Operation and auxiliary load redundant power supply method

Abstract

The invention discloses an operation and auxiliary load redundant power supply method. An auxiliary inversion branch is connected with an auxiliary load through a first output contactor. And the operation inversion branch is connected with an operation motor through a second output contactor. The main contact of the switching contactor is connected between the output side of the main contact of the first output contactor and the input side of the main contact of the second output contactor. And the auxiliary inversion branch inverts the voltage of the intermediate DC bus, isolates and transforms the voltage to output a three-phase alternating current, and supplies the three-phase alternating current to an auxiliary load. The operation inversion branch inverts the voltage of the intermediate direct current bus and outputs variable-frequency and variable-voltage three-phase alternating current to be supplied to an operation motor, and the operation motor is started in a variable-frequency and variable-voltage mode and operates in a fixed-frequency and fixed-voltage mode. The technical problem that an existing power supply method cannot realize redundant power supply, so that auxiliary load power supply cannot be realized when an auxiliary inverter branch has a fault, and a vehicle cannot run due to a fault can be solved.

Description

Technical Field

[0001] This application relates to the field of rail transit electrical technology, and in particular to a redundant power supply device for working and auxiliary loads of rail transit vehicles. Background Technology

[0002] The power supply for rail transit vehicles typically includes both operational and auxiliary loads. Therefore, their power supply systems usually consist of two parts: operational load power supply and auxiliary load power supply. Auxiliary inverters provide power to auxiliary loads, primarily including traction fans, braking resistor fans, converter cooling systems (including fans / pumps), air compressors, and other key traction-related equipment, as well as auxiliary equipment such as electric heaters, air conditioners, and household power outlets. Operational inverters provide power to operational loads, primarily including hydraulic pump motors and other operational devices. Power supply to key equipment has a higher priority than that to operational devices. Due to space or cost constraints, existing rail transit vehicles cannot be designed with dual auxiliary inverter branches for redundant power supply. This results in a failure of the auxiliary inverter branch, preventing auxiliary load power supply and causing vehicle malfunctions and inoperability, indicating poor redundancy. Although some rail transit vehicles currently have two auxiliary load power supply branches, these require significant space and are not economically viable. Furthermore, the characteristics of operational load power supply differ significantly from those of auxiliary load power supply, necessitating a separate operational inverter branch. Meanwhile, the main load and auxiliary load branches are independent of each other, and use two independent control algorithms that cannot be switched between each other.

[0003] The following documents are relevant to this application in the prior art: Document 1 is a Chinese utility model patent applied for by CRRC Zhuzhou Electric Locomotive Co., Ltd. on December 13, 2023, and published on July 5, 2024, with publication number CN221272573U. This utility model discloses an electric locomotive and its auxiliary power supply system. The auxiliary power supply system includes a first auxiliary power supply, a second auxiliary power supply, a first contactor, a second contactor, a third contactor, and a fourth contactor located in each car. The first auxiliary power supply is connected to a first auxiliary load, a third contactor, and a fourth contactor via the first contactor contact. The second auxiliary power supply is connected to a second auxiliary load and a third contactor via the second contactor contact. The fourth contactor contact is also connected to the fourth contactor contacts of other cars via a through busbar. This utility model can ensure the normal operation of auxiliary loads under different fault conditions, improving the power supply redundancy and reliability of the auxiliary power supply system. However, this utility model is mainly used for mutual power supply between cars in a train and does not involve redundant power supply for operation and auxiliary loads.

[0004] Document 2 is a Chinese invention application filed by CRRC Zhuzhou Electric Locomotive Co., Ltd. on December 7, 2016, and published on March 29, 2017, with publication number CN 10654182A. This application discloses a redundant power supply circuit, vehicle, and method for an AC power supply system of a rail transit vehicle. The redundant power supply circuit includes an auxiliary inverter that provides three-phase power to the entire vehicle. The three-phase inverter of the rail transit vehicle is connected in parallel with the auxiliary inverter. The input terminal of the three-phase inverter is connected between a switch and the coil of a first relay. The contacts of the first relay are connected to the coil of a second relay. The contacts of the second relay are connected to the line between the output terminal of the auxiliary inverter and the output terminal of the auxiliary inverter. This invention utilizes the three-phase output function of the inverter inside the vehicle's high-voltage DC inverter air conditioner, adopting an extended power supply method to continue providing AC power to the entire vehicle. This effectively ensures the continued operation of three-phase electrical equipment, preventing adverse consequences such as the need for rescue. Without increasing the vehicle's design cost, it improves the redundancy of the AC system and enhances the vehicle's availability. However, this invention uses the same AC bus, is not completely independently separated, and has different main power supply circuits. Summary of the Invention

[0005] In view of this, the purpose of this application is to provide a redundant power supply method for both operating and auxiliary loads, so as to solve the technical problem that existing power supply methods cannot achieve redundant power supply, resulting in the inability to supply power to auxiliary loads when the auxiliary inverter branch fails, causing vehicle malfunction and inability to drive.

[0006] To achieve the aforementioned objectives, this application provides a technical implementation scheme for a redundant power supply method for both operational and auxiliary loads. The auxiliary inverter branch is connected to the auxiliary load via a first output contactor. The operational inverter branch is connected to the operational motor via a second output contactor. The main contacts of the switching contactor are connected between the output side of the main contacts of the first output contactor and the input side of the main contacts of the second output contactor. The auxiliary inverter branch inverts and isolates the intermediate DC bus voltage to output three-phase AC power, which is then supplied to the auxiliary load. The operational inverter branch inverts the intermediate DC bus voltage to output frequency-converted and voltage-converted three-phase AC power, which is then supplied to the operational motor. The operational motor performs frequency-converted and voltage-converted starting and constant-frequency and constant-voltage operation.

[0007] Furthermore, the auxiliary inverter branch includes a first inverter module and a first pre-charge circuit connected to the input side of the first inverter module. The working inverter branch includes a second inverter module and a second pre-charge circuit connected to the input side of the second inverter module. The first pre-charge circuit causes the bus voltage to rise steadily, and the first inverter module provides three-phase AC power to the auxiliary load. The second pre-charge circuit causes the bus voltage to rise steadily, and the second inverter module supplies power to the working motor.

