of each switch in the bypass switch module 11, as well as the start / stop and power regulation of the bidirectional AC / AC power module 12, based on the real-time status of the grid voltage.

[0040] Communication module 14, connected to control module 13, is used for remote monitoring and operation of the device. (See reference...) Figure 2 Preferably, the communication module 14 adopts a 4G communication gateway device, which uploads the device's operating data to the remote monitoring platform via the 4G mobile communication network, and simultaneously receives remote control commands and sends them to the control module 13 for execution. The communication module 14 and the control module 13 exchange information through a data interaction interface. The information that can be transmitted includes analog quantities, such as the effective value of the mains voltage, the effective value of the load current, and the effective value of the output voltage; alarm quantities, such as overvoltage alarm, overcurrent alarm, and overtemperature alarm; status quantities, such as the current operating mode and the status of each switch; and setting quantities, such as voltage threshold parameters and target voltage values.

[0041] It is understood that the electronic voltage regulator of this application is installed in the power distribution line in a series connection manner. (Refer to...) Figure 2 The device's input terminal IN is connected to the power grid 20 via line impedance Z1, and its output terminal OUT is connected to the user load 30. The series connection method requires no modification to the existing power distribution line topology; simply select a suitable installation point in the line to connect the device in series. Installation is convenient, and the modification cost is low, making it particularly suitable for on-site deployment in low-voltage distribution areas.

[0042] It should be noted that the above description regarding the use of a DSP in the control module 13 and a 4G gateway in the communication module 14 is only applicable to this application. Figure 2The preferred implementation of the specific embodiment shown is illustrated in other embodiments. In other embodiments, the control module 13 can employ any processing architecture capable of data acquisition, logic operation, and PWM signal generation. For example, in some embodiments, the control module 13 can employ a field-programmable gate array (FPGA) to achieve nanosecond-level high-frequency response control; or a microcontroller (MCU / ARM) to reduce system cost; or a multi-core heterogeneous collaborative control architecture of DSP+FPGA, where the DSP is responsible for complex current sharing and protection algorithms, and the FPGA is responsible for low-level high-speed PWM pulse generation and multi-channel synchronous sampling to adapt to higher power level parallel expansion requirements. Similarly, the specific communication medium and protocol of the communication module 14 can be flexibly replaced according to the actual network environment of the distribution area. For example, in a power distribution room with wired fiber optic or Ethernet coverage, the communication module 14 can use wired Ethernet or RS485 bus communication to improve the stability and anti-interference capability of data transmission; in remote areas without 4G signal coverage, the communication module 14 can use low-power wide-area network (LPWAN) technologies such as LoRa to achieve wireless networking; with the development of communication technology, the communication module 14 can also be smoothly upgraded to a 5G cellular network module or a local Wi-Fi mesh network module.

[0043] In one embodiment, the bypass switch module 11 further includes a manual bypass switch S1. (Refer to...) Figure 1 and Figure 2 The manual bypass switch S1 and the electric bypass switch S3 are connected in parallel. The manual bypass switch S1 is a mechanical disconnect switch or knife switch, which is operated manually by maintenance personnel. The manual bypass switch S1 remains open during normal operation and is only manually closed when the device malfunctions or needs to be shut down for maintenance, bypassing the entire device and allowing the power grid to directly supply power to the load.

[0044] Understandably, the manual bypass switch S1, electronic bypass switch S2, and electric bypass switch S3 form a triple-redundant bypass structure, with their respective functions as follows: the electronic bypass switch S2 is responsible for bypass power supply under normal operating conditions and rapid transition during mode switching; the electric bypass switch S3 is responsible for reliable access of the power module under voltage regulation conditions, and its internal different combinations of K1 / K2 and K3 / K4 also realize flexible switching of forward and reverse access of the power module; the manual bypass switch S1 serves as the final safety guarantee, allowing manual intervention in the event of complete device failure. The coordinated operation of these three switches resolves the inherent contradiction between dynamic response speed and long-term operational reliability in existing technologies.

[0045] Continue to refer to Figure 2 The working modes of the device under different operating conditions are explained.

[0046] Mode 1: Bypass mode (normal grid voltage / standby state).

[0047] When the grid voltage is within the preset normal voltage range, the device operates in bypass mode. At this time, the electronic bypass switch S2 is closed, and K1 / K2 and K3 / K4 inside the electric bypass switch S3 are all open, as are K5 and K6 inside the power module. The power supply path is: grid side IN → electronic bypass switch S2 → load side OUT. The bidirectional AC / AC power module 12 is completely disconnected from the main circuit and is in standby mode; the device itself generates almost no additional losses.

[0048] Mode 2: Voltage regulation mode - forward connection (boost / forward buck).

[0049] When the grid voltage is lower than the preset lower voltage limit and voltage boosting is required, the device switches to forward voltage regulation mode. At this time, electronic bypass switch S2 is open, K1 and K2 inside electric bypass switch S3 are closed (K3 and K4 are open), and K5 and K6 inside the power module are closed. The power supply path is: grid side IN → K1 → K5 → bidirectional AC / AC power module 12 → K6 → K2 → load side OUT. In this access mode, port 1 of the bidirectional AC / AC power module 12 corresponds to the grid side, and port 2 corresponds to the load side. The power module operates in a forward mode, boosting and compensating the grid voltage to stabilize the load-side voltage at the preset target value.

[0050] Mode 3: Voltage regulation mode - reverse access (reverse voltage reduction / overvoltage control).

[0051] When the grid voltage exceeds the preset upper voltage limit, or when reverse voltage reduction regulation is required in distributed photovoltaic backfeeding scenarios, the device switches to reverse voltage regulation mode. At this time, electronic bypass switch S2 is open, and K3 and K4 inside electric bypass switch S3 are closed (K1 and K2 are open), while K5 and K6 are closed. The power supply path is: grid side IN → K3 → K6 → bidirectional AC / AC power module 12 (reverse) → K5 → K4 → load side OUT. In this access mode, the bidirectional AC / AC power module 12 is connected to the main circuit in reverse, realizing voltage regulation in overvoltage control or backfeeding scenarios.

[0052] Understandably, by using different closing combinations of the two sets of contactors K1 / K2 and K3 / K4 inside the electric bypass switch S3, the bidirectional AC / AC power module 12 can be flexibly switched to connect to the main power supply circuit in either forward or reverse directions. This design enables the device to not only address low voltage issues (boost voltage) but also overvoltage issues (buck voltage), is compatible with bidirectional power flow in distributed photovoltaic high-penetration scenarios, and meets the needs of new power systems for precise bidirectional control of end-point voltage.

[0053] It should be noted that Mode 4 is the maintenance bypass mode. When the device malfunctions or requires maintenance, the maintenance personnel manually close the manual bypass switch S1, and the power grid directly supplies power to the load through S1. At this time, the status of all other switches does not affect the power supply.

[0054] In one embodiment, the preset normal voltage range is 209V to 235V; the preset lower voltage limit is 200V; the preset upper voltage limit is 240V; and the preset target voltage is 220V.

