A vehicle-mounted power source pre-charging device compatible with single-phase and three-phase

Abstract

The utility model provides a kind of for compatible single-phase, three-phase vehicle-mounted power supply pre-charging charging device, comprising:U, V, W, N, voltage detection unit 1, charging inductance, PFC switch unit, energy storage capacitor, current-limiting inductor, pre-charging resistance, relay, voltage detection unit 2 and MCU control unit.The utility model provides a kind of for compatible single-phase, three-phase vehicle-mounted power supply pre-charging charging device, compatible market vehicle-mounted charging power supply compatible single-phase, three-phase vehicle-mounted power supply pre-charging charging function, and in PFC energy storage capacitor adopts upper and lower series connection mode, can satisfy PFC side bus voltage 800V platform, improve the power density of unit volume, and safe and reliable, the utility model design is simple, small in size, low in cost, both can satisfy adaptive input interface is ac-dc interface, also can satisfy compatible single-phase or three-phase ac input, and can satisfy the capacitor capacity voltage resistance requirement of PFC side bus voltage 800V of vehicle-mounted power supply pre-charging charging device circuit.

Description

Technical Field

[0001] This utility model relates to the field of new energy vehicles, and in particular to a pre-charging device for vehicle power supplies that is compatible with single-phase and three-phase power supplies. Background Technology

[0002] With the rapid development of modern science and technology, the voltage of power batteries for new energy vehicles is getting higher and higher. Currently, the mainstream is the 400V platform, and it is gradually transitioning to the 800V platform. As an important energy conversion part of the new energy vehicle system, the high stability and high reliability of the on-board charging power supply directly affect the performance of the entire new energy vehicle system. Especially in the field of electric vehicles, the stability of its system operation directly affects the power system of new energy vehicles.

[0003] Currently, the mainstream charging power of vehicle power supplies on the market is mainly 3.3kW, 6.6W, and 11kW. Their input is mainly single-phase AC power, three-phase power, or direct charging of the battery through DC charging devices. In order to adapt to the charging interface to allow AC and DC to share a single interface, when the input interface detects DC power, the vehicle power supply's internal detection circuit determines that the main power circuit inside the vehicle is disconnected from the input DC current, which does not meet the vehicle power supply charging mechanism. When the input interface detects AC power, the vehicle power supply's internal detection circuit determines that the main power circuit inside the vehicle is connected to the input AC current. Because the vehicle current is converted from AC voltage to DC current, and the power factor must meet the power consumption standards, and because the vehicle power supply has a large output power, it requires high voltage, high current, and high power when charging. Therefore, the vehicle charger must be soft-started to reach the working state at the beginning of the startup.

[0004] To address this, the vehicle power input interface is adapted to use a single interface for both AC and DC inputs. This adds a relay to the input interface and the internal main power input circuit switch. Simultaneously, it must be compatible with both single-phase and three-phase AC inputs for pre-charging. This requires two relays and a pre-charging resistor for single-phase input, or four relays and four pre-charging resistors for three-phase input. This not only increases cost and size but also introduces issues like arcing under load during faults. For 800V platform power batteries, to reduce transformer size and stress, the PFC side output voltage must be 800V to provide isolated DC voltage for the subsequent DC / DC converter. However, the single capacitor capacity and voltage withstand capability of the PFC side bus in commercially available PFC side circuits cannot meet the 800V requirement. Existing vehicle power pre-charging devices have large circuit sizes and high costs, failing to meet the requirements of AC / DC interface compatibility and single-phase or three-phase AC input, and also failing to meet the 800V capacitor capacity and voltage withstand capability requirements of the PFC side bus.

[0005] Therefore, it is necessary to provide a vehicle power supply pre-charging device compatible with single-phase and three-phase power supplies to solve the above-mentioned technical problems. Utility Model Content

[0006] This utility model provides a vehicle power supply pre-charging device compatible with single-phase and three-phase power supplies. It solves the problems of existing vehicle power supply pre-charging devices having large circuit size, high cost, inability to adapt to AC / DC interfaces and be compatible with single-phase or three-phase AC input, and inability to meet the capacitor capacity withstand voltage requirement of 800V PFC side bus voltage.