[0008] Furthermore, the first pre-charge circuit includes a first charging contactor, a first shorting contactor, and a first charging resistor, wherein the first charging contactor and the first charging resistor are connected in series and then in parallel across the two ends of the first shorting contactor. The second pre-charge circuit includes a second charging contactor, a second shorting contactor, and a second charging resistor, wherein the second charging contactor and the second charging resistor are connected in series and then in parallel across the two ends of the second shorting contactor.

[0009] Furthermore, the auxiliary inverter branch also includes a first line reactor, a first supporting capacitor, and a first discharge resistor. The first supporting capacitor and the first discharge resistor are both connected in parallel to the input side of the first inverter module, and the first line reactor is connected between the first pre-charge circuit and the input side of the first inverter module. The operating inverter branch also includes a second line reactor, a second supporting capacitor, and a second discharge resistor. The second supporting capacitor and the second discharge resistor are both connected in parallel to the input side of the second inverter module, and the second line reactor is connected between the second pre-charge circuit and the input side of the second inverter module. During normal operation, the first line reactor and the first supporting capacitor, and the second line reactor and the second supporting capacitor, form a filtering and energy buffer circuit. When the circuit is powered off, the high voltage across the first supporting capacitor is discharged through the first discharge resistor, and the high voltage across the second supporting capacitor is discharged through the second discharge resistor.

[0010] Furthermore, the auxiliary inverter branch also includes a first fuse connected between the first line reactor and the input side of the first inverter module. The operating inverter branch also includes a second fuse connected between the second line reactor and the input side of the second inverter module. When a short-circuit overcurrent occurs at the rear of the circuit, both the first and second fuses will blow to prevent damage to the power supply.

[0011] Furthermore, a reverse pre-charge circuit is connected to the output side of the main contacts of the first output contactor and the main contacts of the switching contactor. The reverse pre-charge circuit includes a third charging contactor, a third shorting contactor, and a third charging resistor. The third charging contactor and the third charging resistor are connected in series and then in parallel across the two ends of the third shorting contactor.

[0012] Furthermore, an isolation transformer and a filter capacitor are connected in series between the main contacts of the first output contactor and the output side of the main contacts of the switching contactor and the reverse pre-charge circuit.

[0013] Furthermore, when the auxiliary inverter branch is operating normally, the first charging contactor is first closed to charge the first supporting capacitor through the first charging resistor. When the intermediate DC bus voltage of the auxiliary inverter branch meets the requirements or after a set delay, the first short-circuit contactor is closed, and the first charging contactor is opened. The auxiliary inverter module inverts the intermediate DC bus voltage into a constant-voltage, constant-frequency three-phase AC power. After being stepped down by the isolation transformer and filtered by the filter capacitor, a constant-frequency, constant-voltage three-phase sinusoidal AC power is output to supply the auxiliary load.

[0014] Furthermore, when the working inverter branch is operating normally, based on the working motor start signal, after detecting that the intermediate DC bus voltage meets the working inverter input voltage range, the second charging contactor is first closed. Then, after detecting that the intermediate DC bus voltage of the working inverter branch meets the requirements or after a set delay, the second short-circuit contactor is closed, and the second charging contactor is opened. The working inverter module inverts the intermediate DC bus voltage, uses variable voltage and variable frequency to start the working motor, and then supplies power to the working motor at a fixed frequency and fixed voltage.

[0015] Furthermore, during reverse charging, a three-phase AC power input is provided to control the closing of the third charging contactor. When the input three-phase AC power meets the requirements or after a set delay, the third short-circuit contactor closes. After being stepped up by the isolation transformer, the voltage is rectified by the auxiliary inverter module into an intermediate DC bus voltage, which is then supplied to the DC-DC converter to charge the power battery.

[0016] Furthermore, a set of normally closed auxiliary contacts of the first and second output contactors are connected in series with the contacts of the intermediate relay to control the coil power supply of the switching contactor. The output control signal controls the coil of the first output contactor via a set of normally closed auxiliary contacts of the switching contactor. The output control signal controls the coil of the second output contactor via another set of normally closed auxiliary contacts of the switching contactor. A self-locking switch is connected to the coil of the intermediate relay, and the coil of the intermediate relay is controlled in parallel via the self-locking switch or the output control signal.

[0017] Furthermore, when the auxiliary inverter branch fails, the system can manually enter redundant power supply mode by opening the self-locking switch, or automatically enter redundant power supply mode by outputting a high level to the coil of the intermediate relay. When the auxiliary inverter branch is normal, the system can restore normal output mode by resetting the self-locking switch or through a logic program.

[0018] Furthermore, when entering the redundant power supply mode, the main contacts of the first and second output contactors are opened, and the main contacts of the switching contactor are closed. After the constant voltage and constant frequency three-phase AC power is output from the working inverter branch, it is output as three-phase sinusoidal AC power after passing through the isolation transformer and filtering.

[0019] Furthermore, under normal circumstances, the coil of the first output contactor is connected in series with the normally closed auxiliary contact of the switching contactor and is controlled by the output control signal. Similarly, the coil of the second output contactor is connected in series with the normally closed auxiliary contact of the switching contactor and is also controlled by the output control signal. When the main contact of the switching contactor is closed, the normally closed auxiliary contact is mechanically opened, preventing the coils of both the first and second output contactors from being energized. When either the main contact of the first or second output contactor is closed, the corresponding normally closed auxiliary contact is mechanically opened, preventing the coil of the switching contactor from being energized, and keeping the main contact of the switching contactor open.

[0020] Furthermore, when the self-locking switch is opened and the coil of the switching contactor is energized, the main contacts of the switching contactor close, and the two normally closed auxiliary contacts of the switching contactor open. After the normally closed auxiliary contacts of the two switching contactors are open, the coils of the first output contactor and the second output contactor cannot be energized, and the main contacts of the first output contactor and the second output contactor remain open.

[0021] Furthermore, the status of the first charging contactor, the first shorting contactor, the second charging contactor, the second shorting contactor, the first fuse, the second fuse, the first inverter module, and the second inverter module is detected. When a fault is detected in the first charging contactor, the first shorting contactor, the first fuse, or the first inverter module, the system automatically enters a redundant power supply mode and outputs a high level to the coil of the intermediate relay.

[0022] Furthermore, in the redundant power supply mode, the auxiliary load is powered through the second inverter module, switching contactor, isolation transformer, filter capacitor and third short-circuit contactor.

