High-voltage redundant discharge device of vehicle-mounted motor controller
By using an isolation transformer to perform high-voltage active discharge on the low-voltage side, the space and cost problems caused by the discharge of the high-voltage redundant discharge device on the high-voltage side are solved, and the number of components and PCB size is reduced to meet the high-voltage operating needs.
Patent Information
- Application Number
- CN202411479207.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-23
- Publication Date
- 2025-01-10
AI Technical Summary
The existing high-voltage redundant discharge devices discharge on the high-voltage side, resulting in large components and large space occupancy. As the voltage level increases, the requirements for heat dissipation and electrical isolation increase, resulting in tight space and high cost of the vehicle.
Move the high-voltage active discharge branch from the high-voltage side to the low-voltage side, use an isolation transformer to transmit electrical energy, discharge on the low-voltage side, reduce the number and cost of components, and reduce the size of the PCB.
By performing high-voltage active discharge on the low-voltage side, the number and cost of components are reduced, the high-voltage safety distance is reduced, and the PCB space is effectively utilized and reduced, and the bus voltage working needs of up to 1000V are met.
Smart Images
Figure CN119283639A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the field of electric drive, and in particular to a high-voltage redundant discharge device of a vehicle-mounted motor controller. Background Art
[0002] High-voltage bus discharge is one of the keys to the electrical safety of new energy vehicles. In the prior art, generally, in order to ensure safety, a redundant discharge design is often adopted. One is to utilize the normal discharge of the motor winding or IGBT, and the other is to design a resistor redundant discharge module.
[0003] In this way, when normal discharge is not sufficient to eliminate the high voltage of the bus capacitor, discharge can be performed by turning on the discharge resistor.
[0004] However, the redundant discharge of resistors in the prior art is performed on the high voltage side, which has some defects, such as:
[0005] 1. The size of components is often large, and they need to occupy a large area of PCB space, resulting in too small space inside the vehicle when the size of the vehicle remains unchanged;
[0006] 2. It belongs to a high-voltage network, so the electrical isolation requirements are higher, the size is large, and it also brings extremely high heat dissipation requirements.
[0007] Moreover, with the increasing charging speed and other requirements of high-end new energy vehicles, the voltage of the vehicle platform has increased from more than 400V to 800V (the industry calls the platform above 400V an 800V platform), and even beyond 800V. As the voltage level continues to increase, the above defects become more obvious. Summary of the invention
[0008] The purpose of the present invention is to provide a high-voltage redundant discharge device for a vehicle-mounted motor controller. By moving the high-voltage active discharge branch from the high-voltage side to the low-voltage side, using an isolation transformer to transmit electrical energy, and discharging the high-voltage bus on the low-voltage side, so that the high-voltage active discharge branch is on the low-voltage side, on the one hand, the number of components and costs can be reduced, and on the other hand, the low-voltage side does not need to consider a larger high-voltage safety distance, and the size of the PCB can be more effectively utilized and reduced.
[0009] The purpose of the present invention can be achieved by the following technical solutions:
[0010] One aspect of the present invention provides a high-voltage redundant discharge device for a vehicle-mounted motor controller, comprising an isolation transformer, a low-voltage output point, a high-voltage active discharge branch and an anti-reverse current diode, wherein the isolation transformer is an isolation transformer for a high-voltage emergency power supply, the primary coil of the isolation transformer is connected to a high-voltage bus, the secondary coil is connected to the input end of the high-voltage active discharge branch through a low-voltage output point, and is connected to the low-voltage power supply of the motor controller through an anti-reverse current diode, wherein the positive pole of the anti-reverse current diode is connected to the low-voltage output point, and the negative pole is connected to the positive pole of the low-voltage power supply of the motor controller, and a bus capacitor is connected to the high-voltage bus.
[0011] The high-voltage active discharge branch includes a discharge MOS tube, a discharge resistor and a discharge control module. The control signal input end of the discharge MOS tube is connected to the discharge control module, the power input end is connected to the low-voltage output point, the power output end is connected to one end of the discharge resistor, and the other end of the discharge resistor is grounded.
