Multi-path pre-charging circuit with negative electrode side common inductor, high-voltage power distribution system and vehicle

Abstract

The application relates to the technical field of high-voltage power distribution systems, and provides a multi-path pre-charging circuit, a high-voltage power distribution system and a vehicle.The multi-path pre-charging circuit comprises a high-voltage positive bus and a high-voltage negative bus, a plurality of pre-charging branches, each pre-charging branch comprising a pre-charging branch switch and a pre-charging capacitor connected in series, the first end of each pre-charging branch switch being connected to the second end of the pre-charging capacitor of the pre-charging branch, an inductor, the first end of the inductor being connected to the high-voltage negative bus, and the second end of the inductor being connected to the second end of each pre-charging branch switch, and a control unit connected to each pre-charging branch switch and configured to control each pre-charging branch switch to be turned on or turned off, so that the pre-charging capacitors of the plurality of pre-charging branches are sequentially pre-charged.The multi-path pre-charging circuit can improve the integration of the system, reduce the parasitic parameters between the pre-charging branches, and reduce the electromagnetic coupling interference of the high-voltage electrical system.

Description

Technical Field

[0001] This application relates to the field of high-voltage power distribution system technology, and in particular to a multi-path pre-charging circuit with a common inductor on the negative side, a high-voltage power distribution system, and a vehicle. Background Technology

[0002] The high-voltage electrical system of new energy vehicles includes multiple high-voltage electrical devices such as motor controllers, on-board DC / DC converters, and high-voltage drives. Each high-voltage device integrates a large-capacity supporting capacitor. During the initial stage of high-voltage power-on, the voltage across the supporting capacitor is zero. If the high-voltage main contactor (also known as a relay) is directly closed, the high-voltage bus will generate a transient inrush current of thousands of amperes onto the unloaded capacitor. This can easily cause contact erosion of the main contactor, overcurrent breakdown of power devices, and a sudden drop in bus voltage, thereby triggering a high-voltage fault lockout for the entire vehicle. This severely impacts the service life and operational safety of the high-voltage system.

[0003] The active pre-charging circuit uses controllable switching devices to achieve constant current controllable pre-charging. Before the main contactor of the high-voltage bus closes, it can pre-charge the supporting capacitor, enabling it to reach a higher voltage. Active pre-charging circuits offer advantages such as fast pre-charging speed, low operating losses, no resistance heating, and compatibility with high-voltage, high-current platforms. They are gradually replacing traditional resistive passive pre-charging structures and are widely used in applications such as 800V high-voltage vehicle-mounted power distribution modules.

[0004] However, the active pre-charging circuits commonly used in the industry have significant engineering flaws: the stacked arrangement of multiple high-power inductors occupies a huge area on the circuit board (PCB), making it unsuitable for miniaturized integrated designs, and resulting in complex parasitic parameters and severe electromagnetic coupling interference between the various pre-charging branches. Summary of the Invention

[0005] This application provides a multi-path pre-charging circuit, a high-voltage power distribution system, and a vehicle with a shared inductor on the negative side, which can improve the system integration, reduce parasitic parameters between various pre-charging branches, and reduce electromagnetic coupling interference in the high-voltage electrical system.

[0006] In a first aspect, embodiments of this application provide a multi-path pre-charging circuit with a common inductor on the negative side, including: High-voltage positive busbar and high-voltage negative busbar, wherein the high-voltage positive busbar is used to connect to the positive terminal of the power supply and the high-voltage negative busbar is used to connect to the negative terminal of the power supply; Multiple pre-charge branches, each of the pre-charge branches including a pre-charge branch switch and a pre-charge capacitor connected in series, the first end of each pre-charge capacitor being connected to the high-voltage positive bus, the second end of each pre-charge capacitor being connected to the high-voltage negative bus, and the first end of each pre-charge branch switch being connected to the second end of the pre-charge capacitor in the pre-charge branch. An inductor, the first end of which is connected to the high-voltage negative busbar, and the second end of which is connected to the second end of each of the precharge branch switches; A control unit is connected to each of the precharge branch switches, and the control unit is configured to control each of the precharge branch switches to be turned on or off, so that the precharge capacitors of the plurality of precharge branches are precharged sequentially.

[0007] In some embodiments, the control unit is configured to: Control the precharge branch switch of one of the precharge branches to be turned on, so that the precharge capacitor of the precharge branch is precharged; When the pre-charge capacitor is fully pre-charged, the pre-charge branch switch controlling the pre-charge branch is disconnected; After a preset dead time, the precharge branch switch of the next precharge branch is turned on, so that the precharge capacitor of the corresponding precharge branch can be precharged.

[0008] In some embodiments, the control unit is further configured to monitor the voltage of the pre-charged capacitor being pre-charged, and to determine that the pre-charged capacitor is pre-charged when the voltage of the pre-charged capacitor reaches a preset voltage.

[0009] In some embodiments, the multi-path pre-charging circuit further includes an inductor control switch, the first end of which is connected to the high-voltage negative busbar, and the second end of which is connected to the first end of the inductor. The control unit is also connected to the inductor control switch, and the control unit is further configured to control the inductor control switch to be turned on or off.

[0010] In some embodiments, the multi-path pre-charging circuit further includes a freewheeling diode, the anode of which is connected to the node between the inductor control switch and the inductor, and the cathode of which is connected to the high-voltage positive bus. When the inductor control switch and each of the precharge branch switches are open, the inductor and the freewheeling diode form an energy discharge path.

[0011] In some embodiments, the multi-path pre-charge circuit further includes an overcurrent protection unit, the first end of which is connected to the high-voltage positive bus, and the second end of which is connected to the cathode of the freewheeling diode.

[0012] In some embodiments, the multi-path pre-charge circuit further includes a pre-charge master switch, the first terminal of which is connected to the second terminal of the inductor, and the second terminal of which is connected to the second terminal of each of the pre-charge branch switches; The control unit is also connected to the precharge main switch, and the control unit is further configured to control the precharge main switch to be turned on or off.

