Active bleeder circuit, bleeder method, controller, bleeder system and vehicle

Abstract

The invention relates to an active bleeder circuit, a bleeder method, a controller, a bleeder system and a vehicle, and the active bleeder circuit comprises a first transmission bus, a second transmission bus, a first capacitor, a motor control circuit, a motor and a second capacitor. The motor control circuit controls the motor to discharge the first capacitor and / or the second capacitor according to the motor control signal of the injection frequency, no extra discharge device needs to be added, the whole discharge process can be controlled and simplified, and the efficiency and safety of the active discharge action are improved.

Description

Technical Field

[0001] This application relates to the field of electric vehicle technology, and in particular to an active discharge circuit, discharge method, controller, discharge system and vehicle. Background Technology

[0002] With the rapid development of new energy vehicles and the upgrading of their product technologies, especially the widespread use of silicon carbide (SiC) motor controllers, the voltage platform of the vehicle's power battery is becoming increasingly higher, which poses a significant challenge to the high-voltage safety of the entire vehicle. High-voltage safety is the most concerned indicator, involving the vehicle's high-voltage insulation, active high-voltage discharge, passive high-voltage discharge, and high-voltage leakage. Among these, the active discharge function requires the first capacitor to discharge to below 60V within a specified time after the vehicle loses power.

[0003] In existing motor controllers, discharge is mainly achieved through resistors. Resistor discharge requires the addition of external switching transistors and high-power resistors. On the one hand, the hardware design requires the addition of high-power resistors and switching transistors, which increases the cost of controller components. On the other hand, the structure or circuit board needs to provide heat sinks for the discharge resistors, which increases the cost of PCB or structural development and prototyping. The overall cost of implementing the function is too high and the structure and hardware design are relatively complex. Summary of the Invention

[0004] This application provides an active discharge circuit, a vehicle, and a discharge method.

[0005] To achieve the above objectives, according to a first aspect of this application, an active discharge circuit is provided. The active discharge circuit includes a first transmission bus, a second transmission bus, a first capacitor, a motor control circuit, a motor, and a second capacitor. The first transmission bus is used to connect to a first terminal of a battery pack, and the second transmission bus is used to connect to a second terminal of the battery pack. The first capacitor is connected to both the first and second transmission buses. The motor control circuit is connected to both the first and second transmission buses. The motor is connected to the motor control circuit. A first terminal of the second capacitor is electrically connected to the first transmission bus and / or the motor, and a second terminal of the second capacitor is connected to the second transmission bus. The motor control circuit controls the motor to discharge the first capacitor and / or the second capacitor by means of a motor control signal with an injected frequency.

[0006] According to a second aspect of this application, a discharge method is provided, comprising: obtaining a frequency signal; and outputting a motor control signal according to the frequency signal to cause the motor to generate electromagnetic vibration to consume the energy of a first capacitor and / or a second capacitor.

[0007] According to a third aspect of this application, a controller is provided, the controller including a processor connected to a memory for storing a computer program, and the processor for executing the computer program to implement the above-described leakage method.

[0008] According to a fourth aspect of this application, a discharge system is provided, the discharge system including the above-described active discharge circuit and the above-described controller, the controller being used to output a motor control signal to a motor control circuit to cause the motor to generate electromagnetic vibration to consume the energy of the first capacitor and / or the second capacitor.

[0009] According to a fifth aspect of this application, a vehicle is provided, which includes the above-described active discharge circuit, or the above-described controller, or the above-described discharge system.

[0010] In the active discharge circuit of this application embodiment, the motor is controlled by the motor control circuit to discharge the first capacitor and / or the second capacitor according to the motor control signal of the injection frequency. No additional discharge device is required, and the entire discharge process can be simplified, improving the efficiency and safety of the active discharge action.

[0011] Other features and advantages of this application will be described in detail in the following detailed description section. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the 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.

[0013] To gain a more complete understanding of this application and its beneficial effects, the following description will be provided in conjunction with the accompanying drawings, wherein the same reference numerals in the following description denote the same parts.

[0014] Figure 1 A block diagram of an active discharge circuit according to an embodiment of this application is shown;

[0015] Figure 2 This diagram illustrates an active discharge circuit in an embodiment of the present application that includes a motor.

[0016] Figure 3 A schematic diagram illustrating the first scenario of active discharge of a single motor according to an embodiment of this application;

[0017] Figure 4 A schematic diagram illustrating a second scenario of active discharge of a single motor according to an embodiment of this application;

[0018] Figure 5A schematic diagram illustrating a third scenario of active discharge of a single motor according to an embodiment of this application;

[0019] Figure 6 This diagram illustrates a configuration of two motors in the active discharge circuit of an embodiment of this application.

[0020] Figure 7 A schematic diagram illustrating the active discharge of two motors according to an embodiment of this application is shown;

[0021] Figure 8 This diagram illustrates a three-motor configuration in the active discharge circuit of an embodiment of this application.

[0022] Figure 9 A schematic diagram of the three-motor active discharge according to an embodiment of this application is shown;

[0023] Figure 10 A flowchart illustrating the venting method according to an embodiment of this application is shown;

[0024] Figure 11 A schematic diagram is shown for calculating the voltage in the high-order dq coordinates of a multiphase winding. Detailed Implementation

[0025] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the protection scope of this application.

[0026] This application primarily provides an active discharge circuit 100, which is applied to electric vehicles. The active discharge circuit 100 includes a first transmission bus, a second transmission bus, a first capacitor, a motor control circuit, a motor, and a second capacitor. The first transmission bus is used to connect to the first terminal of the battery pack, and the second transmission bus is used to connect to the second terminal of the battery pack. The first capacitor is connected to both the first and second transmission buses. The motor control circuit is connected to both the first and second transmission buses. The motor is connected to the motor control circuit. The first terminal of the second capacitor is electrically connected to the first transmission bus and / or the motor, and the second terminal of the second capacitor is connected to the second transmission bus. The motor control circuit controls the motor to discharge the first capacitor and / or the second capacitor according to a motor control signal with an injected frequency. In the active discharge circuit 100 of this application embodiment, the motor control circuit controls the motor to discharge the first capacitor and / or the second capacitor according to a motor control signal with an injected frequency, eliminating the need for additional components and simplifying the entire discharge process control, thereby improving the efficiency and safety of the active discharge action.

