NBI ion source suppressor power supply based on cascaded phase-shifted BUCK voltage regulator circuit

Abstract

The present application relates to the technical field of nuclear fusion neutral beam high-voltage power supply suppression electrode control, in particular to an NBI ion source suppression electrode power supply based on a cascaded BUCK voltage stabilizing circuit, which is composed of a multi-winding isolation transformer, multiple sets of phase-shifted BUCK voltage stabilizing units and PSM cascaded units to form an NBI ion source suppression electrode power supply with a three-level topology, wherein the multiple sets of phase-shifted BUCK circuits are connected in series and work in phase shift, and the multiple paths of ripple waves are complementary and offset, and compared with a single-stage voltage stabilizing topology, the output ripple coefficient is reduced by more than 60%; in combination with multi-channel closed-loop precise feedback regulation, the voltage stabilizing precision is greatly improved, the ion source suppression electrode micro-voltage regulation and control requirement can be precisely matched, the beam current jitter and ion deviation problems are largely solved, and the NBI beam quality and transmission efficiency are significantly improved.

Description

Technical Field

[0001] This invention relates to the field of high-voltage power supply suppression electrode control technology for nuclear fusion neutral beam, specifically an NBI ion source suppression electrode power supply based on a cascaded out-of-phase BUCK voltage regulator circuit. Background Technology

[0002] The neutral beam injection system is the core heating and driving equipment of a nuclear fusion device. The ion source suppressor power supply, as a key supporting power supply unit for the neutral beam injection ion source, mainly provides a precise and stable high-voltage DC bias voltage for the suppressor. This is used to constrain the ion beam trajectory, suppress reverse electron backflow, and ensure the ion beam extraction quality and beam stability. Its output voltage accuracy, ripple characteristics, dynamic response speed, and operational reliability directly determine the overall working efficiency of the neutral beam injection system.

[0003] Currently, most neutral beam injection suppressor power supplies employ single-frequency rectification and voltage regulation, single-stage DC-DC regulation, or ordinary series switch voltage regulation topologies, which have many inherent defects in practical engineering applications:

[0004] 1. Large output ripple and low voltage regulation accuracy: The single-stage voltage regulation structure has a limited adjustment bandwidth, which cannot meet the high precision and low ripple requirements of the ion source to suppress the minimum voltage. Ripple noise can easily cause ion beam deviation and beam jitter, reducing the utilization efficiency of nuclear fusion beam.

[0005] 2. Slow dynamic response: When faced with transient fluctuations in the ion source load and disturbances in high-voltage operating conditions, the traditional topology has a slow adjustment speed and cannot quickly correct the output voltage deviation. It is prone to instability of the suppressor voltage, which can lead to reverse electron overload and ion source arcing failure.

[0006] 3. Poor withstand voltage and power scalability: The withstand voltage level of single-stage power modules is limited. Under high voltage conditions, the stress concentration of devices leads to high device losses and high failure rates, making it difficult to adapt to the iteration requirements of high-power and high-voltage NBI ion sources.

[0007] 4. Insufficient isolation and safety: Some power supply topologies without power frequency pre-isolation have direct coupling between the high-voltage side and the power grid. Power grid disturbances and surges can easily enter the precision cavity equipment of the ion source, posing a safety hazard of breakdown and burnout of core components.

[0008] 5. Poor switching response matching: Traditional low-speed switching modules cannot match the rapid start-up and shutdown and transient suppression conditions of ion sources. Switching delays can easily lead to beam suppression failure.

[0009] In summary, existing NBI ion source suppressor power supplies have technical shortcomings such as insufficient voltage regulation accuracy, slow dynamic response, high ripple coefficient, poor safety isolation, and weak adaptability to operating conditions. They are unable to meet the operational requirements of the new generation of high-parameter, high-stability nuclear fusion NBI systems, and there is an urgent need for a dedicated power supply solution with a completely new topology architecture. Summary of the Invention

[0010] The purpose of this invention is to provide an NBI ion source suppression electrode power supply based on a cascaded out-of-phase BUCK voltage regulator circuit, addressing the aforementioned problems.