[0013] In some embodiments, the high-voltage positive bus includes a main positive bus, which is used to connect to the positive terminal of the power supply, and a main positive relay is connected in series with the main positive bus. The high-voltage negative bus includes a main negative bus, which is used to connect to the negative terminal of the power supply, and a main negative relay is connected in series with the main negative bus. The plurality of pre-charge branches include a first pre-charge branch, and the first pre-charge branch includes a first pre-charge capacitor; Wherein, the first terminal of the main positive relay is connected to the cathode of the freewheeling diode and connected to a first node, the first node being used to connect to the positive terminal of the power supply, and the second terminal of the main positive relay is connected to the first terminal of the first pre-charge capacitor; or, the first terminal of the main positive relay is used to connect to the positive terminal of the power supply, and the second terminal of the main positive relay is connected to the cathode of the freewheeling diode and the first terminal of the first pre-charge capacitor. The first terminal of the main negative relay is connected to the first terminal of the inductor control switch and then to the second node, which is used to connect to the negative terminal of the power supply. The second terminal of the main negative relay is connected to the second terminal of the first pre-charge capacitor.

[0014] In some embodiments, the high-voltage positive bus further includes an auxiliary power supply positive bus and a DC input positive bus. Both the auxiliary power supply positive bus and the DC input positive bus are used to connect to the positive terminal of the power supply. An auxiliary power supply positive relay is connected in series with the auxiliary power supply positive bus, and a DC input positive relay is connected in series with the DC input positive bus. The high-voltage negative bus also includes an auxiliary power supply negative bus and a DC input negative bus. Both the auxiliary power supply negative bus and the DC input negative bus are used to connect to the negative terminal of the power supply. An auxiliary power supply negative relay is connected in series with the auxiliary power supply negative bus, and a DC input negative relay is connected in series with the DC input negative bus. The plurality of pre-charge branches further include a second pre-charge branch and a third pre-charge branch. The second pre-charge branch includes a second pre-charge capacitor, the first terminal of which is connected to the second terminal of the auxiliary power positive relay, and the second terminal of which is connected to the second terminal of the auxiliary power negative relay. The third pre-charge branch includes a third pre-charge capacitor, the first terminal of which is connected to the second terminal of the DC input positive relay, and the second terminal of which is connected to the second terminal of the DC input negative relay. Wherein, the first terminal of the auxiliary power positive relay and the first terminal of the DC input positive relay are both connected to the first node; or, the first terminal of the auxiliary power positive relay and the first terminal of the DC input positive relay are both connected to the second terminal of the main positive relay. The first terminal of the auxiliary power supply negative relay and the first terminal of the DC input negative relay are both connected to the second node; or, the first terminal of the auxiliary power supply negative relay and the first terminal of the DC input negative relay are both connected to the second terminal of the main negative relay.

[0015] Secondly, embodiments of this application provide a high-voltage power distribution system, including: A battery pack, the battery pack including a positive terminal and a negative terminal; As described in any of the above embodiments, the high-voltage positive bus of the multi-channel pre-charging circuit is connected to the positive terminal, and the high-voltage negative bus of the multi-channel pre-charging circuit is connected to the negative terminal.

[0016] Thirdly, embodiments of this application provide a vehicle that includes the multi-path pre-charging circuit described in any of the above embodiments, or includes the high-voltage power distribution system described above.

[0017] In the multi-channel pre-charging circuit provided in this application embodiment, the first end of the inductor is connected to the high-voltage negative bus, and the second end is connected to the second end of each pre-charging branch switch. Therefore, multiple pre-charging branches can share the same inductor, eliminating the need for a separate inductor in each pre-charging branch. This reduces the number of inductors used, decreases their stacking on the circuit board, reduces the board's footprint, and improves the board's compactness. Furthermore, reducing the number of inductors increases system integration, promotes integrated design of high-voltage electrical systems, and reduces parasitic parameters between pre-charging branches, thus lowering electromagnetic coupling interference in the high-voltage electrical system. In addition, reducing the number of inductors reduces the amount of high-power devices used, lowering overall hardware costs. It also simplifies component count, reduces surface mount technology (SMT), soldering, and testing processes during production, lowers product defect rates, and improves mass production efficiency and product consistency. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments 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 drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the first structure of the multi-channel pre-charging circuit according to an embodiment of this application.

[0020] Figure 2 This is a schematic diagram of a second structure of a multi-channel pre-charging circuit according to an embodiment of this application.

[0021] Figure 3 This is a schematic diagram of a third structure of a multi-channel pre-charging circuit according to an embodiment of this application.

[0022] Figure 4 This is a schematic diagram of the fourth structure of the multi-channel pre-charging circuit in an embodiment of this application.

[0023] Figure 5 This is a schematic diagram of the working process of the multi-channel pre-charging circuit in an embodiment of this application.

