A power conversion system for a maglev train

Abstract

This utility model discloses a power conversion system suitable for maglev trains, comprising a TVS protection module, a high-voltage to low-voltage DC / DC conversion module, a power protection module, and a multi-power output module connected in sequence. The TVS protection module is used to suppress instantaneous high-voltage pulses at the input terminal. The high-voltage to low-voltage DC / DC conversion module converts the input 110V voltage to 12V DC voltage. The power protection module filters, prevents reverse connection, handles overcurrent, and suppresses electromagnetic interference on the 12V DC voltage. The multi-power output module converts the processed 12V DC voltage into dual-channel stable voltages of 3.3V and 5V to simultaneously power different downstream circuit modules. This utility model has advantages such as simple overall structure, strong anti-electromagnetic interference capability, high efficiency and reliability, and stable voltage output.

Description

Technical Field

[0001] This utility model mainly relates to the field of magnetic levitation train technology, specifically to a power conversion system suitable for magnetic levitation trains. Background Technology

[0002] Maglev trains boast numerous advantages, including high speed, low operating noise, strong climbing ability, and environmental friendliness. Currently, exploring operational safety and improving the anti-magnetic interference capabilities and reliability of maglev train equipment have become key focuses. Current research has revealed that power fluctuations are a critical factor affecting equipment safety. Power supply during transmission is susceptible to electromagnetic interference, temperature changes, component noise, and other factors, disrupting the correct operating range and precision of the equipment. DC / DC circuits, as a power management system, offer higher conversion efficiency, a wider input / output voltage range, and stronger anti-interference capabilities compared to charge pumps and LDOs, making them more suitable for power management systems in maglev train equipment. However, DC / DC circuits still face the following challenges: 1. Weak resistance to electromagnetic interference Maglev trains rely on electromagnetic attraction or electric repulsion to levitate the vehicle to a certain height and maintain lateral stability. Therefore, the equipment of maglev trains always operates in a strong magnetic field environment, which greatly affects the stability of power supply and the accuracy of signal transmission, thus compromising the reliability of equipment operation.

[0003] 2. Poor purity of power supply voltage Currently, the mainstream eddy current sensors used in maglev trains all have an input voltage of 24V. Therefore, an external DC / DC converter module is still required to step down the power supply voltage before outputting it to the eddy current sensor. However, the performance of DC / DC converter modules varies among different models of maglev trains, and the power cord lengths also differ, resulting in an unstable 24V power supply to the eddy current sensor, which affects its normal operation.

[0004] 3. Low system reliability Maglev trains are a type of rail transit that features high speed, low noise, and large passenger capacity. They are mainly used in densely populated and economically vibrant urban areas, so the safe and reliable operation of the equipment directly affects the safety of passengers' lives and property.

[0005] However, how to design an integrated power management system to achieve high-low voltage dual-track conversion from 110V to 5V and 3.3V, and meet the requirements of strong anti-electromagnetic interference capability for related equipment of maglev trains, has become an urgent problem to be solved. Utility Model Content

[0006] To address the technical problems existing in the prior art, this utility model provides a power conversion system suitable for maglev trains that has a simple overall structure, strong anti-electromagnetic interference capability, high efficiency and reliability, and stable voltage output.

[0007] To solve the above-mentioned technical problems, the technical solution proposed by this utility model is as follows: A power conversion system suitable for maglev trains includes a TVS protection module, a high-voltage to low-voltage DC / DC conversion module, a power protection module, and a multi-power output module; the TVS protection module, the high-voltage to low-voltage DC / DC conversion module, the power protection module, and the multi-power output module are connected in sequence. The TVS protection module is used to suppress instantaneous high voltage pulses at the input terminal; The high-voltage to low-voltage DC / DC converter module is used to convert the input 110V voltage into 12V DC voltage; The power protection module is used to filter, prevent reverse connection, protect against overcurrent and suppress electromagnetic interference of 12V DC voltage. The multi-power output module is used to convert the processed 12V DC voltage into a dual-channel stable voltage of 3.3V and 5V to simultaneously power different downstream circuit modules.