[0023] By implementing the technical solution of the redundant power supply method for main and auxiliary loads provided in this application, the following beneficial effects are achieved: (1) The redundant power supply method for operation and auxiliary loads in this application is based on two independent power supply branches. The main circuit that integrates the auxiliary inverter branch and the operation inverter branch is adopted. The two power supply branches are completely independent and mutually redundant, which can realize independent power supply of the two branches and realize emergency output of three-phase AC power of the operation inverter branch. In the fault condition, the backup auxiliary inverter unit supplies power to the critical auxiliary load, reducing the number of rescues. (2) In the redundant power supply method for operation and auxiliary loads of this application, the auxiliary inverter branch and the operation inverter branch are independent of each other. They are interlocked by auxiliary contacts or by performing logic operations through the auxiliary control unit to realize interlocking, switching and other logic; only a switching contactor is added to realize redundant power supply for auxiliary loads, saving space and cost; when the auxiliary inverter is abnormal, the operation inverter can realize the auxiliary inverter conversion function through conversion, realizing redundant power supply for operation and auxiliary loads. (3) The redundant power supply method for operation and auxiliary load of this application integrates the reverse pre-charging circuit of the 3AC380V / 50Hz power supply in the warehouse, which can realize the reverse filtering, isolation boost and rectification of the power supply in the warehouse and output to the intermediate DC bus. It can charge the power battery and other loads. Without adding charging branches, it maximizes the use of the main circuit, saves the charger, and integrates the power battery charging function. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other embodiments can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a main circuit topology diagram of a specific embodiment of the redundant power supply device for operation and auxiliary loads on which the method of this application is based; Figure 2 This is a schematic diagram of the control structure of a specific embodiment of the redundant power supply device for operation and auxiliary loads upon which the method of this application is based.

[0026] In the diagram: 1-Control unit, KM11-First charging contactor, KM12-First short-circuit contactor, R11-First charging resistor, L1-First line reactor, C11-First supporting capacitor, R12-First discharge resistor, FR1-First fuse, INV1-First inverter module, KM5-First output contactor, KM21-Second charging contactor, KM22-Second short-circuit contactor, R21-Second charging resistor, L2-Second line reactor, C21-Second supporting capacitor, R22-Second discharge resistor, FR2-Second fuse, INV2-Second inverter module, KM6-Switching contactor, KM7-Second output contactor, T1-Isolation transformer, C12-Filter capacitor, KM3-Third charging contactor, KM4-Third short-circuit contactor, R31-Third charging resistor, M1-Working motor, S1-Self-locking switch, K1-Intermediate relay. Detailed Implementation

[0027] For the sake of clarity and reference, the technical terms, abbreviations, or acronyms used below will be recorded as follows: ACU: Short for Auxiliary Inverter Control Unit.

[0028] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0029] As attached Figure 1 and appendix Figure 2 As shown, a specific embodiment of the redundant power supply method for auxiliary loads in this application is given. The application will be further described below with reference to the accompanying drawings and specific embodiments.

[0030] This application provides a specific embodiment of an efficient and robust method for redundant power supply of operating and auxiliary loads, which can adapt to the complex and ever-changing railway line environment and maintain high detection efficiency while ensuring detection effect.

[0031] Example 1 As attached Figure 1 As shown, an embodiment of the redundant power supply method for operation and auxiliary load of this application specifically includes the following steps: The auxiliary inverter branch is connected to the auxiliary load via the first output contactor KM5; Connect the inverter branch of the work unit to the work motor M1 via the second output contactor KM7; Connect the main contact of switching contactor KM6 between the output side of the main contact of the first output contactor KM5 and the input side of the main contact of the second output contactor KM7; The auxiliary inverter branch inverts and isolates the intermediate DC bus voltage to output three-phase AC power to supply the auxiliary load. The working inverter branch inverts the intermediate DC bus voltage to output frequency- and voltage-converted three-phase AC power, which is supplied to the working motor M1. The working motor M1 starts with frequency conversion and voltage conversion and runs with constant frequency and voltage.

[0032] The auxiliary inverter branch includes a first inverter module INV1 and a first pre-charge circuit connected to the input side of the first inverter module INV1. The working inverter branch includes a second inverter module INV2 and a second pre-charge circuit connected to the input side of the second inverter module INV2. The first pre-charge circuit ensures a smooth rise in the bus voltage, and the first inverter module INV1 provides three-phase AC power to the auxiliary load. The second pre-charge circuit ensures a smooth rise in the bus voltage, and the second inverter module INV2 supplies power to the working motor M1.

[0033] The first pre-charge circuit includes a first charging contactor KM11, a first shorting contactor KM12, and a first charging resistor R11. The first charging contactor KM11 and the first charging resistor R11 are connected in series and then in parallel across the two ends of the first shorting contactor KM12. The second pre-charge circuit includes a second charging contactor KM21, a second shorting contactor KM22, and a second charging resistor R21. The second charging contactor KM21 and the second charging resistor R21 are connected in series and then in parallel across the two ends of the second shorting contactor KM22.

[0034] The auxiliary inverter branch also includes a first line reactor L1, a first supporting capacitor C11, and a first discharge resistor R12. The first supporting capacitor C11 and the first discharge resistor R12 are both connected in parallel to the input side of the first inverter module INV1. The first line reactor L1 is connected between the first pre-charge circuit and the input side of the first inverter module INV1. The operating inverter branch also includes a second line reactor L2, a second supporting capacitor C21, and a second discharge resistor R22. The second supporting capacitor C21 and the second discharge resistor R22 are both connected in parallel to the input side of the second inverter module INV2. The second line reactor L2 is connected between the second pre-charge circuit and the input side of the second inverter module INV2. During normal operation, the first line reactor L1 and the first supporting capacitor C11, and the second line reactor L2 and the second supporting capacitor C21 form a filtering and energy buffer circuit. When the circuit is de-energized, the high voltage across the first supporting capacitor C11 is discharged through the first discharge resistor R12, and the high voltage across the second supporting capacitor C21 is discharged through the second discharge resistor R22.

[0035] The auxiliary inverter branch also includes a first fuse FR1, which is connected between the first line reactor L1 and the input side of the first inverter module INV1. The operating inverter branch also includes a second fuse FR2, which is connected between the second line reactor L2 and the input side of the second inverter module INV2. When a short-circuit overcurrent occurs at the rear of the circuit, both the first fuse FR1 and the second fuse FR2 will blow to prevent damage to the power supply.

