Ground-vehicle-mounted dual-system cooperative suspension test bench auxiliary power supply and control method

Abstract

The invention discloses a ground-vehicle-mounted dual-system cooperative suspension test bench auxiliary power supply and a control method, and relates to the technical field of suspension test bench power supply. The auxiliary power supply comprises a ground power supply unit, a vehicle-mounted power supply unit, a cooperative control unit, an energy storage unit, an inversion unit and a low-voltage power distribution unit, the ground power supply unit converts DC1500V into DC330V, and the vehicle-mounted power supply unit converts the DC330V into DC110V, so that a cascade power supply framework is formed; the cooperative control unit realizes dual-system cooperative switching and parameter regulation and control, and the energy storage unit ensures that the suspension system stably operates for more than 1 minute after power failure; the inversion unit outputs AC 220V, and the low-voltage power distribution unit distributes power to a load. Through a dual-system collaborative redundancy design, intelligent energy storage management and a comprehensive protection mechanism, the problems that an existing power supply is low in reliability, insufficient in power-off endurance and poor in collaboration are solved, and the system is suitable for the strict power supply requirement of the suspension research test bed.

Description

Technical Field

[0001] This invention relates to the field of power supply technology for levitation test benches, and in particular to an auxiliary power supply and control method for levitation test benches with ground-vehicle dual-system coordination. It is applicable to levitation research test benches in the research and development of rail transit levitation technology that have stringent requirements for power supply reliability, multi-voltage level output and emergency endurance. Background Technology

[0002] As the core equipment for the research and development and performance verification of levitation technology in rail transit, the operational stability of the levitation test bench directly determines the accuracy of test data and the safety of the test process. The auxiliary power supply system, as the energy hub of the test bench, must simultaneously provide continuous and stable power to multiple types of loads, including the levitation drive module, control system, and speed and positioning equipment. It must also meet the multi-voltage output requirements of DC330V levitation power supply, DC110V control power supply, and AC220V auxiliary power supply, placing extremely high demands on power supply reliability, redundancy, and adaptability to operating conditions. However, existing levitation test bench auxiliary power supplies mostly adopt a single power supply architecture design, lacking a coordination mechanism between the ground main power supply and the on-board backup power supply. Once the high-voltage input (such as DC1500V) is interrupted, it cannot quickly switch to the backup power supply circuit, easily leading to instability of the levitation system, and consequently causing test interruption or equipment damage.

[0003] In terms of energy storage and power conversion, existing technologies have significant shortcomings. On the one hand, the coordinated control capability between energy storage units and power systems is weak. Most battery management systems (BMS) only have basic charge and discharge protection functions and cannot dynamically adjust charge and discharge strategies according to power supply status and load demand. Furthermore, the matching degree between battery pack selection and actual operating conditions is insufficient, making it difficult to ensure the stable operation of the levitation system for a sufficient period of time after a power outage. On the other hand, the power conversion topology design is not optimized enough. Traditional DC-DC conversion modules suffer from problems such as low conversion efficiency, large output ripple, and severe electromagnetic interference, which not only affect the control accuracy of load equipment but may also interfere with the signal acquisition system of the test bench, leading to distorted test data.

[0004] Furthermore, the existing auxiliary power supply's protection mechanisms and environmental adaptability are insufficient to meet the complex operating conditions required by the test bench. Protection functions are mostly concentrated on basic scenarios such as input overvoltage and output short circuits, and their response to more specific operating conditions such as power component failures, contactor malfunctions, and battery high-temperature graded protection is not timely or accurate enough. At the same time, the interface design lacks standardized specifications, and the wiring compatibility between the main circuit and control circuit is poor, increasing the difficulty of equipment installation, debugging, and subsequent maintenance, thus hindering the test bench's operational efficiency. Summary of the Invention

[0005] The purpose of this invention is to provide an auxiliary power supply and control method for a ground-vehicle dual-system coordinated suspension test rig, which solves the technical problems of low power supply reliability, weak coordinated control capability, insufficient power outage recovery and imperfect protection mechanism of existing suspension test rig auxiliary power supplies, and meets the stringent power supply requirements of suspension research test rigs.

[0006] To achieve the above objectives, the present invention provides the following technical solution: According to one aspect of the present invention, an auxiliary power supply for a ground-vehicle dual-system coordinated suspension test bench is provided, comprising: The ground power supply unit is used to connect to a DC1500V high-voltage input and convert it to a stable DC330V output. The vehicle-mounted power supply unit is electrically connected to the DC330V output terminal of the ground power supply unit and is used to convert DC330V into a stable DC110V output. The collaborative control unit is communicatively connected to the ground power supply unit and the vehicle power supply unit, respectively, and is used to realize dual system power supply switching, parameter control and fault alarm; The energy storage unit includes a DC330V battery pack and a DC110V battery pack, which are connected in parallel with the output terminals of the ground power supply unit and the vehicle power supply unit, respectively. Both battery packs are equipped with a battery management system. The inverter unit is electrically connected to the vehicle power supply unit and is used to convert DC110V to AC220V AC output. The low-voltage power distribution unit is electrically connected to the vehicle-mounted power supply unit and the inverter unit respectively, and is used to provide DC110V and AC220V power to the load equipment of the suspension test bench. The ground power supply unit and the vehicle power supply unit form a cascaded collaborative power supply architecture. The collaborative control unit controls the ground power supply unit as the main power supply and the vehicle power supply unit as the hot backup power supply, or switches to the energy storage unit for power supply when the DC1500V power is cut off, so as to maintain the stable operation of the suspension system for ≥1 minute.

[0007] According to one embodiment of the present invention, the ground power supply unit and the vehicle-mounted power supply unit adopt the same circuit topology.

[0008] According to an embodiment of the present invention, the circuit topology includes an input filter module, a precharge circuit, a main circuit, a three-level LLC converter module, an output rectifier filter module, and an interleaved BUCK converter module connected in series along the current path. The input filtering module is an LC circuit consisting of a first inductor (L1) and first, sixth and ninth capacitors (C1, C6, C9), used to suppress electromagnetic interference on the input side; The pre-charging circuit includes a second contactor (KM2) and a current-limiting resistor (R1) to prevent power-on inrush current; The three-level LLC conversion module includes first, second, fourth, fifth and seventh to fourteenth IGBT modules (Q1-Q2, Q4-Q5, Q7-Q14) and first to third high-frequency transformers (T1-T3), with a switching frequency of 20kHz-50kHz; The output rectifier and filter module includes the second to fourth and the seventh to ninth fast recovery diodes (D2-D4, D7-D9) and the third and eighth capacitors (C3, C8). The interleaved BUCK switching module includes third and sixth IGBT modules (Q3, Q6), fifth and sixth diodes (D5, D6), third and fourth inductors (L3, L4), and fourth and fifth capacitors (C4, C5), with a switching frequency of 30kHz.

