Discharge circuit and motor controller

Abstract

The application provides a discharge circuit and a motor controller, and relates to the technical field of vehicle discharge. The discharge circuit comprises a high-voltage battery, a DC bus capacitor, a high-voltage backup power supply, an active discharge circuit and a switching unit. The DC bus capacitor is connected in parallel with the high-voltage battery. The high-voltage backup power supply comprises a transformer. A first end of a primary winding of the transformer is connected with a first end of the DC bus capacitor, and a second end of the primary winding is connected with a second end of the DC bus capacitor. A first end of a secondary winding of the transformer is connected with a first end of the active discharge circuit, and a second end of the secondary winding is grounded. A second end of the active discharge circuit is connected with the second end of the secondary winding through the switching unit. When active discharge is performed, the energy on the DC bus capacitor can be transmitted to the active discharge circuit on the side of the secondary winding through the transformer for consumption, that is, active discharge can be performed, so that the active discharge function is decoupled from the motor winding and IGBT, and the high-voltage safety of the whole vehicle is effectively ensured.

Description

Technical Field

[0001] This application relates to the field of vehicle discharge technology, and in particular to a discharge circuit and a motor controller. Background Technology

[0002] With the increasing development and popularization of new energy vehicles, the high-voltage safety of the entire vehicle is a concern. To ensure the high-voltage safety of the entire vehicle, the motor controller must discharge the DC bus capacitor in both emergency and non-emergency situations. Typically, the active discharge circuit is required to discharge the DC bus capacitor voltage to below 60V within 3 seconds after the relay disconnects from the battery, while the passive discharge circuit is required to discharge the DC bus capacitor voltage to below 60V within 300 seconds after the battery relay disconnects.

[0003] In related technologies, an insulated gate bipolar transistor (IGBT) can be used for active discharge.

[0004] However, there are certain drawbacks to active discharge via IGBTs, such as incomplete coverage of operating conditions and the ease with which IGBTs can burn out, which makes it impossible to guarantee the high-voltage safety of the entire vehicle. Utility Model Content

[0005] This application provides a discharge circuit and a motor controller to solve the problem that the active discharge through IGBT has certain defects in the related technology, which leads to the inability to guarantee the high voltage safety of the whole vehicle.

[0006] In a first aspect, embodiments of this application provide a discharge circuit, including: a high-voltage battery, a DC bus capacitor, a high-voltage backup power supply, an active discharge circuit, and a switching unit; The DC bus capacitor is connected in parallel with the high-voltage battery. The high-voltage backup power supply includes a transformer. The first end of the primary winding of the transformer is connected to the first end of the DC bus capacitor, and the second end of the primary winding is connected to the second end of the DC bus capacitor. The first end of the secondary winding of the transformer is connected to the first end of the active discharge circuit, and the second end of the secondary winding is grounded. The second terminal of the active discharge circuit is connected to the second terminal of the secondary winding through a switching unit.

[0007] Based on the above technical content, this embodiment places the DC bus capacitor on one side of the primary winding of the transformer in the high-voltage backup power supply, and places the active discharge circuit and switching unit on one side of the secondary winding of the transformer in the high-voltage backup power supply. During active discharge, the energy on the DC bus capacitor can be transferred to the active discharge circuit on the secondary winding side of the transformer for dissipation, thus enabling active discharge. This decouples the active discharge function from the motor winding and IGBT, allowing active discharge even when the motor is in an active short-circuit or safety shutdown state. Furthermore, in this embodiment, energy is dissipated through the active discharge circuit during active discharge, avoiding energy consumption on the IGBT and preventing IGBT burnout, thereby effectively ensuring the high-voltage safety of the entire vehicle. Simultaneously, this embodiment integrates the active discharge circuit with the high-voltage backup power supply, achieving high- and low-voltage isolation by reusing the transformer of the high-voltage backup power supply. Under normal circumstances, the voltage output from the secondary winding of the transformer is low, allowing the switching unit to operate on the low-voltage side, improving system safety and reliability, and eliminating the need for additional isolation devices, effectively reducing costs.

[0008] In one possible implementation, the switching unit includes a first switch and a second switch; The second terminal of the active discharge circuit is connected to the first terminal of the first switch and the first terminal of the second switch, respectively. The second terminal of the first switch is connected to the second terminal of the secondary winding, and the second terminal of the second switch is grounded.