[0011] The technical solution adopted in this invention is as follows: an NBI ion source suppressor power supply based on a cascaded staggered BUCK voltage regulator circuit, which is suitable for supplying power to the NBI suppressor in high current second-level pulse high voltage power supply scenarios, including a multi-winding isolation transformer and multiple voltage regulation and output modules;

[0012] The primary input terminal of the multi-winding isolation transformer is connected to the industrial power frequency AC grid, and the secondary output terminal of the multi-winding isolation transformer outputs isolated AC power.

[0013] Each of the voltage regulation and output modules includes a phase-shifted BUCK voltage regulator unit and a PSM cascade unit;

[0014] The phase-shifting BUCK voltage regulator unit is connected to the secondary output terminal of the multi-winding isolation transformer and is used to rectify and filter the output isolated AC power.

[0015] The PSM cascade unit is connected in series at the output end of the phase-shifting BUCK voltage regulator unit, and is used to quickly complete the path opening, closing and transient voltage fine-tuning.

[0016] Furthermore, the number of independent windings and the number of voltage regulation and output modules on the secondary side of the multi-winding isolation transformer are equal.

[0017] Furthermore, the staggered BUCK voltage regulator units in the multiple voltage regulation and output modules are driven by staggered phases, and the phases of the drive signals are uniformly staggered by a fixed angle.

[0018] Furthermore, the multi-winding isolation transformer adopts a fully insulated encapsulation structure.

[0019] Furthermore, the phase-shifting BUCK regulator unit includes an uncontrolled rectifier circuit, a filter circuit, and a phase-shifting BUCK regulator circuit.

[0020] The uncontrolled rectifier circuit is used to convert the isolated AC power into pulsating DC power to provide DC input for the subsequent DC voltage regulator circuit.

[0021] The filter circuit is used to smooth the pulsating DC output from the rectifier, filter out the power frequency ripple and harmonic components generated during the rectification process, and obtain a stable DC bus voltage.

[0022] The phase-shifting BUCK voltage regulator circuit is used to convert the input DC bus voltage into a continuously adjustable stable output voltage and match the accuracy requirements of the suppression bias voltage.

[0023] Furthermore, the PSM cascade unit includes a sub-module control circuit, which is used to quickly complete the path turn-on, turn-off and transient voltage fine-tuning.

[0024] Furthermore, the uncontrolled rectifier module includes a three-phase uncontrolled diode rectifier bridge;

[0025] The filtering module includes an input filtering capacitor;

[0026] The sub-module control module includes a module output IGBT and a module output freewheeling diode;

[0027] The phase-shifted BUCK voltage regulator module includes a BUCK main switch IGBT, a BUCK freewheeling diode, a BUCK filter inductor, and a BUCK output filter capacitor;

[0028] The three-phase output terminals of the secondary winding of the multi-winding isolation transformer are respectively connected to the three AC input terminals of the three-phase uncontrolled diode rectifier bridge;

[0029] The positive DC output terminal of the three-phase uncontrolled diode rectifier bridge is connected to the positive terminal of the filter capacitor, and the negative DC output terminal of the three-phase uncontrolled diode rectifier bridge is connected to the negative terminal of the input filter capacitor.

[0030] The positive terminal of the input filter capacitor is connected to the collector of the BUCK main switch IGBT, and the negative terminal of the input filter capacitor is connected to the anode of the BUCK freewheeling diode.

[0031] The emitter of the BUCK main switch IGBT is connected to the cathode of the BUCK freewheeling diode and the BUCK filter inductor, respectively.

[0032] The other end of the BUCK filter inductor is connected to the positive terminal of the BUCK output filter capacitor;

[0033] The negative terminal of the BUCK output filter capacitor is connected to the negative terminal of the input filter capacitor, and the positive terminal of the BUCK output filter capacitor is connected to the collector of the module output IGBT.

[0034] The beneficial effects of the present invention include at least one of the following;

[0035] 1. A three-stage topology NBI ion source suppression electrode power supply is constructed by setting up a multi-winding isolation transformer, multiple sets of phase-shifted BUCK voltage regulator units, and PSM cascaded units. The multiple sets of phase-shifted BUCK circuits operate in series with phase shifts, and the multiple ripples complement and cancel each other out. Compared with a single-stage voltage regulator topology, the output ripple coefficient is reduced by more than 60%. With the addition of multi-channel closed-loop precise feedback regulation, the voltage regulation accuracy is greatly improved. It can accurately match the small voltage regulation requirements of the ion source suppression electrode, which largely solves the problems of beam jitter and ion deviation, and significantly improves the beam quality and transmission efficiency of NBI.