[0036] A reverse pre-charge circuit is connected to the output side of the main contacts of the first output contactor KM5 and the main contacts of the switching contactor KM6. The reverse pre-charge circuit includes a third charging contactor KM3, a third shorting contactor KM4, and a third charging resistor R31. The third charging contactor KM3 and the third charging resistor R31 are connected in series and then in parallel across the two ends of the third shorting contactor KM4.

[0037] An isolation transformer T1 and a filter capacitor C12 are connected in series between the main contacts of the first output contactor KM5 and the output side of the main contacts of the switching contactor KM6 and the reverse pre-charge circuit.

[0038] Connect a set of normally closed auxiliary contacts of the first output contactor KM5 and the second output contactor KM7 in series with the contacts of the intermediate relay K1 to control the power supply to the coil of the switching contactor KM6. The output control signal controls the coil of the first output contactor KM5 via a set of normally closed auxiliary contacts of the switching contactor KM6. The output control signal controls the coil of the second output contactor KM7 via another set of normally closed auxiliary contacts of the switching contactor KM6. Connect the self-locking switch S1 to the coil of the intermediate relay K1. The coil of the intermediate relay K1 is controlled in parallel via the self-locking switch S1 or the output control signal, as shown in the attached diagram. Figure 2 As shown.

[0039] When the auxiliary inverter branch is operating normally, the first charging contactor KM11 is closed first, charging the first supporting capacitor C11 through the first charging resistor R11. When the intermediate DC bus voltage of the auxiliary inverter branch meets the requirements or after a set delay, the first short-circuit contactor KM12 is closed, and the first charging contactor KM11 is opened. The auxiliary inverter module inverts the intermediate DC bus voltage into a constant-voltage, constant-frequency three-phase AC power. After being stepped down by the isolation transformer T1 and filtered by the filter capacitor C12, a constant-frequency, constant-voltage three-phase sinusoidal AC power is output to supply the auxiliary load.

[0040] When the inverter branch is operating normally, upon detecting that the intermediate DC bus voltage meets the input voltage range of the inverter based on the start signal of the working motor, the second charging contactor KM21 is closed first. After the intermediate DC bus voltage of the inverter branch meets the requirements or after a set delay, the second short-circuit contactor KM22 is closed, and the second charging contactor KM21 is opened. The inverter module inverts the intermediate DC bus voltage, uses it to start the working motor M1 via variable voltage and frequency conversion, and then supplies power to the working motor M1 at a constant frequency and voltage.

[0041] During reverse charging, a three-phase AC power input is provided to the battery, controlling the closure of the third charging contactor KM3. When the input three-phase AC power meets the requirements or after a set delay, the third short-circuit contactor KM4 closes. After being stepped up by the isolation transformer T1, the voltage is rectified by the auxiliary inverter module to the intermediate DC bus voltage, which is then supplied to the DC-DC converter to charge the power battery.

[0042] When the auxiliary inverter branch fails, the system can manually enter the redundant power supply mode by opening the self-locking switch S1, or automatically enter the redundant power supply mode by outputting a high level to the coil of the intermediate relay K1. When the auxiliary inverter branch is normal, the system can restore the normal output mode by resetting the self-locking switch S1 or by using a logic program.

[0043] Upon entering redundant power supply mode, the main contacts of the first output contactor KM5 and the second output contactor KM7 are opened, while the main contacts of the switching contactor KM6 are closed. A constant-voltage, constant-frequency three-phase AC power is output from the working inverter branch, and after passing through an isolation transformer and filtering, a three-phase sinusoidal AC power is output. In redundant power supply mode, auxiliary loads are powered through the second inverter module INV2, the switching contactor KM6, the isolation transformer T1, the filter capacitor C12, and the third short-circuit contactor KM4.

[0044] Under normal circumstances, the coil of the first output contactor KM5 is connected in series with the normally closed auxiliary contact of the switching contactor KM6 and is controlled by the output control signal. Similarly, the coil of the second output contactor KM7 is connected in series with the normally closed auxiliary contact of the switching contactor KM6 and is also controlled by the output control signal. When the main contact of the switching contactor KM6 closes, the normally closed auxiliary contact is mechanically opened, preventing the coils of both the first and second output contactors KM5 and KM7 from being energized. Conversely, when either the main contact of the first or second output contactor KM5 closes, the corresponding normally closed auxiliary contact is mechanically opened, preventing the coil of the switching contactor KM6 from being energized, and keeping the main contact of the switching contactor KM6 open.

[0045] When the self-locking switch S1 is opened, the coil of the switching contactor KM6 is energized, the main contacts of the switching contactor KM6 close, and the two normally closed auxiliary contacts of the switching contactor KM6 open. After the two normally closed auxiliary contacts of the switching contactor KM6 open, the coils of the first output contactor KM5 and the second output contactor KM7 cannot be energized, and the main contacts of the first output contactor KM5 and the second output contactor KM7 remain open.

[0046] The system monitors the status of the first charging contactor KM11, the first shorting contactor KM12, the second charging contactor KM21, the second shorting contactor KM22, the first fuse FR1, the second fuse FR2, the first inverter module INV1, and the second inverter module INV2. When a fault is detected in the first charging contactor KM11, the first shorting contactor KM12, the first fuse FR1, or the first inverter module INV1, the system automatically enters redundant power supply mode and outputs a high level to the coil of the intermediate relay K1.

[0047] The redundant power supply method for operational and auxiliary loads described in this embodiment, based on the operational load power supply branch involved in the operation vehicle, designs a redundant switching circuit between the operational inverter branch and the auxiliary inverter branch. This allows the operational inverter branch to output the characteristics of the auxiliary inverter branch when the auxiliary inverter branch fails, ensuring power supply to the auxiliary loads, especially critical auxiliary loads such as traction and braking, thus ensuring the availability of critical auxiliary loads in rail transit vehicles and improving vehicle availability. Simultaneously, without changing the existing design schemes of the auxiliary and operational inverter branches, this embodiment achieves redundant design of the auxiliary inverter power supply circuit through power supply circuit design optimization. It enables the operational inverter branch to switch to the auxiliary inverter branch in case of auxiliary inverter anomalies, prioritizing power supply to critical equipment, prioritizing vehicle traction and movement, and emergency return to the workshop or work area. This effectively avoids the technical problem of a single branch auxiliary load power supply anomaly causing the vehicle to be unable to traction or move.