[0009] In this embodiment, a first switch and a second switch are provided in the switching unit. When active discharge is performed, at least one of the first switch and the second switch can be turned on to perform active discharge. If one of the switches cannot be turned on normally, active discharge can still be performed through the other switch, so that the active discharge function can still be controlled when the first switch cannot be turned on, thereby improving reliability.

[0010] In one possible implementation, a fuse is provided between the second terminal of the first switch and the second terminal of the secondary winding. The fuse presents a high impedance state when the first switch fails to turn off or when a short circuit fault occurs in the active discharge circuit.

[0011] Here, when the first switch fails to turn off or a short circuit fault occurs in the active discharge circuit, the fuse presents a high impedance state, cutting off the fault path, so that the active discharge function can still be controlled, effectively preventing circuit burnout or even fire caused by long-term continuous discharge, thus improving safety and reliability.

[0012] In one possible implementation, the discharge circuit further includes a status monitoring module connected between the second terminal of the active discharge circuit and the first terminal of the switching unit. The status monitoring module is used to monitor the execution status of the active discharge circuit in performing active discharge.

[0013] During active discharge, the status monitoring module can acquire the execution status of the active discharge circuit, enabling monitoring of the active discharge process and timely determination of whether the switching unit and the active discharge circuit have malfunctioned.

[0014] In one possible implementation, the status monitoring module includes: a first resistor, a second resistor, and a first switching transistor; The first end of the first resistor is connected between the second end of the active discharge circuit and the first end of the switching unit, and the second end of the first resistor is connected to the control end of the first switching transistor. The first end of the second resistor is connected to the first end of the active discharge circuit, and the second end is connected to the first end of the first switching transistor; the second end of the first switching transistor is grounded. The signal between the second terminal of the second resistor and the first terminal of the first switch is used to characterize the active discharge circuit's active discharge execution state.

[0015] In this embodiment, the on / off state of the first switching transistor is affected by the on / off state of the switching unit, which in turn affects the signal between the second end of the second resistor and the first end of the first switching transistor. Therefore, the signal between the second end of the second resistor and the first end of the first switching transistor can characterize the execution state of the active discharge circuit, which has strong anti-interference capability.

[0016] In one possible implementation, the status monitoring module includes: a third resistor and a fourth resistor; The first end of the third resistor is connected between the second end of the active discharge circuit and the first end of the switching unit; the second end of the third resistor is connected to the first end of the fourth resistor; the second end of the fourth resistor is grounded. The signal between the second terminal of the third resistor and the first terminal of the fourth resistor is used to characterize the active discharge circuit's active discharge execution state.

[0017] Based on the above technical content, the active discharge circuit can monitor the execution status of active discharge using only the third and fourth resistors, resulting in a simple circuit structure and low cost.

[0018] In one possible implementation, the active discharge circuit includes multiple discharge resistors connected in parallel, which are used to dissipate energy when the switching unit is turned on.

[0019] In this embodiment, the active discharge circuit includes multiple discharge resistors connected in parallel, which can distribute energy across multiple discharge resistors, preventing overheating of a single discharge resistor and improving the heat dissipation capacity and long-term reliability of the active discharge circuit. Furthermore, if one discharge resistor fails, the remaining discharge resistors can still operate normally, preventing the active discharge function from failing and improving the robustness of the discharge circuit.

[0020] In one possible implementation, the discharge circuit also includes a passive discharge circuit connected to both ends of the secondary winding of the transformer.

[0021] In this embodiment, the passive discharge circuit is located at both ends of the secondary winding of the transformer, i.e., on the low-voltage side. This effectively reduces the power consumption of the passive discharge circuit and lowers the heat dissipation requirements. Simultaneously, it integrates the passive discharge circuit, the active discharge circuit, and the high-voltage backup power supply, improving the integration of the discharge circuit.

[0022] In one possible implementation, the discharge circuit also includes a microcontroller for controlling the switching unit's on / off state.

[0023] Here, the switching unit is automatically controlled by a microcontroller, eliminating the need for manual intervention and improving the level of automation.

[0024] Secondly, embodiments of this application provide a motor controller, including the discharge circuit of any one of the first aspects.

[0025] Thirdly, embodiments of this application provide a vehicle including the motor controller of the second aspect.

