Partial pre-charge of the high voltage system

Abstract

A system for partially pre-charging a power system includes a high voltage power source, a DC link device with a DC link capacitor, a low voltage power source, and a DC / DC converter. In one embodiment, partial pre-charging of a DC link capacitor may be achieved by: first, DC / DC converter boost from a low voltage power supply; second, charging, by the first circuit, the DC link capacitor to a partially pre-charged state with a voltage from the low-voltage power source; third, the current flowing from the high voltage power supply to the DC link capacitor is limited by the second circuit, thereby charging the DC link capacitor only to a partial pre-charge level. The controller selectively operates the first circuit, the second circuit, or the DC / DC converter to charge the DC link capacitor to a partially pre-charged state.

Description

(19) State Intellectual Property Office (12) Invention Patent Application (10) Application Publication Number (43) Application Publication Date (21) Application Number 202480053381.1 (22) Application Date 2024.08.14 (30) Priority Data 18 / 236,658 2023.08.22 US (85) PCT International Application Entering National Phase Date 2026.02.13 (86) PCT International Application Application Data PCT / US2024 / 042266 2024.08.14 (87) PCT International Application Publication Data WO2025 / 042651 EN 2025.02.27 (71) Applicant: BAE Systems Controls, Inc. Address: New York, USA (72) Inventors: C.C. Jones, R.J. Warworth, A.P. Lyons, J.A. Dupuy (74) Patent Agency: Beijing Sanxing Trademark & ​​Patent Agency (General Partnership) 11216 Patent Attorney: Liu Zhuoran (51) Int.Cl. B60L 53 / 20 (2006.01) B60L 53 / 22 (2006.01) B60L 58 / 27 (2006.01) H02J 7 / 34 (2006.01) B60L 53 / 62 (2006.01) B60L 58 / 10 (2006.01) B60L 58 / 13 (2006.01) H02J 7 / 04 (2006.01) (54) Title of Invention: Partial Precharging of a High-Voltage System (57) Abstract: A system for partially precharging a power system, comprising a high-voltage power supply, a DC-link device with a DC-link capacitor, a low-voltage power supply, and a DC / DC converter. In one embodiment, partial precharging of the DC-link capacitor can be achieved in three ways: first, by boosting the voltage from the low-voltage power supply using the DC / DC converter; second, by charging the DC-link capacitor to a partially precharged state using the voltage from the low-voltage power supply via a first circuit; and third, by limiting the current flowing from the high-voltage power supply to the DC-link capacitor via a second circuit, thereby charging the DC-link capacitor only to a partially precharged level. A controller selectively operates the first circuit, the second circuit, or the DC / DC converter to charge the DC-link capacitor to a partially precharged state.Claims (3 pages), Description (6 pages), Drawings (2 pages), CN 121712665 ​​A, 2026.03.20, CN 1 21 71 26 65 A. 1. A system for partially precharging a power system, comprising: a high-voltage power supply module including a high-voltage DC power supply; a DC link device connected to the high-voltage power supply, the DC link device including a high-voltage DC link capacitor; a low-voltage power supply; a DC / DC converter connected between the DC link capacitor and the low-voltage power supply, the DC / DC converter configured to boost the voltage of the low-voltage power supply; a first circuit configured to charge the DC link capacitor to a partially precharged state using the voltage of the low-voltage power supply; a second circuit configured to limit current flowing from the high-voltage power supply to the DC link capacitor, thereby charging the DC link capacitor to a partially precharged state based on the limited current from the high-voltage power supply; and a controller configured to selectively operate the first circuit, the second circuit, or the DC / DC converter, thereby charging the DC link capacitor to a partially precharged state. 2. The system of claim 1, wherein the second circuit comprises: a pair of contactors for controlling the power supply to charge the high-voltage DC link capacitor; and a resistor network; and a contactor connected in parallel with one of the contactors in the pair, wherein the controller limits the duration of current flowing through the resistor network to gradually charge the DC link capacitor to a partially precharged state. 3. The system of claim 1, wherein the first circuit comprises: a resistor network; and a plurality of contactors connected between the DC link capacitor and the low-voltage power supply, wherein the controller is configured to close the plurality of contactors to allow current to flow through the resistor network to the DC link capacitor, thereby charging the DC link capacitor to a partially precharged state. 4. The system of claim 3, wherein the partially precharged state is equal to the voltage of the low-voltage power supply. 5. The system of claim 3, wherein the controller is configured to disconnect the plurality of contactors in the first circuit to charge the DC link capacitor to a partially precharged state from the low-voltage power supply using a DC / DC converter module. 6. The system of claim 1, further comprising at least one sensor, wherein the controller is configured to detect a fault in the power system based on measurements from the at least one sensor when the DC link capacitor is in a partially precharged state. 7. The system of claim 6, wherein the controller is configured to activate the second circuitry to charge the DC link capacitor from the high-voltage power supply, thereby charging the DC link capacitor to a fully high-voltage precharged state.8. A system for partially precharging a power system, comprising: a high-voltage power supply module including a high-voltage DC power supply; a DC link device connected to the high-voltage power supply, the DC link device including a high-voltage DC link capacitor; a low-voltage power supply; a DC / DC converter connected between the DC link capacitor and the low-voltage power supply, the DC / DC converter configured to boost the voltage of the low-voltage power supply; and a controller configured to charge the DC link capacitor from the low-voltage power supply to a partially precharged state using the DC / DC converter module. 