[0009] According to one embodiment of the present invention, the ground power supply unit has a rated input voltage of DC1500V, a fluctuation range of 1000V-1900V, a rated output power of 40kW, a rated output voltage of DC330V±3%, a DC ripple rate of <2%Vrms, a conversion efficiency of >92%, and an output ripple factor of <3%; the vehicle-mounted power supply unit has a rated input voltage of DC330V, a fluctuation range of 200V-360V, a rated output power of 12kW, a rated output voltage of DC110V±3%, a DC ripple rate of <2%Vrms, a conversion efficiency of >92%, and an output ripple factor of <3%.

[0010] According to one embodiment of the present invention, the DC330V battery pack and the DC110V battery pack of the energy storage unit are both 52Ah lithium iron phosphate batteries with a discharge rate ≤1C; the rated operating voltage of the DC330V battery pack is 330V and the minimum discharge voltage is 290V; the rated operating voltage of the DC110V battery pack is 110V and the minimum discharge voltage is 97V.

[0011] According to one embodiment of the present invention, the battery management system has overvoltage, high temperature and charging overcurrent limiting and protection functions, and supports remote data communication; when the battery cell temperature reaches 55°C, it controls the charger to reduce current or stop charging; when the cell temperature reaches 60°C, it disconnects the battery output contactor.

[0012] According to one embodiment of the present invention, the collaborative control unit includes an MCU controller, a CAN / RS485 communication module and a status monitoring module, which supports local and / or remote display of output voltage, output current, charging current, input voltage and temperature parameters, and can set output voltage, undervoltage / overvoltage protection value, current limiting value and communication baud rate parameters; The status monitoring module includes a voltage sensor, a current sensor, and a temperature sensor, used to collect power supply parameters; it supports parameter setting and status monitoring in local or remote modes.

[0013] On the other hand, the present invention also provides an auxiliary power control method for a ground-vehicle dual-system coordinated suspension test bench, comprising the following steps: S1. System initialization: The collaborative control unit starts a self-test, checks the hardware status and communication connection status of each unit, and the battery management system initializes the battery parameters. S2. Main power supply start-up: The coordination control unit controls the ground power supply unit to connect to DC1500V input and outputs a stable DC330V voltage; at the same time, it controls the vehicle power supply unit to start and outputs a stable DC110V voltage. S3, Energy Storage Management: The battery management system monitors the status of the battery pack in real time and, in coordination with the control unit, controls the charger to execute either float charging or equalization charging strategies based on the battery voltage and capacity. S4. Dual-system collaboration: Under normal operating conditions, the ground power supply unit is the main power supply and the vehicle power supply unit is the backup. The collaborative control unit collects and uploads power supply parameters in real time. S5. Power outage recovery: When DC1500V power is lost, the collaborative control unit switches to the energy storage unit for power supply to maintain the stable operation of the levitation system for ≥1 minute. S6. Fault Protection and Recovery: When an abnormal operating condition is detected, the corresponding protection mechanism is triggered and an alarm is triggered; after power is restored or the fault is cleared, normal operation is automatically restored.

[0014] According to an embodiment of the present invention, in step S1, after the collaborative control unit is powered on, it performs register configuration and communication handshake for each module. The battery management system reads the initial state of the battery. If all module states are normal, it enters the standby state. If a fault is detected, it triggers an audible and visual alarm and records the fault code. In step S2, after receiving the start command, the collaborative control unit first closes the pre-charging circuit of the ground power supply unit, and then closes the main circuit after the input current stabilizes. It then starts the three-level LLC conversion module and the interleaved BUCK conversion module to output DC330V. Subsequently, it starts the vehicle power supply unit to input DC330V and output DC110V, and the inverter unit starts synchronously to output AC220V.

[0015] According to an embodiment of the present invention, in step S3, the battery management system periodically collects battery voltage, temperature, and current data. When the battery capacity is ≤80%, equalization charging is performed, with the equalization charging voltage being DC330V / DC110V rated voltage +5%. When the capacity is ≥95%, it switches to float charging, with the float charging voltage being DC330V / DC110V rated voltage +2%. When the cell temperature reaches 55°C, the charging current drops to 50%, and when it reaches 60°C, the battery output contactor is disconnected. In step S4, the collaborative control unit collects power supply parameters every 200ms and uploads them to the integrated monitoring system via the CAN bus, while also receiving remote control commands. Under normal operating conditions, the ground power supply unit bears 100% load, while the vehicle-mounted power supply unit is in hot standby mode and monitors the main power supply status in real time. In step S5, when the DC1500V input voltage is detected to be lower than 1000V for 10ms, it is determined that the power supply is interrupted. The coordinating control unit immediately controls the ground power supply unit to stop working and closes the output contactor of the energy storage unit. In step S6, when an input overvoltage, undervoltage, output short circuit, or power component overheating fault is detected, the coordinated control unit immediately disconnects the corresponding circuit contactor, triggers an audible and visual alarm, and uploads the fault information. After the fault is cleared or the power supply is restored, the system is automatically restored to normal operation by local reset or remote command startup.

[0016] The auxiliary power supply and control method for a ground-vehicle dual-system coordinated suspension test bench of the present invention have the following advantages compared with the prior art: 1. Dual-system collaborative redundancy design. The ground-vehicle cascaded collaborative power supply architecture, combined with the energy storage unit, achieves triple redundancy power supply, significantly improving power supply reliability and avoiding system instability caused by a single failure; 2. Power Outage Recovery Guarantee. By optimizing the battery capacity (52Ah) and discharge rate (≤1C) design, the suspension system is guaranteed to operate stably for ≥1 minute after a DC1500V power outage, providing sufficient time for emergency response during testing; 3. Intelligent energy storage management. Integrates temperature-graded control and dynamic adjustment of charge / discharge strategies from the battery management system (BMS), extending battery cycle life; 4. High efficiency and stable conversion: Adopting a three-level LLC and interleaved BUCK topology design, the power conversion efficiency is >92%, the output ripple factor is <3%, the DC ripple rate is <2%Vrms, and the electromagnetic compatibility performance is excellent; 5. Comprehensive protection mechanism: Covers all scenarios including input overvoltage / undervoltage, output short circuit, overcurrent, overheating, and battery abnormality, with timely response to prevent equipment damage; 6. It has strong environmental adaptability, supports local / remote parameter setting and status monitoring, and provides real-time feedback of fault information, reducing operation and maintenance costs. Attached Figure Description