[0055] It is understood that the above voltage threshold settings are based on the provisions for 220V single-phase power supply voltage deviation in the national standard GB / T 12325-2008 "Power Quality - Power Supply Voltage Deviation", and are determined in conjunction with the safety margin in engineering practice. The preset normal voltage range is set to 209V~235V. Within this range, the device does not operate, avoiding frequent start-stop due to small voltage fluctuations; when the voltage drops below 200V or exceeds 240V, voltage regulation is triggered. In this application, a certain hysteresis interval is set between the normal voltage range and the start-up threshold (the difference between the lower limit of the normal range 209V and the lower limit of the start-up 200V is 9V, and the difference between the upper limit of the normal range 235V and the upper limit of the start-up 240V is 5V). This hysteresis design can prevent the device from frequently switching on and off when the grid voltage fluctuates slightly near the threshold, extending the service life of the equipment.

[0056] It should be noted that the above voltage threshold parameters can be adjusted and configured according to the actual operating conditions and voltage quality requirements of different transformer substations. Maintenance personnel can remotely modify the parameter settings in the control module 13 through the communication module 14.

[0057] Reference Figure 3 , Figure 3 A circuit diagram of a bidirectional AC / AC power module 12 provided in an embodiment of this application is shown. In one embodiment, the bidirectional AC / AC power module 12 includes a first energy storage inductor L1 and a single-stage three-arm bridge topology.

[0058] Specifically, the single-stage three-arm topology includes a first arm, a second arm, and a third arm. The first arm consists of a series connection of transistors Q1 (upper arm) and Q2 (lower arm), with the midpoint of the first arm being the common connection point of Q1 and Q2. The second arm consists of a series connection of transistors Q3 (upper arm) and Q6 (lower arm), with the midpoint of the second arm being the common connection point of Q3 and Q6. The third arm consists of a series connection of transistors Q4 (upper arm) and Q5 (lower arm), with the midpoint of the third arm being the common connection point of Q4 and Q5. The upper ends of all three arms are connected to the same positive bus node, and the lower ends of all three arms are connected to the same negative bus node.

[0059] The first energy storage inductor L1 is connected in series between the grid side (port 1) and the midpoint of the first bridge arm, and is the energy storage element that realizes the step-up and step-down function. The midpoints of the second and third bridge arms are respectively connected to the input terminals of the second filter inductor L3 on the load side (port 2).

[0060] In one embodiment, all switching transistors are third-generation silicon carbide (SiC) MOSFETs. Preferably, the switching transistor is model SCT012W90G3-4AG with rated parameters of 900V / 12mΩ. Compared to traditional silicon-based devices, silicon carbide MOSFETs have lower on-resistance, faster switching speed, and higher temperature resistance, which can reduce switching losses and conduction losses, enabling the device to achieve high-efficiency operation under high-frequency conditions.

[0061] It is understood that the choice of switching transistor is not limited to silicon carbide MOSFETs. In other embodiments, gallium nitride (GaN) HEMTs or silicon-based superjunction MOSFETs can also be used, as long as the voltage rating and switching speed requirements are met. Multiple switching transistors can also be connected in parallel at each bridge arm position according to the power level requirements to further improve the current carrying capacity of a single bridge arm.

[0062] Reference Figure 3 The bidirectional AC / AC power module 12 also includes a first filter branch and a second filter branch.

[0063] The first filter branch connects the grid side (port 1) to the single-stage three-bridge arm topology and includes the first filter capacitor C1. (Refer to...) Figure 3 The first filter branch is set on the grid side of the bidirectional AC / AC power module 12. Through the synergistic effect of the first energy storage inductor L1 and the first filter capacitor C1, the high-frequency switching ripple generated during the power conversion process is filtered out.

[0064] The second filter branch connects the single-stage three-arm bridge topology to the load side (port 2) and includes a second filter inductor L3 and a second filter capacitor C2. The second filter inductor L3 is connected in series in the power supply line between the bridge arm output and port 2, and the second filter capacitor C2 is connected in parallel between the second filter inductor L3 and the neutral line. The second filter branch is used to filter out high-frequency switching ripple on the load side, ensuring the quality of the voltage waveform from the output to the load.

[0065] Understandably, the design of setting up filter branches on both the grid side and the load side is suitable for applications with bidirectional power flow. When the device operates in boost mode, port 1 is the input and port 2 is the output, with the second filter branch acting as the output filter. When the device operates in reverse access mode, the power flow is reversed, and the first filter branch acts as the output filter. This bidirectional filtering structure ensures that the voltage waveform quality at both ends of the device meets power quality standards regardless of the power flow direction.

[0066] Reference Figure 4 , Figure 4 The diagram shows the PWM timing of each power transistor in the bidirectional AC / AC power module 12 provided in this embodiment. The timing diagram shows, from top to bottom, the waveforms of the input voltage Vin at port 1 and the output voltage Vout at port 2, the drive signal of switch Q2, the drive signal of switch Q1, the drive signals of switches Q3 and Q6, and the drive signals of switches Q4 and Q5.

[0067] Combination Figure 3 and Figure 4 The working principle of the bidirectional AC / AC power module 12 is explained in detail.

[0068] During the positive half-cycle of the AC circuit (Vin>0), the two switches Q3 and Q6 of the second bridge arm remain on, while the two switches Q4 and Q5 of the third bridge arm remain off. (Refer to...) Figure 4 The waveforms of Q3 / Q6 and Q4 / Q5 are shown. Q3 and Q6 remain high (conducting) during the positive half-cycle, while Q4 and Q5 remain low (off). At this time, Q1 and Q2 of the first bridge arm are driven in a high-frequency complementary manner, as shown in the reference diagram. Figure 4 The waveforms of Q1 and Q2 are shown, and their driving pulses alternate in each high-frequency switching cycle.

[0069] In positive boost mode, the specific working process during the positive half-cycle of AC is as follows: When Q2 is on and Q1 is off, the current path on the grid side is: port 1 → L1 → Q2 → Q6 → port 1 (returning to the grid side neutral line), forming an inductor energy storage circuit. During this stage, a positive voltage (equal to the input voltage Vin at port 1) is applied across the first energy storage inductor L1, and the inductor current IL1 increases linearly, storing energy in the inductor.

[0070] When Q2 is off and Q1 is on, the current path on the grid side is: port 1 → L1 → Q1 → Q3 → L3 → port 2 (to the load side), forming an inductor energy release circuit. During this stage, the first energy storage inductor L1 releases the stored energy, and its released voltage is superimposed with the grid side input voltage Vin and output to the load side port 2, achieving a boost effect.