[0026] It is understood that the beneficial effects of the second and third aspects mentioned above can be found in the relevant descriptions in the first aspect mentioned above, and will not be repeated here.

[0027] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this specification. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the 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.

[0029] Figure 1 This is a schematic diagram of the discharge circuit provided in one embodiment of this application; Figure 2 This is a schematic diagram of the discharge circuit provided in another embodiment of this application; Figure 3 This is a schematic diagram of the structure of a status monitoring module provided in one embodiment of this application; Figure 4 This is a schematic diagram of the structure of a status monitoring module provided in another embodiment of this application; Figure 5This is a schematic diagram of the structure of a motor controller provided in one embodiment of this application; Figure 6 This is a schematic diagram of the structure of a vehicle provided in one embodiment of this application. Detailed Implementation

[0030] The present application will be described more clearly below with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the function of the present application, but do not limit the present application in any way. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present application. These all fall within the protection scope of the present application.

[0031] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0032] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0033] In the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0034] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0035] Furthermore, the term "multiple" mentioned in the embodiments of this application should be interpreted as two or more.

[0036] In related technologies, motor controllers can utilize IGBTs for active discharge. For example, active discharge can be achieved through zero-torque control using the motor windings and IGBTs, dissipating energy in the motor windings and IGBTs. However, when in an active short-circuit or safety shutdown state, the IGBT switches cannot be controlled to discharge through the motor windings, thus failing to cover the conditions under which the motor enters a safe mode, resulting in the inability to guarantee the high-voltage safety of the entire vehicle.

[0037] Alternatively, active discharge can be achieved through IGBTs, where the IGBT pulses into a desaturation state, dissipating energy on the IGBT chip. However, this method requires complex control and drive circuits or intelligent drive chips, and improper control can easily cause IGBT burnout, compromising the high-voltage safety of the entire vehicle. To ensure the high-voltage safety of the entire vehicle, it is necessary to consider a new discharge circuit.

[0038] To ensure active discharge even when the motor is in safe operating mode and to prevent IGBTs from burning out due to energy consumption, this application implements an active discharge circuit for active discharge. To avoid using high-voltage MOSFETs, adding isolation devices, and controlling the high-voltage MOSFETs with a high-voltage power supply, a high-voltage backup power supply is introduced. The active discharge circuit and switching unit are located on one side of the secondary winding of the transformer in the high-voltage backup power supply, i.e., on the low-voltage side. The primary winding of the transformer is connected in parallel with the DC bus capacitor, which is the high-voltage side. During active discharge, the energy on the DC bus capacitor is transferred to the active discharge circuit on the secondary winding side of the transformer for dissipation, thus achieving active discharge. This decouples the active discharge function from the motor windings and IGBTs, allowing active discharge even when the motor is in an active short-circuit or safe shutdown state. Furthermore, in this embodiment, energy is dissipated through the active discharge circuit during active discharge, avoiding energy consumption on the IGBTs and thus preventing IGBT burnout, effectively ensuring the high-voltage safety of the entire vehicle. Meanwhile, this embodiment also integrates the active discharge circuit with the high-voltage backup power supply. By reusing the transformer of the high-voltage backup power supply, high and low voltage isolation is achieved. Under normal circumstances, the voltage output by the secondary winding of the transformer is low voltage, which allows the switching unit to work on the low-voltage side, improving the safety and reliability of the system. At the same time, there is no need to set up additional isolation devices, effectively reducing costs.

[0039] refer to Figure 1 , Figure 1 This is a schematic diagram of the discharge circuit provided in one embodiment of this application. Figure 1 As shown, the discharge circuit in this embodiment may include: a high-voltage battery B, a DC bus capacitor C, a high-voltage backup power supply 10, an active discharge circuit 20, and a switching unit 30. Among them, the DC bus capacitor C is connected in parallel with the high-voltage battery B; The high-voltage backup power supply 10 includes a transformer T. The first end of the primary winding of the transformer T is connected to the first end of the DC bus capacitor C, and the second end of the primary winding is connected to the second end of the DC bus capacitor C. The first end of the secondary winding of the transformer T is connected to the first end of the active discharge circuit 20, and the second end of the secondary winding is grounded. The second terminal of the active discharge circuit 20 is connected to the second terminal of the secondary winding through the switching unit 30.