[0024] Explanation of reference numerals in the attached figures: 10 - Battery pack, B+ is the positive terminal of the battery pack, B- is the negative terminal of the battery pack; 21-High voltage positive busbar, 22-High voltage negative busbar, 31-First pre-charge branch, 32-Second pre-charge branch, 33-Third pre-charge branch; 211-Main positive bus, 212-Auxiliary power supply positive bus, 213-DC input positive bus, 221-Main negative bus, 222-Auxiliary power supply negative bus, 223-DC input negative bus; C1 - First pre-charge capacitor, C11 - First terminal of the first pre-charge capacitor, C12 - Second terminal of the first pre-charge capacitor, C2 - Second pre-charge capacitor, C21 - First terminal of the second pre-charge capacitor, C22 - Second terminal of the second pre-charge capacitor, C3 - Third pre-charge capacitor, C31 - First terminal of the third pre-charge capacitor, C32 - Second terminal of the third pre-charge capacitor; S1 - First pre-charge branch switch, S11 - First terminal of the first pre-charge branch switch, S12 - Second terminal of the first pre-charge branch switch, S2 - Second pre-charge branch switch, S21 - First terminal of the second pre-charge branch switch, S22 - Second terminal of the second pre-charge branch switch, S3 - Third pre-charge branch switch, S31 - First terminal of the third pre-charge branch switch, S32 - Second terminal of the third pre-charge branch switch; K1 - Main positive relay, K11 - First terminal of main positive relay, K12 - Second terminal of main positive relay, K2 - Auxiliary power positive relay, K21 - First terminal of auxiliary power positive relay, K22 - Second terminal of auxiliary power positive relay, K3 - DC input positive relay, K31 - First terminal of DC input positive relay, K32 - Second terminal of DC input positive relay, K4 - Main negative relay, K41 - First terminal of main negative relay, K42 - Second terminal of main negative relay, K5 - Auxiliary power negative relay, K51 - First terminal of auxiliary power negative relay, K52 - Second terminal of auxiliary power negative relay, K6 - DC input negative relay, K61 - First terminal of DC input negative relay, K62 - Second terminal of DC input negative relay; L - Inductor, L11 - First terminal of inductor, L12 - Second terminal of inductor, S4 - Inductor control switch, S41 - First terminal of inductor control switch, S42 - Second terminal of inductor control switch, D - Freewheeling diode, FPCU - Overcurrent protection unit, F11 - First terminal of overcurrent protection unit, F12 - Second terminal of overcurrent protection unit, S5 - Precharge master switch, S51 - First terminal of precharge master switch, S52 - Second terminal of precharge master switch; P1 - First node, P2 - Second node. Detailed Implementation

[0025] 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 some embodiments of this application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0026] This application provides a multi-path pre-charging circuit with a shared inductor on the negative side, which can be applied to high-voltage electrical systems of equipment such as new energy vehicles to pre-charge the supporting capacitor integrated inside the high-voltage equipment.

[0027] refer to Figure 1 , Figure 1 This is a schematic diagram of a first structure of a multi-channel pre-charge circuit according to an embodiment of this application. The multi-channel pre-charge circuit includes a high-voltage positive bus 21, a high-voltage negative bus 22, multiple pre-charge branches, an inductor L, and a control unit.

[0028] The multiple pre-charging circuits are used to connect to the battery pack 10 to receive the DC voltage provided by the battery pack 10. The battery pack 10 serves as a power battery, storing electrical energy and supplying power to loads. For example, in one application, the battery pack 10 can serve as a power battery for a new energy vehicle, supplying power to various loads such as the motor, headlights, and air conditioning.

[0029] The battery pack 10 has a positive terminal B+ and a negative terminal B-. In some embodiments, the battery pack 10 includes multiple battery groups connected in series, each battery group including multiple cells connected in series. The multiple battery groups connected in series form the positive terminal B+ and the negative terminal B- of the battery pack 10, and a DC voltage can be output between the positive terminal B+ and the negative terminal B-. In one example, the DC voltage between the positive terminal B+ and the negative terminal B- can be 800V.

[0030] High-voltage positive bus 21 is used to connect to the positive terminal of the power supply, for example, to connect to the positive terminal B+ of battery pack 10. High-voltage negative bus 22 is used to connect to the negative terminal of the power supply, for example, to connect to the negative terminal B- of battery pack 10. The high-voltage positive bus 21 and high-voltage negative bus 22 are used for input or output bus voltage, for example, outputting an 800V bus voltage.

[0031] In one example, the high-voltage positive bus 21 includes a main positive bus 211, an auxiliary power supply positive bus 212, and a DC input positive bus 213, all of which are used to connect to the positive terminal of the power supply. Correspondingly, the high-voltage negative bus 22 includes a main negative bus 221, an auxiliary power supply negative bus 222, and a DC input negative bus 223, all of which are used to connect to the negative terminal of the power supply. The main positive bus 211 and the main negative bus 221 are used to output the main power supply voltage. The auxiliary power supply positive bus 212 and the auxiliary power supply negative bus 222 are used to output the auxiliary power supply voltage. The DC input positive bus 213 and the DC input negative bus 223 are used to input the DC voltage of an external DC power source (such as a DC charging pile) and to charge the battery pack 10.

[0032] Multiple precharge branches, for example, include: Figure 1 The diagram shows a first pre-charge branch 31, a second pre-charge branch 32, and a third pre-charge branch 33. Each pre-charge branch includes a pre-charge branch switch and a pre-charge capacitor connected in series. The first terminal of each pre-charge capacitor is connected to the high-voltage positive bus, and the second terminal of each pre-charge capacitor is connected to the high-voltage negative bus. The first terminal of each pre-charge branch switch is connected to the second terminal of the pre-charge capacitor in the pre-charge branch.

[0033] In one example, the first pre-charge branch 31 includes a first pre-charge branch switch S1 and a first pre-charge capacitor C1 connected in series. The first terminal C11 of the first pre-charge capacitor C1 is connected to the high-voltage positive bus 21, for example, to the main positive bus 211. The second terminal C12 of the first pre-charge capacitor C1 is connected to the high-voltage negative bus 22, for example, to the main negative bus 221. The first terminal S11 of the first pre-charge branch switch S1 is connected to the second terminal C12 of the first pre-charge capacitor C1.

[0034] The second pre-charge branch 32 includes a second pre-charge branch switch S2 and a second pre-charge capacitor C2 connected in series. The first terminal C21 of the second pre-charge capacitor C2 is connected to the high-voltage positive bus 21, for example, to the auxiliary power supply positive bus 212. The second terminal C22 of the second pre-charge capacitor C2 is connected to the high-voltage negative bus 22, for example, to the auxiliary power supply negative bus 222. The first terminal S21 of the second pre-charge branch switch S2 is connected to the second terminal C22 of the second pre-charge capacitor C2.