[0071] During the negative half-cycle of the AC circuit (Vin < 0), the two switches Q4 and Q5 of the third bridge arm remain on, while the two switches Q3 and Q6 of the second bridge arm remain off. (Refer to...) Figure 4 Q4 and Q5 remain high during the negative half-cycle, while Q3 and Q6 remain low. Q1 and Q2 of the first bridge arm are also driven in a high-frequency complementary manner, operating symmetrically to the positive half-cycle. When Q1 is on and Q2 is off, the current path is: port 1 → Q5 → Q1 → L1 → port 1, and the first energy storage inductor L1 stores energy.

[0072] When Q1 is off and Q2 is on, the current path is: port 2 → L3 → Q4 → Q2 → L1 → port 1, and the first energy storage inductor L1 releases energy.

[0073] Understandably, referring to Figure 4 A comparison of the waveforms of Vin and Vout shows that the amplitude of the output voltage Vout is greater than that of the input voltage Vin, and the two are in phase and frequency, indicating that the device achieves direct AC voltage boost conversion. The input voltage at port 1 plus the energy storage voltage of inductor L1 is the output voltage at port 2. By adjusting the duty cycle of the first bridge arms Q1 and Q2, the energy stored and released by the first energy storage inductor L1 can be precisely controlled, thereby achieving continuous and precise adjustment of the output voltage.

[0074] The working principle of reverse buck mode is symmetrical to that of forward boost mode. Taking the positive half-cycle of AC as an example: When Q1 is on and Q2 is off, the current path on the load side is: port 2 → L3 → Q3 → Q1 → L1 → port 1, and the first energy storage inductor L1 stores energy.

[0075] When Q1 is off and Q2 is on, the current in the first energy storage inductor L1 flows through the path: port 1 → Q6 → Q2 → L1 freewheeling energy release.

[0076] The voltage reduction process during the negative half-cycle is symmetrical to that during the positive half-cycle, with Q4 and Q5 remaining on and Q3 and Q6 remaining off.

[0077] It should be noted that regardless of whether it is working in the forward direction (boosting) or the reverse direction (buckling), refer to Figure 4The PWM timing diagram shows that throughout the entire AC cycle, Q1 and Q2 of the first bridge arm are always driven in a high-frequency complementary manner, while the second bridge arm (Q3 / Q6) and the third bridge arm (Q4 / Q5) switch according to the positive and negative half-cycles of the AC current. This control method makes the control logic of the topology extremely simple—the control module 13 only needs to determine the on / off state of the second and third bridge arms based on the polarity of the AC voltage, and simultaneously achieve boost or buck regulation by adjusting the duty cycle of the first bridge arm. This eliminates the need for complex multi-dimensional control algorithms, simplifying the topology control logic and reducing switching losses. The high-frequency complementary drive of the first bridge arm enables the first energy storage inductor to stably store and release energy during the high-frequency cycle, facilitating smooth and continuous boost / buck regulation. This driving method eliminates the need for additional current sharing or bias suppression circuits, helping to reduce control complexity and hardware costs.

[0078] In one embodiment, the key electrical parameters of the bidirectional AC / AC power module 12 are as follows: the switching frequency is 20kHz to 80kHz, preferably 40kHz; the inductance of the first energy storage inductor L1 is 100μH; the inductance of the second filter inductor L3 is 50μH; the capacitance of the first filter capacitor C1 and the second filter capacitor C2 are both 40μF, and the withstand voltage is 300V.

[0079] It should be noted that the matching settings of the above parameters take into account the following engineering factors: the switching frequency is selected at 40kHz, which is near the upper limit of the human ear's audible frequency range, preventing the generation of audible noise. At the same time, with the support of the high-frequency performance of the silicon carbide MOSFET, the switching loss is still within an acceptable range. The energy storage inductor L1 is selected with an inductance of 100μH, which can control the inductor current ripple within 20% to 30% of the rated current at a switching frequency of 40kHz, balancing voltage regulation response speed and current waveform quality. The parameter matching of the inductor and filter capacitor can make the cutoff frequency of the LC filter much lower than the switching frequency, ensuring effective filtering of high-frequency ripple. The withstand voltage of the filter capacitor is selected at 300V, which provides sufficient safety margin relative to the rated voltage of 220V, helping to improve the operating stability and service life of the device under complex operating conditions. In addition, the standardized parameter configuration is conducive to device selection and mass production, reducing manufacturing costs.

[0080] Reference Figure 5 , Figure 5 This diagram illustrates the circuit structure of another bidirectional AC / AC power module 12 provided in an embodiment of this application. Figure 3 Compared to the basic topology shown, the bidirectional AC / AC power module 12 in this embodiment also adds a second energy storage inductor L2 and a fourth bridge arm.

[0081] Specifically, the fourth bridge arm consists of switching transistors Q7 (upper transistor) and Q8 (lower transistor) connected in series. The fourth bridge arm is connected in parallel with the first bridge arm; that is, the upper and lower ends of the fourth bridge arm are connected to the same bus node as the upper and lower ends of the first bridge arm, respectively. The second energy storage inductor L2 is connected in series between the grid side and the midpoint of the fourth bridge arm. (Refer to...) Figure 5 The first energy storage inductor L1 is connected to the midpoint of the first bridge arm (Q1 and Q2), and the second energy storage inductor L2 is connected to the midpoint of the fourth bridge arm (Q7 and Q8). The other ends of the two inductors are connected to the grid side after they merge.

[0082] Understandably, the fourth bridge arm forms a parallel structure with the first bridge arm, with each arm connected to the grid side via its respective energy storage inductor (L1 and L2). During operation, the two arms share the power transmission task, with each arm carrying approximately half of the total current, thus reducing the current stress and heat generation of individual switches and inductors. This expansion method increases the device's power transmission capacity without altering the main topology and control logic.

[0083] In one embodiment, the PWM drive signal of the fourth bridge arm is 180° out of phase with the PWM drive signal of the first bridge arm, forming an interleaved parallel working mode.

[0084] Specifically, in the interleaved parallel operation mode, although the first and fourth bridge arms operate with the same switching frequency and duty cycle, their drive pulses are staggered by half a switching cycle on the time axis. When Q1 of the first bridge arm is on (Q2 is off), Q8 of the fourth bridge arm is on (Q7 is off); when Q2 of the first bridge arm is on (Q1 is off), Q7 of the fourth bridge arm is on (Q8 is off).

[0085] Understandably, the interleaved parallel operation mode has a ripple cancellation effect. The current ripple waveforms of the two inductors have the same shape but are 180° out of phase. After superposition at the grid-side junction, the peaks and valleys of the fundamental frequency ripple are staggered, resulting in a relatively smaller amplitude of the total current ripple and an increase in ripple frequency to twice the switching frequency. The reduction in ripple amplitude directly alleviates the current stress and core loss of the input and output filter components; the increase in ripple frequency makes the filter's attenuation effect more significant. Therefore, the interleaved parallel operation mode can improve the output voltage waveform quality, reduce EMI interference levels, and increase overall conversion efficiency without increasing the size of the filter components.