[0007] To solve the above-mentioned technical problems, this utility model provides a vehicle power supply pre-charging device compatible with single-phase and three-phase power supplies, including: U, V, W, N, voltage detection unit 1, charging inductor, PFC switch unit, energy storage capacitor, current limiting inductor, pre-charging resistor, relay, voltage detection unit 2, and MCU control unit. The U is connected to pin 1 of relay K1-1 via a connecting wire. Pin 2 of relay K1-1 is connected to pin 1 of relay K1-2 via a connecting wire. Pin 2 of relay K1-2 is connected to pin 1 of charging inductor La via a wire. Pin 2 of charging inductor La is connected to the PFC switching unit L. The V is connected to pin 1 of relay K2-1 via a connecting wire. Pin 2 of relay K2-1 is connected to pin 1 of relay K2-2 via a connecting wire. Pin 2 of relay K2-2 is connected to pin 1 of charging inductor Lb via a connecting wire. Pin 2 of charging inductor Lb is connected to the PFC switch unit M. The W is connected to pin 1 of relay K3-1 via a connecting wire. Pin 2 of relay K3-1 is connected to pin 1 of relay K3-2 via a connecting wire. Pin 2 of relay K3-2 is connected to pin 1 of charging inductor Lc via a connecting wire. Pin 2 of charging inductor Lc is connected to the PFC switch unit N. The PFC switch unit H is connected to pin 1 of the energy storage capacitor C1 via a connecting wire. Pin 2 of the energy storage capacitor C1 is connected to pin 1 of the current limiting inductor L1 via a connecting wire. Pin 2 of the current limiting inductor L1 is connected to the PFC switch unit P and pin 1 of the energy storage capacitor C2 via connecting wires. Pin 2 of the energy storage capacitor C2 is connected to pin 1 of the current limiting inductor L2 via a connecting wire. Pin 2 of the current limiting inductor L2 is connected to pin 1 of the pre-charge resistor R1 and pin 1 of the relay K4 via connecting wires.

[0008] Preferably, pin 3 of relay K2-1 is connected to pin 1 of relay K1-1, pin 3 of relay K3-1 is connected to pin 1 of relay K1-1, and N is connected to the PFC switch unit O via a connecting wire.

[0009] Preferably, U, V, W, and N are respectively connected to the voltage detection unit 1 via connecting lines, and the voltage detection unit 1 is connected to the MCU control unit via connecting lines.

[0010] Preferably, relays K1-1 and K1-2 are respectively connected to control switches S1-1 and S1-2 via connecting lines, and are controlled by the MCU control unit to control the activation of K1-1 and K1-2. Similarly, control switches S2-1 and S2-2 for relays K2-1 and K2-2 are controlled by the MCU control unit to control the activation of K2-1 and K2-2. Likewise, control switches S3-1 and S3-2 for relays K3-1 and K3-2 are controlled by the MCU control unit to control the activation of K3-1 and K3-2.

[0011] Preferably, the relay K1-1 includes a relay body, a protective device is provided at the bottom of the outer surface of the relay body, first threaded holes are provided on the front and back sides of the left and right sides of the outer surface of the relay body, and second threaded holes are provided on the front and back sides of the left and right sides of the outer surface of the relay body, and at the bottom of the first threaded holes.

[0012] Preferably, the protective device includes a protective box, a slot, protective blocks, a connecting slot, a mounting plate, and a threaded rod. The protective box is fitted onto the bottom of the outer surface of the relay body. The slot is located in the middle of the top of the protective box. Multiple protective blocks are located at the bottom of the protective box. The connecting slot is located in the middle of the bottom of the protective blocks. Four mounting plates are fixedly installed on the front and rear sides of the top left and right sides of the protective box. The threaded rod is rotatably installed in the middle of the interior of the mounting plate.

[0013] Preferably, the connecting groove is connected to the interior of the slot, and the connecting groove is adapted to the pin shape of the relay body.