[0036] 2. The phase-shifting BUCK voltage regulator unit enables precise control of static parameters, and the high-speed PSM cascade unit achieves nanosecond-level transient response. The dual-structure collaboration can quickly respond to extreme conditions such as ion source load fluctuations, transient arcing, and beam start-up and shutdown, and correct output voltage deviations in real time. Its dynamic anti-disturbance capability far exceeds that of traditional power supplies, significantly reducing the probability of ion source failure and shutdown.

[0037] 3. The phase-shifted BUCK voltage regulator unit, combined with the PSM cascade unit, disperses the high-voltage output stress to multiple sub-modules, avoiding high-voltage stress concentration in a single device, reducing device losses and breakdown risk, and significantly improving the stability of high-voltage, high-power operation of the power supply; at the same time, the output voltage and power level can be flexibly expanded by increasing or decreasing the number of series modules to adapt to the iterative needs of different specifications of NBI ion source equipment.

[0038] 4. The front-mounted multi-winding isolation transformer achieves complete electrical isolation, completely isolating the interference of power grid harmonics, surges, and voltage fluctuations, avoiding damage to precision ion source equipment under abnormal power grid conditions, improving the overall operational safety and reliability of the nuclear fusion device, and adapting to the stringent electromagnetic compatibility conditions of laboratories and nuclear fusion devices.

[0039] 5. The modular design reduces the workload of components by distributing stress in the modules, and the phase-shifting operation mode reduces overall heat loss, resulting in a significant reduction in equipment failure rate. The modular series structure facilitates fault location and individual replacement without the need for overall disassembly and maintenance, greatly reducing the difficulty and cost of later operation and maintenance. Attached Figure Description

[0040] Figure 1 This is a power supply diagram of the NBI ion source suppressor electrode based on a cascaded out-of-phase BUCK regulator circuit;

[0041] Figure 2 This is a topology diagram of a phase-shifted BUCK voltage regulator unit and a PSM cascade unit. Detailed Implementation

[0042] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described in the accompanying drawings can generally be arranged and designed in various different configurations.

[0043] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0044] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other.

[0045] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0046] like Figure 1 As shown, an NBI ion source suppressor power supply based on a cascaded staggered BUCK voltage regulator circuit is suitable for supplying power to the NBI suppressor in high-current, second-level pulse high-voltage power supply scenarios. It includes a multi-winding isolation transformer and multiple voltage regulation and output modules.

[0047] The primary input terminal of the multi-winding isolation transformer is connected to the industrial power frequency AC grid, and the secondary output terminal of the multi-winding isolation transformer outputs isolated AC power.

[0048] Each of the voltage regulation and output modules includes a phase-shifted BUCK voltage regulator unit and a PSM cascade unit;

[0049] The phase-shifting BUCK voltage regulator unit is connected to the secondary output terminal of the multi-winding isolation transformer and is used to rectify and filter the output isolated AC power.

[0050] The PSM cascade unit is connected in series at the output end of the phase-shifting BUCK voltage regulator unit, and is used to quickly complete the path opening, closing and transient voltage fine-tuning.

[0051] The purpose of this design is to create a three-stage NBI ion source suppression electrode power supply by setting up a multi-winding isolation transformer, multiple sets of phase-shifted BUCK voltage regulator units, and PSM cascaded units. The multiple sets of phase-shifted BUCK circuits operate in series with phase shifts, and the multiple ripples complement and cancel each other out. Compared with a single-stage voltage regulator topology, the output ripple coefficient is reduced by more than 60%. With the addition of multi-channel closed-loop precise feedback regulation, the voltage regulation accuracy is greatly improved, which can accurately match the tiny voltage regulation requirements of the ion source suppression electrode, largely solving the problems of beam jitter and ion drift, and significantly improving the NBI beam quality and transmission efficiency.

[0052] Meanwhile, the phase-shifting BUCK voltage regulator unit enables precise control of static parameters, and the high-speed PSM cascade unit achieves nanosecond-level transient response. The dual-structure collaboration can quickly respond to extreme conditions such as ion source load fluctuations, transient arcing, and beam start-up and shutdown, and correct output voltage deviations in real time. Its dynamic anti-disturbance capability far exceeds that of traditional power supplies, significantly reducing the probability of ion source failure and shutdown.