[0048] Example 2 As attached Figure 1 As shown, an embodiment of the redundant power supply device 10 for both working and auxiliary loads, based on the method described in Embodiment 1, specifically includes: an auxiliary inverter branch, a working inverter branch, a control unit 1 (ACU, short for Auxiliary Control Unit), a first output contactor KM5, a switching contactor KM6, and a second output contactor KM7. The auxiliary inverter branch is connected to the auxiliary load via the first output contactor KM5, and the working inverter branch is connected to the working motor via the second output contactor KM7. The main contacts of the switching contactor KM6 are connected between the output side of the main contacts of the first output contactor KM5 and the input side of the main contacts of the second output contactor KM7. The control unit 1 is connected to the auxiliary inverter branch, the working inverter branch, the first output contactor KM5, the switching contactor KM6, and the second output contactor KM7. The auxiliary inverter branch inverts and isolates the intermediate DC bus voltage to output 380V, 50Hz three-phase AC power to supply the auxiliary load. The working inverter branch inverts the intermediate DC bus voltage to output frequency- and voltage-converted three-phase AC power, which is supplied to the working motor M1. The working motor M1 starts with frequency conversion and voltage conversion and runs with constant frequency and voltage.

[0049] The auxiliary inverter branch includes a first inverter module INV1 and a first pre-charge circuit connected to the input side of the first inverter module INV1. The first pre-charge circuit ensures a smooth rise in bus voltage. The working inverter branch includes a second inverter module INV2 and a second pre-charge circuit connected to the input side of the second inverter module INV2. The second pre-charge circuit ensures a smooth rise in bus voltage. The first inverter module INV1 provides three-phase AC power to the auxiliary load, and the second inverter module INV2 provides three-phase 380V AC power to the working motor M1. Both the auxiliary and working inverter branches are equipped with pre-charge circuits, and the two branches are independent to avoid mutual interference.

[0050] The first pre-charge circuit includes a first charging contactor KM11, a first shorting contactor KM12, and a first charging resistor R11. The first charging contactor KM11 and the first charging resistor R11 are connected in series and then in parallel across the two ends of the first shorting contactor KM12. The second pre-charge circuit includes a second charging contactor KM21, a second shorting contactor KM22, and a second charging resistor R21. The second charging contactor KM21 and the second charging resistor R21 are connected in series and then in parallel across the two ends of the second shorting contactor KM22.

[0051] The auxiliary inverter branch also includes a first line reactor L1, a first supporting capacitor C11, and a first discharge resistor R12. The first supporting capacitor C11 and the first discharge resistor R12 are both connected in parallel to the input side of the first inverter module INV1. The first line reactor L1 is connected between the first pre-charge circuit and the input side of the first inverter module INV1. The operating inverter branch also includes a second line reactor L2, a second supporting capacitor C21, and a second discharge resistor R22. The second supporting capacitor C21 and the second discharge resistor R22 are both connected in parallel to the input side of the second inverter module INV2. The second line reactor L2 is connected between the second pre-charge circuit and the input side of the second inverter module INV2. During normal operation, the first line reactor L1 and the first supporting capacitor C11, and the second line reactor L2 and the second supporting capacitor C21 form a filtering and energy buffer circuit. When the vehicle (device) is powered off, the first supporting capacitor C11 and the second supporting capacitor C21 still carry high voltage. The high voltage across the first supporting capacitor C11 can be discharged through the first discharge resistor R12, and the high voltage across the second supporting capacitor C21 can be discharged through the second discharge resistor R22.

[0052] In this embodiment, by setting a first output contactor KM5, when a fault occurs in the first pre-charge circuit, the first line reactor L1, or the first inverter module INV1 of the auxiliary inverter branch, the faulty auxiliary inverter branch can be completely isolated by disconnecting the first output contactor KM5. The auxiliary inverter branch also includes a first fuse FR1, which is connected between the first line reactor L1 and the input side of the first inverter module INV1. The operating inverter branch also includes a second fuse FR2, which is connected between the second line reactor L2 and the input side of the second inverter module INV2. When a short-circuit overcurrent occurs at the back end of the device, the first fuse FR1 and the second fuse FR2 will blow to avoid damage to the power supply.

[0053] The main contacts of the first output contactor KM5 and the output side of the main contacts of the switching contactor KM6 are also connected to a reverse pre-charge circuit. The reverse pre-charge circuit includes a third charging contactor KM3, a third shorting contactor KM4, and a third charging resistor R31. The third charging contactor KM3 and the third charging resistor R31 are connected in series and then in parallel across the two ends of the third shorting contactor KM4.

[0054] An isolation transformer T1 and a filter capacitor C12 are connected in series between the output sides of the main contacts of the first output contactor KM5 and the main contacts of the switching contactor KM6 and the reverse pre-charge circuit. When the auxiliary inverter branch is working normally, the first charging contactor KM11 is closed first, and the first supporting capacitor C11 is charged through the first charging resistor R11. When the intermediate DC bus voltage of the auxiliary inverter branch meets the requirements or after a set delay time, the first short-circuit contactor KM12 is closed and the first charging contactor KM11 is opened. The auxiliary inverter module inverts the intermediate DC bus voltage into a constant voltage and constant frequency three-phase AC power. After being stepped down by the isolation transformer T1, it is filtered by the filter capacitor C12 and output as a constant frequency and constant voltage three-phase sinusoidal AC power to supply the auxiliary load.

[0055] When the inverter branch is operating normally, control unit 1, based on the start signal of the working motor, detects that the intermediate DC bus voltage meets the input voltage range of the working inverter and first closes the second charging contactor KM21. When the intermediate DC bus voltage of the working inverter branch meets the requirements or after a set delay, it closes the second short-circuit contactor KM22 and opens the second charging contactor KM21. The working inverter module inverts the intermediate DC bus voltage, uses it to start the working motor M1 via variable voltage and frequency conversion, and then supplies power to the working motor M1 at a fixed frequency and voltage.