9. A method for partially precharging a power system, the system comprising: a high-voltage power supply module including a high-voltage DC power supply; a DC link device connected to the high-voltage power supply, the DC link device including a high-voltage DC link capacitor; and a DC / DC converter connected between the DC link capacitor and a low-voltage power supply, the method comprising: providing a first circuit configured to charge the DC link capacitor to a partially precharged state using a voltage from the low-voltage power supply; providing a second circuit configured to limit current flowing from the high-voltage power supply to the DC link capacitor, thereby charging the DC link capacitor to a partially precharged state based on the limited current; and selectively operating one of the first circuit, the second circuit, or the DC / DC converter to charge the DC link capacitor to a partially precharged state. 10. The method of claim 9, wherein charging the DC link capacitor to a partially precharged state using the second circuit comprises: controlling a pair of contactors, a resistor network, and a contactor connected in parallel with one of the contactors in the pair of contactors, thereby limiting the current of the high-voltage power supply by allowing current to flow through the resistor network, thereby gradually charging the DC link capacitor to a partially precharged state. 11. The method of claim 9, wherein charging the DC link capacitor to a partially precharged state using the first circuit comprises: closing a plurality of contactors in the first circuit, thereby allowing current to flow through the resistor network, thereby limiting the current from the low-voltage power supply to the DC link capacitor, thereby gradually charging the DC link capacitor to a partially precharged state. 12. The method of claim 9, wherein charging the DC link capacitor to a partially precharged state using a DC / DC converter comprises: disconnecting a plurality of contactors in the first circuit, thereby using the DC / DC converter module to charge the DC link capacitor to a partially precharged state from the low-voltage power supply. 13. The method of claim 9, further comprising: detecting a fault in the power system based on measurements from at least one sensor when the DC link capacitor is in a partially precharged state.14. The method of claim 11, further comprising: detecting a short circuit between the high-voltage DC harness and the AC harness in the power system when the DC link capacitor is in a partially pre-charged state. 15. The method of claim 11, further comprising: detecting a short circuit on the DC link device when the DC link capacitor is in a partially pre-charged state. 16. The method of claim 11, further comprising: detecting a fault in the high-voltage contactor in the power system when the DC link capacitor is in a partially pre-charged state. 17. The method of claim 11, further comprising: detecting a ground fault in the power system when the DC link capacitor is in a partially pre-charged state. 18. The method of claim 11, further comprising: detecting a fault in the high-voltage current sensor in the power system when the DC link capacitor is in a partially pre-charged state. 19. The method of claim 11, further comprising: detecting a fault in the high-voltage contactor in the electrical interface with the on-board charger when the DC link capacitor is in a partially pre-charged state. 20. A system for partially precharging a power system, comprising: a high-voltage power supply module including a high-voltage DC power supply; a DC link device connected to the high-voltage power supply, the DC link device including a high-voltage DC link capacitor; a low-voltage power supply; a circuit configured to limit current flowing from the high-voltage power supply to the DC link capacitor, thereby charging the DC link capacitor to a partially precharged state based on the limited current; and a controller configured to selectively operate the circuit to charge the DC link capacitor to a partially precharged state. 21. A system for partially precharging a power system, comprising: a high-voltage power supply module including a high-voltage DC power supply; a DC link device connected to the high-voltage power supply, the DC link device including a high-voltage DC link capacitor; a low-voltage power supply; a circuit configured to charge the DC link capacitor to a partially precharged state using the voltage of the low-voltage power supply; and a controller configured to selectively operate the circuit to charge the DC link capacitor to a partially precharged state. Claims 3 / 3 Page 4 CN 121712665 ​​A Partial Pre-charging of High Voltage Systems Background Art

[0001] In high-voltage DC power systems, such as electric vehicle (EV) or hybrid electric vehicle (HEV) systems, there exists a high-voltage energy storage system used as a power source for the drive system and operating accessories. The output of this high-voltage energy storage system (which may be a multi-battery pack, supercapacitor, or other system) is equipped with a contactor to prevent high-voltage current from leaving the high-voltage connection before it is switched on.Devices connected to the high-voltage energy storage system include various units such as drive inverters and DC / DC or DC / AC converters, which are used to power drive motors, charge low-voltage batteries, and power electrification accessory loads of the vehicle. These units internally house high-voltage DC link capacitors to buffer high-voltage currents from the high-voltage energy storage system and various loads. Typically, the high-voltage DC link capacitors are pre-charged before closing the contactors in the high-voltage energy storage system to balance the voltage across the contactors. Pre-charging aims to minimize the current on the closing contacts of the main DC link contactor connecting the high-voltage energy storage device and the high-voltage DC link, thereby preventing damage and maximizing the contactor's lifespan. The pre-charge voltage reaches the full voltage of the high-voltage power supply.