[0017] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic diagram of an auxiliary power supply for a ground-vehicle dual-system coordinated suspension test bench according to an embodiment of the present invention; Figure 2 This is a flowchart of an auxiliary power supply control method for a ground-vehicle dual-system coordinated suspension test bench according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the auxiliary power supply providing power to the load equipment of the suspension test bench through a low-voltage power distribution unit according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the circuit topology of the ground power supply unit according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the energy storage architecture of a DC330V battery pack according to an embodiment of the present invention; Figure 6 This is a schematic diagram of the circuit topology of the vehicle power supply unit in an embodiment of the present invention, which converts DC330V to DC110V. Figure 7 This is a schematic diagram of the energy storage architecture of the DC110V battery pack and the AC220V interface of the inverter unit according to an embodiment of the present invention. Figure 8 This is a schematic diagram of the same circuit topology structure for the ground power supply unit and the vehicle power supply unit in an embodiment of the present invention. Detailed Implementation

[0018] To facilitate a clear description of the technical solutions in the embodiments of the present invention, the terms "first" and "second" are used to distinguish identical or similar items with essentially the same function and effect. For example, the first threshold and the second threshold are merely used to distinguish different thresholds and do not limit their order. Those skilled in the art will understand that the terms "first" and "second" do not limit the quantity or execution order, and that the terms "first" and "second" are not necessarily different.

[0019] It should be noted that in this invention, the terms "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in this invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0020] In this invention, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one" or similar expressions refer to any combination of these items, including any combination of singular or plural items. For example, "at least one of a, b, or c" can represent: a, b, c, a combination of a and b, a combination of a and c, a combination of b and c, or a, b, and c, where a, b, and c can be single or multiple.

[0021] like Figure 1 The diagram illustrates an auxiliary power supply for a ground-vehicle dual-system coordinated suspension test bench. The auxiliary power supply includes a ground power supply unit, a vehicle power supply unit, a coordinated control unit, an energy storage unit, an inverter unit, and a low-voltage distribution unit. The ground power supply unit receives a DC 1500V high-voltage input and converts it to a stable DC 330V output. The vehicle power supply unit is electrically connected to the DC 330V output of the ground power supply unit and converts the DC 330V to a stable DC 110V output. The ground power supply unit and the vehicle power supply unit form a cascaded coordinated power supply architecture. The coordinated control unit is communicatively connected to both the ground power supply unit and the vehicle power supply unit, enabling dual-system power switching, parameter control, and fault alarms.

[0022] The energy storage unit includes a DC330V battery pack and a DC110V battery pack, which are connected in parallel to the output terminals of the ground power supply unit and the vehicle power supply unit, respectively. Both battery packs are equipped with a battery management system. The inverter unit is electrically connected to the vehicle power supply unit and is used to convert DC110V to AC220V output. The low-voltage power distribution unit is electrically connected to the vehicle power supply unit and the inverter unit, respectively, and is used to distribute power to the load equipment of the suspension test bench. The coordination control unit controls the ground power supply unit as the main power supply and the vehicle power supply unit as the hot standby power supply, or switches to the energy storage unit for power supply when the DC1500V power is lost, maintaining the stable operation of the suspension system for ≥1 minute.

[0023] The ground power supply unit and the vehicle-mounted power supply unit adopt the same circuit topology. Further, the circuit topology includes an input filter module, a pre-charge circuit, a main circuit, a three-level LLC converter module, an output rectification filter module, and an interleaved BUCK converter module, connected in series along the current path. The input filtering module is an LC circuit composed of inductor L1, capacitor C1, C6, and C9, used to suppress electromagnetic interference on the input side; the pre-charging circuit includes contactor KM2 and current-limiting resistor to avoid power-on inrush current. The three-level LLC conversion module includes IGBT modules Q1-Q2 / Q4-Q5 / Q7-Q14 and high-frequency transformers T1-T3, with a switching frequency of 20kHz-50kHz. The output rectifier and filter module includes fast recovery diodes D2-D4 / D7-D9 and capacitors C3 / C8.

[0024] The interleaved BUCK switching module consists of IGBT modules Q3 / Q6, diodes D5 / D6, inductors L3 / L4, and capacitors C4 / C5, with a switching frequency of 30kHz.

[0025] The rated input voltage of the ground power supply unit is DC1500V, with a fluctuation range of 1000V-1900V, a rated output power of 40kW, a rated output voltage of DC330V±3%, a DC ripple rate of <2%Vrms, a conversion efficiency of >92%, and an output ripple factor of <3%. The rated input voltage of the vehicle power supply unit is DC330V, with a fluctuation range of 200V-360V, a rated output power of 12kW, a rated output voltage of DC110V±3%, a DC ripple rate of <2%Vrms, a conversion efficiency of >92%, and an output ripple factor of <3%.

[0026] Furthermore, the DC330V battery pack and DC110V battery pack of the energy storage unit are both 52Ah lithium iron phosphate batteries with a discharge rate ≤1C; the rated operating voltage of the DC330V battery pack is 330V, and the minimum discharge voltage is 290V; the rated operating voltage of the DC110V battery pack is 110V, and the minimum discharge voltage is 97V.

[0027] Furthermore, the battery management system has overvoltage, high temperature, and charging overcurrent limiting and protection functions, and supports remote data communication; when the battery cell temperature reaches 55°C, it controls the charger to reduce current or stop charging; when the cell temperature reaches 60°C, it disconnects the battery output contactor.

[0028] Furthermore, the collaborative control unit includes an MCU controller, a CAN / RS485 communication module, and a status monitoring module, which supports local or remote display of output voltage, output current, charging current, input voltage, and temperature parameters, and can set output voltage, undervoltage / overvoltage protection values, current limiting values, and communication baud rate parameters. The status monitoring module includes a voltage sensor LV25-P, a current sensor LA25-NP, and a temperature sensor PT100, used to collect power supply parameters; it supports local or remote parameter setting and status monitoring.

[0029] Furthermore, the inverter unit has a rated input of DC110V, an output of AC220V±5%, a frequency of 50Hz±1%, and a conversion efficiency of >90%; it has input reverse connection protection, input overvoltage (137.5V) / undervoltage (77V) protection, output overload (110% of rated power) protection, and output short circuit protection functions.