[0035] The third pre-charge branch 33 includes a third pre-charge branch switch S3 and a third pre-charge capacitor C3 connected in series. The first terminal C31 of the third pre-charge capacitor C3 is connected to the high-voltage positive bus 21, for example, to the DC input positive bus 213. The second terminal C32 of the third pre-charge capacitor C3 is connected to the high-voltage negative bus 22, for example, to the DC input negative bus 223. The first terminal S31 of the third pre-charge branch switch S3 is connected to the second terminal C32 of the third pre-charge capacitor C3.

[0036] The first terminal L11 of the inductor L is connected to the high-voltage negative bus 22, for example, to the main negative bus 221, the auxiliary power supply negative bus 222, and the DC input negative bus 223. The second terminal L12 of the inductor L is connected to the second terminal of each precharge branch switch, for example, to the second terminal S12 of the first precharge branch switch S1, the second terminal S22 of the second precharge branch switch S2, and the second terminal S32 of the third precharge branch switch S3.

[0037] Control unit (with) Figure 1 (Not shown) can be a microcontroller (MCU) or a high-voltage integrated circuit (HVIC). An HVIC is an integrated circuit specifically designed for operation in high-voltage environments, such as 800V, 1200V, or even higher. HVICs can be used in power electronic systems to drive high-voltage power devices (such as IGBTs and MOSFETs) and to achieve electrical isolation and signal conversion between high-voltage and low-voltage circuits. This application does not limit the specific form of the control unit.

[0038] The control unit is connected to each precharge branch switch. The control unit is configured to control each precharge branch switch to be turned on or off, causing the precharge capacitors of multiple precharge branches to be precharged sequentially. In one example, the control unit is connected to the first precharge branch switch S1, the second precharge branch switch S2, and the third precharge branch switch S3 to control their on / off states. It should be noted that the states of the first precharge branch switch S1, the second precharge branch switch S2, and the third precharge branch switch S3 are independent of each other; the on / off state of each precharge branch switch is independently controlled by the control unit.

[0039] In one example, the first precharge branch switch S1, the second precharge branch switch S2, and the third precharge branch switch S3 can all be electronic switches, such as MOSFETs. The control terminals of S1 (e.g., the gate of S1), S2 (e.g., the gate of S2), and S3 (e.g., the gate of S3) are all connected to the control unit. The control unit can independently control the gate level of S1, the gate level of S2, and the gate level of S3 to independently control the conduction or disconnection of S1, S2, and S3.

[0040] In this embodiment, the control unit is used to sequentially control each precharge branch switch to be turned on or off, so that the precharge capacitors of multiple precharge branches are precharged sequentially. For example, the control unit can first control the first precharge branch switch S1 to be turned on (S2 and S3 remain off), so that the bus voltage precharges the first precharge capacitor C1 through the inductor L. When the first precharge capacitor C1 is precharged, the control unit can control S1 to be turned off and control the second precharge branch switch S2 to be turned on (S3 remains off), so that the bus voltage precharges the second precharge capacitor C2 through the inductor L. After the second precharge capacitor C2 is precharged, the control unit can control S2 to be turned off and control the third precharge branch switch S3 to be turned on (S1 remains off), so that the bus voltage precharges the third precharge capacitor C3 through the inductor L. This process is repeated sequentially, so that the precharge capacitors (C1, C2, or C3) of each precharge branch are precharged sequentially through the same inductor L until all precharge capacitors are precharged.

[0041] In some embodiments, the control unit is configured to: control the precharge branch switch of a precharge branch to turn on, so that the precharge capacitor of the precharge branch can be precharged; when the precharge capacitor is fully precharged, control the precharge branch switch of the precharge branch to turn off; after a preset dead time, control the precharge branch switch of the next precharge branch to turn on, so that the precharge capacitor of the corresponding precharge branch can be precharged. The preset dead time is a pre-set dead time duration, the purpose of which is to ensure that after the preset dead time, there is no residual current in the precharge branch and the operating state of each device remains stable.

[0042] The control unit sequentially controls the pre-charging capacitors of each pre-charging branch to pre-charge. After a pre-charging branch is pre-charged and a preset dead time has elapsed, the control unit then controls the pre-charging capacitors of the next pre-charging branch to pre-charge, until all pre-charging capacitors of all pre-charging branches have completed pre-charging.

[0043] For example, in one example, the control unit can first control the first pre-charge switch S1 of the first pre-charge branch 31 to be turned on (S2 and S3 remain off), so that the first pre-charge capacitor C1 can be pre-charged; when the first pre-charge capacitor C1 is pre-charged, the first pre-charge switch S1 is turned off; then, after a preset dead time, the control unit controls the second pre-charge branch switch S2 to be turned on (S1 and S3 remain off), so that the second pre-charge capacitor C2 can be pre-charged; when the second pre-charge capacitor C2 is pre-charged, the control unit controls the second pre-charge branch switch S2 to be turned off; then, after a preset dead time, the control unit controls the third pre-charge branch switch S3 to be turned on (S1 and S2 remain off), so that the third pre-charge capacitor C3 can be pre-charged. By sequentially completing the pre-charge of each pre-charge capacitor in this control method, time-sharing pre-charge of multiple pre-charge branches can be realized.

[0044] It should be noted that in practical applications, there is no strict order in which the pre-charging of each pre-charging branch occurs. As long as one pre-charging branch is pre-charged at a time, proceeding sequentially, until all pre-charging branches have completed their pre-charging. For example, in the above example, each pre-charging capacitor is pre-charged sequentially in the order of C1-C2-C3. In other examples, pre-charging can also be performed sequentially in the order of C2-C1-C3, or in the order of C3-C2-C1. In this embodiment, the specific order of pre-charging for each pre-charging branch is not limited.

[0045] In some embodiments, during the pre-charging process, the pre-charging of the pre-charging capacitor can be determined based on its voltage. For example, in one instance, pre-charging is considered complete when the voltage of the pre-charging capacitor reaches 92% to 96% of the bus voltage.