[0008] Preferably, the TVS protection module includes a TVS tube D1, the cathode of which is connected to the input terminal and the anode is grounded to GND.

[0009] Preferably, the high-voltage to low-voltage DC / DC conversion module includes resistors R1-R6, a feedback network, capacitors C1-C6, inductor L1, MOSFET Q1, SL3038 chip U1, and diodes D3-D6; The large-capacity energy storage capacitor C1 and the filter capacitor C2 are connected in parallel between the input terminal and GND. One end of resistor R1 is connected to the input terminal, and the other end is connected to the VDD terminal of U1 and one end of resistor R6. One end of the filter capacitor C3 is connected to the VDD terminal of U1, and the other end is connected to the chip ground to eliminate high-frequency noise; The cathode of the Zener diode D3 is connected to VDD of U1, and the anode is grounded; the cathode of the switching diode D6 is connected to the anode of the resistor R6. The feedback network is connected to pins VFB1 and VFB2 to control the output voltage of the control module. The drain of Q1 is connected to the input terminal, the gate is connected to the DRV pin of U1, and the source is connected to the VSP pin of U1; the output signal of the DRV pin controls the switching frequency of Q1 to achieve the step-down function. One end of resistors R2-R4 is connected to the source of Q1 and the VSP pin of U1, and the other end of resistors R2-R4 is connected to the VSN pin of U1; R7 to R10 form an output voltage controller, and the specific output voltage is set by adjusting the resistor ratio. One end of inductor L1 is connected to the VSN pin of U1, and the other end is connected to one end of C4, C5, R5 and the other end of R8. The other ends of C4, C5, and R5 are grounded. The cathodes of freewheeling diodes D4 and D5 are connected to resistors R2-R4, and the anodes are grounded.

[0010] Preferably, the feedback network includes resistors R7-R10. One end of R7 and R8 is connected to the VFB1 pin of U1, the other end of R7 is connected to the chip ground and connected to the VCC pin of U1 via capacitor C6, and the other end of R8 is connected to the anode of D6. One end of R9 and R10 is connected to the VFB2 pin of U1, and the other end is connected to the chip ground and the power supply ground, respectively.

[0011] Preferably, the power protection module includes an anti-backflow diode, an input LC filter circuit, a fuse overcurrent protection circuit, an EMI filter circuit, and an output LC filter circuit, wherein the input anti-backflow diode, the LC filter circuit, the fuse overcurrent protection circuit, the EMI filter circuit, and the output LC filter circuit are connected in sequence.

[0012] Preferably, the anti-backflow diode includes diode D2, with its anode connected to the output terminal of the high-voltage to low-voltage DC / DC conversion module and its cathode connected to the subsequent circuit.

[0013] The input LC filter circuit includes an inductor L2, a capacitor C10, and an energy storage capacitor C11; L2 and C10 are connected to the output terminal of the anti-reverse current diode to filter out high-frequency noise signals in the power supply; the parallel energy storage capacitor C11 is used to prevent surge voltage from damaging the circuit and to provide a smoother DC voltage. The fuse overcurrent protection circuit includes fuse X1, which is connected in series in the circuit. When an overcurrent occurs in the circuit, the fuse will melt and disconnect the circuit to prevent large current from damaging the circuit components. The output LC filter circuit includes an inductor L3 and a capacitor C9, with L3 and C9 located at the output of the power protection module.

[0014] Preferably, the EMI filter circuit includes C7, C8, C12, C13, CY1, CY2 and inductor L4; C7, C8 and C12, C13 are X capacitors, and CY1 and CY2 are Y capacitors; C7, C8 and C12, C13 are connected in parallel between the live wire and the neutral wire, responsible for filtering out differential mode interference; CY1 and CY2 are capacitors connected in parallel between the live wire and the ground wire and between the neutral wire and the ground wire, filtering out common mode interference; L4 is a common mode inductor, which suppresses the passage of common mode interference signals and enhances the EMI filtering effect.