[0014] Compared with related technologies, the on-board power supply pre-charging device compatible with single-phase and three-phase power supplies provided by this utility model has the following beneficial effects: This utility model provides a vehicle power supply pre-charging device compatible with both single-phase and three-phase power supplies. It is compatible with the pre-charging functions of both single-phase and three-phase vehicle power supplies on the market. Furthermore, the PFC energy storage capacitors are connected in series, which can meet the 800V PFC bus voltage requirement. This solves the problem of large size caused by large capacitance and high voltage rating of capacitors on the market, while reducing the production cost of vehicle power supplies, increasing the power density per unit volume, and ensuring safety and reliability. This utility model is simple in design, small in size, and low in cost. It can accommodate both AC and DC input interfaces, and is compatible with single-phase or three-phase AC input, while meeting the capacitor capacitance and voltage requirements of 800V PFC bus voltage. Attached Figure Description

[0015] Figure 1 A schematic diagram of the structure of a first embodiment of a vehicle power supply pre-charging device compatible with single-phase and three-phase power supplies provided by this utility model; Figure 2 for Figure 1 The diagram shows the structure of relay K2-1. Figure 3 for Figure 1 The diagram shows the structure of relay K1-1. Figure 4 for Figure 1 The diagram shows the pre-charge resistor structure. Figure 5 A schematic diagram of the structure of a second embodiment of a vehicle power supply pre-charging device compatible with single-phase and three-phase power supplies provided by this utility model; Figure 6 for Figure 5 The diagram shows the structure of the protective device.

[0016] The following are the labels in the diagram: 1. Relay body, 2. First threaded hole, 3. Protective device, 31. Protective box, 32. Slot, 33. Protective block, 34. Connecting slot, 35. Mounting plate, 36. Threaded rod, 4. Second threaded hole. Detailed Implementation

[0017] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0018] First Embodiment Please refer to the following: Figure 1 , Figure 2 , Figure 3 and Figure 4 ,in, Figure 1 A schematic diagram of the structure of a first embodiment of a vehicle power supply pre-charging device compatible with single-phase and three-phase power supplies provided by this utility model; Figure 2 for Figure 1The diagram shows the structure of relay K2-1. Figure 3 for Figure 1 The diagram shows the structure of relay K1-1. Figure 4 for Figure 1 The diagram shows a resistor structure.

[0019] A vehicle power supply pre-charging device compatible with single-phase and three-phase power supplies includes: U, V, W, N, voltage detection unit 1, charging inductor, PFC switch unit, energy storage capacitor, current limiting inductor, pre-charging resistor, relay, voltage detection unit 2, and MCU control unit. The U is connected to pin 1 of relay K1-1 via a connecting wire. Pin 2 of relay K1-1 is connected to pin 1 of relay K1-2 via a connecting wire. Pin 2 of relay K1-2 is connected to pin 1 of charging inductor La via a wire. Pin 2 of charging inductor La is connected to the PFC switching unit L. The V is connected to pin 1 of relay K2-1 via a connecting wire. Pin 2 of relay K2-1 is connected to pin 1 of relay K2-2 via a connecting wire. Pin 2 of relay K2-2 is connected to pin 1 of charging inductor Lb via a connecting wire. Pin 2 of charging inductor Lb is connected to the PFC switch unit M. The W is connected to pin 1 of relay K3-1 via a connecting wire. Pin 2 of relay K3-1 is connected to pin 1 of relay K3-2 via a connecting wire. Pin 2 of relay K3-2 is connected to pin 1 of charging inductor Lc via a connecting wire. Pin 2 of charging inductor Lc is connected to the PFC switch unit N. The PFC switch unit H is connected to pin 1 of the energy storage capacitor C1 via a connecting wire. Pin 2 of the energy storage capacitor C1 is connected to pin 1 of the current limiting inductor L1 via a connecting wire. Pin 2 of the current limiting inductor L1 is connected to the PFC switch unit P and pin 1 of the energy storage capacitor C2 via connecting wires. Pin 2 of the energy storage capacitor C2 is connected to pin 1 of the current limiting inductor L2 via a connecting wire. Pin 2 of the current limiting inductor L2 is connected to pin 1 of the pre-charge resistor R1 and pin 1 of the relay K4 via connecting wires.