[0046] In this embodiment, the control unit is further configured to: monitor the voltage of the pre-charged capacitor undergoing pre-charging; and determine that the pre-charging of the capacitor is complete when the voltage of the pre-charged capacitor reaches a preset voltage. It is understood that the control unit can monitor the voltage of the pre-charged capacitor in real time. For example, it can acquire the voltage of the pre-charged capacitor in real time through a sampling circuit and transmit it to the control unit, which then compares the real-time voltage of the pre-charged capacitor with the preset voltage. The preset voltage can be set to 92%~96% of the bus voltage, for example, 92% of the bus voltage. When the voltage of the pre-charged capacitor reaches the preset voltage, the control unit can determine that the pre-charging of the capacitor is complete.

[0047] In one example, the first precharge branch switch S1, the second precharge branch switch S2, and the third precharge branch switch S3 can all be electronic switches, such as MOSFETs. The body diodes of each MOSFET are all positioned towards the inductor L, effectively blocking reverse current flow and lateral crosstalk between different precharge branches at the hardware level. This ensures that the time-sharing precharge processes of multiple precharge branches are independent and do not interfere with each other, thus improving the circuit's operational stability.

[0048] Understandably, when pre-charging the pre-charge capacitors (C1, C2, or C3), the pre-charge current flows through the inductor L. The inductor L suppresses sudden current changes, thus preventing instantaneous inrush currents in the circuit. After the pre-charge capacitors (C1, C2, and C3) have completed their pre-charge, they already possess a high voltage. Therefore, closing the high-voltage relay at this point will not result in an instantaneous inrush current. Thus, by controlling the pre-charge capacitors in each pre-charge branch, the circuit can be protected from relay contact burning, power devices from overcurrent breakdown, and sudden drops in bus voltage.

[0049] In the multi-channel pre-charging circuit provided in this embodiment, the first end L11 of the inductor L is connected to the high-voltage negative bus 22, and the second end L12 is connected to the second end of each pre-charging branch switch. Therefore, multiple pre-charging branches can share the same inductor L, eliminating the need for a separate inductor in each pre-charging branch. This reduces the number of inductors used, decreases the stacking of inductors on the circuit board (PCB), reduces the PCB footprint, and improves the compactness of the PCB layout. Furthermore, reducing the number of inductors increases system integration, promotes integrated design of high-voltage electrical systems, and reduces parasitic parameters between pre-charging branches, thus reducing electromagnetic coupling interference in the high-voltage electrical system. In addition, reducing the number of inductors reduces the amount of high-power devices used, lowering overall hardware costs. It also simplifies the number of components, reduces surface mount technology (SMT), soldering, and testing processes during production, lowers product defect rates, and improves mass production efficiency and product consistency.

[0050] In some embodiments, continue to refer to Figure 1 The multi-channel pre-charging circuit also includes an inductor control switch S4. The first terminal S41 of the inductor control switch S4 is connected to the high-voltage negative bus 22, for example, to the main negative bus 221, the auxiliary power supply negative bus 222, and the DC input negative bus 223. The second terminal S42 of the inductor control switch S4 is connected to the first terminal L11 of the inductor L, thus connecting the first terminal L11 of the inductor L to the high-voltage negative bus 22.

[0051] The control unit is also connected to the inductor control switch S4. The control unit is further configured to control the inductor control switch S4 to turn on or off. In one example, the inductor control switch S4 can be an electronic switch, such as a MOSFET, and the control unit is connected to the gate of the inductor control switch S4 to control its on or off state.

[0052] In some embodiments, continue to refer to Figure 1 The multi-path pre-charging circuit also includes a freewheeling diode D. The anode of the freewheeling diode D is connected to the node between the inductor control switch S4 and the inductor L. The cathode of the freewheeling diode D is connected to the high-voltage positive bus 21, for example, to the main positive bus 211, the auxiliary power supply positive bus 212, and the DC input positive bus 213.

[0053] When the inductor control switch S4 and each precharge branch switch (S1, S2 and S3) are open, the inductor L and the freewheeling diode D form an energy discharge path so that the electrical energy stored in the inductor L can be smoothly discharged through the freewheeling diode D, suppressing the voltage spikes that occur in the circuit during the switch turn-off process.

[0054] In some embodiments, continue to refer to Figure 1 The multi-path pre-charge circuit also includes an overcurrent protection unit (FPCU). The overcurrent protection unit (FPCU) has a first terminal F11 and a second terminal F12. The first terminal F11 is connected to the high-voltage positive bus 21. For example, the first terminal F11 is connected to the main positive bus 211, the auxiliary power supply positive bus 212, and the DC input positive bus 213. The second terminal F12 is connected to the cathode of the freewheeling diode D, so that the freewheeling diode D is connected to the high-voltage positive bus 21.

[0055] In one example, the overcurrent protection unit FPCU is a fuse. The fuse provides overcurrent protection. When the circuit experiences excessive current due to a fault or other reasons, the FPCU can promptly disconnect the freewheeling diode D from the high-voltage positive bus 21, preventing more serious faults or losses, thus providing protection.

[0056] In some embodiments, reference Figure 2 , Figure 2This is a schematic diagram of a second structure of a multi-channel pre-charging circuit according to an embodiment of this application. The following describes... Figure 2 The multi-channel pre-charging circuit shown is Figure 1 The differences will be explained, and the similarities can be found in the descriptions of the various embodiments above, which will not be repeated here.

[0057] The multi-path pre-charge circuit also includes a pre-charge master switch S5. The first terminal S51 of the pre-charge master switch S5 is connected to the second terminal L12 of the inductor L, and the second terminal S52 of the pre-charge master switch S5 is connected to the second terminal of each pre-charge branch switch, for example, to the second terminal S12 of the first pre-charge branch switch S1, the second terminal S22 of the second pre-charge branch switch S2, and the second terminal S32 of the third pre-charge branch switch S3.