[0030] like Figure 2 As shown, a flowchart of an auxiliary power supply control method for a ground-vehicle dual-system coordinated suspension test bench is presented. The method includes the following steps: S1. System initialization: The collaborative control unit starts a self-test, checks the hardware status and communication connection status of each unit, and the battery management system initializes the battery parameters. S2. Main power supply start-up: The coordination control unit controls the ground power supply unit to connect to DC1500V input and outputs a stable DC330V voltage; at the same time, it controls the vehicle power supply unit to start and outputs a stable DC110V voltage. S3, Energy Storage Management: The battery management system monitors the status of the battery pack in real time and, in coordination with the control unit, controls the charger to execute either float charging or equalization charging strategies based on the battery voltage and capacity. S4. Dual-system collaboration: Under normal operating conditions, the ground power supply unit is the main power supply and the vehicle power supply unit is the backup. The collaborative control unit collects and uploads power supply parameters in real time. S5. Power outage recovery: When DC1500V power is lost, the collaborative control unit switches to the energy storage unit for power supply to maintain the stable operation of the levitation system for ≥1 minute. S6. Fault Protection and Recovery: When an abnormal operating condition is detected, the corresponding protection mechanism is triggered and an alarm is triggered; after power is restored or the fault is cleared, normal operation is automatically restored.

[0031] Furthermore, in step S1, after the collaborative control unit is powered on, it performs register configuration and communication handshake for each module. The BMS reads the initial state of the battery. If all modules are in normal condition, it enters standby mode. If a fault is detected, it triggers an audible and visual alarm and records the fault code.

[0032] Furthermore, in step S2, after receiving the start command, the collaborative control unit first closes the ground power supply unit to output DC330V; then it starts the vehicle power supply unit to output DC110V, and the inverter unit starts synchronously to output AC220V.

[0033] Furthermore, in step S3, the BMS collects battery voltage, temperature, and current data every 100ms. When the battery capacity is ≤80%, the charger is controlled to execute the equalization charging strategy, with the equalization charging voltage being DC330V / DC110V rated voltage +5%. When the capacity is ≥95%, the charger is switched to the float charging strategy, with the float charging voltage being DC330V / DC110V rated voltage +2%. When the cell temperature reaches 55℃, a current reduction command is sent to reduce the charging current to 50%. When the temperature reaches 60℃, the battery output contactor is disconnected.

[0034] Furthermore, in step S4, the collaborative control unit collects power supply parameters every 200ms and uploads them to the integrated monitoring system via the CAN bus, while simultaneously receiving remote control commands. Under normal operating conditions, the ground power supply unit bears 100% load, while the vehicle-mounted power supply unit is in hot standby mode and monitors the main power supply status in real time.

[0035] Furthermore, in step S5, when the DC1500V input voltage is detected to be lower than 1000V for 10ms, it is determined to be a power supply interruption. The coordinating control unit immediately controls the ground power supply unit to stop working and closes the energy storage unit output contactor. The DC330V battery pack supplies power to 4 suspension controllers (2kW / unit) and air compressor (2kW), and the DC110V battery pack supplies power to the vehicle control equipment (2kW) and 4 suspension 110V loads (200W / unit). The total power consumption is 12kW (DC330V) + 2.8kW (DC110V) and the discharge current is 42A (DC330V) + 29A (DC110V).

[0036] Furthermore, in step S6, when input overvoltage (DC1500V>1900V / DC330V>360V), undervoltage (DC1500V<1000V / DC330V<200V), output short circuit (output current>200% of rated current), or power component overheating (IGBT temperature>85℃) faults are detected, the coordinating control unit immediately disconnects the corresponding circuit contactor, triggers an audible and visual alarm, and uploads fault information; after the fault is cleared or power is restored, the system is automatically restored to normal operation by local reset or remote command start-up.

[0037] like Figure 3 As shown, a schematic diagram is given of the auxiliary power supply providing power to the load equipment of the suspension test bench through the low-voltage power distribution unit.

[0038] The DC1500V high-voltage power supply is input to the ground power supply unit to provide energy for the entire power distribution system. Figure 3The lower center section is the DC330V power supply circuit: the DC330V power supply is connected in parallel with the 52Ah / DC330V battery pack, and then supplies power to the 1#-4# suspension controllers, the vehicle power supply unit, and the standby load through circuit breakers QF101-QF106, respectively. The input terminal of the vehicle power supply unit is connected to the DC330V power supply, providing a DC110V output. The output terminal is connected to the inverter through circuit breaker QF209, and the inverter is connected to the low-voltage distribution unit through circuit breaker QF300.

[0039] Figure 3 The upper middle section is a DC110V power supply circuit: After the DC110V power supply is connected in parallel with the 52Ah / DC110V battery pack, it supplies power to the 1#-4# suspension controllers, 1#-2# speed measurement and positioning devices, vehicle control console, and traction inverter through circuit breakers QF201-QF208 respectively. Contactor KM, circuit breaker QF209, and fuse FU form a circuit protection.

[0040] Figure 3 The low-voltage distribution unit on the right side outputs AC220V, which supplies power to the air compressor, vehicle socket, traction converter and standby load respectively through circuit breakers QF301-QF304. Contactor KM and fuse form a circuit protection.

[0041] Example 1: Auxiliary power supply structure for a ground-vehicle dual-system coordinated suspension test bench; The auxiliary power supply for the ground-vehicle dual-system coordinated suspension test bench in this embodiment includes a ground power supply unit, a vehicle power supply unit, a coordinated control unit, an energy storage unit, an inverter unit, and a low-voltage power distribution unit.

[0042] like Figure 4 The diagram shows the circuit topology of the ground power supply unit. The ground power supply unit converts 1500V high-voltage DC to a stable 330V DC. It provides the main power supply for the suspension system of the suspension test bench, and also provides input power to the vehicle-mounted power supply unit and charges the 330V DC battery pack. The rated input voltage is DC1500V, with a fluctuation range of 1000V-1900V; the output voltage is DC330V; and the rated output power is 40kW.

[0043] Fuse F1 provides overcurrent / short-circuit protection. It blows when a large current fault occurs on the input side, cutting off the high-voltage circuit and protecting downstream circuits. The circuit control includes contactor KM1 (main circuit), KM2 (pre-charge circuit), and current-limiting resistors R1 / R2. The pre-charge circuit is formed by contactor KM2 connected in series with the current-limiting resistor. Upon power-up, the pre-charge circuit closes first to prevent inrush current caused by instantaneous capacitor charging. After pre-charging, the main circuit closes to provide a high-current path. Inductor L1 and capacitors C1 / C6 / C9 form the LC filter circuit of the input filter module. L1 = 1mH, C1 / C6 / C9 = 10μF, used to suppress electromagnetic interference (EMI) on the input side, filter out voltage spikes and ripples in the DC1500V input, and stabilize the input voltage.