[0056] During reverse charging, a three-phase AC power input is provided to the battery, and control unit 1 controls the third charging contactor KM3 to close. When the input three-phase AC power meets the requirements or after a set delay, the third short-circuit contactor KM4 closes. After being stepped up by isolation transformer T1, the voltage is rectified by auxiliary inverter module to the intermediate DC bus voltage, which is then supplied to the DC-DC converter to charge the power battery.

[0057] As attached Figure 2 As shown, the device also includes a (power supply redundancy) self-locking switch S1 and an intermediate relay K1. A set of normally closed auxiliary contacts of the first output contactor KM5 and the second output contactor KM7 are connected in series with the contacts of the intermediate relay K1 to control the power supply to the coil of the switching contactor KM6. The output signal of the control unit 1 controls the coil of the first output contactor KM5 via a set of normally closed auxiliary contacts of the switching contactor KM6. The output signal of the control unit 1 controls the coil of the second output contactor KM7 via another set of normally closed auxiliary contacts of the switching contactor KM6. The self-locking switch S1 is connected to the coil of the intermediate relay K1, and the output signal of the self-locking switch S1 or the control unit 1 controls the coil of the intermediate relay K1 in parallel. Under normal circumstances, the coils of the first output contactor KM5 and the second output contactor KM7 are controlled by the control unit 1.

[0058] When the auxiliary inverter branch fails, it can enter the redundant power supply mode in two ways. One is by opening the self-locking switch S1, outputting a high level to the coil of the intermediate relay K1, thus manually entering the redundant power supply mode. The other is that the control unit 1 automatically enters the redundant power supply mode by outputting a high level to the coil of the intermediate relay K1 after performing a logical judgment based on the fault trigger point. The first inverter module INV1 and the second inverter module INV2 are equipped with fault detection units, and the fault signal will be fed back to the control unit 1. The control unit 1 will also detect the status of components such as the first charging contactor KM11, the first shorting contactor KM12, the second charging contactor KM21, the second shorting contactor KM22, the first fuse FR1, and the second fuse FR2. When a fault is detected in the auxiliary inverter branch (including the first charging contactor KM11, the first shorting contactor KM12, the first fuse FR1, and the first inverter module INV1, etc.), it will automatically enter the emergency mode, and the control unit 1 will output a high level to the coil of the intermediate relay K1. In redundant power supply mode, auxiliary loads are powered through the second inverter module INV2, switching contactor KM6, isolation transformer T1, filter capacitor C12, and third short-circuit contactor KM4. When the auxiliary inverter branch is normal, the normal output mode is restored by resetting the self-locking switch S1 or through the logic program. When entering redundant power supply mode, control unit 1 controls the main contacts of the first output contactor KM5 and the second output contactor KM7 to open, and the main contacts of the switching contactor KM6 to close. The constant voltage and constant frequency three-phase AC power output from the working inverter branch is then transformed by the isolation transformer and filtered to output 380V, 50Hz three-phase sinusoidal AC power. The first output contactor KM5, the second output contactor KM7, and the switching contactor KM6 are logically interlocked through auxiliary contacts to avoid the risk of three-phase output grid-connected power supply.

[0059] A hard-wired interlocking circuit is designed using the coils and auxiliary contacts of the first output contactor KM5, the second output contactor KM7, and the switching contactor KM6. The normally closed auxiliary contacts of the first output contactor KM5 and the second output contactor KM7 are connected in series with the coil of the switching contactor KM6. The two sets of normally closed contacts of the switching contactor KM6 are connected in series with the coils of the first output contactor KM5 and the second output contactor KM7, respectively. When the coil is energized, the main contacts close, and the state of the auxiliary contacts changes (normally closed contacts open, normally open contacts close). When the coil is de-energized, the main contacts open, and the auxiliary contacts return to their default state (normally closed contacts close, normally open contacts open). Under normal circumstances, when the contactor coil is energized, the main contacts will actuate. The auxiliary contacts are mechanically linked to the main contacts; when the main contacts close, their normally closed auxiliary contacts will open. In abnormal situations, such as when the main contacts stick together, their normally closed contacts will also open. In this case, a hard-wired interlocking circuit prevents the contacts of the first output contactor KM5, the second output contactor KM7, and the switching contactor KM6 from closing simultaneously. Under normal conditions, the coil of the first output contactor KM5 is connected in series with the normally closed auxiliary contact of the switching contactor KM6 and is controlled by control unit 1. Similarly, the coil of the second output contactor KM7 is connected in series with the normally closed auxiliary contact of the switching contactor KM6 and is also controlled by control unit 1. When the main contacts of the switching contactor KM6 close, the mechanical action causes the normally closed auxiliary contact to open, preventing the coils of the first output contactor KM5 and the second output contactor KM7 from being energized. When any of the main contacts of the first output contactor KM5 or the second output contactor KM7 closes, the mechanical action causes the corresponding normally closed auxiliary contact to open, preventing the coil of the switching contactor KM6 from being energized, and keeping the main contacts of the switching contactor KM6 open.

[0060] When the self-locking switch S1 is opened, the coil of the switching contactor KM6 is energized, the main contacts of the switching contactor KM6 close, and the two normally closed auxiliary contacts of the switching contactor KM6 open. After the two normally closed auxiliary contacts of the switching contactor KM6 open, the coils of the first output contactor KM5 and the second output contactor KM7 cannot be energized, and the main contacts of the first output contactor KM5 and the second output contactor KM7 remain open. The second inverter module INV2 provides three-phase AC 380V power to the external auxiliary load through the switching contactor KM6, the isolation transformer T1, the filter capacitor C12, etc.

[0061] Control unit 1 detects the status of the first charging contactor KM11, the first shorting contactor KM12, the second charging contactor KM21, the second shorting contactor KM22, the first fuse FR1, the second fuse FR2, the first inverter module INV1, and the second inverter module INV2. When a fault is detected in the first charging contactor KM11, the first shorting contactor KM12, the first fuse FR1, or the first inverter module INV1, the control unit 1 automatically enters the redundant power supply mode, and outputs a high level to the coil of the intermediate relay K1.

[0062] It should be noted that other inverter units with inverter function that can output matching three-phase AC power can be used as equivalent replacements for the working inverter unit proposed in this paper.

[0063] In the description of this application, it should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly set on the other element or indirectly set on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0064] It should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0065] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" or "several" means two or more, unless otherwise explicitly specified.