[0027] Figure 1This diagram illustrates an active discharge circuit 100 according to an embodiment of this application. Figure 1 As shown, the active discharge circuit 100 includes a first transmission bus L1, a second transmission bus L2, a first capacitor 103 (C1), a motor control circuit 104, a motor 105, and a charging / discharging interface 108 for a second capacitor 107 (C2). The first transmission bus L1 is used to connect to the first terminal of the battery pack 101, and the second transmission bus L2 is used to connect to the second terminal of the battery pack 101. A first switch module 102 is connected to the battery pack 101, the first capacitor 103 (C1) is connected to the first switch module 102, the motor control circuit 104 is connected to the first capacitor 103 (C1), the motor 105 is connected to the motor control circuit 104, the second switch module 106 is connected to the motor control circuit 104, the second capacitor 107 (C2) is connected to the second switch module 106, and the charging / discharging interface 108 is connected to the second capacitor 107 (C2).

[0028] The first terminal of the battery pack 101 is connected to the first transmission bus L1, and the second terminal of the battery pack 101 is connected to the second transmission bus L2. The bus can be a high-voltage bus. Figure 1 In this configuration, the first switch module 102, the first capacitor 103 (C1), the motor control circuit 104, the second switch module 106, the second capacitor 107 (C2), and the charging / discharging interface 108 can all be mounted between the high-voltage first transmission bus L1 and the high-voltage second transmission bus L2. The battery pack 101, the first switch module 102, the first capacitor 103 (C1), the motor control circuit 104, the second switch module 106, the second capacitor 107 (C2), and the charging / discharging interface 108 are connected in parallel.

[0029] The motor control circuit 104 controls the motor 105 to discharge the first capacitor 103 (C1) and / or the second capacitor 107 (C2) according to the motor control signal of the injection frequency.

[0030] Figure 2 This diagram shows a motor installed in the active discharge circuit 100 according to an embodiment of this application.

[0031] In one embodiment, the first switch module includes a precharge switch K0 and a precharge resistor R. The first end of the precharge switch K0 is connected to the first pole of the battery pack 101 (E1), the second end of the precharge switch K0 is connected to the first end of the precharge resistor R, and the second end of the precharge resistor R is connected to the first transmission bus.

[0032] When the first capacitor C1 needs to be pre-charged, the pre-charge switch K0 is closed, thereby completing the pre-charge of the first capacitor C1; after the pre-charge is completed, the pre-charge switch K0 is opened.

[0033] The first switch module 102 also includes a first switch K1 and a second switch K2. The first end of the first switch K1 is connected to the second terminal of the battery pack, and the second end of the first switch K1 is connected to the second terminal of the first capacitor C1. The first end of the second switch K2 is connected to the first terminal of the battery pack, and the second end of the second switch K2 is connected to the first terminal of the first capacitor C1.

[0034] The first terminal of the first capacitor C1 is connected to the first transmission bus, and the second terminal of the first capacitor C1 is connected to the second transmission bus.

[0035] The motor control circuit includes multiple bridge arms, for example, m bridge arms, where m is a natural number. The two ends of each bridge arm are connected in parallel to a first transmission bus and a second transmission bus, and the midpoint of each bridge arm is connected to the motor. Specifically, the first end of each of the m bridge arms is connected to the first transmission bus, and the second end of each of the m bridge arms is connected to the second transmission bus.

[0036] The motor control circuit is used to control the duty cycle of the upper and / or lower arm of at least one bridge arm to control the active discharge process according to the pulse width modulation signal.

[0037] Each bridge arm includes two power switches connected in series, with the midpoint of each bridge arm located between the two power switches. The power switches can be devices such as bipolar junction transistors (BJTs), metal-oxide-semiconductor field-effect transistors (MOSFETs), or insulated-gate bipolar transistors (IGBTs), and this application is not limited to these. Optionally, the power switches are three-terminal devices.

[0038] The motor includes a stator winding, which in turn includes m-phase coils.

[0039] In some possible implementations, the motor is led out as a neutral line. The first end of each phase coil is connected to the midpoint of one bridge arm, and the second end of each phase coil is connected to the neutral line N1, which is connected to the second switch module 106. Here, N1 can be regarded as the neutral point.

[0040] In some other possible implementations, the motor has phase leads. The m-phase coil includes a first coil and at least one second coil, the first coil being electrically connected to a first terminal of the second capacitor such that the first coil and the at least one second coil are connected in series.

[0041] In one embodiment, the motor is an electrically excited synchronous motor (EESM). The EESM uses excitation windings to generate the rotor's magnetic field, while the stator generates a rotating magnetic field through alternating current. When the rotating magnetic field interacts with the rotor's magnetic field, the motor produces torque, driving the vehicle.

[0042] Taking m=3 as an example, the motor control circuit is a three-phase motor control circuit. In this case, the motor control circuit includes three bridge arms, each of which is connected in parallel to the first and second transmission buses, and the midpoint of each bridge arm is connected to the motor. Specifically, the motor control circuit includes a first bridge arm, a second bridge arm, and a third bridge arm.

[0043] The first bridge arm includes a first power switch VT1 and a second power switch VT2. The first end of the first power switch VT1 is connected to the processor, the second end of the first power switch VT1 is connected to the midpoint of the first bridge arm, the third end of the first power switch VT1 is the first end of the first bridge arm, and the third end of the first power switch VT1 is connected to the first transmission bus. The first end of the second power switch VT2 is connected to the processor, the second end of the second power switch VT2 is the second end of the first bridge arm, the second end of the second power switch VT2 is connected to the second transmission bus, and the third end of the second power switch VT2 is connected to the midpoint of the first bridge arm.

[0044] The second bridge arm includes a third power switch VT3 and a fourth power switch VT4. The first terminal of the third power switch VT3 is connected to the processor, the second terminal of the third power switch VT3 is connected to the midpoint of the second bridge arm, and the third terminal of the third power switch VT3 is connected to the first transmission bus. The first terminal of the fourth power switch VT4 is connected to the processor, the second terminal of the fourth power switch VT4 is connected to the second transmission bus, and the third terminal of the fourth power switch VT4 is connected to the midpoint of the second bridge arm.