[0044] The three-level LLC converter module, consisting of IGBT modules Q1 / Q2 / Q4 / Q5 / Q7-Q14 and high-frequency transformers T1-T3, is the core power conversion module. It uses Infineon FF450R12ME4 IGBT modules and achieves DC 1500V step-down through IGBT high-frequency switching (20kHz~50kHz). The high-frequency transformers T1-T3 have a turns ratio of 15:3, and the three-level topology reduces the IGBT withstand voltage stress.

[0045] The output rectifier and filter module includes capacitors C3 / C8 and fast recovery diodes D2-D4 / D7-D9. The fast recovery diodes perform rectification, and capacitors C3 / C8 filter out the ripple of the rectified voltage after LLC conversion. The capacitors C3 / C8 = 100μF initially stabilize the DC voltage.

[0046] The interleaved BUCK converter module includes IGBT modules Q3 / Q6, diodes D5 / D6, inductors L3 / L4, and capacitors C4 / C5, achieving secondary precise step-down regulation. The switching frequency is 30kHz, and the interleaved topology reduces output ripple and improves current output capability. Inductors L3 / L4 = 2mH and capacitors C4 / C5 = 200μF, achieving a stable DC 330V ± 3% output.

[0047] Figure 4 The circuit topology employs a combination of three-level LLC and interleaved BUCK topology, achieving a conversion efficiency of >92%, balancing the efficiency of high-voltage step-down with the stability of low-voltage output. A pre-charge circuit is configured to address the inrush current issue during high-voltage DC power-up, protecting power components. The power components utilize IGBT modules and fast recovery diodes, adapting to high-frequency switching scenarios and meeting the high reliability requirements of rail transit. Multi-capacitor / inductor graded filtering is employed to suppress ripple throughout the entire input-output link, ensuring output voltage accuracy.

[0048] like Figure 5As shown, the DC 330V output powers the four suspension controllers and air compressor, among other core high-voltage loads, on the suspension test bench. The energy storage unit contains a 52Ah lithium iron phosphate battery pack with 103 cells connected in series, each with a rated voltage of 3.2V and a minimum discharge voltage of 290V. During normal operation of the ground power supply unit, the battery is used for charging and energy storage. In the event of a DC 1500V power outage, the battery acts as an emergency power source to power the suspension system, ensuring stable operation for at least one minute. It also helps to mitigate voltage fluctuations in the ground power supply unit, acting as an energy buffer.

[0049] The BMS is the control core of the DC330V energy storage unit. It uses an STM32H7 controller with a sampling accuracy of ±0.5% and a CAN2.0 communication interface for real-time communication with the collaborative control unit. Its core functions are divided into two categories: status acquisition and hierarchical protection. The battery pack's individual cell voltage, total voltage, charge / discharge current, and cell temperature are collected every 100ms, and the data is uploaded to the collaborative control unit via the CAN bus to provide a basis for adjusting the charge / discharge strategy.

[0050] Overvoltage protection: When the total voltage of the battery pack is ≥346V, the charging circuit is cut off and charging is stopped; Undervoltage protection: When the total battery pack voltage is ≤290V, the discharge circuit is cut off to prevent over-discharge; Overcurrent protection: When the charging / discharging current is ≥52A (1C rate), the current is limited and an alarm is triggered; if the threshold is exceeded, the circuit is disconnected. High-temperature graded protection: ① When the cell temperature is ≥55℃, a current reduction command is sent to reduce the charging current to 50%; ② When the cell temperature is ≥60℃, the contactor KM is directly controlled to disconnect, cutting off the battery output.

[0051] When the ground power supply unit is working normally: the BMS controls the charging strategy according to the battery capacity (equalization charging for capacity ≤80%, float charging for capacity ≥95%), the equalization charging voltage is 330V+5%=346.5V, and the float charging voltage is 330V+2%=336.6V; When the DC1500V power fails: the collaborative control unit detects that the input voltage is <1000V and lasts for 10ms, immediately controls the ground power supply unit to stop, and sends a command to the BMS to close the contactor KM. The battery pack immediately outputs DC330V to power 4 suspension controllers (2kW / unit) and air compressor (2kW), with a total power consumption of 12kW and a discharge current of 42A, ensuring stable operation of the suspension system for ≥1 minute; After the fault is recovered: once power is restored or the fault is cleared, and the BMS detects that the battery status is normal, the coordinated control unit commands the closed loop to restore the ground power supply unit's charging of the battery pack.

[0052] like Figure 6As shown, the complete circuit topology of the vehicle-mounted power supply unit converts DC330V to DC110V, which is completely identical to the topology of the ground power supply unit, with only the hardware parameters matching the voltage level. The vehicle-mounted power supply unit powers DC110V low-voltage loads such as the suspension test bench control system, speed measurement and positioning equipment, and vehicle-mounted control console, charges the DC110V battery pack, and simultaneously provides DC110V input power to the inverter unit. The rated input voltage is DC330V (connected to the output of the ground power supply unit), with a fluctuation range of 200V-360V, and an output of DC110V + / -. The component composition and module order are identical to those of the ground power supply unit. Figure 4 They are exactly the same, except that the high-frequency transformer turns ratio and capacitor / inductor parameters are adapted to meet the requirements of DC330V to DC110V conversion. The rated output power is 12kW and the conversion efficiency is >92%.

[0053] Fuse F1 provides hard overcurrent / short-circuit protection, cutting off fault current on the DC330V input side and protecting the power components of the vehicle unit. Contactors KM1 (main circuit), KM2 (pre-charge circuit), and current-limiting resistors R1 / R2 form a protection circuit control. The pre-charge circuit avoids voltage surges on the vehicle unit capacitors, while the main circuit provides a high-current path for the DC110V load, remotely switched on and off by the co-control unit. Inductor L1 and capacitors C1 / C6 / C9 provide LC filtering to suppress voltage ripple and electromagnetic interference from the ground power supply unit output, stabilize the DC330V input, and prevent interference with the subsequent high-frequency conversion module.

[0054] IGBT modules Q1 / Q2 / Q4 / Q5 / Q7-Q14 and high-frequency transformers T1-T3 achieve three-level LLC conversion; IGBT switching frequency is 20kHz~50kHz (consistent with the ground unit); the transformer turns ratio is adapted to DC330V to DC110V; the three-level topology reduces the IGBT withstand voltage stress; and the conversion efficiency is >92%.

[0055] Capacitors C3 / C8 and fast recovery diodes D2 / D3 / D4 / D7-D9 perform output rectification and filtering. The fast recovery diodes rectify the LLC converter, and capacitors C3 / C8 filter out the rectification ripple, thus initially stabilizing the DC voltage.

