Active discharge control method and device for bus capacitor, motor controller and vehicle

Abstract

This invention provides a method, device, motor controller, and vehicle for active discharge control of a bus capacitor. By obtaining discharge control information and combining it with IGBT switching circuit control, a constant discharge current is formed. This constant discharge current can generate electromagnetic torque in the zero-degree angle direction of the controlled motor rotor, which can lock the rotor of the controlled motor at the zero-degree angle position, avoiding the safety risks caused by motor rotation during the active discharge of the bus capacitor, making the discharge process safer and more reliable. At the same time, by using discharge control information in conjunction with the IGBT switching circuit for active discharge control, there is no need for a complex vector transformation process, making the discharge control process more convenient and efficient.

Description

Technical Field

[0001] This invention relates to the field of vehicle drive control technology, and in particular to an active discharge control method, device, motor controller, and vehicle for a bus capacitor. Background Technology

[0002] With the development of vehicle electrification, high-voltage safety has become a major concern. When the vehicle's high voltage is de-energized, the motor controller's bus capacitor still carries high voltage, posing a risk of electric shock if accidentally touched. Therefore, the motor controller should have the ability to discharge the bus capacitor after the vehicle is powered off. Industry standards require that the motor controller's active discharge time not exceed 3 seconds, or even less than 2 seconds. Thus, active and rapid discharge technology is needed to meet safety discharge requirements.

[0003] Existing active discharge methods for bus capacitors typically employ discharge resistors, switching loss discharge, weak magnetic current discharge, and redundant discharge of auxiliary drive components. These active discharge methods all suffer from slow discharge speed and low discharge reliability.

[0004] Therefore, there is an urgent need for a faster and more reliable method for active discharge control of bus capacitors to solve the above problems. Summary of the Invention

[0005] This invention provides an active discharge control method, device, motor controller, and vehicle for bus capacitors, which solves the defects of slow discharge speed and low discharge reliability in the existing active discharge methods, and realizes fast and reliable active discharge of bus capacitors.

[0006] In a first aspect, the present invention provides an active discharge control method for a bus capacitor, the method comprising:

[0007] Receive active discharge requests and determine whether the conditions for active discharge are met;

[0008] When it is determined that the conditions for active discharge are met, the on / off states of some IGBT switches in the IGBT switching circuit are set, and discharge control information is obtained; wherein, the IGBT switching circuit is used to connect the controlled motor and the bus capacitor.

[0009] According to the discharge control information, the bus capacitor is controlled by the IGBT switching circuit to output a constant discharge current, and the constant discharge current is introduced into the stator winding of the controlled motor to discharge losses, so as to actively discharge the bus capacitor; wherein, the constant discharge current is used to generate electromagnetic torque in the zero-degree angle direction of the rotor of the controlled motor.

[0010] Determine whether the discharge exit conditions have been met. If the discharge exit conditions are met, exit active discharge.

[0011] According to the present invention, an active discharge control method for a bus capacitor is provided, which acquires discharge control information, including:

[0012] The U-phase current of the controlled motor is obtained; wherein, the U-phase current is input to the U-phase of the controlled motor through the IGBT switch of the U-phase upper bridge in the IGBT switching circuit;

[0013] The difference between the U-phase current and the preset target current is used to obtain the current difference value;

[0014] Based on the current difference, the control duty cycle of the IGBT switch of the U-phase upper bridge is determined;

[0015] Based on the control duty cycle and the preset carrier period, the opening and closing times of the IGBT switches on the U-phase upper bridge are calculated and used as discharge control information.

[0016] According to the present invention, an active discharge control method for a bus capacitor is provided, wherein, based on the discharge control information, the IGBT switching circuit controls the bus capacitor to output a constant discharge current, and the constant discharge current is introduced into the stator winding of the controlled motor for loss discharge, so as to actively discharge the bus capacitor, comprising:

[0017] Based on the discharge control information, the opening and closing time of the IGBT switch of the U-phase upper bridge in the IGBT switching circuit is controlled so that the bus capacitor outputs a constant discharge current.

[0018] The constant discharge current is input from the U-phase of the controlled motor to the stator winding via the IGBT switch of the U-phase upper bridge. The constant discharge current is then discharged through the stator winding to actively discharge the bus capacitor.

[0019] According to the present invention, an active discharge control method for a bus capacitor is provided, which determines whether a discharge exit condition has been met, and exits active discharge when the discharge exit condition is met, comprising:

[0020] Obtain the voltage and discharge duration of the bus capacitor;

[0021] The voltage of the bus capacitor is compared with a preset voltage threshold, and the discharge duration is compared with a preset duration threshold.