[0012] The high-voltage active discharge branch further includes a freewheeling diode, the positive electrode of the freewheeling diode is connected to the power output end of the discharge MOS tube, and the negative electrode is connected to the power input end of the discharge MOS tube.
[0013] The freewheeling diode is integrated in the discharge MOS tube.
[0014] The discharge control module comprises a main control unit and a logic control circuit, wherein the input end of the logic control circuit is connected to the main control unit, and the output end is connected to the control signal input end of the discharge MOS tube.
[0015] The device also includes a rectifier diode, a second filter capacitor and a filter resistor, the positive electrode of the rectifier diode is connected to the first end of the secondary coil of the isolation transformer, and the negative electrode is connected to the low-voltage output point, the low-voltage output point is respectively connected to one end of the second filter capacitor and the filter resistor, the other ends of the second filter capacitor and the filter resistor are grounded and connected to the second end of the secondary coil of the isolation transformer.
[0016] The device also includes an RCD absorption circuit and an output voltage closed-loop feedback network. The primary coil of the isolation transformer includes a first primary sub-coil and a second primary sub-coil. The first primary sub-coil is connected to the RCD absorption circuit, and the second primary sub-coil is connected to the output voltage closed-loop feedback network.
[0017] The output voltage closed-loop feedback network includes a voltage detection loop, a high-voltage integrated power module, a second capacitor and a first diode. One end of the RCD absorption circuit is connected to the positive electrode of the high-voltage bus and the second end of the first primary sub-coil, and the other end is connected to the first end of the first primary sub-coil and the high-voltage input end of the high-voltage integrated power module. The first end of the second primary sub-coil is connected to the positive electrode of the first diode, and the other end is connected to the second end of the second capacitor and the negative electrode of the high-voltage bus. The negative electrode of the first diode is connected to the first end of the second capacitor and the power supply end of the high-voltage integrated power module. The two ends of the input end of the voltage detection loop are respectively connected to the two ends of the second capacitor, and the output end is connected to the voltage detection end of the high-voltage integrated power module.
[0018] Another aspect of the present invention provides a vehicle, comprising the high-voltage redundant discharge device as described above.
[0019] Compared with the prior art, the present invention has the following beneficial effects:
[0020] 1. By moving the high-voltage active discharge branch from the high-voltage side to the low-voltage side, the isolation transformer of the high-voltage emergency power supply is used to transmit electrical energy, and the high-voltage bus is discharged on the low-voltage side, so that the high-voltage active discharge branch is on the low-voltage side. On the one hand, since the isolation transformer of the high-voltage emergency power supply is used, the isolation transformer itself and the rectifier module and filter module on the low-voltage side of the isolation transformer can be fully reused, and there is no need to build additional circuits on the high-voltage side, which can reduce the number of components and costs. On the other hand, the low-voltage side does not need to consider a large high-voltage safety distance, and can more effectively utilize and reduce the size of the PCB.
[0021] 2. Since the high-voltage active discharge branch is on the low-voltage side, the discharge MOS tube can be selected as a low-voltage MOS tube, and there is no need to configure a complete discharge circuit. A discharge circuit is formed as a whole with the high-voltage side, thereby further reducing the volume.
[0022] 3. By setting up an anti-reverse current diode, on the one hand, the original low-voltage power supply circuit can be used to further reduce the number of components, and on the other hand, it can also prevent the electric energy in the low-voltage power supply of the motor controller from being consumed by the discharge resistor during discharge.
[0023] 4. The high-voltage integrated power module has a built-in high-voltage startup circuit and a high-voltage SiC MOS tube. It has high functional integration, requires few peripheral circuit components, and can meet the working requirements of a bus voltage of up to 1000V. BRIEF DESCRIPTION OF THE DRAWINGS
[0024] Figure 1 It is a schematic diagram of the principle of the present invention;
[0025] Figure 2 It is a schematic diagram of the principle of a redundant discharge device in the prior art;
[0026] Among them: M1, RCD absorption circuit, M2, high-voltage integrated power module, M3, voltage detection circuit, M4, logic control circuit, M5, main control unit, Q1, discharge MOS tube, D1, first diode, D2, rectifier diode, D3, anti-reverse current diode, D4, freewheeling diode, R3, filter resistor, R4, discharge resistor, C1, bus capacitor, C2, second capacitor, C3, second filter capacitor, C10, high-voltage capacitor, UDC+, positive pole of high-voltage bus, UDC-, negative pole of high-voltage bus, LV_power, on-board low-voltage DC power supply. DETAILED DESCRIPTION
[0027] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.