[0086] In one embodiment, the inductance of the second energy storage inductor L2 is the same as that of the first energy storage inductor L1, both being 100μH. The switching transistor of the fourth bridge arm is a silicon carbide MOSFET of the same model and specifications as that of the first bridge arm. The symmetrical parameter configuration ensures the current balance of the two parallel branches, reducing bias current faults caused by parameter inconsistencies.

[0087] It should be noted that the expansion of parallel bridge arms and energy storage inductors in this application is not limited to two sets. In practical engineering applications, multiple sets of bridge arms and corresponding energy storage inductors can be connected in parallel according to the load level and power requirements of the transformer substation, forming a three-way, four-way, or even more-way interleaved parallel structure. When multiple channels are interleaved in parallel, the phase of the PWM drive signal of each bridge arm is evenly distributed within one switching cycle (for example, the phase difference is 120° when three channels are interleaved, and 90° when four channels are interleaved), to achieve the optimal ripple cancellation effect. The control logic remains consistent; only the number of bridge arms needs to be increased and the phase distribution parameters adjusted.

[0088] Reference Figure 5 In this embodiment, the line impedance Z1 on the grid side is also shown. The line impedance Z1 represents the equivalent impedance of the power supply line from the distribution transformer to the device installation point, and is one of the main factors causing low voltage at the end. The device is installed in series after the line impedance Z1 and before the user load, and compensates for the voltage drop caused by the line impedance Z1 by step-up regulation, so that the user side obtains a stable rated voltage.

[0089] In one embodiment, reference is made to Figure 2 The device is also equipped with surge protection devices SPD1 and SPD2, which are respectively installed between the grid side and the load side and the neutral line, to clamp the device in the event of lightning strikes or surge overvoltage. In addition, the device is also equipped with fuses FU1 and FU2, which are respectively installed in the power supply lines on the grid side and the load side, to disconnect the circuit in the event of a short circuit fault, protecting the device and the line safety.

[0090] It should be noted that the electronic voltage regulating and stabilizing device 10 of this application is a single-phase structure. In a three-phase low-voltage power distribution system, one of these devices can be configured for each phase to achieve independent voltage regulation of the three phases, while also having the ability to independently manage the voltage of each phase under three-phase load imbalance conditions.

[0091] It should be noted that, in a preferred embodiment, in order to overcome the parameter mismatch problems caused by the difference in power inductor winding impedance, inconsistent conduction voltage drop of switching devices, and long-term operation temperature rise and aging in actual engineering, the electronic voltage regulating device 10 of this application further constructs an adaptive closed-loop current sharing control architecture based on the above-mentioned interleaved parallel architecture.

[0092] Specifically, refer to Figure 6The current sharing control architecture is integrated within the control module 13 and mainly includes an interval decoupling unit, a dynamic reference generation unit, a peer deviation adjustment unit, and a cooperative modulation unit. Its working mechanism is as follows: First, the interval decoupling unit uses the zero-crossing signal of the grid voltage to separate and store the real-time branch current data of the first energy storage inductor L1 and the second energy storage inductor L2 in intervals according to the positive and negative half-cycles of the power frequency, thereby eliminating the coupling interference caused by the bidirectional alternation of AC. Secondly, the dynamic reference generation unit calculates the average current of all parallel branches in real time within the corresponding half-cycle after separation of the positive and negative half-cycle intervals, thereby generating independent positive half-cycle current sharing references and negative half-cycle current sharing references. Compared with the traditional single reference mode, this mechanism can accurately match the asymmetric characteristics of AC sinusoidal current and solve the adjustment distortion problem near the zero crossing point; Subsequently, a decentralized, masterless control logic is adopted for the equivalence deviation adjustment unit. For the first and fourth bridge arm branches, the deviation values ​​between their instantaneous currents and the corresponding half-cycle dynamic references are calculated independently, and corresponding duty cycle compensation commands are generated based on these deviation values. In this process, the regulators of the two branches are completely equal in status and serve as references to each other. Disturbances in any single branch will not cause the global reference to fail, eliminating the single-point failure risk of the master-slave architecture. It should be noted that the specific technical meaning of the above-mentioned "equal adjustment status and mutual benchmarking" is as follows: In traditional multi-channel parallel current sharing control, a master-slave architecture is typically used. One branch is designated as the master branch, which outputs a current reference signal. The remaining branches act as follower branches, tracking this reference signal to regulate the current. However, if the current sensor in the master branch drifts, the sampling channel malfunctions, or the parameters of the branch shift due to device aging, the output reference signal itself will be biased. All follower branches will then synchronously track an incorrect reference value, leading to global current sharing failure. This can even trigger a cascading failure, causing multiple branches to experience simultaneous overcurrent. In other words, the master-slave architecture carries a single point of failure risk.

[0093] The symmetrical deviation adjustment unit of this application adopts a decentralized, masterless control logic. The mechanism is as follows: the first and fourth bridge arm branches do not distinguish between master and follower branches in the control architecture; their roles in the current sharing adjustment process are completely symmetrical. Specifically, the dynamic reference generation unit calculates the arithmetic mean of the current of all normally operating parallel branches within the corresponding half-cycle interval in real time. This average value serves as a common current sharing reference and is simultaneously sent to the independent deviation regulator of each branch. Each branch's deviation regulator independently compares its instantaneous current with this common current sharing reference, calculates the deviation value, and generates a duty cycle compensation command specific to that branch. During this process, the duty cycle compensation command of any branch is determined solely by its own current deviation and does not depend on the output signal or status information of another branch. Therefore, disturbances in any branch will not be transmitted to another branch through the reference signal.

[0094] Furthermore, when an abnormal current sampling occurs in a branch (for example, the current sensor output of the fourth bridge arm branch exceeds the reasonable range), the dynamic reference generation unit can identify and automatically discard the current data of the abnormal branch, and regenerate the current sharing reference only based on the current value of the remaining normal branch (i.e., the first bridge arm branch). At this time, the deviation regulator of the normal branch continues to work independently based on the updated reference, and the current sharing adjustment process will not fail globally due to a single-path failure. This mechanism enables the system to have N-1 fault tolerance, that is, it allows any one of the N parallel branches to fail without affecting the effectiveness of the overall current sharing control.

[0095] It is understandable that the above-mentioned peer-to-peer current sharing architecture has advantages over the traditional master-slave architecture in the following aspects: First, it eliminates the risk of single point of failure, and the reliability of the system no longer depends on the health status of a specific branch; Second, the controller structure of each branch is exactly the same, eliminating the need to design different control algorithms for the master and slave branches, simplifying the software architecture and reducing debugging complexity; Third, when the device expands its power capacity or adds more parallel branches, the new branches only need to copy the same deviation regulator and connect it to the dynamic reference generation unit, which has strong scalability and does not require re-specifying the master-slave relationship or modifying the control logic of existing branches.