[0022] When the voltage of the bus capacitor is less than the voltage threshold and the discharge duration is less than the duration threshold, or when the voltage of the bus capacitor is greater than the voltage threshold and the discharge duration is greater than the duration threshold, the discharge exit condition is determined to be met, and the active discharge is exited.

[0023] According to the active discharge control method for a bus capacitor provided by the present invention, after determining whether the discharge exit condition has been met, and exiting active discharge when the discharge exit condition is met, the method further includes:

[0024] Determine whether the active discharge has failed. If the active discharge has failed, then diagnose the main contactor adhesion fault and the resolver abnormality fault.

[0025] According to the active discharge control method for bus capacitors provided by the present invention, when active discharge is determined to have failed, the method diagnoses main contactor adhesion faults and resolver abnormality faults, including:

[0026] The voltage drop of the bus capacitor, the U-phase current of the controlled motor, the rotor position angle of the controlled motor, and the gearbox gear status of the controlled motor are obtained.

[0027] When the voltage drop is less than a preset voltage drop threshold, the U-phase current of the controlled motor is greater than a preset current upper limit threshold, and the duration of the U-phase current of the controlled motor being greater than the current upper limit threshold is greater than a preset duration upper limit threshold, then the main contactor is determined to be stuck.

[0028] When the difference between the rotor position angle of the controlled motor and the preset absolute value of zero deviation is greater than the preset angle deviation threshold, the U-phase current of the controlled motor is greater than the preset upper limit current threshold, the duration of the U-phase current of the controlled motor being greater than the upper limit current threshold is greater than the preset upper limit duration threshold, and the gearbox of the controlled motor is in neutral, then a resolver malfunction is determined.

[0029] According to the present invention, an active discharge control method for a bus capacitor is provided, which determines whether active discharge conditions are met, including:

[0030] It is determined whether the speed of the controlled motor is lower than a preset speed threshold. When the speed of the controlled motor is lower than the preset speed threshold, it is determined that the conditions for active discharge are met.

[0031] Secondly, the present invention also provides an active discharge control device for a bus capacitor, the device comprising:

[0032] The first processing module is used to receive active discharge requests and determine whether the conditions for active discharge are met.

[0033] The second processing module is used to set the opening and closing states of some IGBT switches in the IGBT switching circuit and obtain discharge control information when it is determined that the conditions for active discharge are met; wherein, the IGBT switching circuit is used to connect the controlled motor and the bus capacitor.

[0034] The third processing module is used to control the bus capacitor to output a constant discharge current through the IGBT switching circuit according to the discharge control information, and introduce the constant discharge current into the stator winding of the controlled motor for loss discharge, so as to actively discharge the bus capacitor; wherein, the constant discharge current is used to generate electromagnetic torque in the rotor zero-degree angle direction of the controlled motor.

[0035] The fourth processing module is used to determine whether the discharge exit condition has been met. When the discharge exit condition is met, the active discharge is terminated.

[0036] Thirdly, the present invention also provides a motor controller, wherein the motor controller uses any of the above-described active discharge control methods for the bus capacitor.

[0037] Fourthly, the present invention also provides a vehicle that includes the aforementioned motor controller.

[0038] Fifthly, the present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of the active discharge control method for the bus capacitor as described above.

[0039] In a sixth aspect, the present invention also provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the active discharge control method for the bus capacitor as described above.

[0040] In a seventh aspect, the present invention also provides a computer program product, including a computer program that, when executed by a processor, implements the steps of the active discharge control method for the bus capacitor as described above.

[0041] The present invention provides a method, device, motor controller, and vehicle for active discharge control of a bus capacitor. By obtaining discharge control information and combining it with IGBT switching circuit control, a constant discharge current is formed. This constant discharge current can generate electromagnetic torque in the zero-degree angle direction of the rotor of the controlled motor, which can lock the rotor of the controlled motor at the zero-degree angle position. This avoids the safety risks caused by motor rotation during the active discharge of the bus capacitor, making the discharge process safer and more reliable. At the same time, by using discharge control information in conjunction with the IGBT switching circuit for active discharge control, no complex vector transformation process is required, making the discharge control process more convenient and efficient. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0043] Figure 1 This is one of the flowcharts illustrating the active discharge control method for bus capacitors provided by the present invention;

[0044] Figure 2 This is the second flowchart of the active discharge control method for bus capacitors provided by the present invention;

[0045] Figure 3 This is a schematic diagram showing the connection relationship between the IGBT switching circuit, the motor under control, the bus capacitor, and the power supply.