[0040] In this scenario, when the vehicle is under high voltage, the high-voltage battery B can output high voltage to the DC bus capacitor C. In one implementation, the high-voltage battery B is connected to the DC bus capacitor C via a relay. The purpose of active and passive discharge is to discharge the charge from the DC bus capacitor C after the relay disconnects from the high-voltage battery B, ensuring that its voltage drops below the safe voltage of 60V for a specified time.

[0041] The high-voltage backup power supply 10 serves as a backup power source for the controller circuit. It is typically in an unloaded state and achieves high- and low-voltage isolation based on the transformer T within the high-voltage backup power supply 10. Under normal circumstances, during active discharge, the voltage received by the primary winding of the transformer T is high voltage, while the voltage output by the secondary winding is low voltage.

[0042] Here, the active discharge circuit 20 is used to dissipate the energy of the DC bus capacitor C through the high-voltage backup power supply 10 when the switching unit 30 is turned on. When active discharge is not performed, the switching unit 30 is in the off state.

[0043] The switching unit 30 may include one or more switches. In one implementation scenario, the switch may be a switching transistor.

[0044] In one possible implementation, the active discharge circuit 20 may include a plurality of discharge resistors connected in parallel, which are used to dissipate energy when the switching unit 30 is turned on.

[0045] Here, during active discharge, the active discharge circuit 20 can distribute energy across multiple discharge resistors, preventing individual discharge resistors from overheating and improving the heat dissipation capacity and long-term reliability of the active discharge circuit 20. Furthermore, if one discharge resistor fails, the remaining discharge resistors can still operate normally, preventing the active discharge function from failing and enhancing the robustness of the discharge circuit.

[0046] Optionally, the discharge resistor in the active discharge circuit 20 can be a chip resistor, a cement resistor, a film resistor, a positive temperature coefficient resistor (PTC), etc. This application does not limit the number and type of discharge resistors included in the active discharge circuit 20.

[0047] In some embodiments, the discharge circuit further includes a passive discharge circuit 40, which is connected to both ends of the secondary winding of the transformer T.

[0048] In one possible implementation, the passive discharge circuit 40 may include one or more discharge resistors, which may be connected in series and / or in parallel. The discharge resistors in the passive discharge circuit 40 may also be surface mount resistors, cement resistors, film resistors, PTC resistors, etc. This application does not limit the number or type of discharge resistors included in the passive discharge circuit 40.

[0049] Here, when setting the discharge resistor in the passive discharge circuit 40, the power required to reduce the voltage of the DC bus capacitor C to 60V within 300s can be calculated based on the capacitance value of the DC bus capacitor C and the bus voltage. Based on this power, the resistance value of the discharge resistor in the passive discharge circuit 40 can be determined. Furthermore, the discharge resistor in the passive discharge circuit 40 can serve as a dummy load for the high-voltage backup power supply 10, achieving a near-constant power passive discharge effect, while also stabilizing the output voltage of the high-voltage backup power supply 10 over a wide input voltage range.

[0050] In related technologies, passive discharge can be achieved by using a resistor matrix between the positive and negative high voltage to convert electrical energy into heat energy from the resistors. However, the resistor matrix is ​​large in number and has a large package area, requiring a large printed circuit board (PCB) area. Furthermore, since the power consumption of the resistor is proportional to the square of the high voltage, the power consumption of the resistor is large when the voltage of the high voltage battery B is high, resulting in a high demand for heat dissipation. Therefore, additional heat dissipation measures are needed.

[0051] Here, the passive discharge circuit 40 is placed at both ends of the secondary winding of transformer T, i.e., on the low-voltage side. This effectively reduces the number of discharge resistors, requiring only a smaller PCB area, and also effectively reduces the power consumption of the discharge resistors, thus reducing heat dissipation requirements. In addition, the passive discharge circuit 40, the active discharge circuit 20, and the high-voltage backup power supply 10 are integrated, improving the integration of the discharge circuit.