[0045] The third bridge arm includes a fifth power switch VT5 and a sixth power switch VT6. The first end of the fifth power switch VT5 is connected to the processor, the second end of the fifth power switch VT5 is connected to the midpoint of the third bridge arm, and the third end of the fifth power switch VT5 is connected to the first transmission bus. The first end of the sixth power switch VT6 is connected to the processor, the second end of the sixth power switch VT6 is connected to the second transmission bus, and the third end of the sixth power switch VT6 is connected to the midpoint of the third bridge arm.

[0046] In one embodiment, a parasitic diode is present on each power switch of the bridge arm. Figure 2For example, the first terminal of the parasitic diode VD1 of the first power switch VT1 is connected to the second terminal of the first power switch VT1; the first terminal of the parasitic diode VD3 of the third power switch VT3 is connected to the second terminal of the third power switch VT3; the first terminal of the parasitic diode VD5 of the fifth power switch VT5 is connected to the second terminal of the fifth power switch VT5; the second terminals of the parasitic diodes of the first power switch VT1, the third power switch VT3, and the fifth power switch VT5 are all connected to the first transmission bus; the second terminal of the parasitic diode VD2 of the second power switch VT2 is connected to the third terminal of the second power switch VT2; the second terminal of the parasitic diode VD4 of the fourth power switch VT4 is connected to the third terminal of the fourth power switch VT4; the second terminal of the parasitic diode VD6 of the sixth power switch VT6 is connected to the third terminal of the sixth power switch VT6; the first terminals of the parasitic diodes of the second power switch VT2, the fourth power switch VT4, and the sixth power switch VT6 are all connected to the second transmission bus.

[0047] The stator windings of an electrically excited synchronous motor carry three-phase current, namely phase A, phase B, and phase C. Phase A coils are connected to the midpoint A1 of the first bridge arm, phase B coils to the midpoint B1 of the second bridge arm, and phase C coils to the midpoint C1 of the third bridge arm. The electrically excited synchronous motor can be a three-phase four-wire system. Figure 2 In the circuit, windings A1-A4 can lead out phase A, windings B1-B4 can lead out phase B, and windings C1-C4 can lead out phase C, forming four junction points n1-n4, which are then connected to the neutral line N1. The electrically excited synchronous motor can also be a three-phase, three-wire system.

[0048] In one embodiment, the motor further includes a rotor coil, and the motor control circuit further includes an excitation control module. The excitation control module is connected to the first transmission bus, the second transmission bus, and the rotor coil. The excitation control module is used to control the excitation parameters of the rotor of the electrically excited synchronous motor. The excitation parameters can be parameters such as excitation voltage and excitation current.

[0049] The excitation control module includes a seventh power switch VT7, an eighth power switch VT10, a first diode VD8, and a second diode VD9. The first terminal of the seventh power switch VT7 is connected to the processor, the second terminal of the seventh power switch VT7 is connected to the second terminal of the first diode VD8, and the third terminal of the seventh power switch VT7 is connected to the first transmission bus. The first terminal of the first diode VD8 is connected to the second transmission bus. The first terminal of the eighth power switch VT10 is connected to the processor, the second terminal of the eighth power switch VT10 is connected to the first terminal of the second transmission bus, and the third terminal of the eighth power switch VT10 is connected to the first terminal of the second diode VD9. The second terminal of the second diode VD9 is connected to the third terminal of the seventh power switch VT7.

[0050] A parasitic diode exists on both the seventh power switch VT7 and the eighth power switch VT10. The first terminal of the parasitic diode of the seventh power switch VT7 is connected to the second terminal of the seventh power switch VT7, and the second terminal of the parasitic diode of the seventh power switch VT7 is connected to the third terminal of the seventh power switch VT7; the first terminal of the parasitic diode of the eighth power switch VT10 is connected to the second terminal of the eighth power switch VT10, and the second terminal of the parasitic diode of the eighth power switch VT10 is connected to the third terminal of the eighth power switch VT10.

[0051] The first end of the rotor coil is connected to the midpoint between the seventh power switch VT7 and the first diode VD8, and the second end of the rotor coil is connected to the midpoint between the eighth power switch VT10 and the second diode VD9. The first end of the rotor coil can be a positive terminal, and the second end of the rotor coil can be a negative terminal. Optionally, the first end of the rotor coil is connected to the second terminal of the first diode VD8, and the second end of the rotor coil is connected to the first terminal of the second diode VD9.

[0052] The second switch module 106 includes a third switch K3 and a fourth switch K4. The fourth switch K4 is a motor switch. The first end of the third switch K3 is connected to the second end of the second capacitor C2, and the second end of the third switch K3 is connected to the charging and discharging interface. The first end of the fourth switch K4 is connected to the neutral point of the multiphase coil or the first coil in the multiphase coil, and the second end of the fourth switch K4 is connected to the first end of the second capacitor C2.

[0053] The second switch module 106 also includes a fifth switch K5, which is a first-pole switch. The first end of the fifth switch K5 is connected to the first transmission bus, and the second end of the fifth switch K5 is connected to the first end of the second capacitor C2.

[0054] The first end of the second capacitor C2 is connected to the charging and discharging interface, and the second end of the second capacitor C2 is connected to the second transmission bus.

[0055] In one embodiment, each bridge arm includes an upper bridge arm and a lower bridge arm. During active discharge, the upper and lower bridge arms of at least one bridge arm of the motor control circuit are alternately turned on, so that the bus voltage across the first capacitor and the interface voltage across the second capacitor are charged and discharged back and forth through the bridge arm and the motor winding, thereby dissipating the energy consumed by the bridge arm and the motor winding. The motor control circuit is used to control the duty cycle of the upper and / or lower bridge arms of at least one bridge arm according to the pulse width modulation signal to control the active discharge process.

[0056] In one embodiment, the active discharge circuit includes multiple motors configured to discharge using motors that are functioning normally and whose temperatures are within a safe range.

[0057] In one embodiment, the plurality of motors includes a first motor and a second motor, the second motor being connected to a second motor control circuit and the first motor being connected to a first motor control circuit. The first motor is an electrically excited synchronous motor and the second motor is a first AC motor. The priority of using the first motor for discharge is higher than the priority of using the second motor for discharge.