[0046] Figure 4 This is a schematic diagram illustrating the principle of obtaining discharge control information;

[0047] Figure 5 This is a schematic diagram showing the signal transmission relationship between the vehicle controller, the multi-function controller, the transmission controller, the motor to be controlled, and the bus capacitor.

[0048] Figure 6 This is a schematic diagram of the active discharge control device for the bus capacitor provided by the present invention.

[0049] Figure 7 This is a schematic diagram of the structure of the electronic device provided by the present invention. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0051] Figure 1 and Figure 2 An embodiment of the present invention illustrates an active discharge control method for a bus capacitor, the method comprising:

[0052] Step 110: Receive an active discharge request and determine whether the conditions for active discharge are met.

[0053] In this embodiment, the main criterion for determining whether the conditions for active discharge are met is the rotational speed of the controlled motor. Specifically, it is determined whether the rotational speed of the controlled motor is lower than a preset speed threshold. When the rotational speed of the controlled motor is lower than the preset speed threshold, it is determined that the conditions for active discharge are met.

[0054] In practical applications, the preset speed threshold can be set to 10 rpm. When the speed of the controlled motor is below 10 rpm, it can be considered that the conditions for active discharge are met. Of course, in the actual discharge control process, before entering the active discharge state, it is also necessary to execute the following... Figure 2 The preparatory steps shown are as follows:

[0055] Step 201: The vehicle controller sends a high-voltage power-down command;

[0056] Step 202: The multi-function controller disconnects the main contactor and sends the main contactor status to the vehicle controller;

[0057] Step 203: The vehicle controller sends an active discharge request. After determining that the active discharge request is valid, it enters the active discharge condition determination stage, specifically determining whether the motor speed is lower than 10 rpm. If it is not lower than 10 rpm, it returns to step 202; if it is lower than 10 rpm, it enters the active discharge stage.

[0058] In other words, before actively discharging, it is necessary to confirm that the vehicle has been energized and that the main contactor has been disconnected. At the same time, it is also necessary to check whether the active discharge request issued by the vehicle controller is valid in order to ensure the safety of discharge control.

[0059] Step 120: When it is determined that the conditions for active discharge are met, the on / off state of some IGBT switches in the IGBT switching circuit is set, and discharge control information is obtained; wherein, the IGBT switching circuit is used to connect the controlled motor and the bus capacitor.

[0060] Figure 3 The diagram illustrates the connection relationships between the IGBT switching circuit, the controlled motor, the bus capacitor, and the power supply. The IGBT switching circuit includes an IGBT switch V1 (U-phase upper bridge), an IGBT switch V2 (U-phase lower bridge), an IGBT switch V3 (V-phase upper bridge), an IGBT switch V4 (V-phase lower bridge), an IGBT switch V5 (W-phase upper bridge), and an IGBT switch V6 (W-phase lower bridge). One end of the IGBT switching circuit is connected to the bus capacitor C, and the other end is connected to the U-phase, V-phase, and W-phase of the controlled motor, respectively. Figure 2In this diagram, U0 represents the voltage of the bus capacitor C, K1 represents the main positive relay, K2 represents the pre-charge relay, and K3 represents the main negative relay. The main positive relay K1 is connected to the positive terminal of the power supply E through the fuse FU, and the main negative relay K3 is connected to the negative terminal of the power supply E. The pre-charge relay K2 is connected in series with a capacitor R. Batt This indicates the supply voltage of the power source.

[0061] Combined with appendix Figure 3 The process of setting the on / off states of some IGBT switches in an IGBT switching circuit can specifically include:

[0062] Set the IGBT switch V2 of the U-phase lower bridge in the IGBT switching circuit to the off state.

[0063] Set both the IGBT switch V4 of the V-phase lower bridge and the IGBT switch V6 of the W-phase lower bridge in the IGBT switching circuit to the closed state.

[0064] Set both IGBT switch V3 on the V-phase upper bridge and IGBT switch V5 on the W-phase upper bridge in the IGBT switching circuit to the off state.

[0065] In this way, the discharge current flows from the positive terminal of the bus capacitor C through the IGBT switch V1 on the upper bridge of phase U, enters the stator winding of the motor from the U phase of the motor under control, and is output through the V-phase and W-phase windings respectively. It then returns to the negative terminal of the bus capacitor C through the IGBT switches V4 on the lower bridge of phase V and V6 on the lower bridge of phase W, forming a closed loop. Specifically, this is achieved through... Figure 2 The direction indicated by the middle arrow clearly shows the flow of the discharge current. As the discharge current flows through the stator windings of the motor, it achieves active discharge through heat loss.