[0052] In this embodiment, the DC bus capacitor C is located on one side of the primary winding of the transformer T in the high-voltage backup power supply 10, while the active discharge circuit 20 and the switching unit 30 are located on one side of the secondary winding of the transformer T in the high-voltage backup power supply 10. During active discharge, the energy on the DC bus capacitor C can be transferred through the transformer T to the active discharge circuit 20 on the secondary winding side for dissipation, thus enabling active discharge. This decouples the active discharge function from the motor windings and IGBTs, allowing active discharge to be achieved even when the motor is in an active short-circuit or safety off state. Furthermore, in this embodiment, energy is dissipated through the active discharge circuit 20 during active discharge, avoiding energy consumption on the IGBTs and preventing IGBT burnout, thereby effectively ensuring the high-voltage safety of the entire vehicle. Meanwhile, this embodiment also integrates the active discharge circuit 20 with the high-voltage backup power supply 10. By reusing the transformer T of the high-voltage backup power supply 10, high and low voltage isolation is achieved. Under normal circumstances, the voltage output by the secondary winding of the transformer T is low voltage, so that the switching unit 30 works on the low-voltage side, which improves the safety and reliability of the system. At the same time, there is no need to set up additional isolation devices, which effectively reduces costs.

[0053] In addition, in this embodiment of the application, when the active discharge circuit 20 is conducting active discharge with the switch unit 30 turned on, the situation of failure of the active discharge circuit 20 or failure of the switch unit 30 can also be considered to improve safety. Figure 2 This is a schematic diagram of the discharge circuit provided in another embodiment of this application, as shown below. Figure 2 As shown, in some embodiments, the switching unit 30 includes a first switch K1 and a second switch K2; The second terminal of the active discharge circuit 20 is connected to the first terminal of the first switch K1 and the first terminal of the second switch K2, respectively. The second terminal of the first switch K1 is connected to the second terminal of the secondary winding, and the second terminal of the second switch K2 is grounded.

[0054] In one implementation scenario, the first switch K1 can be used as the main switch of the active discharge circuit 20, and the second switch K2 can be used as the backup switch of the active discharge circuit 20. During active discharge, the first switch K1 is in the on state. However, if the first switch K1 fails to open normally, the second switch K2 can be turned on, thus ensuring that the active discharge function remains controlled even when the first switch K1 fails to open, improving reliability. When not actively discharging, both the first switch K1 and the second switch K2 are in the off state.

[0055] In another implementation scenario, both the first switch K1 and the second switch K2 are in the on state during active discharge. If one switch fails to turn on normally, active discharge can still continue based on the other switch.

[0056] In one possible implementation, the first switch K1 and the second switch K2 can be switching transistors, which can be metal-oxide-semiconductor field-effect transistors (MOSFETs), bipolar transistors, etc. Specifically, they can be N-channel MOSFETs.

[0057] In this embodiment, the active discharge circuit 20 and the MOSFET are located on one side of the secondary winding of transformer T. Since the voltage output of the secondary winding is low, the MOSFET can be a low-voltage MOSFET. Compared to using a high-voltage MOSFET and a discharge resistor for active discharge on the high-voltage side, where energy is consumed in the discharge resistor, this embodiment does not require additional isolation devices and a power supply on the high-voltage side, or the addition of a microcontroller on the high-voltage side. Therefore, the structure of the discharge circuit is simplified, and the cost is reduced.

[0058] In some embodiments, the discharge circuit further includes a microcontroller 60 for controlling the switching unit 30 on and off.

[0059] In one implementation scenario, taking an N-channel MOSFET as an example, both the first switch K1 and the second switch K2 are used. In this case, the microcontroller 60 can be connected to the control terminals of the first switch K1 and the second switch K2 respectively. The first terminal of the first switch K1 is connected to the second terminal of the active discharge circuit 20, and the second terminal of the first switch K1 is connected to the second terminal of the secondary winding. The first terminal of the second switch K2 is connected to the second terminal of the active discharge circuit 20, and the second terminal of the second switch K2 is grounded. It should be noted that the control terminals of the first and second switches K1 and K2 are the gates, the first terminal is the drain, and the second terminal is the source. Furthermore, since the microcontroller 60 and both the first and second switches K1 and K2 are on the low-voltage side, there is no need to set up isolation devices between the microcontroller and the first and second switches K1 and K2, resulting in advantages such as simple circuitry, small size, and low cost.

[0060] At this time, when no active discharge is required, the microcontroller 60 can control the first switch K1 and the second switch K2 to close.

[0061] When active discharge is required, in one implementation scenario, the microcontroller 60 can control at least one of the first switch K1 and the second switch K2 to turn on to perform active discharge, and the energy of the DC bus capacitor C is converted by the high-voltage backup power supply 10 and consumed in the discharge resistor included in the active discharge circuit 20.