[0056] The IGBT module (Q3, Q6), diodes (D5, D6), inductors (L3, L4), and capacitors (C4, C5) implement interleaved BUCK switching, achieving precise secondary voltage regulation to DC110V±3%, with a switching frequency of 30kHz. The interleaved topology reduces output ripple and is suitable for the high-precision power supply requirements of low-voltage control loads.

[0057] The onboard power supply unit and the ground power supply unit share a common topology template, reducing design, production, and maintenance complexity and improving dual-system compatibility. They are cascaded and adapted: the input directly connects to the ground power supply unit's output, forming a cascaded step-down architecture of DC1500V→DC330V→DC110V, adapting to the high-voltage input and multi-voltage output requirements of rail transit. Under normal operating conditions, it is in hot standby mode, monitoring the ground power supply unit's status in real time. If the ground unit fails, it can quickly take over power supply, improving system redundancy. The ground unit is the primary power supplier, and the onboard unit is in hot standby mode. Both are uniformly scheduled by a collaborative control unit. In the event of a ground unit failure, the onboard unit uninterruptedly takes over the DC330V to DC110V conversion. The onboard power supply unit is connected in parallel with a 110V battery pack. Under normal conditions, it charges the battery; when the DC1500V power is lost, the battery powers it (or directly powers low-voltage loads). The onboard power supply unit provides a stable DC110V input to the inverter unit, ensuring the accuracy and stability of the AC220V output.

[0058] like Figure 7 The diagram illustrates the energy storage architecture of the DC110V battery pack and the AC220V conversion interface of the inverter unit. The DC110V battery pack is a 52Ah lithium iron phosphate battery with a single cell voltage of 3.2V, 34 cells connected in series, a rated voltage of 110V, a minimum discharge voltage of 97V, and BMS protection functions consistent with the DC330V branch. The battery management system uses an STM32H7 controller with a sampling accuracy of ±0.5%, a CAN2.0 communication interface, and supports overvoltage, undervoltage (97V), overcurrent (52A), and high temperature (55℃ / 60℃) protection. Designed with the same capacity as the DC330V battery pack, ensuring synchronized power outage duration for both energy storage units, with a total range supporting stable operation of the suspension system for ≥1 minute; Overvoltage protection: disconnects the charging circuit when the total battery voltage is ≥115.5V (rated 110V+5%); Undervoltage protection: disconnects the discharge circuit when the total battery voltage is ≤97V to prevent over-discharge; Overcurrent protection: limits the current and alarms when the charging / discharging current is ≥52A (1C rate), disconnects the circuit if the threshold is exceeded; High-temperature graded protection: the charging current drops to 50% when the cell temperature is ≥55℃, and disconnects the battery output contactor KM when the temperature is ≥60℃.

[0059] The inverter unit has a rated input of DC110V, an output of AC220V±5%, a frequency of 50Hz±1%, and a conversion efficiency of >90%. It features input reverse connection protection, input overvoltage (137.5V) / undervoltage (77V) protection, output overload (110% rated power) protection, and output short circuit protection.

[0060] The MCU of the collaborative control unit is a TITMS320F28335 with an operating frequency of 150MHz; the communication module is a dual-bus CAN / RS485 with a baud rate of 9600bps-115200bps and supports the Modbus protocol; the status monitoring module uses a voltage sensor LV25-P, a current sensor LA25-NP, and a temperature sensor PT100 to collect power supply parameters.

[0061] In the low-voltage power distribution unit, circuit breakers QF201-QF208 are Schneider C65N series with rated current of 16A-63A; contactor KM is Schneider LC1D series with rated voltage of DC110V; and fuses FU1-FU3 are ceramic fuses with rated current of 50A-100A, realizing power distribution and circuit protection for each load of the suspension test bench.

[0062] like Figure 8 As shown, the ground power supply unit and the vehicle-mounted power supply unit adopt the same circuit topology. The circuit topology includes an input filter module, a pre-charge circuit, a main circuit, a three-level LLC converter module, an output rectification filter module, and an interleaved BUCK converter module, which are connected in series along the current path. The input filtering module is an LC circuit composed of a first inductor L1 and first, sixth and ninth capacitors C1, C6 and C9, used to suppress electromagnetic interference on the input side and filter out voltage spikes and ripples. The pre-charging circuit includes a second contactor KM2 and a current-limiting resistor R1 to prevent the surge current generated by the instantaneous charging of the capacitor when the power is on, thus protecting the power components; the main circuit contactor KM1 provides a high current path for the load and is remotely controlled by the collaborative control unit.

[0063] The three-level LLC conversion module includes first, second, fourth, fifth, and seventh to fourteenth IGBT modules Q1-Q2, Q4-Q5, Q7-Q14, and first to third high-frequency transformers T1-T3, with a switching frequency of 20kHz-50kHz; it is used to achieve DC voltage conversion through IGBT high-frequency switching, and the three-level topology reduces the IGBT withstand voltage stress.

[0064] The output rectification and filtering module includes second to fourth and seventh to ninth fast recovery diodes D2-D4, D7-D9 and third and eighth capacitors C3 and C8, which are used to rectify the AC voltage after LLC conversion into DC and filter out rectification ripple. The interleaved BUCK converter module includes third and sixth IGBT modules Q3 and Q6, fifth and sixth diodes D5 and D6, third and fourth inductors L3 and L4, and fourth and fifth capacitors C4 and C5. The switching frequency is 30kHz, which is used for secondary precise step-down regulation to reduce output ripple and improve voltage accuracy.

[0065] All switching devices use IGBT modules (the ground unit uses Infineon FF450R12ME4, and the vehicle unit is compatible with the same IGBT), which are suitable for high-frequency switching scenarios from 20kHz to 50kHz; all rectifier devices use fast recovery diodes to meet high-frequency rectification requirements and reduce rectification losses. Figure 4 The ground unit is compatible with DC1500V→DC330V and is equipped with large-size IGBTs and high-ratio transformers. Figure 6 The vehicle-mounted unit is compatible with DC330V→DC110V and is equipped with transformer turns ratio and capacitor / inductor parameters adapted to low voltage. Components of the same specifications and models can be selected to improve the versatility of the supply chain.

[0066] The three-level LLC topology directly solves the core loss problem in high-voltage DC-DC conversion by achieving full-load soft switching to eliminate switching losses, reducing device withstand voltage stress to reduce conduction / switching losses, optimizing the resonant cavity to improve energy transmission efficiency, reducing reverse recovery losses on the rectifier side, and adapting to high-frequency switching to reduce magnetic component losses. This is the key technical means for achieving a conversion efficiency of >92% in this invention. Furthermore, through targeted parameter design and device selection, this invention realizes the efficiency improvement effect of the topology, providing a replicable design solution for efficiency optimization of high-voltage industrial-grade auxiliary power supplies.