[0066] See attached Figure 4 The process of acquiring discharge control information may specifically include:

[0067] First, obtain the U-phase current I of the controlled motor. u Among them, the U-phase current is input to control the U-phase of the motor through the IGBT switch of the U-phase upper bridge in the IGBT switching circuit;

[0068] Then, the U-phase current I u With the preset target current I ref By subtracting the values, we obtain the current difference.

[0069] Then, based on the current difference, the control duty cycle D of the IGBT switch on the U-phase upper bridge is determined. This process can be implemented within the PI controller.

[0070] Finally, based on the obtained control duty cycle D and the preset carrier period T, the control duty cycle D is multiplied by the carrier period T to calculate the on / off time t of the IGBT switch on the U-phase upper bridge. k This serves as discharge control information.

[0071] In this embodiment, the duty cycle control of the U-phase upper bridge adopts PI closed-loop control. The difference between the target current and the U-phase current is used as the input of the PI controller, and the output is the duty cycle of the U-phase upper bridge control. The switching time is calculated through the carrier period to realize switching control, and then realize current closed-loop control.

[0072] The discharge current can be directly controlled by the discharge control information. This method of controlling the discharge current by controlling the duty cycle of the U-phase upper bridge does not require complex vector transformation, and the control process is simple and reliable.

[0073] Step 130: According to the discharge control information, the bus capacitor is controlled to output a constant discharge current through the IGBT switching circuit, and the constant discharge current is introduced into the stator winding of the controlled motor to discharge losses, so as to actively discharge the bus capacitor; wherein, the constant discharge current is used to generate electromagnetic torque in the zero-degree direction of the rotor of the controlled motor.

[0074] In an exemplary embodiment, based on discharge control information, the IGBT switching circuit controls the bus capacitor to output a constant discharge current, and introduces this constant discharge current into the stator windings of the controlled motor for loss discharge, thereby actively discharging the bus capacitor. Specifically, this process may include:

[0075] First, based on the discharge control information, the on / off time of the IGBT switch on the U-phase upper bridge in the IGBT switching circuit is controlled to ensure that the bus capacitor outputs a constant discharge current. In this way, the magnitude of the constant discharge current can be adjusted by the on and off time of the IGBT switch on the U-phase upper bridge.

[0076] Then, the constant discharge current is input from the U phase of the controlled motor to the stator winding through the IGBT switch of the U phase upper bridge. The constant discharge current is discharged through the stator winding to actively discharge the bus capacitor.

[0077] In this embodiment, the IGBT switch of the U-phase lower bridge is pre-set to be normally off, the IGBT switches of the V and W phase upper bridges are normally off, and the IGBT switches of the V and W lower bridges are normally closed. In this way, by controlling the opening and closing time of the IGBT switch of the U-phase upper bridge through the discharge control information, the generated constant discharge current can be transferred from the positive terminal of the bus capacitor through the IGBT switch of the U-phase upper bridge, enter the motor stator winding from the U phase, be output through the V and W phase windings, and return to the negative terminal of the bus capacitor through the IGBT switches of the V and W lower bridges, forming a closed loop. This allows the constant discharge current to be dissipated as heat energy during its flow through the motor windings, thus achieving active discharge.

[0078] It is easy to see that in this embodiment, because a constant discharge current is given to the controlled motor during active discharge, the current will generate directional electromagnetic torque, locking the motor rotor in a set position. Even if the resolver is not calibrated or a resolver failure occurs, active discharge can still be achieved, and there will be no risk of the motor continuing to rotate.

[0079] Step 140: Determine whether the discharge exit condition has been met. If the discharge exit condition has been met, exit active discharge.

[0080] See appendix Figure 2 The process involves determining whether the discharge exit conditions have been met. If the discharge exit conditions are met, the active discharge process is terminated. This can specifically include:

[0081] First, obtain the voltage of the bus capacitor (i.e., the bus voltage) and the discharge duration; this step corresponds to step 204, where the multi-in-one controller performs active discharge control and records the discharge current and discharge duration.

[0082] Next, the discharge duration is compared with a preset duration threshold; this step corresponds to step 205, determining whether the discharge duration is less than the duration threshold, which can be set to 2 seconds, i.e., determining whether the discharge duration is less than 2 seconds. Then, the bus capacitor voltage is compared with a preset voltage threshold, this step corresponds to step 206, determining whether the bus voltage is less than the voltage threshold, which can be set to 60Vdc, i.e., determining whether the bus voltage is lower than 60Vdc.

[0083] Finally, when the voltage of the bus capacitor is less than the voltage threshold and the discharge duration is less than the duration threshold, that is, when the active discharge time is less than 2 seconds and the bus voltage is less than 60Vdc, corresponding to step 207, the active discharge is completed and the discharge stops.