[0062] Specifically, if one of the first switch K1 and the second switch K2 cannot be turned on normally, the other switch can be turned on to actively discharge.

[0063] Here, the microcontroller 60 can automatically control the switching unit 30 to open and close without manual intervention, thus improving the level of automation.

[0064] In some embodiments, a fuse F is provided between the second end of the first switch K1 and the second end of the secondary winding. When the first switch K1 fails to turn off or the active discharge circuit 20 experiences a short circuit fault, the fuse F presents a high impedance state.

[0065] Under normal circumstances, fuse F is in a low-resistance state, which does not affect the short-term active discharge (3 seconds). However, if the first switch K1 fails to turn off or a short circuit fault occurs in the active discharge circuit 20, the current flowing through fuse F will increase, causing the temperature of fuse F to rise. This will cause it to switch from a low-resistance state to a high-resistance state, cutting off the fault path and ensuring that the active discharge function remains controlled. This effectively prevents prolonged continuous discharge from causing circuit burnout or even fire, thus improving safety and reliability.

[0066] In one possible implementation, fuse F is a resettable fuse, optionally a positive temperature coefficient resistor. After the temperature drops, it automatically returns to a low-resistance state, eliminating the need to replace fuse F and improving the maintenance convenience of the discharge circuit.

[0067] In summary, by configuring a first switch K1 and a second switch K2 in the switching unit 30, active discharge can be initiated by turning on at least one of the first switch K1 and the second switch K2. Even if one switch fails to turn on normally, active discharge can still be initiated through the other switch, ensuring that the active discharge function remains controllable even when the first switch K1 cannot be turned on, thus improving reliability. Furthermore, by placing a fuse F between the second terminal of the first switch K1 and the second terminal of the secondary winding, the active discharge function remains controllable even if the first switch K1 fails to turn off or a short circuit fault occurs in the active discharge circuit 20, further improving safety and reliability. This embodiment also uses a microcontroller 60 to control the switching unit 30, eliminating the need for manual intervention and improving automation.

[0068] In addition, in this embodiment of the application, when active discharge is performed through the active discharge circuit 20, the execution status of the active discharge circuit 20 can also be monitored. (Referring to...) Figure 2 As shown, the discharge circuit also includes a status monitoring module 50, which is connected between the second terminal of the active discharge circuit 20 and the first terminal of the switching unit 30. The status monitoring module 50 is used to monitor the execution status of the active discharge circuit 20 in performing active discharge.

[0069] The active discharge circuit 20 performs active discharge in two states: active discharge is performed and active discharge is not performed. In one implementation scenario, if the switching unit 30 includes a first switch K1 and a second switch K2, and both the first switch K1 and the second switch K2 are MOSFETs, the active discharge circuit 20 can be monitored by monitoring the voltage between the drain and source terminals of the MOSFETs.

[0070] Here, during active discharge, the status monitoring module 50 can obtain the execution status of the active discharge circuit 20, realize the monitoring of the active discharge process, and also determine in a timely manner whether the switching unit 30 and the active discharge circuit 20 have malfunctioned.

[0071] Figure 3 This is a schematic diagram of the structure of a status monitoring module provided in an embodiment of this application, with reference to... Figure 3 As shown, in some embodiments, the status monitoring module 50 includes: a first resistor R1, a second resistor R2, and a first switch Q1; The first end of the first resistor R1 is connected between the second end of the active discharge circuit 20 and the first end of the switching unit 30, and the second end of the first resistor R1 is connected to the control end of the first switching transistor Q1. The first end of the second resistor R2 is connected to the first end of the active discharge circuit 20, and the second end is connected to the first end of the first switching transistor Q1; the second end of the first switching transistor Q1 is grounded. The signal between the second terminal of the second resistor R2 and the first terminal of the first switch Q1 is used to characterize the active discharge circuit 20's active discharge execution state.

[0072] In one possible implementation, the active discharge circuit 20's active discharge execution state can be determined by the voltage signal between the second terminal of the second resistor R2 and the first terminal of the first switch Q1. In this case, the microcontroller 60 can connect to the second terminal of the second resistor R2 and the first terminal of the first switch Q1 via an I / O port to read the state of the voltage signal between them.