[0028] Although the existing high voltage redundant discharge devices have various forms, the basic principles are the same as Figure 2 As shown, it is mainly composed of a discharge MOS tube Q1 and a discharge resistor R4. Since it is on the high-voltage side, the discharge MOS tube Q1 needs to use a high-voltage MOS, which is costly and bulky. In addition, the gate-level drive also needs to consider isolation, which further increases the volume.
[0029] In order to solve the above problems, the present application provides a high-voltage redundant discharge device for a vehicle-mounted motor controller, such as Figure 1 As shown, it includes an isolation transformer TR1, a low-voltage output point, a high-voltage active discharge branch and an anti-reverse current diode D3. The isolation transformer TR1 is an isolation transformer for a high-voltage emergency power supply. The primary coil of the isolation transformer TR1 is connected to the high-voltage bus, and the secondary coil is connected to the input end of the high-voltage active discharge branch through the low-voltage output point, and is connected to the low-voltage power supply of the motor controller through the anti-reverse current diode D3, wherein the positive pole of the anti-reverse current diode D3 is connected to the low-voltage output point, and the negative pole is connected to the positive pole of the low-voltage power supply of the motor controller, and the high-voltage bus is connected to a bus capacitor C1.
[0030] By moving the high-voltage active discharge branch from the high-voltage side to the low-voltage side, using the isolation transformer to transmit electrical energy, and discharging the high-voltage bus on the low-voltage side, the high-voltage active discharge branch is on the low-voltage side. On the one hand, since the isolation transformer of the high-voltage emergency power supply is used, the isolation transformer itself and the rectifier module and filter module on the low-voltage side of the isolation transformer can be fully reused, and there is no need to build additional circuits on the high-voltage side, which can reduce the number of components and costs. On the other hand, the low-voltage side does not need to consider the larger high-voltage safety distance, and can more effectively utilize and reduce the size of the PCB.
[0031] The high-voltage active discharge branch includes a discharge MOS tube Q1, a discharge resistor R4 and a discharge control module. The control signal input end of the discharge MOS tube Q1 is connected to the discharge control module, the power input end is connected to the low-voltage output point, and the power output end is connected to one end of the discharge resistor R4. The other end of the discharge resistor R4 is grounded.
[0032] Although the discharge MOS tube Q1 and the discharge resistor R4 are also used, since the high-voltage active discharge branch is on the low-voltage side, the discharge MOS tube Q1 does not need to use a high-voltage MOS tube. The use of a low-voltage MOS tube can greatly reduce costs and reduce volume. In addition, generally, in almost all embodiments, the isolation transformer TR1 can use the isolation transformer in the low-voltage power supply charging circuit of the existing motor controller. Therefore, when the present application is actually implemented, it is only necessary to connect a high-voltage active discharge branch to the low-voltage output point, and add an anti-reverse current diode D3 between the low-voltage output point and the low-voltage power supply of the motor controller. The function of the anti-reverse current diode D3 is to prevent the electric energy in the on-board low-voltage DC power supply from flowing through the low-voltage output point and then being consumed by the discharge resistor R4 when the discharge MOS tube Q1 is turned on.
[0033] Generally, the high-voltage active discharge branch also includes a freewheeling diode D4, the positive electrode of the freewheeling diode D4 is connected to the power output end of the discharge MOS tube Q1, and the negative electrode is connected to the power input end of the discharge MOS tube Q1. In most embodiments, the freewheeling diode D4 is integrated into the discharge MOS tube Q1 to further improve the integration.
[0034] Generally, the discharge control module includes a main control unit M5 and a logic control circuit M4. The input end of the logic control circuit M4 is connected to the main control unit M5, and the output end is connected to the control signal input end of the discharge MOS tube Q1. The discharge control module controls whether the discharge MOS tube Q1 is turned on according to actual needs. The specific control logic is not involved in this application, and the design in the prior art can be referred to. For example, the discharge MOS tube Q1 can be turned on for discharge when a vehicle collides.