[0096] Finally, the cooperative modulation unit receives the aforementioned duty cycle compensation command. Under basic operating conditions, a fixed 180° staggered phase is maintained between the first and fourth bridge arms to achieve optimal ripple cancellation. When a steady-state current imbalance occurs between branches, the cooperative modulation unit prioritizes issuing a small duty cycle correction for current sharing correction. If the duty cycle correction reaches a preset boundary, the cooperative modulation unit will further output a very small range of phase fine-tuning signals to achieve dual-degree-of-freedom cooperative compensation of phase and duty cycle, ensuring that current sharing adjustment does not destroy the original ripple cancellation effect.

[0097] It is understandable that by integrating the hardware-level multi-interleaved parallel topology with the aforementioned software-level adaptive closed-loop current sharing control architecture, the device of this application achieves high-power capacity expansion while also having the following effects: First, it improves the risk of current imbalance in the open-loop fixed phase-shift mode. Even under harsh conditions such as device parameter deviation or aging drift, it can still ensure the uniform distribution of current stress in each parallel branch, avoid single branch overcurrent breakdown, and improve the long-term reliability of the device. Second, the combination of independent positive and negative half-cycle references and dual-degree-of-freedom coordinated adjustment can correct current imbalance without destroying the high-frequency ripple cancellation effect brought about by the original interleaved parallel connection, thus achieving a balance between low output ripple and high current sharing accuracy, and further optimizing the power supply quality on the load side. Third, the peer-to-peer architecture without master and slave can improve the system's fault tolerance and redundancy. When a single branch experiences sampling anomalies or minor faults, the dynamic reference generation unit can automatically remove abnormal data and quickly reconstruct the reference among the remaining normal branches, ensuring uninterrupted power supply needs in industrial sites.

[0098] Reference Figure 7 , Figure 7 A flowchart of a control method for an electronic voltage regulator device according to an embodiment of this application is shown. This application also discloses a control method for an electronic voltage regulator device, applied to the electronic voltage regulator device in any of the above embodiments, comprising the following steps: Step S1: Real-time acquisition of voltage and current signals from the power grid side.

[0099] Specifically, the digital signal processor (DSP) in control module 13 acquires the instantaneous voltage and current values ​​from the power grid side in real time through a data acquisition circuit. (Refer to...) Figure 2 Voltage acquisition is achieved through voltage sensors connected to the power grid, while current acquisition is achieved through current transformers CT1 and CT2. The sampling frequency is typically several to tens of times the switching frequency to ensure sampling accuracy and control loop bandwidth.

[0100] Understandably, real-time acquisition of voltage signals is used not only to determine whether the grid voltage exceeds limits, but also to perform AC voltage zero-crossing detection when the bidirectional AC / AC power module 12 is operating, providing an accurate phase reference for the switching of bridge arm channels during the positive and negative half-cycles. Current signal acquisition is used for current closed-loop control and overcurrent protection during the power conversion process.

[0101] Step S2: Determine whether the voltage signal is within the preset normal voltage range; if so, control the electronic bypass switch S2 to remain closed and control the electric bypass switch S3 to remain open, so that the bidirectional AC / AC power module is in standby mode and the power is supplied to the load by the power grid.

[0102] Specifically, the control module 13 calculates the effective value of the collected grid voltage and compares the result with a preset normal voltage range (e.g., 209V~235V). If the effective voltage value is within the preset normal voltage range, the control module 13 maintains the closed state of the electronic bypass switch S2, and K1 / K2 and K3 / K4 inside the electric bypass switch S3 remain open. K5 and K6 inside the power module can also be selectively opened as needed. The load directly obtains grid power through the electronic bypass switch S2, and all switches of the bidirectional AC / AC power module 12 remain in the off state (standby state), and the device does not generate additional power consumption.

[0103] Understandably, when the grid voltage is normal, completely disconnecting the power module from the main circuit and placing it in standby mode not only avoids unnecessary switching and conduction losses but also extends the lifespan of power devices and magnetic components. Simultaneously, the load current flows only through the electronic bypass switch S2, resulting in lower steady-state losses.

[0104] Step S3: If the voltage signal is determined to be lower than the preset lower voltage limit or higher than the preset upper voltage limit, control the electronic bypass switch S2 to open, control the electric bypass switch S3 to close, and start the bidirectional AC / AC power module to boost or buck the grid voltage so that the load side voltage is stabilized at the preset target value.

[0105] Specifically, when the control module 13 detects that the effective value of the mains voltage is lower than the preset lower voltage limit (e.g., 200V), it determines that a boost regulation is needed and controls K1 and K2 inside the electric bypass switch S3 to close (K3 and K4 to open), so that the power module is connected to the main circuit in a forward manner. When the effective value of the mains voltage is detected to be higher than the preset upper voltage limit (e.g., 240V), it determines that a buck regulation is needed and controls K3 and K4 to close (K1 and K2 to open), so that the power module is connected to the main circuit in a reverse manner. In either case of exceeding the limit, the control module 13 also simultaneously controls K5 and K6 inside the power module to close, so that the bidirectional AC / AC power module 12 is fully connected to the power supply circuit.

[0106] During the switching from bypass mode to voltage regulation mode, the control module 13 performs the following timing control: First, it controls the corresponding contactor group (K1 / K2 or K3 / K4) of the electric bypass switch S3 to close and K5 and K6 to connect the power module to the main circuit and establish a power supply path; then, it starts the PWM drive signal of the bidirectional AC / AC power module 12; after confirming that the power module output is stable, it controls the electronic bypass switch S2 to open and completely switches the power supply circuit to the power module.

[0107] It is understandable that this application can achieve flexible switching between forward and reverse access of bidirectional AC / AC power modules to the main circuit by using different closing combinations of the contactors inside the same set of electric bypass switches, without the need to add additional reversing switches or modify hardware wiring; this design enables the device to take into account both boost and buck bidirectional regulation functions, adapting to the governance needs of bidirectional power flow fluctuations in high-penetration distributed photovoltaic areas, and reducing equipment hardware costs and control complexity.

[0108] In one embodiment, during the process of the bidirectional AC / AC power module 12 starting from standby state to rated output, the control module 13 executes a soft-start control strategy. Specifically, the soft-start process includes: when the control module 13 activates the PWM drive signals of the first bridge arms Q1 and Q2, it sets the initial duty cycle to a small preset value (preset initial value, for example, 5% to 10%), and then gradually increases the duty cycle according to a preset slope function, so that the stored energy and released energy of the first energy storage inductor L1 gradually increase, and the output voltage rises smoothly from the grid voltage value to the preset target value. The duration of the soft start is determined according to the power level and load characteristics of the system. In a preferred embodiment, the soft start time is 50ms to 200ms.

[0109] Understandably, soft-start control is used to improve device startup safety. When the device switches from bypass mode to voltage regulation mode, the bidirectional AC / AC power module 12 suddenly starts working from standby. If the switching transistor of the first bridge arm is directly driven with the target duty cycle, the first energy storage inductor L1 will experience a current step change from zero to the rated value in a very short time, generating a current overshoot (inrush current) much greater than the steady-state operating value. This inrush current may not only trigger overcurrent protection, leading to startup failure, but also exert excessive electrical stress on the power switching transistor and the energy storage inductor. Repeated occurrences over a long period will accelerate device aging. In addition, the voltage surge caused by the current overshoot may also generate a resonant overshoot through the filter branch, affecting the voltage waveform quality on the load side and impacting sensitive loads (such as precision instruments, frequency converters, etc.).