[0053] Furthermore, the phase-shifted BUCK voltage regulator unit, combined with the PSM cascade unit, disperses the high-voltage output stress to multiple sub-modules, avoiding high-voltage stress concentration in a single device, reducing device losses and breakdown risks, and significantly improving the stability of high-voltage, high-power operation of the power supply. At the same time, the output voltage and power levels can be flexibly expanded by increasing or decreasing the number of series modules to adapt to the iterative needs of NBI ion source equipment of different specifications.

[0054] Furthermore, the front-mounted multi-winding isolation transformer achieves complete electrical isolation, thoroughly isolating grid harmonics, surges, and voltage fluctuations from interference, preventing damage to precision ion source equipment under abnormal grid conditions, improving the overall operational safety and reliability of the nuclear fusion device, and adapting to the stringent electromagnetic compatibility conditions of laboratories and nuclear fusion devices.

[0055] Meanwhile, in this embodiment, the number of independent windings and the number of voltage regulation and output modules on the secondary side of the multi-winding isolation transformer are equal.

[0056] Meanwhile, the multi-winding isolation transformer adopts a fully insulated encapsulation structure.

[0057] In practical applications, as a core isolation component at the front end of the system, a customized multi-winding isolation transformer with industrial frequency is used. The primary input is connected to the industrial frequency AC power grid, and the secondary output outputs an isolated AC voltage. The transformer adopts a fully insulated encapsulated structure to achieve complete electrical isolation between the power grid side and the downstream high-voltage stabilization and switching units, isolating interference signals such as power grid surges, harmonics, and voltage fluctuations. At the same time, it improves the insulation withstand voltage level under high-voltage conditions, eliminates the risk of high-low voltage crosstalk, and provides a clean and isolated input power supply for the downstream circuits.

[0058] In this embodiment, the staggered BUCK voltage regulator units in the multiple voltage regulation and output modules are driven by staggered phases, and the phases of the driving signals are uniformly staggered by a fixed angle.

[0059] In practical applications, the AC voltage output from the power frequency isolation transformer is rectified and filtered before being connected to a series structure of multiple staggered-phase BUCK voltage regulator units. The circuits in these multiple staggered-phase BUCK voltage regulator units employ a staggered-phase drive strategy, with the phases of the switching transistor drive signals in each sub-circuit uniformly staggered by a fixed angle. Each staggered-phase BUCK voltage regulator unit independently performs voltage reduction and regulation functions, and the overall output voltage level is improved through series stacking. The staggered-phase operating mode enables the mutual cancellation of multiple current ripples, significantly reducing the overall output voltage and current ripple. Simultaneously, a closed-loop sampling feedback circuit is used to collect the voltage and current signals at the power output terminal in real time, dynamically correcting the duty cycle of each BUCK circuit to achieve high-precision voltage regulation under full load conditions.

[0060] In this embodiment, multiple high-speed power switching modules are connected in series at the output of the phase-shifted BUCK voltage regulator unit to form a high-speed series-connected switch regulation array. The high-speed switching modules employ high-frequency, fast-switching devices with microsecond-level switching response speeds, enabling rapid path switching, turn-off, and transient voltage fine-tuning based on the NBI ion source's operating timing and beam status feedback signals. The switching modules work in conjunction with the circuitry in the phase-shifted BUCK voltage regulator unit. The voltage regulator unit is responsible for static high-precision voltage regulation and ripple suppression, while the high-speed switching unit is responsible for dynamic transient adjustment and rapid start-stop control. The two units work together to achieve static high-precision stability and dynamic rapid response of the suppressor voltage.

[0061] In practical use, such as Figure 2 As shown, a topology of a phase-shifted BUCK regulator unit and a PSM cascade unit is provided, including an uncontrolled rectifier module, a filter module, a phase-shifted BUCK regulator module, and a sub-module control module.

[0062] The uncontrolled rectifier module includes a three-phase uncontrolled diode rectifier bridge, the filter module includes an input filter capacitor, the sub-module control module includes a module output IGBT and a module output freewheeling diode, and the phase-shifting BUCK voltage regulator module includes a BUCK main switch IGBT, a BUCK freewheeling diode, a BUCK filter inductor, and a BUCK output filter capacitor.