[0035] In addition, the present application provides a high-voltage redundant discharge device that can be used in conjunction with a conventional high-voltage discharge device. The conventional high-voltage discharge device can be in various forms, for example, it can discharge through motor windings, it can also discharge through IGBTs, or discharge in other ways.
[0036] In most embodiments, the device further includes a rectifier diode D2, a second filter capacitor C3 and a filter resistor RD3, wherein the positive electrode of the rectifier diode D2 is connected to the first end of the secondary coil of the isolation transformer TR1, and the negative electrode is connected to the low-voltage output point, and the low-voltage output point is respectively connected to one end of the second filter capacitor C3 and the filter resistor RD3, and the other ends of the second filter capacitor C3 and the filter resistor R3 are grounded and connected to the second end of the secondary coil of the isolation transformer TR1. In this way, a stable DC can be output to power the low-voltage power supply of the motor controller.
[0037] In addition, the device also includes an RCD absorption circuit M1 and an output voltage closed-loop feedback network. The primary coil of the isolation transformer TR1 includes a first primary sub-coil and a second primary sub-coil. The first primary sub-coil is connected to the RCD absorption circuit M1, and the second primary sub-coil is connected to the output voltage closed-loop feedback network.
[0038] The output voltage closed-loop feedback network includes a voltage detection loop M3, a high-voltage integrated power module M2, a second capacitor C2 and a first diode D1. One end of the RCD absorption circuit M1 is connected to the positive electrode of the high-voltage bus and the second end of the first primary sub-coil, and the other end is connected to the first end of the first primary sub-coil and the high-voltage input end of the high-voltage integrated power module M2. The first end of the second primary sub-coil is connected to the positive electrode of the first diode D1, and the other end is connected to the second end of the second capacitor C2 and the negative electrode of the high-voltage bus. The negative electrode of the first diode D1 is connected to the first end of the second capacitor C2 and the power supply end of the high-voltage integrated power module M2. The two ends of the input end of the voltage detection loop M3 are respectively connected to the two ends of the second capacitor C2, and the output end is connected to the voltage detection end of the high-voltage integrated power module M2.
[0039] The high-voltage integrated power module M2 has a built-in high-voltage startup circuit and a high-voltage SiC MOS tube. It has high functional integration, requires fewer peripheral circuit components, and can meet the maximum bus voltage operating requirements of 1000V.
[0040] Furthermore, in most embodiments, the first ends of the first primary sub-coil, the second primary sub-coil and the secondary coil are the same-named ends.
[0041] The RCD absorption loop M1 and the first primary sub-coil of the isolation transformer TR1 form a peak voltage absorption loop, which can effectively reduce the MOS tube turn-off voltage spike caused by the transformer leakage inductance and reduce the voltage stress of the primary power MOS tube. The output voltage closed-loop feedback loop composed of the high-voltage integrated power module M2, the voltage detection loop M3, the second primary sub-coil of the transformer TR1, the first diode D1 for rectification, and the second capacitor C2 for output filtering ensures the stability of the output power supply voltage by quickly adjusting the duty cycle of the gate opening inside the high-voltage integrated power module M2 through the voltage closed loop.
[0042] The main power circuit of the primary power supply is composed of the high-voltage integrated power module M2 and the first primary sub-coil of the isolation transformer TR1. The energy transfer of the transformer winding is realized by turning on and off the MOS inside the integrated power module M2. The integrated power module M2 has the functions of high-voltage startup, over-current, over-voltage and under-voltage protection.
[0043] In addition, another aspect of the present application provides a vehicle, characterized in that the vehicle is equipped with the above-mentioned high-voltage redundant discharge device.
[0044] If the above functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc., which can store program code.