[0020] Pin 3 of relay K2-1 is connected to pin 1 of relay K1-1, pin 3 of relay K3-1 is connected to pin 1 of relay K1-1, and N is connected to the PFC switch unit O via a connecting wire.

[0021] U, V, W, and N are respectively connected to the voltage detection unit 1 via connecting lines, and the voltage detection unit 1 is connected to the MCU control unit via connecting lines.

[0022] Relays K1-1 and K1-2 are respectively connected to control switches S1-1 and S1-2 via connecting lines. The MCU control unit controls the activation of K1-1 and K1-2. Similarly, the MCU control unit controls the activation of relays K2-1 and K2-2 via control switches S2-1 and S2-2. Likewise, the MCU control unit controls the activation of relays K3-1 and K3-2 via control switches S3-1 and S3-2.

[0023] Pin 2 of the current-limiting inductor L2 is connected to pin 1 of the pre-charge resistor R1, pin 1 of the relay K4, and pin 1 of the detection diode D1 via connecting wires. Pin 2 of the detection diode D1 is connected to the voltage detection unit 2. Pin 2 of the pre-charge resistor R1 is connected to pin 2 of the relay K4 and the PFC switch unit K via connecting wires.

[0024] U, V, W, and N are all alternating current. Voltage detection unit 1 detects the voltage of AC inputs U, V, and W and reports it to the MCU control unit. The MCU control unit uses internal logic to determine whether the input is DC voltage, single-phase AC voltage, or three-phase AC voltage. When it is determined to be DC voltage, the MCU control unit enables control switch S1-1 to be low, and relay K1-1 is not energized. When it is determined to be single-phase AC voltage, the MCU control unit enables control switch S1-1 to be high, control switch S1-2 to be high, control switch S2-1 to be low, control switch S2-2 to be high, control switch S3-1 to be low, and control switch S3-... When the voltage level is high, relays K1-1 and K1-2 are activated, while relays K2-1, K2-2, K3-1, and K3-2 are deactivated and activated. When the voltage is determined to be three-phase AC, the MCU control unit enables switch S1-1 to be high, switch S1-2 to be high, switch S2-1 to be high, switch S2-2 to be high, switch S3-1 to be high, and switch S3-2 to be high, thereby controlling relays K1-1, K1-2, K2-1, K2-2, K3-1, and K3-2 to be activated. Voltage detection unit 2 detects the output voltage at point H of PFC control unit and reports it to MCU control unit. MCU control unit uses internal logic to determine when to enable control switch S4 to be high level, thereby controlling relay K4 to close. By detecting the change in anode level of diode D1, MCU determines whether K4 is fully closed, thus realizing the vehicle power supply pre-charging function.

[0025] The relay is a key component in the pre-charging circuit of the vehicle power supply. The selected single-pole relay model is HF / 15FK-T / 12-ZS3T, the double-pole relay model is HF115KF-T / 12-HS3T, and the soft-start resistor is PPL14560HA3D4CCP.

[0026] The working principle of the on-board power supply pre-charging device compatible with single-phase and three-phase power supplies provided by this utility model is as follows: During operation, after the vehicle power input interface is connected to the system power supply, the voltage detection unit 1 detects the voltage between point A and point G and reports it to the MCU control unit. The MCU control unit then uses logic to determine whether the system power supply is DC or AC. When it detects and determines that it is DC voltage, it executes the instruction to keep relay K1-1 inactive. That is, when it is determined to be DC voltage, the MCU control unit enables the control switch S1-1 to be low, and relay K1-1 is not energized. When it detects and determines that it is AC voltage between point A and point G, and the voltage between detection point C and point G is 0V and the voltage between detection point E and point G is 0V, the MCU determines that it is single-phase AC power and executes the instruction to activate relay K1-1, relay K1-2, relay K2-2, and relay K3-2. That is, when it is determined to be single-phase AC voltage, the MCU control unit enables the control switches S1-1, S1-2, S2-2, and S3-2 to be high, and relays K1-1, K1-2, K2-2, and K3-2 are energized.