[0084] Alternatively, when the bus capacitor voltage is greater than the voltage threshold and the discharge duration is greater than the duration threshold, i.e., the active discharge time exceeds 2 seconds and the bus voltage exceeds 60Vdc, corresponding to step 208, the active discharge fails and the active discharge stops. Therefore, in both of these states, it can be determined that the discharge exit condition has been met and the active discharge is exited.

[0085] According to the active discharge control method for a bus capacitor provided by the present invention, after determining whether the discharge exit condition has been met, and exiting active discharge when the discharge exit condition is met, the method further includes:

[0086] Determine whether the active discharge has failed. If the active discharge has failed, then diagnose the main contactor adhesion fault and the resolver abnormality fault.

[0087] It should be noted that when the bus capacitor voltage is greater than the voltage threshold and the discharge duration is greater than the duration threshold, the active discharge can be considered a failure. After the active discharge fails, further diagnosis of resolver faults and contactor sticking faults can be performed.

[0088] Specifically, when active discharge fails, the diagnosis of main contactor adhesion fault and resolver abnormality fault can include:

[0089] First, obtain the voltage drop of the bus capacitor, the U-phase current of the controlled motor, the rotor position angle of the controlled motor, and the gearbox gear status of the controlled motor.

[0090] Then, when the voltage drop is less than the preset voltage drop threshold, the U-phase current of the controlled motor is greater than the preset upper current threshold, and the duration of the U-phase current of the controlled motor being greater than the upper current threshold is greater than the preset duration upper threshold, the main contactor is determined to be stuck.

[0091] Finally, when the difference between the rotor position angle of the controlled motor and the preset absolute value of zero deviation is greater than the preset angle deviation threshold, the U-phase current of the controlled motor is greater than the preset upper limit current threshold, the duration of the U-phase current of the controlled motor being greater than the upper limit current threshold is greater than the preset upper limit duration threshold, and the gearbox of the controlled motor is in neutral, then the resolver is determined to be faulty.

[0092] See appendix Figure 5 The acquisition of discharge control information and the diagnosis of faults can be realized in the all-in-one controller. Specifically, the U-phase current I of the motor under test can be obtained. u The signals from the rotary converter are all input to the multi-function controller. At the same time, the gear position status information of the gearbox connected to the electrode under test is also transmitted to the multi-function controller through the gearbox controller. The multi-function controller also communicates with the vehicle controller to receive the high-voltage power-down command and active discharge command issued by the vehicle controller, and controls the active discharge process of the bus capacitor according to the active discharge command.

[0093] It is understood that this all-in-one controller can be understood as an integration of a motor controller and a PDU (Power Distribution Unit) controller. In this embodiment, it can realize power supply control and active discharge control of the bus capacitor.

[0094] In an exemplary embodiment, after exiting active discharge, if it is determined that the active discharge failed, and it is further determined that the voltage drop ΔU of the bus capacitor during the discharge process is less than 20Vdc, i.e., step 209, the U-phase current I... uIf the current draw is greater than 30A and the duration is greater than 0.5 seconds, and the voltage and current sensors are functioning correctly (step 210), then proceed to step 211, where a main contactor adhesion fault can be determined. If the above conditions are not met during this process, the active discharge is considered complete, and the discharge stops.

[0095] After exiting active discharge, if active discharge is determined to have failed, and it is further determined that the absolute value of the deviation between the acquired motor rotor position angle and zero exceeds 5 degrees (i.e., step 212), the U-phase current I during the discharge process... u If the voltage and current are greater than 30A and the duration is greater than 0.5 seconds (step 214), the gearbox is in neutral. At this time, the voltage and current sensors are fault-free (step 215), and the process proceeds to step 216 to determine if the resolver is faulty. During this process, if the absolute value of the deviation of the motor rotor position angle from zero is less than 5 degrees, the process proceeds to step 213 to determine if the resolver is normal.

[0096] This embodiment utilizes the active discharge process to diagnose main contactor adhesion faults and resolver abnormality faults, eliminating the need for additional complex diagnostic circuits. While maintaining a simple structure, it also enhances functionality.

[0097] The active discharge control device for bus capacitors provided by the present invention will be described below. The active discharge control device for bus capacitors described below can be referred to in correspondence with the active discharge control method for bus capacitors described above.

[0098] Figure 6 An active discharge control device for a bus capacitor provided in an embodiment of the present invention is shown. The device includes:

[0099] The first processing module 610 is used to receive an active discharge request and determine whether the conditions for active discharge are met.