[0015] Preferably, the multi-power output module includes a low-dropout DC / DC converter circuit and an LDO circuit, wherein the output terminal of the low-dropout DC / DC converter circuit is connected to the input terminal of the LDO circuit.

[0016] Preferably, the low-dropout DC / DC conversion circuit includes a chip U3 of model xcl225, capacitors C15, C17, C18, C20, and resistors R12 and R13; one end of C15 and C20 is connected to the positive terminal of the 12V_2 input, and the other end is grounded to GND_2; the en / ss pin and Vin pin of chip U3 are connected to the positive terminal of the 12V_2 input; one end of resistor R12, capacitor C17, and C18 is connected to the I2 pin of chip U3, the other end of resistor R12 and capacitor C17 is connected to the fb pin of chip U3, and connected to GND_2 through resistor R13, and the other end of capacitor C18 is connected to GND_2.

[0017] Preferably, the LDO circuit includes a chip U2 of model TLV751, capacitors C14, C16, C19, and C21; The EN2 pin of U2 is connected to the I2 pin of chip U3; C14 is a filter capacitor and C19 is an energy storage capacitor, connected to GND_2, with the other end connected to the IN1 and OUT2 pins of chip U2, to filter out ripple interference for the 5V output voltage and achieve output voltage stability; C16 is a filter capacitor and C21 is an energy storage capacitor, connected to the OUT1 output terminal, to filter out ripple interference for the 3.3V output voltage and achieve output voltage stability; One end of C16 and C21 is connected to pin OUT1 of chip U2, and the other end is connected to GND_2.

[0018] Compared with the prior art, the advantages of this utility model are: This invention effectively clamps and discharges instantaneous high-voltage pulses from the input terminal through a TVS protection module, resisting external power fluctuations and surge impacts from the source, providing a robust first line of defense for subsequent circuits. The high-voltage to low-voltage DC / DC converter module efficiently and stably steps down the 110V input commonly found in maglev trains to 12V. Its built-in overvoltage protection mechanism ensures that the core conversion chip is not damaged under abnormal high voltage conditions, improving the system's robustness. Following this, the power protection module integrates LC filtering, fuse overcurrent protection, reverse connection protection, and professional EMI filtering circuitry. This module works synergistically to deeply filter out high-frequency noise, common-mode and differential-mode interference on the power lines, significantly purifying the power supply and fundamentally enhancing the system's electromagnetic compatibility (EMC) performance in complex electromagnetic environments. Ultimately, through two-stage precise conversion (low-dropout DC / DC conversion and dual-channel LDO regulation) of the multi-power output module, the system can simultaneously output 3.3V and 5V voltages with extremely low ripple, meeting the precise and synchronous power supply requirements of various functional modules in the eddy current sensor, such as the microcontroller, FPGA, AD converter, and sensor probe, for multiple voltage values. In summary, this invention has a clear overall structure, achieving not only highly integrated power management from high-voltage input to multiple low-voltage outputs, but also significantly improving the power quality, electromagnetic interference resistance, and long-term operational safety and reliability of the entire sensor system, providing crucial power assurance for the safe and stable operation of maglev trains. Attached Figure Description

[0019] Figure 1 This is a block diagram of an embodiment of the power conversion system of this utility model applicable to maglev trains.

[0020] Figure 2 The circuit diagrams for the TVS protection module and the high-voltage to low-voltage DC / DC conversion module of this utility model are shown in an embodiment.

[0021] Figure 3 This is a circuit diagram of the power protection module of this utility model in an embodiment.