[0067] The ground power supply unit adopts a 15:3 transformation ratio to precisely match the DC1500V→DC330V step-down requirement, avoiding energy loss caused by transformer transformation ratio mismatch. Infineon FF450R12ME4 IGBTs (low on-resistance, fast switching speed) and fast recovery diodes with low reverse recovery charge are selected to further reduce device losses. The parameters of the resonant inductor, magnetizing inductor, and resonant capacitor are precisely calculated based on the load power consumption (40kW / 12kW) and switching frequency (20kHz-50kHz) to achieve soft switching across the entire load range. It is cascaded with an interleaved BUCK topology: the three-level LLC achieves coarse step-down at high voltage, and the interleaved BUCK achieves fine stabilization at low voltage. The losses of the two topologies are decoupled from each other, avoiding the concentration of losses caused by a single topology bearing all the step-down tasks, further improving the overall conversion efficiency to be stable above 92%.

[0068] This invention cascades a three-level LLC converter with an interleaved BUCK topology, and the ground / vehicle-mounted power supply units use the same topology template (only the voltage level is adapted for parameter matching). This leverages the high-voltage soft-switching advantage of the three-level LLC converter to reduce device withstand voltage stress, while the interleaved BUCK topology achieves precise low-voltage regulation (ripple factor <3%), ultimately achieving a conversion efficiency of >92%. The triple redundancy design of this invention reduces the probability of power outages by more than 90%. Even if the DC 1500V high-voltage input is interrupted, the energy storage unit can still maintain power supply for ≥1 minute, avoiding data loss and equipment damage, demonstrating significant technical effectiveness.

[0069] Example 2: Control process details; Initialization Phase S1: After the collaborative control unit is powered on, it performs register configuration and communication handshake for each module. The BMS system reads the initial state of the battery. If all modules are in normal condition, it enters standby mode. If a fault is detected, it triggers an audible and visual alarm and records the fault code.

[0070] Main power supply start-up phase S2: After receiving the start command, the coordination control unit first closes the ground power supply unit to output DC330V; then it starts the vehicle power supply unit to output DC110V, and the inverter unit starts synchronously to output AC220V.

[0071] Energy storage management phase S3: The BMS system collects battery voltage, temperature, and current data every 100ms. When the battery capacity is ≤80%, it controls the charger to perform equalization charging (DC330V / DC110V rated voltage +5%). When the capacity is ≥95%, it switches to float charging (DC330V / DC110V rated voltage +2%). When the cell temperature reaches 55℃, it sends a current reduction command (charging current is reduced to 50%). When it reaches 60℃, it disconnects the battery output contactor.

[0072] Dual-system collaboration phase S4: The collaborative control unit collects power supply parameters every 200ms and uploads them to the integrated monitoring system via the CAN bus. At the same time, it receives remote control commands and can set output voltage, current limit value, and communication baud rate parameters. Under normal operating conditions, the ground power supply unit bears 100% load, the vehicle power supply unit is in hot standby state, and the main power supply status is monitored in real time.

[0073] S5 Power Outage Recovery Phase: When the DC1500V input voltage is detected to be below 1000V for 10ms, it is determined to be a power outage. The coordinating control unit immediately controls the ground power supply unit to stop working, and at the same time closes the output contactor of the energy storage unit. The DC330V battery pack supplies power to 4 suspension controllers (2kW / unit) and air compressor (2kW), and the DC110V battery pack supplies power to the vehicle control equipment (2kW) and 4 suspension 110V loads (200W / unit). The total power consumption is 12kW (DC330V) + 2.8kW (DC110V), and the discharge current is 42A (DC330V) + 29A (DC110V), ensuring stable operation of the suspension system for ≥1 minute.

[0074] Fault Protection and Recovery Phase S6: When an input overvoltage (DC1500V>1900V / DC330V>360V), undervoltage (DC1500V<1000V / DC330V<200V), output short circuit (output current>200% of rated current), or power component overheating (IGBT temperature>85℃) fault is detected, the coordinated control unit immediately disconnects the corresponding circuit contactor, triggers an audible and visual alarm, and uploads the fault information; after the fault is cleared or the power supply is restored, the system is automatically restored to normal operation by local reset or remote command start-up.

[0075] Although the invention has been described herein in conjunction with various embodiments, those skilled in the art will understand and implement other variations of the disclosed embodiments by reviewing the accompanying drawings, disclosure, and other materials. In this specification, the word "comprising" does not exclude other components or steps, and "a" or "an" does not exclude multiple components. A single processor or other unit can implement several functions listed in the specification. While certain measures are described in different embodiments, this does not mean that these measures cannot be combined to produce good results.

[0076] Although the invention has been described in conjunction with specific features and embodiments, it is obvious that various modifications and combinations can be made therein without departing from the spirit and scope of the invention. Accordingly, this specification and drawings are merely illustrative of the invention and are considered to cover any and all modifications, variations, combinations, or equivalents within the scope of the invention. Clearly, those skilled in the art can make various alterations and modifications to the invention without departing from its spirit and scope. Thus, if such modifications and modifications fall within the scope of the invention and its equivalents, the invention is also intended to include such modifications and modifications.

Claims

1. An auxiliary power supply for a ground-vehicle dual-system coordinated suspension test bench, characterized in that, The auxiliary power supply includes: The ground power supply unit is used to connect to a DC1500V high-voltage input and convert it to a stable DC330V output. The vehicle-mounted power supply unit is electrically connected to the DC330V output terminal of the ground power supply unit and is used to convert DC330V into a stable DC110V output. The collaborative control unit is communicatively connected to the ground power supply unit and the vehicle power supply unit, respectively, and is used to realize dual system power supply switching, parameter control and fault alarm; The energy storage unit includes a DC330V battery pack and a DC110V battery pack, which are connected in parallel with the output terminals of the ground power supply unit and the vehicle power supply unit, respectively. Both battery packs are equipped with a battery management system. The inverter unit is electrically connected to the vehicle power supply unit and is used to convert DC110V to AC220V AC output. The low-voltage power distribution unit is electrically connected to the vehicle-mounted power supply unit and the inverter unit respectively, and is used to provide DC110V and AC220V power to the load equipment of the suspension test bench. The ground power supply unit and the vehicle power supply unit form a cascaded collaborative power supply architecture. The collaborative control unit controls the ground power supply unit as the main power supply and the vehicle power supply unit as the hot backup power supply, or switches to the energy storage unit for power supply when the DC1500V power is cut off, so as to maintain the stable operation of the suspension system for ≥1 minute.