[0110] In a preferred embodiment, the soft-start process also incorporates current closed-loop limiting control. As the duty cycle gradually increases, the control module 13 continuously monitors the current signal of the first energy storage inductor L1, for example, through current transformer CT1. If the inductor current exceeds a preset current limit value, such as 120% of the rated current, the increase in the duty cycle is paused, and the duty cycle is only increased again after the current falls below the limit value. This dual soft-start mechanism of "duty cycle ramp + current limiting" suppresses the current inrush and voltage resonance overshoot generated at the moment the power module is put into operation, reduces the electrical impact on the power switch and load, and ensures that the device startup process is smooth and controllable under various load conditions, mitigating the adverse effects of startup shocks on devices and loads.

[0111] It is understandable that, in addition to the conventional limiting control during soft start and steady-state voltage regulation, the control module 13 in this embodiment also has a hardware-level rapid response mechanism to deal with sudden severe faults. For example, in actual operating conditions, if an extremely rare load short circuit occurs, causing the inductor current (such as the current collected by the current transformer CT1) to far exceed the normal voltage regulation range, the control module 13 will trigger the highest priority fault fallback action: immediately shutting off and blocking the PWM drive signal of the first bridge arm (Q1 and Q2), forcing the bidirectional AC / AC power module 12 to stop working; at the same time, based on the millisecond-level rapid response characteristics of the electronic bypass switch S2, the control module 13 synchronously controls the electronic bypass switch S2 to close. Since the electronic bypass switch S2 is connected in parallel with the bidirectional AC / AC power module 12, this action realizes seamless bypass switching under fault conditions, and the grid current is transferred to the branch of the electronic bypass switch S2 within microseconds, ensuring that the power supply continuity on the load side is not affected by severe short circuit faults. After the fault is cleared and locked, maintenance personnel can obtain the fault record and troubleshoot through the communication module 14. This mechanism, which integrates rapid fault clearing with bypass switch timing, further enhances the device's survivability and power supply reliability under extreme operating conditions.

[0112] It should be noted that the soft-start control strategy in this application is also linked with the timing control of the bypass switch module 11. During the soft-start process, the electronic bypass switch S2 remains closed, supplying power in parallel with the bidirectional AC / AC power module 12, which is currently ramping up its output, ensuring that the load receives continuous and stable power throughout the entire soft-start process. Only when the control module 13 confirms that the output voltage of the bidirectional AC / AC power module 12 has stably reached the preset target value will it control the electronic bypass switch S2 to open, completing the final switching of the power supply circuit. This linkage mechanism tightly connects the soft-start process with the mode switching process, achieving a smooth transition with zero interruption from bypass power supply to voltage regulation power supply.

[0113] When switching back from voltage regulation mode to bypass mode, control module 13 executes the reverse timing sequence: first, it controls the electronic bypass switch S2 to close, supplying power in parallel with the bidirectional AC / AC power module 12; then, it gradually reduces the duty cycle of the first bridge arm to zero (soft shutdown), so that the output voltage of the bidirectional AC / AC power module 12 slowly drops back to the grid voltage value; after confirming that the bidirectional AC / AC power module 12 has completely stopped power transmission, it shuts off the PWM drive signal, controls K5 and K6 to open and the corresponding contactor group of the electric bypass switch S3 to open, so that the bidirectional AC / AC power module 12 is disconnected from the main circuit.

[0114] Understandably, during the switch from voltage regulation mode back to bypass mode, the power supply continuity is also ensured through the parallel transition between the electronic bypass switch S2 and the bidirectional AC / AC power module 12. The electronic bypass switch S2 is closed and establishes a bypass power supply path before the bidirectional AC / AC power module 12 completely stops working, ensuring that the load power supply is not interrupted during the switching process.

[0115] Step S4: During the operation of the bidirectional AC / AC power module 12, the bridge arm channel is switched according to the cycle of the AC power.

[0116] Specifically, during the positive half-cycle of the AC circuit, the two switches Q3 and Q6 of the second bridge arm are kept on while the two switches Q4 and Q5 of the third bridge arm are kept off; during the negative half-cycle of the AC circuit, the two switches Q3 and Q6 of the second bridge arm are kept off while the two switches Q4 and Q5 of the third bridge arm are kept on; throughout the entire AC cycle, the two switches Q1 and Q2 of the first bridge arm are driven in a high-frequency complementary manner, so that the first energy storage inductor L1 alternately stores and releases energy during the high-frequency switching cycle.

[0117] Understandably, the timing of bridge arm channel switching needs to be precisely synchronized with the zero-crossing point of the AC voltage. Control module 13 determines the start and end times of each half-cycle by performing zero-crossing detection on the acquired AC voltage signal, and completes the switching between the second and third bridge arms near the zero-crossing point. The advantage of zero-crossing switching is that the current flowing through the switching transistor is minimized at the zero-crossing point, and the transient disturbance generated during the switching process is minimized, which helps reduce the transient fluctuations of the output voltage.

[0118] It should be noted that control module 13 employs a closed-loop control strategy during voltage regulation. Control module 13 continuously acquires the output voltage signal from the load side, compares it with a preset target value, calculates the required duty cycle adjustment using a PI (proportional-integral) regulator, and writes the updated duty cycle value into the PWM generation module, achieving real-time tracking and regulation of the output voltage. When the grid voltage fluctuates, the closed-loop controller can adjust the duty cycle within several switching cycles, causing the output voltage to return to the target value, achieving millisecond-level dynamic response.

[0119] It should be noted that during the voltage regulation operation in step S4 above, especially when facing complex operating conditions such as severe fluctuations in grid voltage or sudden load changes, in order to prevent the bidirectional AC / AC power module 12 from being damaged due to abnormal operating conditions, the control module 13 runs a hierarchical adaptive overcurrent protection mechanism in parallel while executing the voltage regulation logic, as the underlying safety guarantee for the voltage regulation process.