[0066] It should be noted that the structures, proportions, sizes, etc., shown in the accompanying drawings of this specification are only used to complement the content disclosed in the specification for those skilled in the art to understand and read, and are not intended to limit the conditions under which this application can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and purposes that this application can produce, should still fall within the scope of the technical content disclosed in this application.

[0067] By implementing the technical solution of the redundant power supply method for operation and auxiliary loads described in the specific embodiments of this application, the following technical effects can be achieved: (1) The redundant power supply method for operation and auxiliary load described in the specific embodiments of this application is based on two independent power supply branches. It adopts a main circuit that integrates both auxiliary inverter branch and operation inverter branch. The two power supply branches are completely independent and mutually redundant, which can realize independent power supply for the two branches and realize emergency output of three-phase AC power from the operation inverter branch. In the event of a fault, the backup auxiliary inverter unit supplies power to the critical auxiliary load, reducing the number of rescue operations. (2) The redundant power supply method for the operation and auxiliary load described in the specific embodiments of this application is that the auxiliary inverter branch and the operation inverter branch are independent of each other. They are interlocked by auxiliary contacts or by performing logical operations through the auxiliary control unit to realize interlocking, switching and other logic; only a switching contactor is added to realize the redundant power supply of the auxiliary load, saving space and cost; when the auxiliary inverter is abnormal, the operation inverter can realize the auxiliary inverter conversion function through conversion to realize the redundant power supply of the operation and auxiliary load. (3) The redundant power supply method for operation and auxiliary load described in the specific embodiments of this application integrates the reverse pre-charging circuit of the 3AC380V / 50Hz power supply in the warehouse, which can realize the reverse filtering, isolation boost and rectification of the power supply in the warehouse and output to the intermediate DC bus. It can charge the power battery and other loads. Without adding charging branches, it maximizes the use of the main circuit, saves the charger, and integrates the power battery charging function.

[0068] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0069] The above description is merely a preferred embodiment of this application and is not intended to limit this application in any way. Although this application has been disclosed above with reference to preferred embodiments, it is not intended to limit this application. Any person skilled in the art can make many possible variations and modifications to the technical solutions of this application using the methods and techniques disclosed above, or modify them into equivalent embodiments with equivalent changes, without departing from the spirit and technical essence of this application. Therefore, any simple modifications, equivalent substitutions, equivalent changes, and modifications made to the above embodiments based on the technical essence of this application without departing from the content of the technical solutions of this application shall still fall within the protection scope of the technical solutions of this application.

Claims

1. A method for redundant power supply to main and auxiliary loads, characterized in that: The auxiliary inverter branch is connected to the auxiliary load via the first output contactor (KM5); The inverter branch is connected to the working motor (M1) via the second output contactor (KM7); Connect the main contact of the switching contactor (KM6) between the output side of the main contact of the first output contactor (KM5) and the input side of the main contact of the second output contactor (KM7); The auxiliary inverter branch inverts and isolates the intermediate DC bus voltage to output three-phase AC power, which is then supplied to the auxiliary load. The working inverter branch inverts the intermediate DC bus voltage to output frequency- and voltage-converting three-phase AC power, which is supplied to the working motor (M1). The working motor (M1) starts with frequency conversion and voltage conversion and operates with constant frequency and voltage.

2. The method for redundant power supply of main and auxiliary loads according to claim 1, characterized in that: The auxiliary inverter branch includes a first inverter module (INV1) and a first pre-charge circuit connected to the input side of the first inverter module (INV1); the working inverter branch includes a second inverter module (INV2) and a second pre-charge circuit connected to the input side of the second inverter module (INV2); the first pre-charge circuit causes the bus voltage to rise steadily, and the first inverter module (INV1) provides three-phase AC power to the auxiliary load; the second pre-charge circuit causes the bus voltage to rise steadily, and the second inverter module (INV2) supplies power to the working motor (M1).

3. The method for redundant power supply of main and auxiliary loads according to claim 2, characterized in that: The first pre-charge circuit includes a first charging contactor (KM11), a first short-circuit contactor (KM12), and a first charging resistor (R11). The first charging contactor (KM11) and the first charging resistor (R11) are connected in series and then connected in parallel across the two ends of the first short-circuit contactor (KM12). The second pre-charge circuit includes a second charging contactor (KM21), a second short-circuit contactor (KM22), and a second charging resistor (R21). The second charging contactor (KM21) and the second charging resistor (R21) are connected in series and then connected in parallel across the two ends of the second short-circuit contactor (KM22).

4. The method for redundant power supply to operating and auxiliary loads according to claim 3, characterized in that: The auxiliary inverter branch further includes a first line reactor (L1), a first supporting capacitor (C11), and a first discharge resistor (R12). The first supporting capacitor (C11) and the first discharge resistor (R12) are both connected in parallel to the input side of the first inverter module (INV1). The first line reactor (L1) is connected between the first pre-charge circuit and the input side of the first inverter module (INV1). The working inverter branch further includes a second line reactor (L2), a second supporting capacitor (C21), and a second discharge resistor (R22). The second supporting capacitor (C21) and the second discharge resistor (R22) are connected in parallel to the first inverter module (INV1). Both are connected in parallel to the input side of the second inverter module (INV2), and the second line reactor (L2) is connected between the second pre-charge circuit and the input side of the second inverter module (INV2). During normal operation, the first line reactor (L1) and the first supporting capacitor (C11), and the second line reactor (L2) and the second supporting capacitor (C21) form a filtering and energy buffer circuit. When the circuit is de-energized, the high voltage across the first supporting capacitor (C11) is discharged through the first discharge resistor (R12), and the high voltage across the second supporting capacitor (C21) is discharged through the second discharge resistor (R22).

5. The method for redundant power supply to operating and auxiliary loads according to claim 4, characterized in that: The auxiliary inverter branch also includes a first fuse (FR1), which is connected between the first line reactor (L1) and the input side of the first inverter module (INV1); the working inverter branch also includes a second fuse (FR2), which is connected between the second line reactor (L2) and the input side of the second inverter module (INV2); when a short circuit overcurrent occurs at the back end of the circuit, the first fuse (FR1) and the second fuse (FR2) will blow to avoid damage to the power supply.