[0002] In the high-voltage energy storage system, the contactors are typically in the open state until the high-voltage DC link capacitors are pre-charged through a resistor network or other means. This pre-charging function gradually charges the capacitors in the connected loads before the contactors close.

[0003] If not detected in time, many faults may exist in the system, causing the contactors to malfunction when closed and high voltage is present.

[0004] To address this technical problem, a system and method for partially pre-charging a high-voltage system to a low-voltage state are disclosed, thereby thoroughly checking the high-voltage system and load for operational defects before connecting the high-voltage power supply.

[0005] In one embodiment, a system for partially pre-charging a power system is disclosed. The power system includes: a high-voltage power supply module including a high-voltage DC power supply; a DC link device including a high-voltage DC link capacitor connected to the high-voltage power supply; a low-voltage power supply connected to the DC link capacitor; and a DC / DC converter connected between the DC link capacitor and the low-voltage power supply. In one embodiment, the DC / DC converter is configured in a boost mode to boost the voltage of the low-voltage power supply. In one embodiment, a controller is configured to charge the DC link capacitor from the low-voltage power supply to a partially pre-charged state using the DC / DC converter module in boost mode.

[0006] In one embodiment, a system for partially precharging a power system includes: a first circuit configured to charge a DC-link capacitor to a partially precharged state using a voltage from a low-voltage power supply; and a second circuit configured to limit the current flowing from a high-voltage power supply to the DC-link capacitor, thereby charging the DC-link capacitor to a partially precharged state based on the limited current. A controller is configured to selectively operate one of the first circuit, the second circuit, or a DC / DC converter to charge the DC-link capacitor to a partially precharged state.

[0007] In one embodiment, the second circuit includes a pair of contactors for controlling the current supply to charge the high-voltage DC link capacitor, a resistor network, and a contactor connected in parallel with one of the pair of contactors, wherein the controller allows current to flow through the resistor network, thereby gradually charging the DC link capacitor to a partially pre-charged state. In one embodiment, the first circuit includes a resistor network and a plurality of contactors connected between the DC link capacitor and a low-voltage power supply, wherein the controller is configured to close the plurality of contactors, thereby allowing current to flow through the resistor network to the DC link capacitor, thereby gradually charging the DC link capacitor to a partially pre-charged state. In one embodiment, the partially pre-charged state is equal to the voltage of the low-voltage power supply. In one embodiment, the controller is configured to disconnect the plurality of contactors in the first circuit, thereby charging the DC link capacitor to a partially pre-charged state from the low-voltage power supply using a DC / DC converter module in boost mode.

[0008] In one embodiment, the controller is configured to detect a fault in the power system based on measurements from one or more sensors when the DC link capacitor is in a partially pre-charged state. In one embodiment, the controller is configured to disconnect the sensor and activate a second circuit to gradually charge the DC link capacitor from the high-voltage power supply, thereby charging the DC link capacitor to a fully high-voltage precharged state.

[0009] In one embodiment, a method of partially precharging a power system includes: providing a first circuit configured to charge a DC link capacitor to a partially precharged state using the voltage of a low-voltage power supply; providing a second circuit configured to limit the current flowing from the high-voltage power supply to the DC link capacitor, thereby charging the DC link capacitor to a partially precharged state based on the limited current; and selectively operating one of the first circuit, the second circuit, and a DC / DC converter to charge the DC link capacitor to a partially precharged state.

[0010] In one embodiment, the method includes controlling a pair of contactors, a resistor network, and a contactor connected in parallel with one of the contactors in the pair of contactors to limit the current flowing through the resistor network, thereby gradually charging the DC link capacitor to a partially precharged state. In one embodiment, the method includes closing a plurality of contactors in the first circuit, such that current flows through the resistor network to the DC link capacitor, thereby gradually charging the DC link capacitor to a partially precharged state. In one embodiment, the method includes disconnecting multiple contactors in a first circuit to charge a DC link capacitor from a low-voltage power supply to a partially pre-charged state when the DC / DC converter module is in boost mode.