[0100] The second processing module 620 is used to set the opening and closing states of some IGBT switches in the IGBT switching circuit and obtain discharge control information when it is determined that the conditions for active discharge are met; wherein, the IGBT switching circuit is used to connect the controlled motor and the bus capacitor.

[0101] The third processing module 630 is used to control the bus capacitor to output a constant discharge current through the IGBT switching circuit according to the discharge control information, and introduce the constant discharge current into the stator winding of the controlled motor to discharge losses, so as to actively discharge the bus capacitor; wherein, the constant discharge current is used to generate electromagnetic torque in the rotor zero-degree angle direction of the controlled motor.

[0102] The fourth processing module 640 is used to determine whether the discharge exit condition has been met. When the discharge exit condition is met, the active discharge is exited.

[0103] In an exemplary embodiment, the first processing module 610 is specifically used to: determine whether the speed of the controlled motor is lower than a preset speed threshold, and when the speed of the controlled motor is lower than the preset speed threshold, determine that the conditions for active discharge are met.

[0104] In an exemplary embodiment, the second processing module 620 may specifically be used to: set the IGBT switch of the U-phase lower bridge in the IGBT switching circuit to the off state; set the IGBT switches of both the V-phase lower bridge and the W-phase lower bridge in the IGBT switching circuit to the closed state; and set the IGBT switches of both the V-phase upper bridge and the W-phase upper bridge in the IGBT switching circuit to the off state.

[0105] In an exemplary embodiment, the second processing module 620 may specifically be used to: acquire the U-phase current of the controlled motor; wherein the U-phase current is input to control the U-phase of the motor via the IGBT switch of the U-phase upper bridge in the IGBT switching circuit; subtract the U-phase current from the preset target current to obtain the current difference value; calculate the control duty cycle of the IGBT switch of the U-phase upper bridge based on the current difference value; and calculate the opening and closing time of the IGBT switch of the U-phase upper bridge based on the control duty cycle and the preset carrier period, as discharge control information.

[0106] In an exemplary embodiment, the third processing module 630 may specifically be used to: control the opening and closing time of the IGBT switch on the U-phase upper bridge in the IGBT switching circuit according to the discharge control information, so that the bus capacitor outputs a constant discharge current; input the constant discharge current from the U-phase of the controlled motor into the stator winding through the IGBT switch on the U-phase upper bridge, and perform loss discharge on the constant discharge current through the stator winding.

[0107] In an exemplary embodiment, the fourth processing module 640 may specifically be used to: obtain the voltage and discharge duration of the bus capacitor; compare the voltage of the bus capacitor with a preset voltage threshold and compare the discharge duration with a preset duration threshold; when the voltage of the bus capacitor is less than the voltage threshold and the discharge duration is less than the duration threshold, or when the voltage of the bus capacitor is greater than the voltage threshold and the discharge duration is greater than the duration threshold, determine that the discharge exit condition has been met and exit active discharge.

[0108] More preferably, the above-mentioned active discharge control device for the bus capacitor may further include:

[0109] The fault diagnosis module is used to determine whether active discharge has failed. When active discharge is determined to have failed, it diagnoses the main contactor adhesion fault and the resolver abnormality fault.

[0110] In an exemplary embodiment, the fault diagnosis module described above can be specifically used to: acquire the voltage drop of the bus capacitor, the U-phase current of the controlled motor, the rotor position angle of the controlled motor, and the gearbox gear position status of the controlled motor; when the voltage drop is less than a preset voltage drop threshold, the U-phase current of the controlled motor is greater than a preset upper current threshold, and the duration of the U-phase current of the controlled motor being greater than the upper current threshold is greater than a preset duration upper threshold, then a main contactor adhesion fault is determined; when the difference between the rotor position angle of the controlled motor and a preset zero deviation absolute value is greater than a preset angle deviation threshold, the U-phase current of the controlled motor is greater than a preset upper current threshold, the duration of the U-phase current of the controlled motor being greater than the upper current threshold is greater than a preset duration upper threshold, and the gearbox gear position of the controlled motor is in neutral, then a resolver abnormality fault is determined.

[0111] In addition, this embodiment of the invention also provides a motor controller that uses any of the above-mentioned active discharge control methods for bus capacitors to achieve reliable control of active discharge of bus capacitors.

[0112] Furthermore, this embodiment of the invention also provides a vehicle equipped with the aforementioned motor controller, which can ensure the rapid and reliable realization of the active discharge process of the bus capacitor.