6. The method for redundant power supply to operating and auxiliary loads according to any one of claims 3 to 5, characterized in that: A reverse pre-charge circuit is connected to the output side of the main contacts of the first output contactor (KM5) and the main contacts of the switching contactor (KM6); the reverse pre-charge circuit includes a third charging contactor (KM3), a third shorting contactor (KM4) and a third charging resistor (R31), the third charging contactor (KM3) and the third charging resistor (R31) are connected in series and then in parallel across the two ends of the third shorting contactor (KM4).

7. The method for redundant power supply of main and auxiliary loads according to claim 6, characterized in that: An isolation transformer (T1) and a filter capacitor (C12) are connected in series between the main contacts of the first output contactor (KM5) and the output side of the main contacts of the switching contactor (KM6) and the reverse pre-charge circuit.

8. The method for redundant power supply of main and auxiliary loads according to claim 7, characterized in that: When the auxiliary inverter branch is working normally, the first charging contactor (KM11) is closed first, and the first supporting capacitor (C11) is charged through the first charging resistor (R11); when the intermediate DC bus voltage of the auxiliary inverter branch meets the requirements or after a set delay time, the first short-circuit contactor (KM12) is closed and the first charging contactor (KM11) is opened; the auxiliary inverter module inverts the intermediate DC bus voltage into constant voltage and constant frequency three-phase AC power, which is stepped down by the isolation transformer (T1), filtered by the filter capacitor (C12), and then output as constant frequency and constant voltage three-phase sinusoidal AC power to supply the auxiliary load.

9. The method for redundant power supply of operating and auxiliary loads according to claim 3, 4, 5, 7 or 8, characterized in that: When the working inverter branch is working normally, according to the working motor start signal, after detecting that the intermediate DC bus voltage meets the working inverter input voltage range, the second charging contactor (KM21) is closed first. After the intermediate DC bus voltage of the working inverter branch meets the requirements or after a set delay time, the second short-circuit contactor (KM22) is closed and the second charging contactor (KM21) is opened. The working inverter module inverts the intermediate DC bus voltage, starts the working motor (M1) with variable voltage and frequency, and then supplies power to the working motor (M1) with fixed frequency and voltage.

10. The method for redundant power supply of main and auxiliary loads according to claim 9, characterized in that: When reverse charging is performed, three-phase AC power is input into the battery, controlling the third charging contactor (KM3) to close. When the input three-phase AC power meets the requirements or after a set delay, the third short-circuit contactor (KM4) closes. After being stepped up by the isolation transformer (T1), the voltage is rectified by the auxiliary inverter module into an intermediate DC bus voltage, which is then supplied to the DC-DC converter to charge the power battery.

11. The method for redundant power supply of operating and auxiliary loads according to claim 3, 4, 5, 7, 8 or 10, characterized in that: Connect a set of normally closed auxiliary contacts of the first output contactor (KM5) and the second output contactor (KM7) in series with the contacts of the intermediate relay (K1) to control the coil power supply of the switching contactor (KM6); output control signal through a set of normally closed auxiliary contacts of the switching contactor (KM6) to control the coil of the first output contactor (KM5). The output control signal controls the coil of the second output contactor (KM7) via another set of normally closed auxiliary contacts of the switching contactor (KM6); the self-locking switch (S1) is connected to the coil of the intermediate relay (K1), and the coil of the intermediate relay (K1) is controlled in parallel through the self-locking switch (S1) or the output control signal.

12. The method for redundant power supply of main and auxiliary loads according to claim 11, characterized in that: When the auxiliary inverter branch fails, the redundant power supply mode can be manually entered by opening the self-locking switch (S1), or the redundant power supply mode can be automatically entered by outputting a high level to the coil of the intermediate relay (K1); when the auxiliary inverter branch is normal, the normal output mode can be restored by resetting the self-locking switch (S1) or by the logic program.

13. The method for redundant power supply of operating and auxiliary loads according to claim 12, characterized in that: When entering the redundant power supply mode, the main contacts of the first output contactor (KM5) and the second output contactor (KM7) are opened, and the main contacts of the switching contactor (KM6) are closed. After the constant voltage and constant frequency three-phase AC power is output from the working inverter branch, it is output as three-phase sinusoidal AC power after isolation transformer and filtering.

14. The method for redundant power supply of operating and auxiliary loads according to claim 12 or 13, characterized in that: Under normal circumstances, the coil of the first output contactor (KM5) is connected in series with the normally closed auxiliary contact of the switching contactor (KM6) and is controlled by the output control signal. The coil of the second output contactor (KM7) is connected in series with the normally closed auxiliary contact of the switching contactor (KM6) and is controlled by the output control signal. When the main contact of the switching contactor (KM6) is closed, the normally closed auxiliary contact is mechanically opened, and the coils of the first output contactor (KM5) and the second output contactor (KM7) cannot be energized. When either the main contact of the first output contactor (KM5) or the second output contactor (KM7) is closed, the mechanical action causes the corresponding normally closed auxiliary contact to open, the coil of the switching contactor (KM6) cannot be energized, and the main contact of the switching contactor (KM6) remains open.

15. The method for redundant power supply of main and auxiliary loads according to claim 14, characterized in that: When the self-locking switch (S1) is opened, the coil of the switching contactor (KM6) is energized, the main contacts of the switching contactor (KM6) close, and the two normally closed auxiliary contacts of the switching contactor (KM6) open. After the normally closed auxiliary contacts of the two switching contactors (KM6) are opened, the coils of the first output contactor (KM5) and the second output contactor (KM7) cannot be energized, and the main contacts of the first output contactor (KM5) and the second output contactor (KM7) remain open.

16. The method for redundant power supply of operating and auxiliary loads according to claim 12, 13 or 15, characterized in that: The system detects the status of the first charging contactor (KM11), the first short-circuit contactor (KM12), the second charging contactor (KM21), the second short-circuit contactor (KM22), the first fuse (FR1), the second fuse (FR2), the first inverter module (INV1), and the second inverter module (INV2). When a fault is detected in the first charging contactor (KM11), the first short-circuit contactor (KM12), the first fuse (FR1), or the first inverter module (INV1), the system automatically enters the redundant power supply mode and outputs a high level to the coil of the intermediate relay (K1).

17. The method for redundant power supply of operating and auxiliary loads according to claim 16, characterized in that: In redundant power supply mode, the auxiliary load is powered through the second inverter module (INV2), switching contactor (KM6), isolation transformer (T1), filter capacitor (C12) and third short-circuit contactor (KM4).

Images