[0027] After relays K1-1, K1-2, K2-2, and K3-2 are energized, the U-phase AC voltage passes through charging inductors La, Lb, and Lc, and the internal diode of the PFC switching unit. The rectified voltage then passes through electrolytic capacitor C1, current-limiting inductor L1 and C2, current-limiting inductor L2, and pre-charge resistor R1 to complete the primary pre-charge voltage of the bus PFC, which is 1.414 times the input AC voltage. Voltage detection unit 2 detects the output voltage at point H of the PFC control unit and reports it to the MCU control unit. The MCU control unit uses internal logic operations to determine when to enable control switch S4 to be high, thereby controlling the energization of relay K4. When relay K4 is energized, the MCU control unit uses internal logic operations and internal control mechanisms to enable the PFC control switch, turning on its internal MOSFET and making the bus PFC voltage reach 800V.

[0028] When the voltage between point A and point G is detected and determined to be AC ​​voltage, and the voltage between detection point C and point G is 220V AC RMS, and the voltage between detection point E and point G is 220V AC RMS, the MCU determines that it is three-phase AC power and executes the operation commands of relays K1-1, K1-2, K2-1, K2-2, K3-1, and K3-2. That is, when it is determined to be three-phase AC voltage, the MCU control unit enables the control switches S1-1, S1-2, S2-1, S2-2, S3-1, and S3-2 to be at a high level, and relays K1-1, K1-2, K2-1, K2-2, K3-1, and K3-2 are energized. After relays K1-1, K1-2, K2-1, K2-2, K3-1, and K3-2 are energized, the U-phase AC voltage, V-phase AC voltage, and W-phase AC voltage are respectively energized through charging inductors La, Lb, and Lc, and the internal diode of the PFC switching unit. Internal control connects point O to point P. The rectified voltage, through electrolytic capacitor C1, current-limiting inductor L1 and C2, current-limiting inductor L2, and pre-charge resistor R1, completes the primary pre-charge voltage of the bus PFC, which is 2.8 times the input AC voltage. Voltage detection unit 2 detects the output voltage at point H of the PFC control unit and reports it to the MCU control unit. The MCU control unit uses internal logic to determine when to enable control switch S4 to a high level, thereby controlling the energization of relay K4. When relay K4 is energized, the MCU control unit, through internal logic and internal control mechanisms, enables the PFC control switch, turning on its internal MOSFET, so that the bus PFC voltage reaches 800V.

[0029] The MCU determines whether K4 is fully engaged by detecting the change in the anode level of D1.

[0030] During the entire on-board power supply pre-charging process, voltage detection unit 1 needs to detect the input port voltage and report it to the MCU control unit to determine whether it is DC voltage, single-phase AC voltage, or three-phase AC voltage. Then, the MCU control unit uses internal logic operations to control the corresponding relay to engage in the corresponding control mode. Voltage detection unit 2 detects the bus voltage status under single-phase AC voltage or three-phase AC voltage to complete the bus pre-charging function. The MCU controls the drive state of the PFC switch unit to complete the bus voltage under single-phase AC input or three-phase AC input and the action of relay K4 to complete the bus output of 800V.

[0031] Compared with related technologies, the on-board power supply pre-charging device compatible with single-phase and three-phase power supplies provided by this utility model has the following beneficial effects: This utility model provides a vehicle power supply pre-charging device compatible with both single-phase and three-phase power supplies. It is compatible with the pre-charging functions of both single-phase and three-phase vehicle power supplies on the market. Furthermore, the PFC energy storage capacitors are connected in series, which can meet the 800V PFC bus voltage requirement. This solves the problem of large size caused by large capacitance and high voltage rating of capacitors on the market, while reducing the production cost of vehicle power supplies, increasing the power density per unit volume, and ensuring safety and reliability. This utility model is simple in design, small in size, and low in cost. It can accommodate both AC and DC input interfaces, and is compatible with single-phase or three-phase AC input, while meeting the capacitor capacitance and voltage requirements of 800V PFC bus voltage.