[0011] In one embodiment, the method includes: detecting a fault in the power system based on measurement results from at least one sensor while the DC link capacitor is in a partially precharged state; in one embodiment, the method includes: detecting a short circuit between a high-voltage DC harness and an AC harness in the power system while the DC link capacitor is in a partially precharged state; in one embodiment, the method includes: detecting a short circuit on a DC link device while the DC link capacitor is in a partially precharged state; in one embodiment, the method includes: detecting a fault in a high-voltage contactor in the power system while the DC link capacitor is in a partially precharged state. In one embodiment, the method includes: detecting a ground fault in the power system while the DC link capacitor is in a partially precharged state. In one embodiment, the method includes: detecting a fault in a high-voltage current sensor in the power system while the DC link capacitor is in a partially precharged state.

[0012] FIG1 is a block diagram of an embodiment of the system for partially precharging a power system according to the present disclosure.

[0013] FIG2 is a block diagram of an embodiment of the system for partially precharging a power system according to the present disclosure.

[0014] FIG3 is a flowchart of a method for partially precharging a power system according to the present disclosure.

[0015] FIG4 is a flowchart of a method for partially precharging a power system according to the present disclosure.

[0016] Other features and the structure and operation of various embodiments will be described in detail below with reference to the accompanying drawings. In the drawings, the same reference numerals denote the same or similar functional elements. Specification 2 / 6 pages 6 CN 121712665 ​​A Detailed Description

[0017] As shown in FIG1, the vehicle power system 10 includes a module including a high-voltage DC link device 12 and a high-voltage power supply module 14. The high-voltage power supply module 14 includes a high-voltage DC power supply 16. The high-voltage DC link device 12 includes a high-voltage DC link capacitor 20. In some embodiments, the high-voltage DC power supply 16 may be a high-voltage energy storage device, such as a multi-battery pack for powering an electric vehicle (EV) or a hybrid electric vehicle (HEV). In some embodiments, the high-voltage DC link device 12 is an inverter for an electric vehicle or a hybrid electric vehicle. In some embodiments, the high-voltage power supply module 14 includes contactors 18 and 19 for controlling the power supply to charge the high-voltage DC link capacitor 20 included in the high-voltage DC link device 12. When both contactors 18 and 19 are closed, the DC link capacitor 20 is charged to the full voltage of the high-voltage power supply 16, thereby charging the DC link capacitor 20 to a high-voltage state. It should be understood that the "contactor" can be implemented by an electromechanical switching device or a solid-state switching device, as both can also be used in the pre-charging circuit described herein.

[0018] The high-voltage power supply module 14 may also include circuitry 22 configured to precharge the DC link capacitor 20 before closing contactors 18 and 19. In some embodiments, circuitry 22 is configured to gradually charge the DC link capacitor 20 from the high-voltage power supply 16 to a high-voltage state. Those skilled in the art will appreciate that this pre-charging function is used to protect the contactors and loads from damage by large currents while the DC link capacitor is charging. Without this "pre-charging" function, contactors 18 and 19, as well as any load, could be damaged when they are closed. Partial pre-charging can reduce the total arc flash energy at startup, which helps reduce damage from short circuits in the battery and other components, thereby improving the health and reliability of various system components.

[0019] In one embodiment, circuitry 22 includes a resistor network 24 and a contactor 26 connected in parallel with contactor 19. To charge the DC link capacitor 20 to a pre-charged state, contactor 19 is opened, and contactors 18 and 26 are closed. Resistor network 24 slows the current flowing from high-voltage power supply 16 to DC link capacitor 20, thereby gradually charging DC link capacitor 20 to a pre-charged state. In an alternative embodiment, circuit 22 may be connected in parallel with contactor 18 instead of contactor 19 and perform a similar function.

[0020] In one embodiment, the high-voltage DC link capacitor 20 is partially pre-charged to a voltage lower than the high-voltage power supply voltage by limiting the current flowing through circuit 22. In one embodiment, controller 28 limits the duration of the current flowing through circuit 22. In one embodiment, controller 28 uses voltage 54, measured by sensor V4 or a similar sensor at the output of the high-voltage energy storage device, to measure the voltage and stop pre-charging in the partially pre-charged state. Controller 28 controls the pre-charge activation of circuit 22 and other test circuits described below, which are connected to the various contactors and components of power system 10 via communication and / or control paths, thereby activating / deactivating them.

[0021] In one embodiment, after pre-charging begins, the controller 28 disconnects the contactor 26 after a period of time, thereby charging the DC link capacitor 20 to a lower voltage 54 (measured by sensor V4) compared to the full high-voltage power supply 16, thus operating the circuit 22. This charging state, where the capacitor is charged to a voltage lower than the full voltage of the high-voltage power supply 16, is hereinafter referred to as a partial pre-charge state. The partial pre-charge state is a lower voltage compared to the full high-voltage power supply 16, thereby enabling various integrity tests of the power system 10 at a lower voltage. To maintain the high-voltage DC link voltage in a partial pre-charge state during testing, the contactor 26 can be periodically re-closed.After the test is completed in a partially precharged state, the controller 28 recloses the contactor 26, thereby precharging the high-voltage DC link capacitor 20 to the full voltage of the high-voltage power supply 16.