[0058] In one embodiment, the second motor is an asynchronous motor, and the plurality of motors also include a third motor, which is a synchronous motor. The third motor is connected to a third motor control circuit, and the priority of using the second motor for discharge is higher than the priority of using the third motor for discharge.

[0059] By rationally setting the priority of the venting devices, the normal functioning of the venting device can be guaranteed to a greater extent, thus ensuring the normal operation of the entire vehicle.

[0060] Figure 3 This diagram illustrates a first scenario of active discharge of a single motor according to an embodiment of this application.

[0061] like Figure 3 As shown, in the mode of boost charging the battery pack through the charging and discharging port, the bus voltage across the first capacitor C1 and the interface voltage across the second capacitor C2 are inconsistent. It is necessary to level the bus voltage across the first capacitor C1 and the interface voltage across the second capacitor C2 before active discharge so that the bus voltage across the first capacitor C1 and the interface voltage across the second capacitor C2 are consistent.

[0062] In the mode where the charging port of the battery pack is used for boost charging, the third switch K3 and the fourth switch K4 are in the energized state. To ensure that the bus voltage across the first capacitor C1 and the interface voltage across the second capacitor C2 are consistent, the first switch K1, the second switch K2, and the third switch K3 are adjusted to the open state, while the fourth switch K4 remains energized. Multiple upper bridge arms of the motor control circuit are turned on, so that... Figure 3 For example, in the motor control circuit, the first power switch VT1, the third power switch VT3, and the fifth power switch VT5 are all upper bridge arms and are all in the conducting state, thereby turning on the three-phase coils of the motor. Since the first capacitor C1 stores charge, a clockwise current loop is formed between the first capacitor C1, the upper bridge arm of the motor control circuit, the motor, and the fourth switch K4 of the second switch module 106. Because the fourth switch K4 remains in the energized state, current flows through the second capacitor C2, thereby quickly making the bus voltage across the first capacitor C1 and the interface voltage across the second capacitor C2 consistent.

[0063] It should be noted that since the three-phase coils of the motor are turned on together, the phase current of the motor is consistent, which will not cause torque fluctuation problems. Moreover, it can shorten the balance time of the bus voltage across the first capacitor C1 and the interface voltage across the second capacitor C2, making the entire voltage balance process very fast.

[0064] Figure 4 This diagram illustrates a second scenario of active discharge of a single motor according to an embodiment of this application.

[0065] like Figure 4 As shown, after the bus voltage across the first capacitor C1 and the interface voltage across the second capacitor C2 are consistent, the fifth switch K5 can be adjusted from the open state to the closed state so that there is no voltage difference across the fifth switch K5, thereby avoiding the generation of inrush current.

[0066] After the fifth switch K5 is engaged, multiple upper bridge arms of the motor control circuit are disconnected, while multiple lower bridge arms of the motor control circuit are turned on. Figure 4 For example, in the motor control circuit, the second power switch VT2, the fourth power switch VT4, and the sixth power switch VT6 are all lower bridge arms and are all in the ON state. At this time, a clockwise current loop is formed between the second capacitor C2, the motor, the lower bridge arm of the motor control circuit, the first capacitor C1, the first transmission bus, and the fifth switch K5, and another counterclockwise current loop is formed between the second capacitor C2, the motor, the lower bridge arm of the motor control circuit, and the second transmission bus.

[0067] Figure 5 A schematic diagram illustrating a third scenario of active discharge of a single motor according to an embodiment of this application is shown.

[0068] like Figure 5 As shown, the fourth switch K4 and the fifth switch K5 remain in the energized state, multiple upper bridge arms of the motor control circuit are conducting, while multiple lower bridge arms of the motor control circuit are disconnected. At this time, a clockwise current loop is formed between the fourth switch K4, the motor, the upper bridge arms of the motor control circuit, and the fifth switch K5.

[0069] It should be noted that, Figure 3 The first scenario Figure 4 The second scenario and Figure 5 The third scenario can be implemented sequentially, in turn. According to... Figures 3 to 5 In this control method, the upper and lower bridge arms of the motor control circuit are alternately turned on. During the alternating control process, the processor can send pulse width modulation signals to the first terminal of each power switch to perform pulse width modulation. The duty cycle of the pulse width modulation signal can be adjusted from small to large according to the order of time.

[0070] In one embodiment, the active discharge circuit 100 may include two motors, comprising a first motor 1051 and a second motor 1052. The second motor is connected to a second motor control circuit, and the first motor is connected to a first motor control circuit. The second motor may be a synchronous motor, an asynchronous motor, an electrically excited motor, etc., and the first motor may be a synchronous motor, an asynchronous motor, an electrically excited motor, etc.

[0071] Figure 6 This diagram shows a schematic of two motors arranged in the active discharge circuit 100 of an embodiment of this application.

[0072] like Figure 6 As shown, the structure of the second motor control circuit is similar to... Figure 2 The motor control circuits are identical in structure, with the second motor control circuit connected to both the first and second transmission buses. The second motor is connected to the midpoint of each bridge arm of the second motor control circuit.

[0073] and Figure 2 The difference is that, in Figure 6 In addition to the first capacitor C1, the circuit also includes a thirty-first capacitor C31. The first motor control circuit is connected to the second and first terminals of the thirty-first capacitor C31. The second terminal of the thirty-first capacitor C31 is connected to the second terminal of the first capacitor C1 through an inductor L, and the first terminal of the thirty-first capacitor C31 is connected to the first terminal of the first capacitor C1. The first motor is connected to the midpoint of each bridge arm of the first motor control circuit.

[0074] Figure 7 This diagram illustrates the active discharge of two motors according to an embodiment of this application.

[0075] like Figure 7 As shown, this is the mode where the charging and discharging port performs boost charging of the battery pack. To make the bus voltage across the first capacitor C1 and the interface voltage across the second capacitor C2 consistent, the second switch K2, the first switch K1, and the third switch K3 are adjusted to the open state, while the fourth switch K4 remains in the closed state. Multiple upper bridge arms of the second motor control circuit are turned on, thereby turning on the three-phase coils of the second motor. At this time, a clockwise current loop is formed between the first capacitor C1, the upper bridge arms of the second motor control circuit, the second motor, and the fourth switch K4. Additionally, the thirty-first capacitor C31, the inductor L, and the first capacitor C1 also form a counter-clockwise current loop, allowing the voltages on both the first capacitor C1 and the thirty-first capacitor C31 to discharge.