Claims
1. A high voltage redundant discharge device for a vehicle motor controller, characterized in that: The invention comprises an isolation transformer (TR1), a low-voltage output point, a high-voltage active discharge branch and an anti-reverse current diode (D3), wherein the isolation transformer (TR1) is an isolation transformer for a high-voltage emergency power supply, the primary coil of the isolation transformer (TR1) is connected to a high-voltage bus, the secondary coil is connected to an input end of the high-voltage active discharge branch through a low-voltage output point, and is connected to a low-voltage power supply of a motor controller through an anti-reverse current diode (D3), wherein the positive electrode of the anti-reverse current diode (D3) is connected to the low-voltage output point, and the negative electrode is connected to the positive electrode of the low-voltage power supply of the motor controller, and a bus capacitor (C1) is connected to the high-voltage bus.
2. The high-voltage redundant discharge device of a vehicle-mounted motor controller according to claim 1, characterized in that: The high-voltage active discharge branch comprises a discharge MOS tube (Q1), a discharge resistor (R4) and a discharge control module, wherein a control signal input end of the discharge MOS tube (Q1) is connected to the discharge control module, an electric energy input end is connected to a low-voltage output point, an electric energy output end is connected to one end of the discharge resistor (R4), and the other end of the discharge resistor (R4) is grounded.
3. A high-voltage redundant discharge device for a vehicle-mounted motor controller according to claim 2, characterized in that: The high-voltage active discharge branch further comprises a freewheeling diode (D4), the positive electrode of the freewheeling diode (D4) being connected to the power output end of the discharge MOS tube (Q1), and the negative electrode of the freewheeling diode (D4) being connected to the power input end of the discharge MOS tube (Q1).
4. The high-voltage redundant discharge device of a vehicle-mounted motor controller according to claim 3, characterized in that: The freewheeling diode (D4) is integrated in the discharge MOS tube (Q1).
5. The high-voltage redundant discharge device of a vehicle-mounted motor controller according to claim 2, characterized in that: The discharge control module comprises a main control unit (M5) and a logic control circuit (M4); the input end of the logic control circuit (M4) is connected to the main control unit (M5), and the output end is connected to the control signal input end of the discharge MOS tube (Q1).
6. The high-voltage redundant discharge device of a vehicle-mounted motor controller according to claim 1, characterized in that: The device also includes a rectifier diode (D2), a second filter capacitor (C3) and a filter resistor (RD3), wherein the positive electrode of the rectifier diode (D2) is connected to the first end of the secondary coil of the isolation transformer (TR1), and the negative electrode is connected to the low-voltage output point, and the low-voltage output point is respectively connected to one end of the second filter capacitor (C3) and the filter resistor (RD3), and the other ends of the second filter capacitor (C3) and the filter resistor (RD3) are grounded and connected to the second end of the secondary coil of the isolation transformer (TR1).
7. The high-voltage redundant discharge device of a vehicle-mounted motor controller according to claim 1, characterized in that: The device also includes an RCD absorption circuit (M1) and an output voltage closed-loop feedback network, the primary coil of the isolation transformer (TR1) includes a first primary sub-coil and a second primary sub-coil, the first primary sub-coil is connected to the RCD absorption circuit (M1), and the second primary sub-coil is connected to the output voltage closed-loop feedback network.
8. The high-voltage redundant discharge device of a vehicle-mounted motor controller according to claim 7, characterized in that: The output voltage closed-loop feedback network comprises a voltage detection loop (M3), a high-voltage integrated power module (M2), a second capacitor (C2) and a first diode (D1); one end of the RCD absorption circuit (M1) is connected to the positive electrode of the high-voltage bus and the second end of the first primary sub-coil, and the other end is connected to the first end of the first primary sub-coil and the high-voltage input end of the high-voltage integrated power module (M2); the first end of the second primary sub-coil is connected to the positive electrode of the first diode (D1), and the other end is connected to the second end of the second capacitor (C2) and the negative electrode of the high-voltage bus; the negative electrode of the first diode (D1) is connected to the first end of the second capacitor (C2) and the power supply end of the high-voltage integrated power module (M2); the two ends of the input end of the voltage detection loop (M3) are respectively connected to the two ends of the second capacitor (C2), and the output end is connected to the voltage detection end of the high-voltage integrated power module (M2).
9. A vehicle, characterized in that: It comprises a high voltage redundant discharge device as described in any one of claims 1-8.