[0022] In one embodiment, the vehicle electrical system 10 may also include a low-voltage power supply 30. In one embodiment, the low-voltage power supply 30 is a low-voltage battery for powering accessories of an electric vehicle or hybrid vehicle. In one embodiment, a circuit 32 similar to the circuit 22 used on the high-voltage power supply module 14 may be used, which includes contactors and resistors. In this embodiment, the partial precharge only raises the voltage of the high-voltage DC link capacitor 20 to the voltage of the low-voltage battery 30. The circuit 32 includes contactors 34 and 36, and may include contactor 38 and a resistor network 40. During the partial precharge using the low-voltage energy 30, contactors 18 and 19 of the high-voltage power supply module 14, and (if any) contactor 26, are disconnected. Controller 28 performs partial pre-charging via operating circuit 32 by closing contactors 34 and 38 (if any) while keeping contactor 36 open, allowing DC link capacitor 20 to be gradually pre-charged to the voltage of low-voltage power supply 30 via resistor network 40. If gradual pre-charging is not required, contactor 38 and resistor network 40 are not configured, and if contactors 34 and 36 are designed to carry current when closed, they can be closed immediately. Once partially pre-charged, controller 28 can disconnect contactors 34, 36, and 38, isolating low-voltage power supply 30 and allowing various integrity tests on power system 10 at that voltage. To maintain the high-voltage DC link voltage in a partially pre-charged state during testing, contactors 34, 36, and 38 can be periodically re-closed. After testing, controller 28 can operate circuit 22 to complete the full pre-charge of DC link capacitor 20.

[0023] In some embodiments, the vehicle electrical system 10 may further include a DC / DC converter module 42 connected between the high-voltage DC link device 12 and the low-voltage power supply 30. In one embodiment, the DC / DC converter 42 may transfer current from the high-voltage power supply 16 to the low-voltage power supply 30 in buck mode, which facilitates charging of the low-voltage battery 30 during operation, but this is not necessary in this embodiment. In one embodiment, the DC / DC converter module 42 may transfer current from the low-voltage power supply 30 to the high-voltage power supply 16 in boost mode. Partial precharging using the boost mode of the DC / DC converter 42 charges connected electronics, wiring harnesses, and any other DC loads to a certain voltage, thereby allowing sensors on the system to verify the integrity of the high-voltage system before full precharging and the closure of the high-voltage power contactors 18 and 19.The controller 28 regulates the high-voltage DC link device 12 via the DC / DC converter 42, transmitting or even boosting the voltage from the low-voltage energy source 30, thereby charging the high-voltage DC link capacitor 20.

[0024] When the low-voltage battery 30 is boosted using the DC / DC converter, the low-voltage battery resistor network 32 is disconnected. In DC / DC converter boost mode, all contactors 34, 38, and 36 are disconnected. In one embodiment, if there is no DC / DC converter in the system, the resistor network 32 can be used to precharge the DC link capacitor 20. In another embodiment, if the DC / DC converter 42 can only buck and not boost, the resistor network 32 can be used to charge the low-voltage battery 30 from the high-voltage power supply 16. There are three independent precharging methods: 1) using circuit 22; 2) using circuit 32; and 3) using the DC / DC converter 42. These three methods are activated independently by the controller 28. When using boost mode, all contactors on circuits 22 and 32 are disconnected; when using circuit 32, all contactors in circuit 22 are disconnected and boost is disabled; when using circuit 22, all contactors in circuit 32 are disconnected and boost is disabled. The architecture shown in Figure 1 includes hardware supporting all three methods. In other embodiments, the architecture may include a combination of any two methods, or only one method to establish a partial precharge state. For example, in one embodiment, circuit 32 is not included, so the partial precharge state is established by boost mode of DC / DC converter 42 or by using circuit 22. In another embodiment, DC / DC converter 42 is not included, so the partial precharge state is established by using circuit 32 or circuit 22. In another embodiment, neither DC / DC converter 42 nor circuit 32 is included, so the partial precharge state is established by using circuit 22.

[0025] In one embodiment, voltage sensors 44 and 50 for detecting voltages V1 and V2 may be used to detect various faults at the partial precharge voltage. In one embodiment, when the high-voltage DC link capacitor 20 is in a partially pre-charged state, sensor 44 can detect a high-voltage short circuit on the DC link device 12. Controller 28 can be programmed to determine whether voltage V1 rises during the partial pre-charge process; if voltage V1 does not rise, a fault is identified. In another embodiment, contactor 46, used to protect the on-board charger plug 48 from high-voltage surges, can close, and voltage V2 can be measured by sensor 50. Controller 28 determines whether the voltage V2 outside contactor 46 is equal to V1, thereby ensuring its proper functioning and assessing whether a short circuit exists on the charger plug 48 side of contactor 46.Similarly, other sensors can be arranged around system 10 to perform testing methods commonly used by those skilled in the art of propulsion system design.