[0073] In one implementation scenario, when no active discharge is performed, the switching unit 30 is in the off state. At this time, the control terminal of the first switching transistor Q1 receives the voltage output from the secondary winding of the transformer T through the active discharge circuit 20 and the first resistor R1, which turns on the first switching transistor Q1. At this time, the I / O port of the microcontroller 60 reads a low level.

[0074] In another implementation scenario, when actively discharging, the switching unit 30 is in the on state. Since the second terminal of the switching unit 30 is grounded, the voltage at the control terminal of the first switching transistor Q1 is pulled low, causing the first switching transistor Q1 to be turned off. At this time, the I / O port of the microcontroller 60 reads a high level.

[0075] As can be seen from the above, based on Figure 3 The status monitoring module 50 shown illustrates that the on / off state of the switching unit 30 affects the on / off state of the first switching transistor Q1, which in turn affects the signal between the second terminal of the second resistor R2 and the first terminal of the first switching transistor Q1. Therefore, the signal between the second terminal of the second resistor R2 and the first terminal of the first switching transistor Q1 can characterize the execution state of the active discharge circuit 20, exhibiting strong anti-interference capability. Optionally, the high / low level read from the I / O port of the microcontroller 60 can determine whether the switching unit 30 is on, and thus whether the active discharge circuit 20 has performed active discharge.

[0076] In one implementation scenario, if during active discharge, the microcontroller 60 controls the first switch K1 in the switching unit 30 to be turned on, but the I / O port of the microcontroller 60 reads a low level through the status monitoring module 50, indicating that the first switch K1 has failed to be turned on normally, in order to ensure the smooth progress of active discharge, the microcontroller 60 can control the second switch K2 in the switching unit 30 to be turned on.

[0077] It should be noted that, Figure 3 The first switching transistor Q1 shown is an NPN transistor. In addition, it can also be a PNP transistor, and the connection relationship needs to be adapted accordingly.

[0078] remove Figure 3 Besides the one structure shown for the status monitoring module 50, the status monitoring module 50 can also have other structures, as detailed in the references. Figure 4 As shown, Figure 4 This is a schematic diagram of the structure of a status monitoring module provided in another embodiment of this application. The status monitoring module 50 includes: a third resistor R3 and a fourth resistor R4; The first end of the third resistor R3 is connected between the second end of the active discharge circuit 20 and the first end of the switching unit 30. The second end of the third resistor R3 is connected to the first end of the fourth resistor R4. The second end of the fourth resistor R4 is grounded. The signal between the second end of the third resistor R3 and the first end of the fourth resistor R4 is used to characterize the active discharge circuit 20's active discharge execution state.

[0079] Here, the signal between the second terminal of the third resistor R3 and the second terminal of the fourth resistor R4 can also be read by the microcontroller 60. Specifically, it can be a voltage signal.

[0080] In one possible implementation, the analog-to-digital converter (ADC) port of the microcontroller 60 is connected to the second terminal of the third resistor R3 and the first terminal of the fourth resistor R4. The voltage between the second terminal of the third resistor R3 and the first terminal of the fourth resistor R4 is read through the ADC port, thereby determining the execution state of the active discharge circuit 20 in performing active discharge.

[0081] In one implementation scenario, when no active discharge is performed, the switching unit 30 is in the off state. At this time, the ADC port of the microcontroller 60 can read the voltage output from the secondary winding of the transformer T after being divided by the active discharge circuit 20 and the third resistor R3.

[0082] In another implementation scenario, when actively discharging, the switching unit 30 is in the on state, and the voltage read by the ADC port of the microcontroller 60 is about 0V.

[0083] Therefore, based on Figure 4 The status monitoring module 50 shown can determine whether the switching unit 30 is turned on by reading the voltage from the ADC port of the microcontroller 60, and thus determine whether the active discharge circuit 20 has performed active discharge.

[0084] Here, the monitoring of the active discharge execution status of the active discharge circuit 20 can be achieved using only the third resistor R3 and the fourth resistor R4. The circuit structure is simple and the cost is low.

[0085] It should be noted that this embodiment only illustrates the structures of two state monitoring modules 50. Other structures can also be used to monitor the execution state of the active discharge circuit 20 in active discharge. For example, the fourth resistor R4 in the figure above can be replaced with a Zener diode, etc. This application does not limit it.