[0063] The three-phase output terminals of the secondary winding of the multi-winding isolation transformer are respectively connected to the three AC input terminals of the three-phase uncontrolled diode rectifier bridge;

[0064] The positive DC output terminal of the three-phase uncontrolled diode rectifier bridge is connected to the positive terminal of the filter capacitor, and the negative DC output terminal of the three-phase uncontrolled diode rectifier bridge is connected to the negative terminal of the input filter capacitor.

[0065] The positive terminal of the input filter capacitor is connected to the collector of the BUCK main switch IGBT, and the negative terminal of the input filter capacitor is connected to the anode of the BUCK freewheeling diode.

[0066] The emitter of the BUCK main switch IGBT is connected to the cathode of the BUCK freewheeling diode and the BUCK filter inductor, respectively.

[0067] The other end of the BUCK filter inductor is connected to the positive terminal of the BUCK output filter capacitor;

[0068] The negative terminal of the BUCK output filter capacitor is connected to the negative terminal of the input filter capacitor, and the positive terminal of the BUCK output filter capacitor is connected to the collector of the module output IGBT.

[0069] The purpose of this design is to ensure that, based on the uncontrolled rectifier module, filter module, phase-shifted BUCK voltage regulator module, sub-module control module, and necessary bypass switch topology, the module output IGBT remains on during normal voltage regulation. The sub-module control module outputs a PWM signal to drive the BUCK main switch IGBT, and the output voltage can be continuously adjusted from 0 to the rated value by adjusting the PWM duty cycle. At the same time, the BUCK filter inductor and the output filter capacitor work together to filter out switching ripple.

[0070] In the module bypass state, the submodule control module simultaneously turns off the BUCK main switch IGBT and the module output IGBT. The current in the PSM cascade link flows through the module output freewheeling diode, making the output voltage of this module approximately 0.

[0071] In fault protection mode, when an overvoltage, overcurrent, or overheating fault occurs inside the module, the submodule control unit immediately shuts off the BUCK main switch IGBT and the module output IGBT, disconnecting the module from the cascaded link.

[0072] In this embodiment, to monitor the three-level topology, the entire power supply is also equipped with a global closed-loop control unit. This unit synchronously collects the front-end grid voltage, the operating parameters of the intermediate BUCK module, the output load parameters of the back-end, and the ion source operating condition signals. This enables adaptive adjustment of the phase misalignment angle, precise matching of switching timing, and dynamic calibration of output parameters. Simultaneously, it integrates overvoltage, overcurrent, overheat, short circuit, and arcing protection functions. In fault conditions, it quickly shuts down the high-speed switching module and the BUCK drive signal, ensuring the safety of the ion source cavity and the power supply itself.

[0073] It should be noted that in practical use, if a single-stage phase-shifting BUCK voltage regulator unit is used in conjunction with a single-switch transistor voltage regulation topology, the multi-module phase-shifting series structure is eliminated, and a single-stage voltage regulation and single-switch control are adopted.

[0074] This implementation of phase-free ripple cancellation results in large output ripple and low voltage regulation accuracy; a single device bears all the high-voltage stress, making it prone to overheating and breakdown; the dynamic response speed is slow, making it unable to adapt to the transient operating conditions of the ion source, and the overall performance is far lower than that of the topology in this embodiment.

[0075] Meanwhile, in practical applications, if a power frequency rectification is used in conjunction with a linear voltage regulator topology, voltage regulation can be achieved by using a traditional power frequency rectification followed by linear voltage regulation structure.

[0076] This linear regulation method results in extremely high losses and severe heat generation, making it unsuitable for high-power applications. It lacks fast switching response capability and has extremely poor dynamic disturbance rejection capability. It also lacks phase misalignment ripple suppression mechanism and has poor beam current stability. It is only suitable for low-voltage, static ordinary power supply scenarios and is completely unsuitable for NBI nuclear fusion special power supplies.

[0077] Furthermore, in practical applications, the DC-DC series topology without front-end isolation is used, which means eliminating the front-end power frequency isolation transformer and directly adopting multi-stage DC-DC series voltage regulation.

[0078] This implementation lacks electrical isolation between the power grid and the high-voltage load, making it easy for power grid surges and harmonics to enter the precision equipment of the ion source. It also results in poor electromagnetic compatibility, extremely high safety risks, weak anti-interference capabilities, and a significantly increased equipment failure rate, failing to meet the high reliability and safety requirements of nuclear fusion devices.