[0026] During partial pre-charge, chassis faults can be measured using industry-standard methods, for example, the circuit 62 on the high-voltage DC link device 12 can be used to detect DC grounding or vehicle chassis faults. Controller 28 is programmed to detect voltage changes relative to the vehicle chassis. A fault-free state is indicated when the voltage V5 across resistor 64 is equal to the voltage V6 across the same resistor 66. At this time, both voltages V5 and V6 are half the DC link capacitor voltage. Wherein, voltage V5 measures the voltage between the negative DC link line 68 and chassis ground, and voltage V6 measures the voltage between the positive DC link line 70 and chassis ground. When a ground short circuit occurs in the system, voltages V5 and V6 will no longer be equal. For example, if the chassis is short-circuited to the negative DC link line 68, V5 will be equal to 0V, while V6 will show the full DC link voltage. If the chassis is short-circuited to the positive DC link 70, V6 will be equal to 0V and V5 will be equal to the negative DC link voltage. After the test is completed, the controller 28 is configured to disconnect the sensor and the test circuit and activate the circuit 22, thereby causing the DC link capacitor 20 to gradually charge from the high-voltage power supply 16 to a full high-voltage precharge state.

[0027] In one embodiment, as shown in FIG2, a system 80 for partially precharging a power system includes: a high-voltage power supply 82 having a second circuit 96; a DC link device 84 having a high-voltage DC link capacitor 86 connected to a contactor of the second circuit 96 of the high-voltage power supply 82; and a DC / DC converter 88 connected between the DC link device 84 and the low-voltage power supply 92 via a first circuit 90. The DC / DC converter 88 is configured in boost mode to boost the voltage of the low-voltage power supply 92. The controller 94 is configured to use the DC / DC converter 88 in boost mode to charge the DC link capacitor 86 from the low-voltage power supply 92 to a partially precharge state. In one embodiment, controller 94 keeps the normally open contactor of the first circuit 90 open, thereby charging the DC link capacitor 86 to a partially precharged state from the low-voltage power supply 92 using the DC / DC converter 88 in boost mode. Alternatively, controller 94 closes contactor 90, thereby directly charging the DC link capacitor 86 to a partially precharged state from the low-voltage power supply 92.

[0028] FIG3 is a flowchart of one embodiment of a method for partially precharging a power system including: a high-voltage power supply module; a DC link device connected to the high-voltage power supply, the DC link device including a high-voltage DC link capacitor; a low-voltage power supply connected to the DC link capacitor; and a DC / DC converter connected between the DC link capacitor and the low-voltage power supply.The method includes: step S1, namely providing a first circuit configured to charge a DC link capacitor to a partially precharged state using a voltage from a low-voltage power supply; and step S2, namely providing a second circuit configured to limit the current flowing from a high-voltage power supply to the DC link capacitor, thereby charging the DC link capacitor to a partially precharged state based on the limited current. Step S3 includes selectively operating the first circuit, the second circuit, or a DC / DC converter to charge the DC link capacitor to a partially precharged state.

[0029] In one embodiment, charging the DC link capacitor to a partially precharged state in step S3 includes: charging the DC link capacitor 86 to a partially precharged state using the DC / DC converter 88 from a low-voltage power supply 92 when the DC / DC converter 88 is in boost mode. In one embodiment of step S3, the contactor in the first circuit 90 may be disconnected or absent, and the contactor in the second circuit 96 also remains disconnected.

[0030] In one embodiment, charging the DC link capacitor to a partially precharged state in step S3 includes: controlling a second circuit 96, which may include a pair of contactors, a resistor network, and a contactor connected in parallel with one of the contactors in the pair of contactors, thereby limiting the current flowing through the resistor network, thereby gradually charging the DC link capacitor 86 to a partially precharged state from the high-voltage power supply 82.

[0031] In one embodiment, charging the DC link capacitor 86 to a partially precharged state using a first circuit 90 in step S3 includes: closing a plurality of contactors in the first circuit, thereby allowing current to flow through the resistor network to the DC link capacitor 86, thereby gradually charging the DC link capacitor to a partially precharged state from the low-voltage power supply 92. Specification 5 / 6 pages 9 CN 121712665 ​​A