[0086] In addition to using the microcontroller 60, the voltage comparator can be combined with logic gate circuits to trigger corresponding indicators, thereby enabling the monitoring of the active discharge circuit 20's active discharge execution status.

[0087] In summary, during active discharge, the status monitoring module 50 can acquire the execution status of the active discharge circuit 20, thereby monitoring the active discharge process and determining in a timely manner whether the switching unit 30 and the active discharge circuit 20 have malfunctioned.

[0088] Figure 5 This is a schematic diagram of the structure of a motor controller provided in one embodiment of this application. Figure 5As shown, the motor controller 200 of this embodiment includes a discharge circuit 100. The structure of the discharge circuit 100 can be referred to in any of the above embodiments, and will not be described in detail here.

[0089] Figure 6 This is a schematic diagram of the structure of a vehicle provided in one embodiment of this application. Figure 6 As shown, the vehicle 300 in this embodiment includes a motor controller 200.

[0090] Those skilled in the art will understand that Figure 6 This is merely an example of a vehicle and does not constitute a limitation on the vehicle. It may include more or fewer components than shown, or combinations of certain components, or different components, such as input / output devices, network access devices, buses, etc.

[0091] In the above embodiments, the descriptions of each embodiment have different focuses. For parts that are not described in detail or recorded in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0092] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0093] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A discharge circuit, characterized in that, include: High-voltage battery, DC bus capacitor, high-voltage backup power supply, active discharge circuit and switching unit; The DC bus capacitor is connected in parallel with the high-voltage battery. The high-voltage backup power supply includes a transformer, wherein the first end of the primary winding of the transformer is connected to the first end of the DC bus capacitor, and the second end of the primary winding is connected to the second end of the DC bus capacitor; the first end of the secondary winding of the transformer is connected to the first end of the active discharge circuit, and the second end of the secondary winding is grounded. The second terminal of the active discharge circuit is connected to the second terminal of the secondary winding through the switching unit.

2. The discharge circuit according to claim 1, characterized in that, The switching unit includes a first switch and a second switch; The second terminal of the active discharge circuit is connected to the first terminal of the first switch and the first terminal of the second switch, respectively. The second terminal of the first switch is connected to the second terminal of the secondary winding, and the second terminal of the second switch is grounded.

3. The discharge circuit according to claim 2, characterized in that, A fuse is provided between the second end of the first switch and the second end of the secondary winding. The fuse presents a high impedance state when the first switch fails to turn off or when the active discharge circuit experiences a short circuit fault.

4. The discharge circuit according to any one of claims 1 to 3, characterized in that, The discharge circuit also includes a status monitoring module, which is connected between the second terminal of the active discharge circuit and the first terminal of the switching unit. The status monitoring module is used to monitor the execution status of the active discharge circuit in performing active discharge.

5. The discharge circuit according to claim 4, characterized in that, The status monitoring module includes: a first resistor, a second resistor, and a first switching transistor; The first end of the first resistor is connected between the second end of the active discharge circuit and the first end of the switching unit, and the second end of the first resistor is connected to the control end of the first switching transistor. The first end of the second resistor is connected to the first end of the active discharge circuit, and the second end is connected to the first end of the first switching transistor; the second end of the first switching transistor is grounded. The signal between the second end of the second resistor and the first end of the first switch is used to characterize the active discharge circuit's active discharge execution state.

6. The discharge circuit according to claim 4, characterized in that, The status monitoring module includes: a third resistor and a fourth resistor; The first end of the third resistor is connected between the second end of the active discharge circuit and the first end of the switching unit; the second end of the third resistor is connected to the first end of the fourth resistor; the second end of the fourth resistor is grounded. The signal between the second end of the third resistor and the first end of the fourth resistor is used to characterize the active discharge circuit's active discharge execution state.

7. The discharge circuit according to any one of claims 1 to 3, characterized in that, The active discharge circuit includes multiple discharge resistors connected in parallel, which are used to dissipate energy when the switching unit is turned on.

8. The discharge circuit according to any one of claims 1 to 3, characterized in that, The discharge circuit also includes a passive discharge circuit, which is connected to both ends of the secondary winding of the transformer.

9. The discharge circuit according to any one of claims 1 to 3, characterized in that, The discharge circuit also includes a microcontroller for controlling the switching unit's on / off state.

10. A motor controller, characterized in that, Includes the discharge circuit described in any one of claims 1 to 9.

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