[0022] Figure 4 This is a circuit diagram of the multi-power output module of this utility model in an embodiment. Detailed Implementation

[0023] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0024] like Figure 1As shown, the power conversion system for maglev trains provided in this embodiment includes a TVS (High Voltage Surge) protection module, a high-voltage to low-voltage DC / DC conversion module, a power protection module, and a multi-power output module (including a low-dropout DC / DC conversion module and an LDO module); the TVS protection module, the high-voltage to low-voltage DC / DC conversion module, the power protection module, and the multi-power output module are connected in sequence. The 110V input voltage first passes through a TVS protection module to prevent damage to downstream circuits (such as eddy current sensors) due to external power fluctuations. It then passes through a high-to-low voltage DC / DC converter module, which steps it down to 12V. During this step-down process, if the chip input voltage exceeds 12V, the module's overvoltage protection mechanism is triggered to prevent chip breakdown. The output then goes to a power protection module, which removes high-frequency noise, common-mode and differential-mode interference from the power supply voltage through reverse connection protection, LC filtering, fuse overcurrent protection, TVS protection, and EMI filtering. A protection mechanism is added to terminate operation promptly in case of reverse connection, overvoltage, or overcurrent to prevent equipment damage. The filtered and regulated standard 12V DC output is then sent to a low-dropout DC / DC converter module, where it is converted to 5.5V for the LDO module. Depending on the different power voltage requirements of the downstream circuits, the LDO module operates in dual-channel mode, simultaneously outputting stable 3.3V and 5V voltages to synchronously power all sensor modules. This enables the eddy current sensor to have strong resistance to electromagnetic interference and ensures the safe and reliable operation of the system.

[0025] The sensor circuit contains various sensing modules and signal processing modules, each requiring different power supply voltages. The microcontroller module, FPGA module, and AD conversion module require a 3.3V power supply, while the eddy current sensing module, 485 calibration module, and 485 differential signal output module require a 5V power supply.

[0026] TVS protection modules, also known as high-voltage pulse modules, can quickly clamp circuits to a safe level when they encounter instantaneous overvoltage and discharge large instantaneous currents to ground. When the circuit is operating normally, the TVS protection module is in a high-impedance state and has almost no effect on the circuit. When an instantaneous overvoltage occurs, the TVS will change from a high-impedance state to a low-impedance state at an extremely fast speed to achieve the clamping and current discharge functions. After the transient pulse, the TVS automatically returns to the high-impedance state, and the circuit resumes normal operation.

[0027] like Figure 2 As shown, the TVS protection module includes a TVS diode D1, where the cathode of TVS diode D1 is connected to the input terminal and the anode is grounded to GND; that is, TVS diode D1 is connected in parallel between the input terminal and ground; when a momentary high voltage occurs, D1 will change from a high resistance state to a low resistance state at an extremely fast speed, realizing the clamping and current discharge functions to protect the circuit.

[0028] like Figure 2 As shown, the high-voltage to low-voltage DC / DC converter module is composed of an SL3038 chip forming a wide input voltage step-down constant voltage and constant current DC / DC controller, combined with a BUCK circuit, to achieve a 110V voltage step-down to 12V.