[0032] FIG4 is a flowchart of one embodiment of the selective operation of the partial precharge state process in step S3. In step S4, the selective partial precharge state process is initiated. In step S5, the controller determines whether to select a DC / DC converter to charge the DC link capacitor to a partially precharged state. If a DC / DC converter is selected in step S5 (i.e., "Yes"), the method proceeds to step S6. At this point, the controller activates multiple contactors in the first circuit to partially pre-charge the DC link capacitor from the low-voltage power supply, while the DC / DC converter module is in boost mode. If a DC / DC converter is not selected in step S5 (i.e., "No"), the method proceeds to step S7. At this point, the controller determines whether to select the first circuit to partially pre-charge the DC link capacitor.If the first circuit is selected in step S7 (i.e., "Yes"), the method proceeds to step S8, where the controller closes multiple contactors in the first circuit, allowing current to flow through the resistor network to the DC link capacitor, thereby gradually charging the DC link capacitor to a partially pre-charged state. If the first circuit is not selected in step S7 (i.e., "No"), the method proceeds to step S9, where the controller determines whether to select the second circuit to charge the DC link capacitor to a partially pre-charged state. If the second circuit is selected in step S9 (i.e., "Yes"), the method proceeds to step S10, where the controller operates a pair of contactors, a resistor network, and a contactor connected in parallel with one of the contactors in the pair, thereby limiting the current flowing through the resistor network, thereby gradually charging the DC link capacitor to a partially pre-charged state. If the second circuit is not selected in step S9 (i.e., "No"), the method ends in step S11.

[0033] The method of charging the DC link capacitor to a partially pre-charged state in steps S6, S8, and S10 enables various tests of the power system to be performed at a lower voltage in step S12. Testing in a partially precharged state can reduce damage caused by conductor short circuits and other component failures.

[0034] In one embodiment, step S12 includes: detecting a fault in the power system based on measurements from at least one sensor while the DC link capacitor is in a partially precharged state. In one embodiment, step S12 includes: detecting a short circuit between a high-voltage DC harness and an AC harness in the power system while the DC link capacitor is in a partially precharged state. In one embodiment, step S12 includes: detecting a short circuit on a DC link device while the DC link capacitor is in a partially precharged state. In one embodiment, step S12 includes: detecting a disconnected high-voltage harness while the DC link capacitor is in a partially precharged state. In one embodiment, step S12 includes: detecting a fault in a high-voltage contactor in the power system while the DC link capacitor is in a partially precharged state. In one embodiment, step S12 includes: detecting a ground fault in the power system while the DC link capacitor is in a partially precharged state. In one embodiment, step S12 includes: detecting a fault in a high-voltage current sensor in the power system while the DC link capacitor is in a partially precharged state. In one embodiment, step S12 includes: a fault in the high-voltage energy storage vehicle charger interface when the DC link capacitor is in a partially pre-charged state.

[0035] If the DC link capacitor discharges during the test, requiring additional switching of the first circuit (S5 to S6) and the second circuit (S7 to S8) to return the DC link capacitor to a partially pre-charged state, then step S14 is required.The advantage of using step S10 of the DC / DC converter is that the DC link device can be continuously kept in a partially precharged state and step S14 is not required.

[0036] Although the invention has been particularly shown and described in conjunction with its preferred embodiments, those skilled in the art will understand that changes in form and detail as described above and in other aspects may be made without departing from the spirit and scope of the invention. Therefore, the scope of the invention should not be limited to the specific forms and details described and illustrated, but should be included within the scope of the appended claims. Specification 6 / 6 pages 10 CN 121712665 ​​A Figure 1 Figure 2 Specification Drawings 1 / 2 pages 11 CN 121712665 ​​A Figure 3 Figure 4 Specification Drawings 2 / 2 pages 12 CN 121712665 ​​A.

Claims

1. A system for partially precharging a power system, comprising: High-voltage power supply module, which includes a high-voltage DC power supply; A DC link device connected to a high-voltage power supply, the DC link device including a high-voltage DC link capacitor; Low-voltage power supply; A DC / DC converter connected between a DC link capacitor and a low-voltage power supply, the DC / DC converter being configured to boost the voltage of the low-voltage power supply; The first circuit is configured to charge the DC link capacitor to a partially precharged state using the voltage of the low-voltage power supply. The second circuit is configured to limit the current flowing from the high-voltage power supply to the DC link capacitor, thereby charging the DC link capacitor to a partially precharged state based on the limiting current from the high-voltage power supply. as well as A controller configured to selectively operate the first circuit, the second circuit, or the DC / DC converter to charge the DC link capacitor to a partially precharged state.

2. The system according to claim 1, wherein, The second circuit includes: a pair of contactors for controlling the power supply to charge the high-voltage DC link capacitor; and a resistor network; and a contactor connected in parallel with one of the contactors in the pair, wherein the controller limits the duration of the current flowing through the resistor network, thereby gradually charging the DC link capacitor to a partially precharged state.

3. The system according to claim 1, wherein, The first circuit includes: a resistor network; and a plurality of contactors connected between the DC link capacitor and the low-voltage power supply, wherein the controller is configured to close the plurality of contactors, thereby allowing current to flow through the resistor network to the DC link capacitor, thereby charging the DC link capacitor to a partially precharged state.