[0058] The control unit is also connected to the precharge master switch S5. The control unit is also configured to control the precharge master switch S5 to be turned on or off. In one example, the precharge master switch S5 can be an electronic switch, such as a MOSFET, and the control unit is connected to the gate of the precharge master switch S5 to control the precharge master switch S5 to be turned on or off.

[0059] In some embodiments, reference Figure 1 and Figure 2 The main positive bus 211 is connected in series with the main positive relay K1, and the main negative bus 221 is connected in series with the main negative relay K4.

[0060] In this configuration, the first terminal K11 of the main positive relay K1 is connected to the cathode of the freewheeling diode D at the first node P1, for example... Figure 1 and Figure 2 As shown, the first terminal K11 of the main positive relay K1 is connected to the first node P1, and the cathode of the freewheeling diode D is connected to the first node P1 via the overcurrent protection unit FPCU. The first node P1 is used to connect to the positive terminal of the power supply, such as the positive terminal B+ of the battery pack 10. The second terminal K12 of the main positive relay K1 is connected to the first terminal C11 of the first pre-charge capacitor C1.

[0061] The first terminal K41 of the main negative relay K4 and the first terminal L11 of the inductor L are connected to the second node P2, for example. Figure 1 and Figure 2 As shown, the first terminal K41 of the main negative relay K4 is connected to the second node P2, and the first terminal L11 of the inductor L is connected to the second node P2 via the inductor control switch S4. The second node P2 is used to connect to the negative terminal of the power supply, such as the negative terminal B- of the battery pack 10. The second terminal K42 of the main negative relay K4 is connected to the second terminal C12 of the first pre-charge capacitor C1.

[0062] In some embodiments, reference Figure 3 , Figure 3This is a schematic diagram of a third structure of a multi-channel pre-charging circuit according to an embodiment of this application. The following describes... Figure 3 The multi-channel pre-charging circuit shown is Figure 1 The differences will be explained, and the similarities can be found in the descriptions of the various embodiments above, which will not be repeated here.

[0063] Among them, Figure 3 In the circuit topology shown, the connection relationship of the main positive relay K1 is as follows: Figure 1 The circuit topology shown is different. Specifically, the first terminal K11 of the main positive relay K1 is used to connect to the positive terminal of the power supply, such as the positive terminal B+ of the battery pack 10. The second terminal K12 of the main positive relay K1 is connected to the first terminal L11 of the inductor L and the first terminal C11 of the first pre-charge capacitor C1. For example, the second terminal K12 of the main positive relay K1 is connected to the first node P1, the first terminal L11 of the inductor L is connected to the first node P1 via the freewheeling diode D and the overcurrent protection unit FPCU, and the first terminal C11 of the first pre-charge capacitor C1 is connected to the first node P1.

[0064] It is understandable that by setting the main positive relay K1 between the positive terminal of the power supply (e.g., the positive terminal B+ of the battery pack 10) and the first node P1, the connection or disconnection of the positive terminal of the power supply can be controlled by the connection or disconnection of the main positive relay K1, thus facilitating the high-voltage power control of the entire circuit.

[0065] In some embodiments, continue to refer to Figure 1 and Figure 2 The auxiliary power positive bus 212 is connected in series with the auxiliary power positive relay K2, the DC input positive bus 213 is connected in series with the DC input positive relay K3, the auxiliary power negative bus 222 is connected in series with the auxiliary power negative relay K5, and the DC input negative bus 223 is connected in series with the DC input negative relay K6.

[0066] Specifically, the first terminal C21 of the second pre-charge capacitor C2 is connected to the second terminal K22 of the auxiliary power positive relay K2, and the second terminal C22 of the second pre-charge capacitor C2 is connected to the second terminal K52 of the auxiliary power negative relay K5. The first terminal C31 of the third pre-charge capacitor C3 is connected to the second terminal K32 of the DC input positive relay K3, and the second terminal C32 of the third pre-charge capacitor C3 is connected to the second terminal K62 of the DC input negative relay K6.

[0067] The first terminal K21 of the auxiliary power positive relay K2 and the first terminal K31 of the DC input positive relay K3 are both connected to the first node P1, as follows: Figure 1 and Figure 2 As shown. The first terminal K51 of the auxiliary power supply negative relay K5 and the first terminal K61 of the DC input negative relay K6 are both connected to the second terminal K42 of the main negative relay K4, as follows. Figure 1 and Figure 2 As shown.

[0068] In some embodiments, such as Figure 3 As shown, when the main positive relay K1 is located between the positive terminal of the power supply (e.g., the positive terminal B+ of the battery pack 10) and the first node P1, the first terminal K21 of the auxiliary power positive relay K2 and the first terminal K31 of the DC input positive relay K3 are both connected to the second terminal K12 of the main positive relay K1.

[0069] In some embodiments, reference Figure 4 , Figure 4 This is a schematic diagram of a fourth structure of a multi-channel pre-charging circuit according to an embodiment of this application. The following describes... Figure 4 The multi-channel pre-charging circuit shown is Figure 3 The differences will be explained, and the similarities can be found in the descriptions of the various embodiments above, which will not be repeated here.

[0070] Among them, Figure 4 In the circuit topology shown, the connection relationship of the main negative relay K4 is as follows: Figure 3 The circuit topology shown is different. Specifically, the first terminal K41 of the main negative relay K4 is connected to the second node P2, and the second terminal K42 of the main negative relay K4 is connected to the second terminal C12 of the first pre-charge capacitor C1. The first terminal K51 of the auxiliary power negative relay K5 and the first terminal K61 of the DC input negative relay K6 are both connected to the second node P2.

[0071] The following describes the workflow of the multi-channel pre-charging circuit in an embodiment of this application. (Reference) Figure 5 , Figure 5 This is a schematic diagram of the operation of a multi-channel pre-charging circuit according to an embodiment of this application. The operation of the multi-channel pre-charging circuit includes the following steps S110~S220: S110, pre-charging started.