[0032] Second Embodiment Please refer to the following: Figure 5 and Figure 6 Based on the first embodiment of this application, which provides a vehicle power supply pre-charging device compatible with both single-phase and three-phase power supplies, the second embodiment of this application proposes another vehicle power supply pre-charging device compatible with both single-phase and three-phase power supplies. The second embodiment is merely a preferred embodiment of the first embodiment, and its implementation will not affect the separate implementation of the first embodiment.

[0033] Specifically, the second embodiment of this application provides a vehicle power supply pre-charging device compatible with single-phase and three-phase power supplies, which differs in that the relay K1-1 includes a relay body 1, a protective device 3 is provided at the bottom of the outer surface of the relay body 1, and first threaded holes 2 are provided on the front and rear sides of the left and right sides of the outer surface of the relay body 1, and second threaded holes 4 are provided on the front and rear sides of the left and right sides of the outer surface of the relay body 1, and at the bottom of the first threaded holes 2.

[0034] The protective device 3 includes a protective box 31, a slot 32, a protective block 33, a connecting slot 34, a mounting plate 35, and a threaded rod 36. The protective box 31 is fitted onto the bottom of the outer surface of the relay body 1. The slot 32 is formed in the middle of the top of the protective box 31. Multiple protective blocks 33 are formed in the bottom of the protective box 31. The connecting slot 34 is formed in the middle of the bottom of the protective blocks 33. Four mounting plates 35 are fixedly installed on the front and rear sides of the top left and right sides of the protective box 31. The threaded rod 36 is rotatably installed in the middle of the interior of the mounting plate 35.

[0035] The connecting slot 34 is connected to the interior of the slot 32, and the connecting slot 34 is compatible with the pin shape of the relay body 1.

[0036] The number of protective blocks 33 is matched with the pins of the relay body 1.

[0037] The threaded rod 36 passes through the mounting plate 35 and engages with the threaded hole inside, confining the protective box 31 to the bottom of the outer surface of the relay body 1.

[0038] The working principle of the on-board power supply pre-charging device compatible with single-phase and three-phase power supplies provided by this utility model is as follows: During operation, the threaded rod 36 first engages with the second threaded hole 4 at the bottom of the outer surface of the relay body 1. The protective box 31 is wrapped around the bottom of the outer surface of the relay body 1 by opening a slot 32. The pins of the relay body 1 are inserted into the connecting slot 34 and wrapped by the protective block 33.

[0039] When the pin needs to be inserted into the socket, the threaded rod 36 is threaded into the inside of the first threaded hole 2, so that the protective box 31 moves upward along the outer surface of the relay body 1, and the protective block 33 slides upward on the pin surface through the connecting groove 34, with part of the pin bottom exposed for easy insertion into the socket.

[0040] Compared with related technologies, the on-board power supply pre-charging device compatible with single-phase and three-phase power supplies provided by this utility model has the following beneficial effects: This utility model provides a vehicle power supply pre-charging device compatible with single-phase and three-phase power supplies. By adjusting the height of the protective device 3 on the outer surface of the relay body 1, the protective block 33 can either wrap around the pins of the relay body 1 or move upward to expose the pins. This device has a simple structure and is highly practical. When the relay is not in use, the protective tube 33, including the pins, provides protection. When the relay body 1 needs to be used, the protective tube 33 is moved upward to expose the pins, making it easy to insert the pins into the relay socket. The protective device 3 effectively protects the exposed pins without affecting the connection between the pins and the socket, thus improving the practicality of the device.

[0041] The above description is merely an embodiment of this utility model and does not limit the patent scope of this utility model. Any equivalent structural or procedural transformations made based on the content of this utility model specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this utility model.