4. The system according to claim 3, wherein, The pre-charge state of this part is equal to the voltage of the low-voltage power supply.

5. The system according to claim 3, wherein, The controller is configured to disconnect the plurality of contactors in the first circuit, thereby charging the DC link capacitor to a partially precharged state from a low-voltage power supply using a DC / DC converter module.

6. The system of claim 1, further comprising at least one sensor, wherein, The controller is configured to detect faults in the power system based on measurements from the at least one sensor when the DC link capacitor is in a partially precharged state.

7. The system according to claim 6, wherein, The controller is configured to activate the second circuit to charge the DC link capacitor from the high-voltage power supply, thereby charging the DC link capacitor to a full high-voltage precharge state.

8. A system for partially precharging an electric power system, comprising: High-voltage power supply module, which includes a high-voltage DC power supply; A DC link device connected to a high-voltage power supply, the DC link device including a high-voltage DC link capacitor; Low-voltage power supply; A DC / DC converter connected between a DC link capacitor and the low-voltage power supply, the DC / DC converter being configured to boost the voltage of the low-voltage power supply; The controller is configured to charge the DC link capacitor to a partially precharged state from the low-voltage power supply using a DC / DC converter module.

9. A method for partially precharging a power system, the system comprising: A high-voltage power supply module includes a high-voltage DC power supply and a DC link device connected to the high-voltage power supply, the DC link device including a high-voltage DC link capacitor. A DC / DC converter connected between a DC link capacitor and a low-voltage power supply, the method comprising: A first circuit is provided, configured to charge the DC link capacitor to a partially precharged state using the voltage of the low-voltage power supply. A second circuit is provided, configured to limit the current flowing from the high-voltage power supply to the DC link capacitor, thereby charging the DC link capacitor to a partially pre-charged state based on the limited current; and Selectively operate one of the first circuit, the second circuit, or the DC / DC converter to charge the DC link capacitor to a partially precharged state.

10. The method according to claim 9, wherein, Using the second circuit to charge the DC link capacitor to a partially precharged state includes controlling a pair of contactors, a resistor network, and a contactor connected in parallel with one of the contactors in the pair of contactors, thereby limiting the current of the high-voltage power supply by allowing the current of the high-voltage power supply to flow through the resistor network, thereby gradually charging the DC link capacitor to a partially precharged state.

11. The method according to claim 9, wherein, Charging the DC link capacitor to a partially precharged state using the first circuit includes: closing a plurality of contactors in the first circuit to allow current to flow through the resistor network, thereby limiting the current from the low-voltage power supply to the DC link capacitor, thereby gradually charging the DC link capacitor to a partially precharged state.

12. The method according to claim 9, wherein, Charging the DC link capacitor to a partially precharged state using the DC / DC converter includes: disconnecting multiple contactors in the first circuit, thereby charging the DC link capacitor to a partially precharged state from the low-voltage power supply using the DC / DC converter module.

13. The method of claim 9, further comprising: When the DC link capacitor is in a partially precharged state, a fault in the power system is detected based on the measurement results of at least one sensor.

14. The method of claim 11, further comprising: When the DC link capacitor is in a partially precharged state, a short circuit between the high-voltage DC harness and the AC harness in the power system is detected.

15. The method of claim 11, further comprising: A short circuit is detected on the DC link device when the DC link capacitor is in a partially precharged state.

16. The method of claim 11, further comprising: A fault in the high-voltage contactor of the power system is detected when the DC link capacitor is in a partially precharged state.

17. The method of claim 11, further comprising: A ground fault in the power system is detected when the DC link capacitor is in a partially precharged state.

18. The method of claim 11, further comprising: A fault in the high-voltage current sensor in the power system is detected when the DC link capacitor is in a partially precharged state.

19. The method of claim 11, further comprising: When the DC link capacitor is in a partially precharged state, a fault is detected in the high-voltage contactor at the electrical interface with the vehicle charger.

20. A system for partially precharging an electric power system, comprising: High-voltage power supply module, which includes a high-voltage DC power supply; A DC link device connected to a high-voltage power supply, the DC link device including a high-voltage DC link capacitor; Low-voltage power supply; The circuit is configured to limit the current flowing from the high-voltage power supply to the DC link capacitor, thereby charging the DC link capacitor to a partially precharged state based on the limited current. A controller configured to selectively operate the circuit to charge the DC link capacitor to a partially precharged state.

21. A system for partially precharging an electric power system, comprising: High-voltage power supply module, which includes a high-voltage DC power supply; A DC link device connected to a high-voltage power supply, the DC link device including a high-voltage DC link capacitor; Low-voltage power supply; The circuit is configured to charge the DC link capacitor to a partially precharged state using the voltage of the low-voltage power supply. A controller configured to selectively operate the circuit to charge the DC link capacitor to a partially precharged state.

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