[0079] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A power supply for an NBI ion source suppressor based on a cascaded out-of-phase BUCK regulator circuit, suitable for supplying power to the NBI suppressor in high-current, second-level pulse high-voltage power supply scenarios, characterized in that... Includes a multi-winding isolation transformer and multiple voltage regulation and output modules; The primary input terminal of the multi-winding isolation transformer is connected to the industrial power frequency AC grid, and the secondary output terminal of the multi-winding isolation transformer outputs isolated AC power. Each of the voltage regulation and output modules includes a phase-shifted BUCK voltage regulator unit and a PSM cascade unit; The phase-shifting BUCK voltage regulator unit is connected to the secondary output terminal of the multi-winding isolation transformer and is used to rectify and filter the output isolated AC power. The PSM cascade unit is connected in series at the output end of the phase-shifting BUCK voltage regulator unit to quickly complete the path turn-on, turn-off and transient voltage fine-tuning.

2. The NBI ion source suppression electrode power supply based on a cascaded out-of-phase BUCK voltage regulator circuit according to claim 1, characterized in that, The number of independent windings and the number of voltage regulation and output modules on the secondary side of the multi-winding isolation transformer are equal.

3. The NBI ion source suppression electrode power supply based on a cascaded out-of-phase BUCK voltage regulator circuit according to claim 1, characterized in that, In the multiple voltage regulation and output modules, the phase-shifted BUCK voltage regulator unit adopts phase-shifted driving, and the phase of the driving signal is uniformly shifted by a fixed angle.

4. The NBI ion source suppression electrode power supply based on a cascaded out-of-phase BUCK voltage regulator circuit according to claim 1, characterized in that, The multi-winding isolation transformer adopts a fully insulated encapsulation structure.

5. A NBI ion source suppression electrode power supply based on a cascaded out-of-phase BUCK voltage regulator circuit according to claim 1, characterized in that, The phase-out BUCK regulator unit includes an uncontrolled rectifier circuit, a filter circuit, and a phase-out BUCK regulator circuit. The uncontrolled rectifier circuit is used to convert the isolated AC power into pulsating DC power to provide DC input for the subsequent DC voltage regulator circuit. The filter circuit is used to smooth the pulsating DC output from the rectifier, filter out the power frequency ripple and harmonic components generated during the rectification process, and obtain a stable DC bus voltage. The phase-shifting BUCK voltage regulator circuit is used to convert the input DC bus voltage into a continuously adjustable stable output voltage and match the accuracy requirements of the suppression bias voltage.

6. A NBI ion source suppression electrode power supply based on a cascaded out-of-phase BUCK voltage regulator circuit according to claim 5, characterized in that, The PSM cascaded unit includes a sub-module control circuit, which is used to quickly complete the path turn-on, turn-off and transient voltage fine-tuning.

7. A NBI ion source suppression electrode power supply based on a cascaded out-of-phase BUCK voltage regulator circuit according to claim 6, characterized in that, The uncontrolled rectifier module includes a three-phase uncontrolled diode rectifier bridge; The filtering module includes an input filtering capacitor; The sub-module control module includes a module output IGBT and a module output freewheeling diode; The phase-shifted BUCK voltage regulator module includes a BUCK main switch IGBT, a BUCK freewheeling diode, a BUCK filter inductor, and a BUCK output filter capacitor; The three-phase output terminals of the secondary winding of the multi-winding isolation transformer are respectively connected to the three AC input terminals of the three-phase uncontrolled diode rectifier bridge; The positive DC output terminal of the three-phase uncontrolled diode rectifier bridge is connected to the positive terminal of the filter capacitor, and the negative DC output terminal of the three-phase uncontrolled diode rectifier bridge is connected to the negative terminal of the input filter capacitor. The positive terminal of the input filter capacitor is connected to the collector of the BUCK main switch IGBT, and the negative terminal of the input filter capacitor is connected to the anode of the BUCK freewheeling diode. The emitter of the BUCK main switch IGBT is connected to the cathode of the BUCK freewheeling diode and the BUCK filter inductor, respectively. The other end of the BUCK filter inductor is connected to the positive terminal of the BUCK output filter capacitor; The negative terminal of the BUCK output filter capacitor is connected to the negative terminal of the input filter capacitor, and the positive terminal of the BUCK output filter capacitor is connected to the collector of the module output IGBT.

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