[0076] In one embodiment, the active discharge circuit 100 may include three motors: a first motor 1051, a second motor 1052, and a third motor 1053. The first motor is connected to a first motor control circuit, the second motor is connected to a second motor control circuit, and the third motor is connected to a third motor control circuit. The first motor can be a synchronous motor, an asynchronous motor, an electrically excited motor, etc.; the second motor can be a synchronous motor, an asynchronous motor, an electrically excited motor, etc.; and the third motor can be a synchronous motor, an asynchronous motor, an electrically excited motor, etc.

[0077] Figure 8 This diagram shows a three-motor configuration in the active discharge circuit 100 of an embodiment of this application.

[0078] like Figure 8 As shown, the structures of the first motor control circuit, the second motor control circuit, and the third motor control circuit are all similar to... Figure 2 The motor control circuits are identical in structure. The first motor control circuit is connected to the first and second terminals of the thirty-first capacitor C31, the second motor control circuit is connected to the first and second terminals of the first capacitor C1, and the third motor control circuit is connected to the first and second terminals of the twenty-first capacitor C21. The first motor is connected to the midpoint of each bridge arm of the first motor control circuit, the second motor is connected to the midpoint of each bridge arm of the second motor control circuit, and the third motor is connected to the midpoint of each bridge arm of the third motor control circuit.

[0079] and Figure 2 The difference is that the first terminal of the thirty-first capacitor C31 is connected to the first terminal of the inductor L, the second terminal of the inductor L is connected to the first terminal of the first capacitor C1, the second terminal of the thirty-first capacitor C31 is connected to the second terminal of the first capacitor C1 and the second terminal of the twenty-first capacitor C21, and the first terminal of the twenty-first capacitor C21 is connected to the first terminal of the battery pack through the second switch K2.

[0080] Figure 9 This diagram illustrates a three-motor active discharge method according to an embodiment of this application.

[0081] like Figure 9 As shown, for the three-electric drive system, in the boost charging mode, DC charging and discharging interface 1 is charged, the third switch K3 and the fourth switch K4 are engaged, and after charging is completed, the twenty-first capacitor C21, the first capacitor C1 and the thirty-first capacitor C31 are discharged.

[0082] During the active discharge process, the third switch K3 needs to be disconnected, the fourth switch K4 needs to be kept engaged, and then the first switch K1 and the second switch K2 need to be disconnected. By controlling the switches of different drive winding bridge arms to be in phase or out of phase, and at the same time increasing the switching frequency of the bridge arms, the three-phase current can be controlled to flow into or out of the charging port simultaneously, and the busbar and the charging port can be discharged simultaneously.

[0083] During active discharge, when the bus voltage surges above the battery pack's maximum voltage or a certain safe value, the duty cycle of the pulse width modulation signal in the motor control circuit is adjusted to direct current to the charging port. When the charging port voltage surges close to the current bus voltage or a certain safe value, the duty cycle is adjusted to direct charging current to the bus side, thereby achieving rapid discharge of the bus and second capacitor C2 voltages without generating torque fluctuations or even causing minor noise issues such as gear rattles. After discharge is complete, the fourth switch K4 is disconnected.

[0084] When multiple charging ports are charging simultaneously, such as DC charging / discharging port 1 and DC charging / discharging port 2 charging simultaneously, after charging is completed, during the active discharge process, it is necessary to disconnect the third switch K3 and the fifth switch K5, keep the fourth switch K4 and the sixth switch K6 engaged, and then select at least one motor to perform active discharge using the above scheme.

[0085] In one embodiment, the multi-motor drive of this application can take various forms. For example, the active discharge circuit 100 includes one electrically excited motor, or one electrically excited motor and one permanent magnet synchronous motor, or one electrically excited motor and one or two permanent magnet synchronous motors, or one electrically excited motor, one permanent magnet synchronous motor and one asynchronous motor, etc. Another example is that the active discharge circuit 100 includes two permanent magnet synchronous motors and one asynchronous motor. Yet another example is that the active discharge circuit 100 includes a system of one, two, or four permanent magnet synchronous motors, etc. It is understood that this application does not limit the specific combination of multi-motor drives.

[0086] In one embodiment, the processor can also receive the temperature and fault status of the motor windings, power modules, etc., and select at least one motor control circuit for control based on the temperature and fault status. By selecting at least one controller module without faults and with a temperature within a safe range for active discharge based on the temperature and fault status of the motor windings, power modules, etc., the processor can achieve active discharge of the capacitors inside the motor control circuit. Selecting a power module without faults and with a temperature within a safe range for discharge reduces the risk of secondary damage and aggravated damage, thus enhancing safety.

[0087] In one embodiment, the power winding module with no faults and a temperature within a safe range is preferentially selected for active discharge, followed by the electrically excited motor drive winding module circuit. If the electrically excited drive system has a fault, the asynchronous motor winding module is selected for active discharge, and finally the permanent magnet synchronous motor winding module is selected. If all electric drive systems have faults, the DC / DC system and the OBC system are selected for active discharge, reporting an active discharge fault in the electric drive system. This maximizes the guarantee of normal active discharge function and ensures the safety of the entire vehicle.

[0088] It's worth noting that electrically excited motors have dedicated excitation bridge arms. Even if the motor's zero position is inaccurate, using the excitation bridge arm for discharge eliminates the need for zero-position and d-q axis current control. This avoids the torque fluctuations, gear grinding, and abnormal noise issues that synchronous motors experience due to zero-position inaccuracies and d-q axis current control fluctuations. Secondly, asynchronous motors are preferable. Asynchronous motors are single-sided excited, lack permanent magnets, and do not require zero-position or d-axis current control fluctuations, making them less prone to gear grinding and abnormal noise issues. Finally, permanent magnet synchronous motors are the best choice. Permanent magnet synchronous motors have a rotor magnetic field; zero-position inaccuracies or d-axis current control fluctuations can easily cause gear grinding and abnormal noise issues.

[0089] Figure 10 A flowchart illustrating the venting method according to an embodiment of this application is shown. Figure 10 As shown, the discharge method is applied to the above-mentioned active discharge circuit, and the discharge method includes the following steps:

[0090] Step S10: Obtain the frequency signal.