[0029] Specifically, the high-voltage to low-voltage DC / DC conversion module includes resistors R1-R10, capacitors C1-C6, inductor L1, MOSFET Q1, SL3038 chip U1, and diodes D3-D6; A large-capacity energy storage capacitor C1 and a filter capacitor C2 are connected in parallel between the input terminal and GND; the energy storage capacitor C1 provides the module with a transient large current, and the filter capacitor C2 eliminates high-frequency noise signals, making the module work more stably. One end of resistor R1 is connected to the input terminal, and the other end is connected to the VDD terminal of U1 and one end of resistor R6; resistors R1 and R6 divide the input power supply to provide power voltage for SL3038 chip U1. The filter capacitor C3 is connected in parallel to the power supply terminal VDD of the SL3038 chip, that is, one end is connected to the VDD terminal of U1 and the other end is grounded to eliminate high-frequency noise. The cathode of Zener diode D3 is connected to VDD of U1, and the anode is connected to the chip ground; the cathode of switching diode D6 is connected to the anode of resistor R6. Zener diodes D3 and D6 are used to clamp the supply voltage of the SL3038 chip to ensure it operates within a safe voltage range. When the chip voltage is within the appropriate range, D3 is in reverse cutoff, with almost no current flowing through it, and D6 is also in reverse cutoff. When the chip voltage exceeds the Zener value of D3, D3 enters reverse breakdown, clamping the chip input voltage to 12V. At this time, current flows through D3 to D6, and then to chip ground. D3 and D6 form an overvoltage protector; when the voltage difference between the chip power supply and chip ground exceeds a set value, it clamps the chip input voltage to prevent it from being damaged by breakdown. R7, R8, R9, and R10 (feedback network) are connected to pins VFB1 and VFB2, controlling the module's output voltage. MOSFET Q1 is connected as a switching device to the DRV pin; the DRV pin output signal controls the switching frequency of Q1 to achieve a step-down function. Specifically, one end of R7 and R8 is connected to pin VFB1 of U1, the other end of R7 is connected to chip ground and then connected to the VCC terminal of U1 via capacitor C6, and the other end of R8 is connected to the anode of D6; one end of R9 and R10 is connected to pin VFB2 of U1, and the other ends are connected to chip ground and power ground, respectively; the drain of Q1 is connected to the input terminal, the gate is connected to the DRV pin of U1, and the source is connected to the VSP pin of U1. One end of resistors R2-R4 is connected to the drain of Q1 and the VSP pin of U1, and the other end of resistors R2-R4 is connected to the VSN pin of U1; R7-R10 form an output voltage controller, and the specific output voltage is set by adjusting the resistor ratio.

[0030] One end of inductor L1 is connected to the VSN pin of U1, and the other end is connected to one end of C4, C5, R5 and the other end of R8. The other ends of C4, C5, and R5 are grounded. The cathodes of freewheeling diodes D4 and D5 are connected to one end of R2-R4, and the anodes are grounded. The current released by inductor L1 flows through the load resistor R5 and the freewheeling diodes D4 and D5 to form the main power circuit. The large-capacity capacitor C5 at the output terminal is connected in parallel with the load resistor R5 to achieve filtering and voltage regulation. Diode D2 ( Figure 3 (Middle) Connected to the load output terminal to achieve reverse connection protection function and protect the circuit.

[0031] After the input voltage is protected and filtered by D1, C1, and C2, one path is used to divide the voltage between R1 and R6 to power U1, and the other path is used as the main power input. According to the information of the feedback network (R7-R10), U1 controls the switch of Q1 through the DRV pin. With the cooperation of L1, C5, D4, and D5, the high voltage is chopped, freewheeled, and filtered to finally obtain a stable 12V output.

[0032] like Figure 3 As shown, the power protection module consists of four parts: an input LC filter circuit, a fuse overcurrent protection circuit, an EMI filter circuit, and an output LC filter circuit. The input LC filter circuit includes an inductor L2, a capacitor C10, and an energy storage capacitor C11. L2 and C10 are connected to the output of the high-voltage to low-voltage DC / DC converter module to form an LC filter circuit, which filters out high-frequency noise signals in the power supply. The parallel energy storage capacitor C11 is used to prevent surge voltage from damaging the circuit and to provide a smoother DC voltage.

[0033] The fuse overcurrent protection circuit includes fuse X1, which is connected in series in the circuit. When an overcurrent occurs in the circuit, the fuse will blow, cutting off the circuit and preventing large current from damaging the circuit components.