[0120] Specifically, this protection mechanism is integrated into the control module 13, and mainly achieves the fusion of voltage regulation and protection through the following architecture: First, at the data acquisition layer, while the control module 13 acquires the signal required for voltage regulation in step S1, it extracts the current amplitude, current change rate, and voltage-current phase relationship of the first energy storage inductor L1 in real time as fault characteristic quantities. Second, at the logic analysis layer, the control module 13 intelligently classifies and identifies overcurrent conditions based on the characteristic quantities: if it is identified as a normal overload with a slow current rise, long duration, and no steep peak, the first-level warning current limiting logic is triggered; if it is identified as a severe overload with a continuously aggravating overload or a current reaching a higher threshold, the second-level stepped power reduction logic is triggered. At the action execution layer, the above protection actions are deeply coupled with the preceding voltage regulation control: for the first-level warning current limiting, the control module... 13 does not interrupt the voltage regulation process. Instead, it clamps the output current within the rated range by dynamically fine-tuning the PWM duty cycle of the first bridge arm (i.e., reducing the modulation ratio) to maintain continuous power supply to the load. For the second-stage stepped power reduction, control module 13 adopts a stepped strategy to gradually reduce the output voltage and power, suppressing device temperature rise. When the severe overload fault is cleared and the rated output needs to be restored, control module 13 automatically calls the aforementioned soft-start control strategy (i.e., duty cycle ramp + current limiting) to achieve smooth recovery. Finally, if the logic judgment layer identifies a severe short-circuit fault with extremely high current amplitude and current change rate meeting the microsecond-level sudden increase characteristics, or detects continuous energy backflow, it triggers the third-stage millisecond-level hard shutdown protection. At this time, control module 13 immediately blocks the PWM drive signals of the first bridge arm and all related bridge arms, and simultaneously controls the electronic bypass switch S2 with millisecond-level response characteristics to close. Utilizing the contactless fast conduction characteristic of S2, the power supply circuit is quickly switched to bypass state within microseconds to ensure uninterrupted power supply to the load side.

[0121] Understandably, through the above design, the control method of this application not only achieves high-precision voltage regulation in steady state, but also constructs a three-dimensional protection system in transient state that ensures uninterrupted power supply in minor faults, stress reduction in severe faults, and bypassing in malignant faults, thereby improving the robustness and survivability of the entire voltage regulation control method under complex industrial conditions.

[0122] Referring to Figure 8, the underlying control logic of the above-mentioned graded protection and voltage regulation fusion method is as follows: the control module 13 synchronously samples and preprocesses the voltage and current signals on the grid side, and identifies the working range of AC voltage by dividing the power frequency range and distinguishing between positive and negative half cycles; then, based on the multi-type overcurrent fault identification algorithm and combined with the graded adaptive overcurrent protection logic, it generates a PWM drive control signal to drive the three-bridge AC / AC topology to complete the voltage transformation, and finally outputs a stable voltage to the load 30 side.

[0123] Furthermore, referring to Figure 9, at the specific execution level of the above control logic, after the device is powered on, it first completes system initialization, sampling calibration, and initial configuration of protection parameters, and then enters the real-time synchronous voltage and current sampling stage; after performing power frequency cycle segmentation, filtering, and decoupling operations on the sampled data, it intelligently identifies the overcurrent fault type and executes the corresponding protection strategy according to the fault level: When no overcurrent is detected, the device maintains normal operation and monitors cyclically, while adaptive threshold optimization is performed based on temperature, aging and zero-crossing conditions. When a common overcurrent fault is detected, such as 1.2 to 1.5 times the rated current, lasting for ≥20ms, the first-level protection is activated, and the fault is suppressed by warning current limiting and dynamic duty cycle current stabilization; if the fault is cleared, normal voltage regulation is automatically restored; otherwise, it switches to severe overcurrent fault handling. When a severe overcurrent fault is detected, such as 1.8 times or more of the rated current for ≥10ms, the secondary protection is activated to suppress the fault through stepped power reduction and stress reduction control; if the fault is cleared, the rated output is restored through soft start; otherwise, it switches to short circuit / energy backflow high-risk fault handling. When a high-risk fault of short circuit / energy backflow is detected, such as more than 2.5 times the rated current, large di / dt, backflow, lasting ≥4ms, the three-level protection is immediately activated. The PWM signal is blocked in milliseconds and hard shutdown protection is performed. Then the fault is locked, the data is recorded, uploaded to the cloud platform, and intelligent self-recovery and self-judgment are performed.

[0124] Understandably, this application implements a graded and differentiated response for overcurrent conditions of varying severity: the first level of current limiting ensures uninterrupted voltage regulation during minor overloads; the second level of stepped power reduction prevents power outages caused by direct shutdowns, and the soft-start recovery mechanism prevents secondary impacts; the third level of hard shutdown, combined with the millisecond-level response of the electronic bypass switch, enables rapid bypassing on the load side under extreme short-circuit faults, constructing a three-dimensional protection system that ensures uninterrupted power supply during minor faults, stress reduction during heavy loads, and power supply protection during severe faults, thereby improving the device's survivability and power supply reliability under complex operating conditions.

[0125] In one embodiment, the power supply circuit switching process also includes a control step involving a manual bypass switch S1: when a fault is detected in the electronic voltage regulator or a maintenance command is received, the manual bypass switch S1 is closed to bypass the entire device. In the manual bypass state, both the bidirectional AC / AC power module 12 and the electronic bypass switch S2 are in the open state, and the power grid directly supplies power to the load through the manual bypass switch S1.

[0126] Understandably, the coordinated control of multiple bypasses can quickly ensure power supply to the load when the device malfunctions, reducing the risk of power outages; the multi-angle switching and protection logic helps to improve the overall safety of the device and the convenience of on-site operation and maintenance.

[0127] In summary, the implementation principle of the electronic voltage regulating device and its control method in this application embodiment is as follows: This device is connected in series to the user side at the end of the power grid. It utilizes a bidirectional AC / AC power module 12 with a single-stage three-bridge topology to directly convert the AC voltage, eliminating the need for intermediate DC links and large-capacity electrolytic capacitors, thus simplifying system control. The control module 13 actively judges the voltage status by real-time acquisition of grid voltage and current, automatically switching between bypass mode and voltage regulation mode. In voltage regulation mode, different closed combinations of K1 / K2 or K3 / K4 within the electric bypass switch S3 enable forward or reverse connection of the power module. Combined with controlling the PWM duty cycle of the first bridge arm, the grid-side port voltage is directly converted to a preset target voltage and output to the load side. The fast response characteristics of the electronic bypass switch S2 in the bypass switch module 11 ensure the continuity of load power supply during mode switching. The linkage between the soft-start strategy and the mode switching timing ensures a smooth and controllable startup process. The manual bypass switch S1 serves as the final safety guarantee, ensuring that the device does not affect user power consumption even in extreme conditions. The communication module 14 enables remote monitoring, data reading, and operation control of the equipment via the network, thereby improving the level of intelligent operation and maintenance of the transformer substation.