[0091] Step S20: Output a motor control signal according to the frequency signal so that the motor generates electromagnetic vibration to consume the energy of the first capacitor and / or the second capacitor.

[0092] In one embodiment, outputting a motor control signal based on a frequency signal includes: performing amplitude mapping processing on the frequency signal to obtain current and / or voltage in the corresponding amplitude dimension; obtaining current and / or voltage control signals in an nth-order synchronous rotating coordinate system based on the current and / or voltage in the amplitude dimension; injecting the current and / or voltage control signals in the nth-order synchronous rotating coordinate system into the harmonic vector control system of the motor, so as to output a motor control signal using the vector control system, wherein the vector control system is a vector control system based on the rotor magnetic field orientation established by the motor.

[0093] The frequency signal can be, for example, but is not limited to, an audio signal.

[0094] In one embodiment, obtaining current and / or voltage control signals in an nth-order synchronous rotating coordinate system based on current and / or voltage in amplitude dimensions includes: performing nth-order synchronous coordinate transformation on the motor phase currents to extract nth-order synchronous coordinate feedback harmonic current values; obtaining target harmonic current values ​​based on current in amplitude dimensions; and performing proportional-integral adjustment on the feedback harmonic current values ​​and the target harmonic current values ​​to obtain voltage control signals in an nth-order synchronous rotating coordinate system.

[0095] In one embodiment, the motor control signal is used to control the duty cycle of the switch in the motor control circuit.

[0096] The specific explanations for each of the above steps are as follows:

[0097] A vector control system based on the rotor magnetic field orientation is established.

[0098] In one embodiment, vector control, also known as field-oriented control (FOC), is a technique that uses a frequency converter to control an AC motor. The motor's output is controlled by adjusting the frequency, voltage, and angle of the frequency converter. There are various methods for establishing a vector control system, and this application is not limited to any particular method. Optionally, the motor described above is a permanent magnet synchronous motor.

[0099] The extracted audio signal or sine signal is subjected to amplitude mapping processing to obtain the current in the corresponding amplitude dimension.

[0100] In one embodiment, an audio signal is extracted. This audio signal can be extracted from a music file. The music file can be a song file, such as files in various music formats like mp3, wma, wav, flac, and ape; it can also be a sine signal sin(2πf ts), such as a high-frequency sine wave with a frequency f ranging from 300Hz to 1000Hz; a MIDI file; a song file transmitted via Bluetooth; a digital signal processed by a music chip; an analog signal processed by a chip; an analog signal amplified by a power amplifier; a PCM encoded file; an analog input from a microphone; or a digital signal corresponding to a music file.

[0101] After extracting the audio signal, the controller performs amplitude mapping processing. Specifically, the extracted audio signal is first standardized to per-unit (signal value range -1 to 1). Then, based on the maximum current amplitude that the controller can use to respond to music, the per-unit processed audio signal is multiplied and converted to obtain the current Is and / or voltage Us in amplitude dimension corresponding to the controller. Is is distributed to the dq axis of the nth-order synchronous rotating coordinate system via the angle theta, resulting in the target harmonic current values ​​Isdn and Isqn that the motor drive system can control; and / or voltage values ​​Us are distributed to the nth-order target voltage signals Usdn1 and Usqn1 on the dq axis of the nth-order synchronous rotating coordinate system via the angle theta. theta = K × 2πF Ts + theta_init, where K ∈ real numbers, F is the frequency of the injected signal, which controls the rotation frequency of the rotating magnetic field. A high-speed rotating magnetic field scanning the rotor magnetic field will not cause the rotor to rotate. Ts is time, and theta_init is the initial angle of the injection, ranging from 0 to 360 degrees, which can be expressed by the following formula:

[0102] Isdn = Is×cos(theta) formula (1)

[0103] Isqn = Is×sin(theta) formula (2)

[0104] Usdn1 = Us×cos(theta) formula (3)

[0105] Usqn1 = Us×sin(theta) formula (4)

[0106] The current Is is distributed to the dq axis of the nth-order synchronous rotating coordinate system through the angle theta, to obtain the given target harmonic current values ​​Isdn and Isqn (such as currents Id5th, Iq5th, Id7th, Iq7th). The motor phase currents are transformed by the nth-order synchronous coordinate system respectively, and the nth-order synchronous coordinate feedback harmonic current values ​​are extracted. The target harmonic current values ​​and feedback harmonic current values ​​are processed by a PI regulator to obtain the nth-order control voltage signals Usdn and Usqn on the corresponding nth-order synchronous rotating coordinate system. The nth-order control voltage signals Usdn and Usqn are then transformed by the nth-order synchronous coordinate system to obtain the voltage control signals of the motor drive system.

[0107] The voltage value Us is distributed to the nth-order target voltage signals Usdn1 and Usqn1 on the dq axis of the nth-order synchronous rotating coordinate system via the angle theta. The nth-order target voltage signals Usdn1 and Usqn1 can also be obtained through the equivalent model of the motor parameters in the nth-order dq-axis synchronous rotating coordinate system. For example, Isdn and Isqn are obtained through the equivalent model of the motor parameters in the nth-order dq-axis synchronous rotating coordinate system. The nth-order dq-axis synchronous rotating coordinate system is then converted to the nth-order target voltage signals Usdn1 and Usqn1 through a current conversion module. The nth-order target voltage signals Usdn1 and Usqn1 can be expressed by the following formula:

[0108] Usdn1=[Isdn×(Rs+s×Ldn)-we×Lqn×Isqn]×Kp / Us Formula (5)

[0109] Usqn1=[Isqn×(Rs+s×Lqn)+we×Ldn×Isdn+we×ψfn]×Kp / Us Formula (6)

[0110] Where s is the variable of the Laplace transform, and Kp is not equal to zero. The current conversion module can also be a pure proportional coefficient relationship or a proportional-differential relationship, etc., to obtain the target voltage control signals Usdn1 and Usqn1 as shown in the following formulas:

[0111] Usdn1=Isdn×Kp formula (7)

[0112] Usqn1=Isqn×Kp formula (8)

[0113] Where Kp is not equal to zero.