2. The auxiliary power supply according to claim 1, characterized in that, The ground power supply unit and the vehicle-mounted power supply unit use the same circuit topology.

3. The auxiliary power supply according to claim 2, characterized in that, The circuit topology includes an input filter module, a pre-charge circuit, a main circuit, a three-level LLC converter module, an output rectifier filter module, and an interleaved BUCK converter module connected in series along the current path. The input filtering module is an LC circuit consisting of a first inductor (L1) and first, sixth and ninth capacitors (C1, C6, C9), used to suppress electromagnetic interference on the input side; The pre-charging circuit includes a second contactor (KM2) and a current-limiting resistor (R1) to prevent power-on inrush current; The three-level LLC conversion module includes first, second, fourth, fifth and seventh to fourteenth IGBT modules (Q1-Q2, Q4-Q5, Q7-Q14) and first to third high-frequency transformers (T1-T3), with a switching frequency of 20kHz-50kHz; The output rectifier and filter module includes the second to fourth and the seventh to ninth fast recovery diodes (D2-D4, D7-D9) and the third and eighth capacitors (C3, C8). The interleaved BUCK switching module includes third and sixth IGBT modules (Q3, Q6), fifth and sixth diodes (D5, D6), third and fourth inductors (L3, L4), and fourth and fifth capacitors (C4, C5), with a switching frequency of 30kHz.

4. The auxiliary power supply according to claim 1, characterized in that, The rated input voltage of the ground power supply unit is DC1500V, with a fluctuation range of 1000V-1900V, a rated output power of 40kW, a rated output voltage of DC330V±3%, a DC ripple rate of <2%Vrms, a conversion efficiency of >92%, and an output ripple factor of <3%. The rated input voltage of the vehicle power supply unit is DC330V, with a fluctuation range of 200V-360V, a rated output power of 12kW, a rated output voltage of DC110V±3%, a DC ripple rate of <2%Vrms, a conversion efficiency of >92%, and an output ripple factor of <3%.

5. The auxiliary power supply according to claim 1, characterized in that, The energy storage unit's DC330V and DC110V battery packs are both 52Ah lithium iron phosphate batteries with a discharge rate ≤1C. The rated operating voltage of the DC330V battery pack is 330V, and the minimum discharge voltage is 290V. The rated operating voltage of the DC110V battery pack is 110V, and the minimum discharge voltage is 97V.

6. The auxiliary power supply according to claim 1, characterized in that, The battery management system has overvoltage, high temperature, and charging overcurrent limiting and protection functions, and supports remote data communication; when the battery cell temperature reaches 55°C, it controls the charger to reduce current or stop charging; when the cell temperature reaches 60°C, it disconnects the battery output contactor.

7. The auxiliary power supply according to claim 1, characterized in that, The collaborative control unit includes an MCU controller, a CAN / RS485 communication module, and a status monitoring module. It supports local and / or remote display of output voltage, output current, charging current, input voltage, and temperature parameters, and allows setting of output voltage, undervoltage / overvoltage protection values, current limiting values, and communication baud rate parameters. The status monitoring module includes a voltage sensor, a current sensor, and a temperature sensor, used to collect power supply parameters; it supports parameter setting and status monitoring in local or remote modes.

8. A method for controlling the auxiliary power supply of a ground-vehicle dual-system coordinated suspension test bench, applied to the auxiliary power supply described in any one of claims 1-7, characterized in that, The method includes the following steps: S1. System initialization: The collaborative control unit starts a self-test, checks the hardware status and communication connection status of each unit, and the battery management system initializes the battery parameters. S2. Main power supply start-up: The coordination control unit controls the ground power supply unit to connect to DC1500V input and outputs a stable DC330V voltage; at the same time, it controls the vehicle power supply unit to start and outputs a stable DC110V voltage. S3, Energy Storage Management: The battery management system monitors the status of the battery pack in real time and, in coordination with the control unit, controls the charger to execute either float charging or equalization charging strategies based on the battery voltage and capacity. S4. Dual-system collaboration: Under normal operating conditions, the ground power supply unit is the main power supply and the vehicle power supply unit is the backup. The collaborative control unit collects and uploads power supply parameters in real time. S5. Power outage recovery: When DC1500V power is lost, the collaborative control unit switches to the energy storage unit for power supply to maintain the stable operation of the levitation system for ≥1 minute. S6. Fault Protection and Recovery: When an abnormal operating condition is detected, the corresponding protection mechanism is triggered and an alarm is triggered; after power is restored or the fault is cleared, normal operation is automatically restored.

9. The method according to claim 8, characterized in that, In step S1, after the collaborative control unit is powered on, it performs register configuration and communication handshake for each module. The battery management system reads the initial state of the battery. If all modules are in normal state, it enters standby state. If a fault is detected, it triggers an audible and visual alarm and records the fault code. In step S2, after receiving the start command, the collaborative control unit first closes the pre-charging circuit of the ground power supply unit, and then closes the main circuit after the input current stabilizes. It then starts the three-level LLC conversion module and the interleaved BUCK conversion module to output DC330V. Subsequently, it starts the vehicle power supply unit to input DC330V and output DC110V, and the inverter unit starts synchronously to output AC220V.

10. The method according to claim 9, characterized in that, In step S3, the battery management system periodically collects battery voltage, temperature, and current data. When the battery capacity is ≤80%, equalization charging is performed, with the equalization charging voltage being DC330V / DC110V rated voltage +5%. When the capacity is ≥95%, it switches to float charging, with the float charging voltage being DC330V / DC110V rated voltage +2%. When the cell temperature reaches 55℃, the charging current drops to 50%, and when it reaches 60℃, the battery output contactor is disconnected. In step S4, the collaborative control unit collects power supply parameters every 200ms and uploads them to the integrated monitoring system via the CAN bus, while also receiving remote control commands. Under normal operating conditions, the ground power supply unit bears 100% load, while the vehicle-mounted power supply unit is in hot standby mode and monitors the main power supply status in real time. In step S5, when the DC1500V input voltage is detected to be lower than 1000V for 10ms, it is determined that the power supply is interrupted. The coordinating control unit immediately controls the ground power supply unit to stop working and closes the output contactor of the energy storage unit. In step S6, when an input overvoltage, undervoltage, output short circuit, or power component overheating fault is detected, the coordinated control unit immediately disconnects the corresponding circuit contactor, triggers an audible and visual alarm, and uploads the fault information. After the fault is cleared or the power supply is restored, the system is automatically restored to normal operation by local reset or remote command startup.

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