[0034] The EMI filter circuit includes capacitors C7, C8, C12, C13, CY1, CY2, and inductor L4. C7, C8, C12, and C13 are X capacitors, and CY1 and CY2 are Y capacitors, all of which are safety capacitors. C7, C8, C12, and C13 are connected in parallel between the live and neutral wires to filter differential-mode interference. CY1 and CY2 are capacitors connected in parallel between the live and ground wires, and between the neutral and ground wires, to filter common-mode interference. L4 is a common-mode inductor, which suppresses common-mode interference signals and enhances the EMI filtering effect. The EMI filter circuit suppresses unwanted electromagnetic noise conducted through the power lines, preventing external interference from entering the equipment and preventing internal noise from affecting subsequent circuits. It effectively solves conducted and radiated interference, achieving electromagnetic compatibility.

[0035] The output LC filter circuit includes inductor L3 and capacitor C9. L3 and C9 are located at the output of the power protection module and connected to the multi-power output module to further optimize the power signal.

[0036] like Figure 4 As shown, a two-stage step-down converter is used to convert 12V to 3.3V and 5V through a low-dropout DC / DC converter circuit and an LDO circuit.

[0037] The low-dropout DC / DC converter circuit includes chip U3 (XCL225 model, 12V to 5.5V), capacitors C15, C17, C18, and C20, and resistors R12 and R13. One end of C15 and C20 is connected to the positive terminal of the 12V_2 input, and the other end is grounded to GND_2. The en / ss and Vin pins of chip U3 are connected to the positive terminal of the 12V_2 input. C15 is a filter capacitor, and C20 is an energy storage capacitor. Their main function is to filter out high-frequency noise and low-frequency ripple in the 12V power input and reduce the impact of power fluctuations on the operation of XCL225.

[0038] One end of resistor R12, capacitor C17, and capacitor C18 is connected to pin I2 of chip U3. The other end of resistor R12 and capacitor C17 is connected to pin fb of chip U3, and then connected to GND_2 via resistor R13. The other end of capacitor C18 is connected to GND_2. R12 and C17 are connected in parallel between the chip's output voltage detection port fb and output port I2. R13 is connected between port fb and ground. C18 is connected between port I2 and ground. By adjusting the impedance values ​​of R12, R13, C17, and C18, the output voltage is set to 5.5V.

[0039] The LDO circuit includes chip U2 (TLV751 chip, 5.5V to 3.3V and 5V, fixed output version is selected to reduce the need for external resistor network), capacitors C14, C16, C19, and C21. The EN2 pin of U2 is connected to the I2 pin of chip U3; one end of C14 and C19 is connected to GND_2, and the other end is connected to the IN1 and OUT2 pins of chip U2; C16 is a filter capacitor and C21 is an energy storage capacitor, connected to the OUT1 output terminal to filter out ripple interference for the 3.3V output voltage and achieve output voltage stability. One end of C16 and C21 is connected to pin OUT1 of chip U2, and the other end is connected to GND_2; C14 is a filter capacitor and C19 is an energy storage capacitor, connected to the OUT2 output terminal to filter out ripple interference for the 5V output voltage and achieve output voltage stability.

[0040] The LDO circuit is used to generate a stable power supply voltage required by subsequent circuits. The module's power input is connected to a low-dropout DC / DC converter to obtain a 5.5V startup voltage. Using an external input, it controls a dual-channel low-dropout (LDO) regulator to simultaneously output 3.3V and 5V, ensuring the different power supply voltage requirements of subsequent circuits.