[0114] The audio signal is converted into a current vector Is (n-order target current Isdn, Isqn) and a voltage vector Us (n-order target voltage Usdn, Usqn) on the dq axis in an n-order synchronous rotating coordinate system, where n is a real number. The direction can be positive or negative. For example, the order can be positive n = 1, 2, 3, 4, 5, 6, 7..., and negative n = 0, -1, -2, -3, -4, -5, -6, -7... etc. For example, the audio signal can be converted into a 7th-order dq axis current vector Is7 (current Isd7, Isq7) or a -5th-order dq axis voltage vector Us-5 (voltage Usd-5, Usq-5), etc., and the current and / or voltage are injected into the n-order dq axis synchronous rotating coordinate system. The use of a higher-order rotating coordinate system increases control complexity, but prevents the motor from vibrating and producing noise during the injection of high-order harmonic currents and / or voltages.

[0115] Harmonics are injected into the vector control system based on voltage control signals. The target harmonic current value and the feedback harmonic current value are processed by a PI regulator to obtain the corresponding nth-order control voltage signals Usdn and Usqn in the nth-order synchronous rotating coordinate system; and / or the nth-order target voltages Usdn1 and Usqn1 are superimposed and, after nth-order synchronous coordinate inverse transformation, the voltage control signal is obtained; the voltage control signal is injected into the original FOC closed-loop control system; the duty cycle of the bridge arm control signal is adjusted to make the motor generate electromagnetic vibration and emit a sound corresponding to the audio signal, consuming the energy of the first capacitor and / or the second capacitor, without causing motor vibration and noise.

[0116] Among them, the current Is and the voltage Us must be less than the maximum allowable current and voltage of the system.

[0117] Figure 11 A schematic diagram is shown for calculating the voltage in the high-order dq coordinates of a multiphase winding.

[0118] like Figure 11 As shown, for example, firstly, the phase currents of the multi-phase motor are transformed by coordinates of -5dq and +7dq orders respectively. Then, the -5th and +7th harmonic currents are extracted by a low-pass filter. Next, Is is distributed to the dq axis of the nth-order synchronous rotating coordinate system through the angle theta, obtaining the given target harmonic current values ​​(currents Id5th, Iq5th, Id7th, Iq7th). The target harmonic current values ​​and the feedback harmonic current values ​​are then processed by a PI controller to obtain the corresponding control voltage signals Usdn and Usqn (voltages Ud5th, Uq5th, Ud7th, Uq7th) in the nth-order synchronous rotating coordinate system. The target harmonic current values ​​are shown below:

[0119] Id5th=Is×cos(theta), Iq5th=Is×sin(theta);

[0120] Id7th=Is×cos(theta), Iq7th=Is×sin(theta);

[0121] Then, the control voltage signals Usdn and Usqn in the nth-order synchronous rotating coordinate system are injected into the motor vector control after inverse coordinate transformation. Among them, the voltages Ud5th, Uq5th, Ud7th, and Uq7th are transformed by inverse PARK to obtain the voltages in the stationary coordinate system (voltages Uα5th, Uβ5th, Uα7th, and Uβ7th), which are then injected into the original FOC closed-loop control system.

[0122] For example, the nth-order target voltages Usdn1 and Usqn1 are extracted as follows:

[0123] Ud5th1=Us×cos(theta), Uq5th1=Us×sin(theta);

[0124] Ud7th1=Us×cos(theta), Uq7th1=Us×sin(theta);

[0125] Then, the nth-order target voltages Usdn1 and Usqn1 are inversely transformed and injected into the motor vector control: voltages Ud5th1, Uq5th1, Ud7th1, Uq7th1. After undergoing an nth-order inverse PARK transformation, the voltages in the stationary coordinate system (voltages Uα5th, Uβ5th, Uα7th, Uβ7th) are obtained and injected into the original FOC closed-loop control system.

[0126] By controlling the amplitude and / or voltage of the harmonic current in the multiple synchronous rotating coordinate system to control the magnetic field consumption capacity, the first and second capacitors are actively discharged. Furthermore, by controlling the frequency of the harmonic current in the multiple synchronous rotating coordinate system to control the rotation frequency of the rotating magnetic field, the motor achieves the effect of no torque, thus avoiding noise problems such as vibration and gear grinding.

[0127] Furthermore, the high-order harmonic current and / or voltage injection of this application, and the target value of multiple harmonics according to the amplitude and frequency of music or according to the high-frequency sine wave, this control method will not cause problems such as motor tooth grinding or abnormal noise even if the zero position is inaccurate, because the high-speed rotating harmonic current scanning the rotor magnetic field will not cause the rotor to rotate. If the frequency is too high, the rotor simply cannot react and cannot respond, and the harmonic torque will become smaller.

[0128] In summary, the novel active discharge method and circuit topology based on a switching module proposed in this application make the active discharge action more efficient and safer. It solves the problem in existing active discharge technologies where the motor control circuit is limited by the operating state of the external load, requiring discharge only through an external discharge resistor or an external motor. Furthermore, the discharge strategy provided in this application can select at least one controller module with no faults and a temperature within a safe range for active discharge based on the temperature and fault status of the motor windings and power module, thus achieving a novel active discharge method for the internal capacitors of the motor control circuit and ensuring vehicle safety. Whether for single-motor or multi-motor direct charging and electric drive boost charging, the entire discharge process is simple to control and can adjust the current flow in a timely manner based on the bus voltage and charging port voltage. This prevents voltage surges caused by simultaneous discharge of the bus and charging port, protecting components, and avoiding minor noises such as torque fluctuations and gear grinding.

[0129] This application also provides a controller, which includes a processor connected to a memory for storing a computer program and executing the computer program to implement the above-described leakage method.

[0130] This application also provides a discharge system, which includes the above-described active discharge circuit and the above-described controller. The controller is used to output a motor control signal to the motor control circuit so that the motor generates electromagnetic vibration to consume the energy of the first capacitor and / or the second capacitor.

[0131] This application also provides a vehicle including an active discharge circuit. In the above embodiments, the descriptions of each embodiment have different focuses; for parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0132] The embodiments, implementation methods, and related technical features of this application can be combined and substituted for each other without conflict.