[0113] Figure 7 An example is a schematic diagram of the physical structure of an electronic device, such as... Figure 7 As shown, the electronic device may include a processor 710, a communication interface 720, a memory 730, and a communication bus 740. The processor 710, communication interface 720, and memory 730 communicate with each other via the communication bus 740. The processor 710 can call logic instructions in the memory 730 to execute an active discharge control method for the bus capacitor. This method includes: receiving an active discharge request and determining whether active discharge conditions are met; when active discharge conditions are met, setting the on / off states of some IGBT switches in the IGBT switching circuit and acquiring discharge control information; wherein the IGBT switching circuit is used to connect the controlled motor and the bus capacitor; according to the discharge control information, controlling the bus capacitor to output a constant discharge current through the IGBT switching circuit, and introducing the constant discharge current into the stator winding of the controlled motor for loss discharge, thereby actively discharging the bus capacitor; wherein the constant discharge current is used to generate electromagnetic torque in the zero-degree angle direction of the rotor of the controlled motor; determining whether the discharge exit condition is met, and exiting active discharge when the discharge exit condition is met.

[0114] Furthermore, the logical instructions in the aforementioned memory 730 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, essentially, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0115] On the other hand, the present invention also provides a computer program product, the computer program product including a computer program stored on a non-transitory computer-readable storage medium, the computer program including program instructions, when the program instructions are executed by the computer, the computer can execute the active discharge control method for the bus capacitor provided by the above methods, the method including: receiving an active discharge request and determining whether active discharge conditions are met; when it is determined that active discharge conditions are met, setting the on / off state of some IGBT switches in the IGBT switching circuit and acquiring discharge control information; wherein, the IGBT switching circuit is used to connect the controlled motor and the bus capacitor; according to the discharge control information, controlling the bus capacitor to output a constant discharge current through the IGBT switching circuit, and introducing the constant discharge current into the stator winding of the controlled motor for loss discharge, so as to actively discharge the bus capacitor; wherein, the constant discharge current is used to generate electromagnetic torque in the rotor zero-degree angle direction of the controlled motor; determining whether the discharge exit condition is met, and exiting active discharge when the discharge exit condition is met.

[0116] In another aspect, the present invention also provides a non-transitory computer-readable storage medium storing a computer program thereon. When executed by a processor, the computer program implements the active discharge control method for the bus capacitors provided above. The method includes: receiving an active discharge request and determining whether active discharge conditions are met; when active discharge conditions are met, setting the on / off state of some IGBT switches in the IGBT switching circuit and acquiring discharge control information; wherein the IGBT switching circuit is used to connect the controlled motor and the bus capacitor; according to the discharge control information, controlling the bus capacitor to output a constant discharge current through the IGBT switching circuit, and introducing the constant discharge current into the stator winding of the controlled motor for loss discharge, so as to actively discharge the bus capacitor; wherein the constant discharge current is used to generate electromagnetic torque in the rotor zero-degree angle direction of the controlled motor; determining whether the discharge exit condition is met, and exiting active discharge when the discharge exit condition is met.

[0117] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, i.e., they may be located in one location or distributed across multiple network units. Some or all of the modules may be selected based on actual needs to achieve the objectives of the present embodiment. Persons of ordinary skill in the art will be able to understand and implement the present invention without inventive effort.

[0118] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0119] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention 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; and these 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 the present invention.

Claims

1. A method for actively discharging a bus capacitor, characterized in that, include: Receive active discharge requests and determine whether the conditions for active discharge are met; When it is determined that the conditions for active discharge are met, the on / off states of some IGBT switches in the IGBT switching circuit are set, and discharge control information is obtained; wherein, the IGBT switching circuit is used to connect the controlled motor and the bus capacitor. According to the discharge control information, the bus capacitor is controlled by the IGBT switching circuit to output a constant discharge current, and the constant discharge current is introduced into the stator winding of the controlled motor to discharge losses, so as to actively discharge the bus capacitor; wherein, the constant discharge current is used to generate electromagnetic torque in the zero-degree angle direction of the rotor of the controlled motor. Determine whether the discharge exit conditions have been met. If the discharge exit conditions are met, exit the active discharge process, including: Obtain the voltage and discharge duration of the bus capacitor; The voltage of the bus capacitor is compared with a preset voltage threshold, and the discharge duration is compared with a preset duration threshold. When the voltage of the bus capacitor is less than the voltage threshold and the discharge duration is less than the duration threshold, or when the voltage of the bus capacitor is greater than the voltage threshold and the discharge duration is greater than the duration threshold, the discharge exit condition is determined to be met, and the active discharge is exited.