Claims

1. A pre-charging device for vehicle power supplies compatible with single-phase and three-phase power supplies, characterized in that, include: U, V, W, N, voltage detection unit 1, charging inductor, PFC switch unit, energy storage capacitor, current limiting inductor, pre-charge resistor, relay, voltage detection unit 2 and MCU control unit; The U is connected to pin 1 of relay K1-1 via a connecting wire. Pin 2 of relay K1-1 is connected to pin 1 of relay K1-2 via a connecting wire. Pin 2 of relay K1-2 is connected to pin 1 of charging inductor La via a wire. Pin 2 of charging inductor La is connected to the PFC switching unit L. The V is connected to pin 1 of relay K2-1 via a connecting wire. Pin 2 of relay K2-1 is connected to pin 1 of relay K2-2 via a connecting wire. Pin 2 of relay K2-2 is connected to pin 1 of charging inductor Lb via a connecting wire. Pin 2 of charging inductor Lb is connected to the PFC switch unit M. The W is connected to pin 1 of relay K3-1 via a connecting wire. Pin 2 of relay K3-1 is connected to pin 1 of relay K3-2 via a connecting wire. Pin 2 of relay K3-2 is connected to pin 1 of charging inductor Lc via a connecting wire. Pin 2 of charging inductor Lc is connected to the PFC switch unit N. The PFC switch unit H is connected to pin 1 of the energy storage capacitor C1 via a connecting wire. Pin 2 of the energy storage capacitor C1 is connected to pin 1 of the current limiting inductor L1 via a connecting wire. Pin 2 of the current limiting inductor L1 is connected to the PFC switch unit P and pin 1 of the energy storage capacitor C2 via connecting wires. Pin 2 of the energy storage capacitor C2 is connected to pin 1 of the current limiting inductor L2 via a connecting wire. Pin 2 of the current limiting inductor L2 is connected to pin 1 of the pre-charge resistor R1 and pin 1 of the relay K4 via connecting wires.

2. The on-board power supply pre-charging device compatible with single-phase and three-phase power supplies according to claim 1, characterized in that, Pin 3 of relay K2-1 is connected to pin 1 of relay K1-1, pin 3 of relay K3-1 is connected to pin 1 of relay K1-1, and N is connected to the PFC switch unit O via a connecting wire.

3. A vehicle-mounted power supply pre-charging device compatible with single-phase and three-phase power supplies according to claim 1, characterized in that, U, V, W, and N are respectively connected to the voltage detection unit 1 via connecting lines, and the voltage detection unit 1 is connected to the MCU control unit via connecting lines.

4. A vehicle-mounted power supply pre-charging device compatible with single-phase and three-phase power supplies according to claim 1, characterized in that, Relays K1-1 and K1-2 are respectively connected to control switches S1-1 and S1-2 via connecting lines. The MCU control unit controls the activation of K1-1 and K1-2. Similarly, the MCU control unit controls the activation of relays K2-1 and K2-2 via control switches S2-1 and S2-2. Likewise, the MCU control unit controls the activation of relays K3-1 and K3-2 via control switches S3-1 and S3-2.

5. A vehicle-mounted power supply pre-charging device compatible with single-phase and three-phase power supplies according to claim 1, characterized in that, The relay K1-1 includes a relay body, a protective device is provided at the bottom of the outer surface of the relay body, first threaded holes are provided on the front and back sides of the left and right sides of the outer surface of the relay body, and second threaded holes are provided on the front and back sides of the left and right sides of the outer surface of the relay body, and at the bottom of the first threaded holes.

6. A vehicle-mounted power supply pre-charging device compatible with single-phase and three-phase power supplies according to claim 5, characterized in that, The protective device includes a protective box, a slot, protective blocks, a connecting slot, a mounting plate, and a threaded rod. The protective box is fitted onto the bottom of the outer surface of the relay body. The slot is located in the middle of the top of the protective box. Multiple protective blocks are located at the bottom of the protective box. The connecting slot is located in the middle of the bottom of the protective blocks. Four mounting plates are fixedly installed on the front and back sides of the top of the protective box. The threaded rod is rotatably installed in the middle of the interior of the mounting plate.

7. A vehicle-mounted power supply pre-charging device compatible with single-phase and three-phase power supplies according to claim 6, characterized in that, The connecting slot is connected to the interior of the slot, and the connecting slot is compatible with the pin shape of the relay body.

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