[0072] S120, High-voltage insulation detection and system self-test. If normal, proceed to step S130; if abnormal, return to step S110. During this process, the entire vehicle undergoes high-voltage insulation detection, component fault self-test, and system status verification. If all tests are normal, the system enters the high-voltage pre-charge standby state. If any abnormality is detected, it indicates a system fault. In this case, an error report or fault alarm can be issued, and the pre-charge process will not continue until the fault is resolved.

[0073] S130, the entire vehicle is pre-energized with high voltage.

[0074] S140, close the main positive relay, and open the main negative relay (all switching devices are initially in the open state). Specifically, the control unit issues a command to close the main positive relay K1, while the main negative relay K4 remains in the open state, and all switching devices are initially in the off and locked state.

[0075] S150, Relay closing and opening status diagnosis. If normal, proceed to step S160; if abnormal, return to step S140. The system diagnoses the closing and opening status of relays. If the status of all relays is consistent with expectations (main positive relay closed, main negative relay open, other relays open), it indicates that the relay status is normal. If the status of any relay is inconsistent with expectations, it indicates that there is a relay fault, such as relay sticking or inability to close. In this case, an error report or fault alarm can be issued, and the pre-charging process will not continue until the fault is resolved.

[0076] S160: The first pre-charge branch switch and the main pre-charge switch are turned on, and the inductor control switch is enabled to start pre-charging of the first pre-charge branch. The control unit can select the first pre-charge capacitor C1 of the first pre-charge branch 31 as the target, and control the main pre-charge switch S5, the first pre-charge branch switch S1, and the inductor control switch S4 to turn on. At this time, the second pre-charge branch switch S2 and the third pre-charge branch switch S3 remain open. The bus voltage forms a complete pre-charge circuit through the inductor control switch S4, the inductor L, the main pre-charge switch S5, the first pre-charge branch switch S1, and the first pre-charge capacitor C1. The inductor L stores energy, causing the voltage of the first pre-charge capacitor C1 to rise slowly.

[0077] S170: Monitor whether the voltage value of the first pre-charge capacitor reaches the preset threshold of the high-voltage bus. If yes, proceed to step S180; otherwise, return to step S160.

[0078] S180, the first pre-charge branch pre-charge is complete. The control unit monitors whether the voltage value of the first pre-charge capacitor C1 reaches a preset threshold (e.g., 92% of the bus voltage). If the preset threshold is reached, it is determined that the first pre-charge capacitor C1 is pre-charged.

[0079] S190, the inductor control switch, the first pre-charge branch switch, and the pre-charge main switch are turned off in sequence. When the first pre-charge capacitor C1 is fully pre-charged, the control unit sequentially controls the inductor control switch S4, the first pre-charge branch switch S1, and the pre-charge main switch S5 to turn off. The electrical energy stored in the inductor L is smoothly discharged through the freewheeling diode D, suppressing voltage spikes during the switch-off process.

[0080] S200: Wait for the preset dead time to ensure there is no residual current in the circuit and the device is stable. If normal, proceed to step S210; if abnormal, return to step S190.

[0081] S210, following the same control logic, sequentially completes the pre-charging operations of the second pre-charging branch and the third pre-charging branch. After waiting for a preset dead time to ensure that there is no residual current in the circuit and the device state is stable, the control unit sequentially controls the second pre-charging branch 32 and the third pre-charging branch 33 to perform pre-charging operations according to the same control logic.

[0082] S220: After all pre-charge branches have reached the required pre-charge level, the control unit closes the main negative relay and the main positive relay, fully connecting the high-voltage main circuit and putting the vehicle's high-voltage system into normal operating mode. After all pre-charge branches have reached the required pre-charge level, the control unit closes the main negative relay K4 and the main positive relay K1, connecting the high-voltage main circuit and putting the vehicle's high-voltage system into normal operating mode.

[0083] This application also provides a high-voltage power distribution system. The high-voltage power distribution system includes a battery pack and multiple pre-charging circuits. The battery pack is, for example, a... Figures 1-4 The battery pack 10 shown includes a positive terminal B+ and a negative terminal B-. The multi-channel pre-charge circuit is any of the multi-channel pre-charge circuits described above. Specifically, the high-voltage positive bus 21 of the multi-channel pre-charge circuit is connected to the positive terminal B+ of the battery pack 10, and the high-voltage negative bus 22 of the multi-channel pre-charge circuit is connected to the negative terminal B- of the battery pack 10.

[0084] This application also provides a vehicle, which includes the multi-path pre-charging circuit of any of the above embodiments, or includes the above high-voltage power distribution system.

[0085] The vehicles can be private cars, such as sedans, SUVs, MPVs, or pickup trucks. They can also be commercial vehicles, such as vans, buses, small trucks, or large semi-trailers. Vehicles can be new energy vehicles, such as hybrid vehicles or pure electric vehicles.

[0086] In the description of this application, it should be understood that terms such as “first” and “second” are used only to distinguish similar objects and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated.

[0087] It should be noted that in the embodiments of this application, "connection" can be understood as electrical connection. The connection between two electrical components can be a direct or indirect connection between the two electrical components. For example, the connection between A and B can be a direct connection between A and B, or an indirect connection between A and B through one or more other electrical components.

[0088] The multi-path pre-charging circuit, high-voltage power distribution system, and vehicle provided in the embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application, and the descriptions of the embodiments above are only for the purpose of helping to understand this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A multi-path pre-charging circuit with a shared inductor on the negative side, characterized in that, include: High-voltage positive busbar and high-voltage negative busbar, wherein the high-voltage positive busbar is used to connect to the positive terminal of the power supply and the high-voltage negative busbar is used to connect to the negative terminal of the power supply; Multiple pre-charge branches, each of the pre-charge branches including a pre-charge branch switch and a pre-charge capacitor connected in series, the first end of each pre-charge capacitor being connected to the high-voltage positive bus, the second end of each pre-charge capacitor being connected to the high-voltage negative bus, and the first end of each pre-charge branch switch being connected to the second end of the pre-charge capacitor in the pre-charge branch. An inductor, the first end of which is connected to the high-voltage negative busbar, and the second end of which is connected to the second end of each of the precharge branch switches; A control unit is connected to each of the precharge branch switches and is configured to control each of the precharge branch switches to be turned on or off, so that the precharge capacitors of the plurality of precharge branches are precharged sequentially.