2. The active discharge control method for a bus capacitor according to claim 1, characterized in that, Obtain discharge control information, including: The U-phase current of the controlled motor is obtained; wherein the U-phase current is input to the U-phase of the controlled motor through the IGBT switch of the U-phase upper bridge in the IGBT switching circuit; The difference between the U-phase current and the preset target current is used to obtain the current difference value; Based on the current difference, the control duty cycle of the IGBT switch of the U-phase upper bridge is determined; Based on the control duty cycle and the preset carrier period, the opening and closing times of the IGBT switches on the U-phase upper bridge are calculated and used as discharge control information.

3. The active discharge control method for a bus capacitor according to claim 2, characterized in that, According to the discharge control information, the IGBT switching circuit controls the bus capacitor to output a constant discharge current, and the constant discharge current is introduced into the stator winding of the controlled motor for loss discharge, so as to actively discharge the bus capacitor, including: Based on the discharge control information, the opening and closing time of the IGBT switch of the U-phase upper bridge in the IGBT switching circuit is controlled so that the bus capacitor outputs a constant discharge current. The constant discharge current is input from the U-phase of the controlled motor to the stator winding via the IGBT switch of the U-phase upper bridge. The constant discharge current is then discharged through the stator winding to actively discharge the bus capacitor.

4. The active discharge control method for a bus capacitor according to claim 1, characterized in that, After determining whether the discharge exit conditions have been met, and upon meeting these conditions, the process of exiting active discharge includes: Determine whether the active discharge has failed. If the active discharge has failed, then diagnose the main contactor adhesion fault and the resolver abnormality fault.

5. The active discharge control method for a bus capacitor according to claim 4, characterized in that, When active discharge fails, the main contactor adhesion fault and resolver abnormality fault are diagnosed, including: The voltage drop of the bus capacitor, the U-phase current of the controlled motor, the rotor position angle of the controlled motor, and the gearbox gear status of the controlled motor are obtained. When the voltage drop is less than a preset voltage drop threshold, the U-phase current of the controlled motor is greater than a preset current upper limit threshold, and the duration of the U-phase current of the controlled motor being greater than the current upper limit threshold is greater than a preset duration upper limit threshold, then the main contactor is determined to be stuck. When the difference between the rotor position angle of the controlled motor and the preset absolute value of zero deviation is greater than the preset angle deviation threshold, the U-phase current of the controlled motor is greater than the preset upper limit current threshold, the duration of the U-phase current of the controlled motor being greater than the upper limit current threshold is greater than the preset upper limit duration threshold, and the gearbox of the controlled motor is in neutral, then a resolver malfunction is determined.

6. The active discharge control method for a bus capacitor according to claim 1, characterized in that, Determining whether conditions for active discharge are met includes: It is determined whether the speed of the controlled motor is lower than a preset speed threshold. When the speed of the controlled motor is lower than the preset speed threshold, it is determined that the conditions for active discharge are met.

7. An active discharge control device for a bus capacitor, characterized in that, include: The first processing module is used to receive active discharge requests and determine whether the conditions for active discharge are met. The second processing module is used to set the opening and closing states of some IGBT switches in the IGBT switching circuit and obtain discharge control information when it is determined that the conditions for active discharge are met; wherein, the IGBT switching circuit is used to connect the controlled motor and the bus capacitor. The third processing module is used to control the bus capacitor to output a constant discharge current through the IGBT switching circuit according to the discharge control information, and introduce the constant discharge current into the stator winding of the controlled motor for loss discharge, so as to actively discharge the bus capacitor; wherein, the constant discharge current is used to generate electromagnetic torque in the rotor zero-degree angle direction of the controlled motor. The fourth processing module is used to determine whether the discharge exit condition has been met. When the discharge exit condition is met, the active discharge is terminated. This includes: Obtain the voltage and discharge duration of the bus capacitor; The voltage of the bus capacitor is compared with a preset voltage threshold, and the discharge duration is compared with a preset duration threshold. When the voltage of the bus capacitor is less than the voltage threshold and the discharge duration is less than the duration threshold, or when the voltage of the bus capacitor is greater than the voltage threshold and the discharge duration is greater than the duration threshold, the discharge exit condition is determined to be met, and the active discharge is exited.

8. A motor controller, characterized in that, The motor controller uses an active discharge control method for bus capacitors as described in any one of claims 1 to 6.

9. A vehicle, characterized in that, Including a motor controller as described in claim 8.

10. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the steps of the active discharge control method for the bus capacitor as described in any one of claims 1 to 6.

11. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the active discharge control method for the bus capacitor as described in any one of claims 1 to 6.

12. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the active discharge control method for the bus capacitor as described in any one of claims 1 to 6.

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