[0133] The above are merely preferred embodiments of this application and are not intended to limit this application in any way. Although the descriptions of each embodiment in this application have different focuses, and the parts not described in detail in a certain embodiment can be referred to the relevant descriptions of other embodiments, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of this application without departing from the content of the technical solution of this application shall still fall within the scope of the technical solution of this application.

Claims

1. An active discharge circuit, characterized in that, include: A first transmission bus and a second transmission bus, wherein the first transmission bus is used to connect to the first terminal of the battery pack and the second transmission bus is used to connect to the second terminal of the battery pack; A first capacitor is connected to the first transmission bus and the second transmission bus; The motor control circuit is connected to the first transmission bus and the second transmission bus; An electric motor, connected to the motor control circuit; The second capacitor has a first terminal electrically connected to the first transmission bus and / or the motor, and a second terminal connected to the second transmission bus. The motor control circuit controls the motor to discharge the first capacitor and / or the second capacitor by means of a motor control signal with an injection frequency.

2. The active discharge circuit according to claim 1, characterized in that, The active discharge circuit includes a first switch module connected to the battery. The first switch module includes a first switch and a second switch. The first switch is connected between the second terminal of the battery pack and the second terminal of the first capacitor. The second switch is connected between the first terminal of the battery pack and the first terminal of the first capacitor.

3. The active discharge circuit according to claim 2, characterized in that, The first terminal of the second capacitor is electrically connected to the first transmission bus, and the motor is electrically connected to the first terminal of the first capacitor through a motor switch.

4. The active discharge circuit according to claim 3, characterized in that, The motor control circuit includes multiple bridge arms, with both ends of each bridge arm connected to the first transmission bus and the second transmission bus. The midpoint of each bridge arm is connected to the motor. The motor includes a stator winding, which includes multi-phase coils. The first end of each phase coil is connected to the midpoint of one bridge arm.

5. The active discharge circuit according to claim 4, characterized in that, The second end of each phase coil in the multiphase coil is connected to the neutral line, and the neutral line is used to electrically connect to the first end of the second capacitor; Alternatively, the multiphase coil may include a first coil and at least one second coil, wherein the first coil is used to electrically connect to a first terminal of the second capacitor, such that the first coil is connected in series with the at least one second coil.

6. The active discharge circuit according to claim 4, characterized in that, The motor further includes a rotor coil, and the motor control circuit further includes an excitation control module. The excitation control module is connected to the first transmission bus, the second transmission bus, and the rotor coil. The excitation control module is used to control the excitation parameters of the rotor of the electrically excited synchronous motor.

7. The active discharge circuit according to claim 6, characterized in that, The active discharge circuit also includes a third switch, the first end of which is connected to the second end of the second capacitor, and the second end of which is connected to the charging and discharging interface.

8. The active discharge circuit according to claim 7, characterized in that, Each bridge arm includes an upper bridge arm and a lower bridge arm. During the active discharge process, the upper and lower bridge arms of at least one bridge arm of the motor control circuit are alternately turned on so that the bus voltage across the first capacitor and the interface voltage across the second capacitor are charged and discharged back and forth through the bridge arm and the motor winding, thereby discharging the energy consumed by the bridge arm and the motor winding.

9. The active discharge circuit according to claim 8, characterized in that, The motor control circuit is used to control the duty cycle of the upper and / or lower arm of at least one bridge arm to control the active discharge process according to the pulse width modulation signal.

10. The active discharge circuit according to claim 9, characterized in that, The active discharge circuit is equipped with multiple motors, which are configured to discharge using motors that are capable of normal operation and whose temperature is within a safe range.

11. The active discharge circuit according to claim 10, characterized in that, The plurality of motors includes a first motor and a second motor. The second motor is connected to a second motor control circuit, and the first motor is connected to a first motor control circuit. The first motor is an electrically excited synchronous motor, and the second motor is a first AC motor. The priority of using the first motor for discharge is higher than the priority of using the second motor for discharge.

12. The active discharge circuit according to claim 11, characterized in that, The second motor is an asynchronous motor, and the plurality of motors also includes a third motor, which is a synchronous motor. The third motor is connected to a third motor control circuit, and the priority of using the second motor for discharge is higher than the priority of using the third motor for discharge.

13. A method for releasing water, characterized in that, The discharge method is applied to the active discharge circuit as described in any one of claims 1 to 12, and the discharge method includes: Obtain the frequency signal; The motor control signal is output according to the frequency signal so that the motor generates electromagnetic vibration to consume the energy of the first capacitor and / or the second capacitor.

14. The method according to claim 13, characterized in that, The step of outputting the motor control signal according to the frequency signal includes: Amplitude mapping is performed on the frequency signal to obtain the current and / or voltage in the corresponding amplitude dimensions; Based on the current and / or voltage in the amplitude dimension, the current and / or voltage control signal in the nth-order synchronous rotating coordinate system is obtained; The current and / or voltage control signals on the nth-order synchronous rotating coordinate system are injected into the harmonic vector control system of the motor, so as to output the motor control signal using the vector control system. The vector control system is a vector control system based on the rotor magnetic field orientation established by the motor.

15. The venting method according to claim 14, characterized in that, The process of obtaining the current and / or voltage control signal in the nth-order synchronous rotating coordinate system based on the current and / or voltage in the amplitude dimension includes: The motor phase currents are subjected to nth-order synchronous coordinate transformations to extract the nth-order synchronous coordinate feedback harmonic current values. The target harmonic current value is obtained based on the current in the amplitude dimension; The feedback harmonic current value and the target harmonic current value are proportionally and integrally adjusted to obtain a voltage control signal in a synchronous rotating coordinate system of order n.

16. The venting method according to any one of claims 13-15, characterized in that, The motor control signal is used to control the duty cycle of the switch in the motor control circuit.

17. A controller, characterized in that, The method includes a processor connected to a memory for storing a computer program, and the processor for executing the computer program to implement the method according to any one of claims 13 to 16.

18. A discharge system, characterized in that, The device includes the active discharge circuit according to any one of claims 1-12 and the controller according to claim 17, wherein the controller is used to output the motor control signal to the motor control circuit so that the motor generates electromagnetic vibration to consume the energy of the first capacitor and / or the second capacitor.

19. A vehicle, characterized in that, It includes the active discharge circuit as described in any one of claims 1 to 12, or the controller as described in claim 17, or the discharge system as described in claim 18.

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