2. The multi-channel pre-charging circuit according to claim 1, characterized in that, The control unit is configured to: Control the precharge branch switch of one of the precharge branches to be turned on, so that the precharge capacitor of the precharge branch is precharged; When the pre-charge capacitor is fully pre-charged, the pre-charge branch switch controlling the pre-charge branch is disconnected; After a preset dead time, the precharge branch switch of the next precharge branch is turned on, so that the precharge capacitor of the corresponding precharge branch can be precharged.

3. The multi-channel pre-charging circuit according to claim 2, characterized in that, The control unit is also configured to monitor the voltage of the pre-charged capacitor during pre-charging, and to determine that the pre-charging of the pre-charged capacitor is complete when the voltage of the pre-charged capacitor reaches a preset voltage.

4. The multi-channel pre-charging circuit according to claim 1, characterized in that, The multi-path pre-charging circuit also includes an inductor control switch, the first end of which is connected to the high-voltage negative bus, and the second end of which is connected to the first end of the inductor. The control unit is also connected to the inductor control switch, and the control unit is further configured to control the inductor control switch to be turned on or off.

5. The multi-channel pre-charging circuit according to claim 4, characterized in that, The multi-path pre-charging circuit also includes a freewheeling diode, the anode of which is connected to the node between the inductor control switch and the inductor, and the cathode of which is connected to the high-voltage positive bus. When the inductor control switch and each of the precharge branch switches are open, the inductor and the freewheeling diode form an energy discharge path.

6. The multi-channel pre-charging circuit according to claim 5, characterized in that, The multi-channel pre-charge circuit also includes an overcurrent protection unit. The first end of the overcurrent protection unit is connected to the high-voltage positive bus, and the second end of the overcurrent protection unit is connected to the cathode of the freewheeling diode.

7. The multi-channel pre-charging circuit according to claim 5, characterized in that, The multi-path pre-charging circuit also includes a pre-charging master switch, the first terminal of which is connected to the second terminal of the inductor, and the second terminal of which is connected to the second terminal of each of the pre-charging branch switches; The control unit is also connected to the precharge main switch, and the control unit is also configured to control the precharge main switch to be turned on or off.

8. The multi-channel pre-charging circuit according to claim 5, characterized in that, The high-voltage positive busbar includes a main positive busbar, which is used to connect to the positive terminal of the power supply. A main positive relay is connected in series with the main positive busbar. The high-voltage negative busbar includes a main negative busbar, which is used to connect to the negative terminal of the power supply. A main negative relay is connected in series with the main negative busbar. The plurality of pre-charge branches include a first pre-charge branch, and the first pre-charge branch includes a first pre-charge capacitor; Wherein, the first terminal of the main positive relay is connected to the cathode of the freewheeling diode and connected to a first node, the first node being used to connect to the positive terminal of the power supply, and the second terminal of the main positive relay is connected to the first terminal of the first pre-charge capacitor; or, the first terminal of the main positive relay is used to connect to the positive terminal of the power supply, and the second terminal of the main positive relay is connected to the cathode of the freewheeling diode and the first terminal of the first pre-charge capacitor. The first terminal of the main negative relay is connected to the first terminal of the inductor control switch and then to the second node, which is used to connect to the negative terminal of the power supply. The second terminal of the main negative relay is connected to the second terminal of the first pre-charge capacitor.

9. The multi-channel pre-charging circuit according to claim 8, characterized in that: The high-voltage positive bus also includes an auxiliary power supply positive bus and a DC input positive bus. Both the auxiliary power supply positive bus and the DC input positive bus are used to connect to the positive terminal of the power supply. An auxiliary power supply positive relay is connected in series with the auxiliary power supply positive bus, and a DC input positive relay is connected in series with the DC input positive bus. The high-voltage negative bus also includes an auxiliary power supply negative bus and a DC input negative bus. Both the auxiliary power supply negative bus and the DC input negative bus are used to connect to the negative terminal of the power supply. An auxiliary power supply negative relay is connected in series with the auxiliary power supply negative bus, and a DC input negative relay is connected in series with the DC input negative bus. The plurality of pre-charge branches further include a second pre-charge branch and a third pre-charge branch. The second pre-charge branch includes a second pre-charge capacitor, the first terminal of which is connected to the second terminal of the auxiliary power positive relay, and the second terminal of which is connected to the second terminal of the auxiliary power negative relay. The third pre-charge branch includes a third pre-charge capacitor, the first terminal of which is connected to the second terminal of the DC input positive relay, and the second terminal of which is connected to the second terminal of the DC input negative relay. Wherein, the first terminal of the auxiliary power positive relay and the first terminal of the DC input positive relay are both connected to the first node; or, the first terminal of the auxiliary power positive relay and the first terminal of the DC input positive relay are both connected to the second terminal of the main positive relay. The first terminal of the auxiliary power supply negative relay and the first terminal of the DC input negative relay are both connected to the second node; or, the first terminal of the auxiliary power supply negative relay and the first terminal of the DC input negative relay are both connected to the second terminal of the main negative relay.

10. A high-voltage power distribution system, characterized in that, include: A battery pack, the battery pack including a positive terminal and a negative terminal; The multi-channel pre-charging circuit as described in any one of claims 1 to 9, wherein the high-voltage positive bus of the multi-channel pre-charging circuit is connected to the positive terminal, and the high-voltage negative bus of the multi-channel pre-charging circuit is connected to the negative terminal.

11. A vehicle, characterized in that, It includes the multi-path pre-charging circuit as described in any one of claims 1 to 9, or the high-voltage power distribution system as described in claim 10.

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