[0041] This invention effectively clamps and discharges instantaneous high-voltage pulses from the input terminal through a TVS protection module, resisting external power fluctuations and surge impacts from the source, providing a robust first line of defense for subsequent circuits. The high-voltage to low-voltage DC / DC converter module efficiently and stably steps down the 110V input commonly found in maglev trains to 12V. Its built-in overvoltage protection mechanism ensures that the core conversion chip is not damaged under abnormal high voltage conditions, improving the system's robustness. Following this, the power protection module integrates LC filtering, fuse overcurrent protection, reverse connection protection, and professional EMI filtering circuitry. This module works synergistically to deeply filter out high-frequency noise, common-mode and differential-mode interference on the power lines, significantly purifying the power supply and fundamentally enhancing the system's electromagnetic compatibility (EMC) performance in complex electromagnetic environments. Ultimately, through two-stage precise conversion (low-dropout DC / DC conversion and dual-channel LDO regulation) of the multi-power output module, the system can simultaneously output 3.3V and 5V voltages with extremely low ripple, meeting the precise and synchronous power supply requirements of various functional modules in the eddy current sensor, such as the microcontroller, FPGA, AD converter, and sensor probe, for multiple voltage values. In summary, this invention features a simple overall structure, achieving highly integrated power management from high-voltage input to multiple low-voltage outputs. It also significantly improves the power quality, electromagnetic interference resistance, and long-term operational safety and reliability of the entire sensor system, providing crucial power assurance for the safe and stable operation of maglev trains.

[0042] The above are merely preferred embodiments of this utility model. The protection scope of this utility model is not limited to the above embodiments. All technical solutions falling within the scope of this utility model's concept are within its protection scope. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principle of this utility model should be considered within its protection scope.

Claims

1. A power conversion system suitable for maglev trains, characterized in that, It includes a TVS protection module, a high-voltage to low-voltage DC / DC converter module, a power protection module, and a multi-power output module; the TVS protection module, the high-voltage to low-voltage DC / DC converter module, the power protection module, and the multi-power output module are connected in sequence; The TVS protection module is used to suppress instantaneous high voltage pulses at the input terminal; The high-voltage to low-voltage DC / DC converter module is used to convert the input 110V voltage into 12V DC voltage; The power protection module is used to filter, prevent reverse connection, protect against overcurrent and suppress electromagnetic interference of 12V DC voltage. The multi-power output module is used to convert the processed 12V DC voltage into a dual-channel stable voltage of 3.3V and 5V to simultaneously power different downstream circuit modules.

2. The power conversion system for maglev trains according to claim 1, characterized in that, The TVS protection module includes a TVS tube D1, the cathode of which is connected to the input terminal and the anode is grounded to GND.

3. The power conversion system for maglev trains according to claim 1 or 2, characterized in that, The high-voltage to low-voltage DC / DC conversion module includes resistors R1-R6, a feedback network, capacitors C1-C6, inductor L1, MOSFET Q1, SL3038 chip U1, and diodes D3-D6. The large-capacity energy storage capacitor C1 and the filter capacitor C2 are connected in parallel between the input terminal and GND. One end of resistor R1 is connected to the input terminal, and the other end is connected to the VDD terminal of U1 and one end of resistor R6. One end of the filter capacitor C3 is connected to the VDD terminal of U1, and the other end is connected to the chip ground to eliminate high-frequency noise; The cathode of Zener diode D3 is connected to VDD of U1, and the anode is connected to the chip ground; the cathode of switching diode D6 is connected to the anode of resistor R6. The feedback network is connected to pins VFB1 and VFB2 to control the output voltage of the control module; the drain of Q1 is connected to the input terminal, the gate is connected to the DRV pin of U1, and the source is connected to the VSP pin of U1; the output signal of the DRV pin controls the switching frequency of Q1 to achieve the step-down function. One end of resistors R2-R4 is connected to the source of Q1 and the VSP pin of U1, and the other end of resistors R2-R4 is connected to the VSN pin of U1; R1 to R4 form an output voltage controller, and the specific output voltage can be set by adjusting the resistance ratio. One end of inductor L1 is connected to the VSN pin of U1, and the other end is connected to one end of C4, C5, R5 and the other end of R8. The other end of C4, C5, R5 is grounded. The cathodes of freewheeling diodes D4 and D5 are connected to one end of R2-R4, and the anodes are connected to one end of C4, C5, R5 and grounded.