[0128] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. An electronic voltage regulator, connected in series between a power grid (20) and a load (30), characterized in that, include: The bypass switch module (11) includes an electronic bypass switch S2 and an electric bypass switch S3 connected in parallel; A bidirectional AC / AC power module (12) is connected in series with the electric bypass switch S3. It includes a first energy storage inductor L1 and a single-stage three-arm topology. The single-stage three-arm topology includes a first arm, a second arm, and a third arm. The first energy storage inductor L1 is connected in series between the power grid (20) and the midpoint of the first arm. During the positive half-cycle of AC, the first arm and the second arm are connected in series to form a first energy transfer path. During the negative half-cycle of the AC circuit, the first bridge arm and the third bridge arm are connected in series to form a second energy transfer path. The control module (13) is connected to the bypass switch module (11) and the bidirectional AC / AC power module (12) respectively. It is used to collect the grid voltage and grid current in real time and control the bidirectional AC / AC power module (12) to change the voltage. When the grid voltage is detected to be within the preset normal voltage range, the electronic bypass switch S2 is closed and the electric bypass switch S3 is opened. The bidirectional AC / AC power module (12) is in standby mode and the load (30) is powered by the grid (20). When the grid voltage is detected to be lower than the preset lower voltage limit or higher than the preset upper voltage limit, the electronic bypass switch S2 is opened and the electric bypass switch S3 is closed. The bidirectional AC / AC power module (12) is used to adjust the voltage by boosting or bucking the voltage so that the voltage of the load (30) is stabilized at the preset target value. The communication module (14) is connected to the control module (13) and is used for remote monitoring and operation.

2. The electronic voltage regulating and stabilizing device according to claim 1, characterized in that, The bypass switch module (11) also includes a manual bypass switch S1, which is connected in parallel with the electric bypass switch S3. When the device malfunctions or is under maintenance, the manual bypass switch S1 is closed to bypass the device.

3. The electronic voltage regulating and stabilizing device according to claim 1, characterized in that, During the positive half-cycle of AC, the switch of the second bridge arm remains on and the switch of the third bridge arm remains off; during the negative half-cycle of AC, the switch of the second bridge arm remains off and the switch of the third bridge arm remains on; throughout the entire AC cycle, the upper and lower bridge arm switches of the first bridge arm are driven in a high-frequency complementary manner, so that the first energy storage inductor L1 alternately stores and releases energy during the high-frequency switching cycle to perform boost or buck regulation.

4. The electronic voltage regulating and stabilizing device according to claim 1, characterized in that, The electric bypass switch S3 includes a first set of contactor switches and a second set of contactor switches. When the grid voltage is boosted, the control module (13) controls the first set of contactor switches to close and controls the second set of contactor switches to open, so that the bidirectional AC / AC power module (12) is connected to the main power supply circuit in a positive manner. When the grid voltage is reduced, the control module (13) controls the second set of contactor switches to close and the first set of contactor switches to open, so that the bidirectional AC / AC power module (12) is connected to the main power supply circuit in reverse.

5. The electronic voltage regulating and stabilizing device according to claim 1, characterized in that, The bidirectional AC / AC power module (12) also includes a second energy storage inductor L2, and the single-stage three-arm topology also includes a fourth arm, which is connected in parallel with the first arm. The second energy storage inductor L2 is connected in series between the power grid (20) and the midpoint of the fourth arm.

6. The electronic voltage regulating and stabilizing device according to claim 5, characterized in that, The PWM drive signal of the fourth bridge arm is 180° out of phase with the PWM drive signal of the first bridge arm, forming an interleaved parallel working mode.

7. The electronic voltage regulating and stabilizing device according to claim 6, characterized in that, The control module (13) integrates an adaptive closed-loop current sharing control architecture, which includes: The interval decoupling unit is used to separate and store the branch currents of the first energy storage inductor L1 and the second energy storage inductor L2 according to the positive and negative half-cycles of the power frequency based on the zero-crossing signal of the grid voltage. The dynamic reference generation unit is used to calculate the average current of all parallel branches in each half-cycle and generate independent positive half-cycle current sharing references and negative half-cycle current sharing references. The equal deviation adjustment unit is used to calculate the deviation value between the instantaneous current of each branch and the corresponding half-cycle current sharing reference, and generate duty cycle compensation command. The cooperative modulation unit is used to receive the duty cycle compensation command to maintain the basic interleaved phase, and to send the duty cycle correction amount first when the branch current is unbalanced. When the correction amount reaches the preset boundary, it outputs the phase fine-tuning signal for cooperative compensation.

8. The electronic voltage regulating and stabilizing device according to any one of claims 1-7, characterized in that, The control module (13) also integrates a hierarchical adaptive overcurrent protection mechanism, which includes: The first-level warning current limiting logic is triggered when the current of the first energy storage inductor L1 is detected to rise slowly and the duration exceeds the preset time. The control module (13) clamps the output current within the rated range by dynamically fine-tuning the PWM duty cycle of the first bridge arm without interrupting the voltage regulation process. The second-level stepped power reduction logic is triggered when the overload condition is detected to be continuously aggravated or the current reaches a preset threshold higher than that of the first level. The control module (13) adopts a stepped strategy to gradually reduce the output voltage and power. When the overload fault is cleared, the control module (13) restores the rated output by gradually increasing the PWM duty cycle of the first bridge arm. The third-level hard shutdown protection logic is triggered when the current amplitude exceeds the preset limit and the current change rate meets the sudden increase characteristic. The control module (13) blocks the PWM drive signal of all bridge arms in the bidirectional AC / AC power module (12) and synchronously controls the electronic bypass switch S2 to close, switching the power supply circuit to bypass state.

9. A control method for an electronic voltage regulator, applied to the electronic voltage regulator as described in any one of claims 1 to 8, characterized in that, Including the following steps: S1. Real-time acquisition of voltage and current signals from the power grid (20); S2. Determine whether the voltage signal is within the preset normal voltage range; if so, control the electronic bypass switch S2 to remain closed and control the electric bypass switch S3 to remain open, so that the bidirectional AC / AC power module (12) is in standby mode and the power grid (20) supplies power to the load (30); S3. If it is determined that the voltage signal is lower than the preset lower voltage limit or higher than the preset upper voltage limit, control the electronic bypass switch S2 to open, control the electric bypass switch S3 to close, and start the bidirectional AC / AC power module (12) to boost or deboost the grid voltage so that the voltage on the load (30) side is stabilized at the preset target value. S4. During the operation of the bidirectional AC / AC power module (12), the bridge arm channel is switched according to the AC cycle: during the positive half-cycle of AC, the switch of the second bridge arm is kept on and the switch of the third bridge arm is kept off; during the negative half-cycle of AC, the switch of the second bridge arm is kept off and the switch of the third bridge arm is kept on; throughout the entire AC cycle, the upper bridge arm switch and the lower bridge arm switch of the first bridge arm are driven in a high-frequency complementary manner, so that the first energy storage inductor L1 alternately stores and releases energy.

10. The control method of the electronic voltage regulating and stabilizing device according to claim 9, characterized in that, When starting the bidirectional AC / AC power module (12) in step S3, a soft-start step is also included: Set the initial duty cycle of the first bridge arm to a preset initial value, and gradually increase the duty cycle according to a preset slope function; During the increase of the duty cycle, if the current of the first energy storage inductor L1 is detected to exceed the preset current limit value, the increase of the duty cycle is paused; during the soft start, the electronic bypass switch S2 is kept closed until the output voltage stabilizes and reaches the preset target value, after which the electronic bypass switch S2 is opened.

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