4. The power conversion system for maglev trains according to claim 3, characterized in that, The feedback network includes resistors R7-R10. One end of R7 and R8 is connected to pin VFB1 of U1, the other end of R7 is connected to the chip ground and connected to the VCC terminal of U1 via capacitor C6, and the other end of R8 is connected to the anode of D6. One end of R9 and R10 is connected to pin VFB2 of U1, and the other end is connected to the chip ground and the power ground, respectively.

5. The power conversion system for maglev trains according to claim 1 or 2, characterized in that, The power protection module includes an anti-backflow diode, an input LC filter circuit, a fuse overcurrent protection circuit, an EMI filter circuit, and an output LC filter circuit, which are connected in sequence.

6. The power conversion system for maglev trains according to claim 5, characterized in that, The anti-backflow diode includes diode D2, with its anode connected to the output terminal of the high-voltage to low-voltage DC / DC conversion module and its cathode connected to the subsequent circuit. The input LC filter circuit includes an inductor L2, a capacitor C10, and an energy storage capacitor C11; L2 and C10 are connected to the cathode of the anti-reverse-current diode D2 to filter out high-frequency noise signals in the power supply; the parallel energy storage capacitor C11 is used to prevent surge voltage from damaging the circuit and to provide a smoother DC voltage. The fuse overcurrent protection circuit includes fuse X1, which is connected in series in the circuit. When an overcurrent occurs in the circuit, the fuse will melt and disconnect the circuit to prevent large current from damaging the circuit components. The output LC filter circuit includes an inductor L3 and a capacitor C9, with L3 and C9 located at the output of the power protection module.

7. The power conversion system for maglev trains according to claim 6, characterized in that, The EMI filter circuit includes C7, C8, C12, C13, CY1, CY2 and inductor L4; C7, C8, C12, and C13 are X capacitors, and CY1 and CY2 are Y capacitors; C7, C8, C12, and C13 are connected in parallel between the live wire and the neutral wire, responsible for filtering out differential mode interference; CY1 and CY2 are capacitors connected in parallel between the live wire and the ground wire and between the neutral wire and the ground wire, filtering out common mode interference; L4 is a common mode inductor, which suppresses the passage of common mode interference signals and enhances the EMI filtering effect.

8. The power conversion system for maglev trains according to claim 1 or 2, characterized in that, The multi-power output module includes a low-dropout DC / DC converter circuit and an LDO circuit, with the output terminal of the low-dropout DC / DC converter circuit connected to the input terminal of the LDO circuit.

9. The power conversion system for maglev trains according to claim 8, characterized in that, The low-dropout DC / DC converter circuit includes an xcl225 chip U3, capacitors C15, C17, C18, and C20, and resistors R12 and R13. One end of C15 and C20 is connected to the positive terminal of the 12V_2 input, and the other end is grounded to GND_2. The en / ss and Vin pins of chip U3 are connected to the positive terminal of the 12V_2 input. One end of resistor R12, capacitor C17, and C18 is connected to pin I2 of chip U3, and the other end of resistor R12 and capacitor C17 is connected to pin fb of chip U3, and connected to GND_2 via resistor R13. The other end of capacitor C18 is connected to GND_2.

10. The power conversion system for maglev trains according to claim 8, characterized in that, The LDO circuit includes a chip U2 of model TLV751, and capacitors C14, C16, C19, and C21. The EN2 pin of U2 is connected to the I2 pin of chip U3; C14 is a filter capacitor and C19 is an energy storage capacitor, one end of which is connected to GND_2, and the other end is connected to the IN1 and OUT2 pins of chip U2, to filter out ripple interference for the 5V output voltage and ensure output voltage stability; C16 is a filter capacitor and C21 is an energy storage capacitor, connected to the OUT1 output terminal, to filter out ripple interference for the 3.3V output voltage and achieve output voltage stability; one end of C16 and C21 is connected to the OUT1 pin of chip U2, and the other end is connected to GND_2.

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