Power assembly, open-circuit fault positioning and fault-tolerant control method and electric vehicle

Abstract

The invention discloses a power assembly, an open-circuit fault positioning and fault-tolerant control method and a vehicle, which are used for positioning a fault point of a motor controller in time, realizing fault-tolerant control and reducing potential safety hazards. The power assembly comprises a motor controller and a driving motor, wherein the motor controller comprises an inverter circuit and a control device. In the process that the control device is used for outputting three-phase current at the bridge arm midpoint of the three-phase bridge arm, the control device is used for responding to the open-circuit fault of any one of the three-phase bridge arms, and the phase current output at the bridge arm midpoint of the any one of the three-phase bridge arms is output before the magnitude of the phase current output at the bridge arm midpoint of the any one of the three-phase bridge arms is reduced to zero. And controlling the upper bridge arm switch tube and the lower bridge arm switch tube of the bridge arm of any phase to be switched off and controlling the control switch corresponding to the bridge arm of any phase to be switched off. And the bridge arm midpoints of the other two phases of bridge arms are controlled to output fault-tolerant current, driving current is generated on a three-phase winding of the motor through the fault-tolerant current, the driving current drives the driving motor to output torque, and the vehicle is continuously driven to run.

Description

Technical Field

[0001] The present application relates to the technical field of electric vehicles, and particularly to a powertrain, an open-circuit fault location and fault-tolerant control method, and an electric vehicle. Background Art

[0002] Currently, electric vehicles represented by pure electric and hybrid vehicles are becoming increasingly popular among consumers, and the interior space and comfort of electric vehicles are also constantly increasing. A power conversion device is usually provided in the motor controller of an electric vehicle. The power conversion device is used to convert the direct current provided by the power battery into alternating current to supply power to the drive motor, and the drive motor drives the wheels to rotate. However, the switching tubes in the power conversion device are relatively prone to failure. If a switching tube fails, it will increase the current and voltage burdens on other components, and may cause other types of system failures, and even lead to the paralysis of the vehicle speed control system. Especially after the switching tube fails, the electric vehicle will stop at any position on the road surface, thus bringing serious safety hazards. Summary of the Invention

[0003] The present application provides a powertrain, an open-circuit fault location and fault-tolerant control method, and a vehicle, which are used to timely locate the fault point of the motor controller and implement fault-tolerant control, so as to reduce safety hazards.

[0004] In a first aspect, an embodiment of the present application provides a powertrain with open - circuit fault location and fault - tolerant control. The powertrain includes a motor controller and a drive motor. The motor controller includes an inverter circuit and a control device. The inverter circuit includes a three - phase bridge arm, three - phase control switches, and two capacitors. Among them, the three - phase bridge arm is connected between the first pole and the second pole of the power battery. Each phase of the three - phase bridge arm includes an upper - arm switch tube and a lower - arm switch tube. The mid - point of each phase of the bridge arm is connected to one phase of the three - phase windings of the drive motor. One end of the first capacitor of the two capacitors is used to connect to the first pole of the power battery, and one end of the other capacitor is used to connect to the second pole of the power battery. The second end of one capacitor is used to connect to the second end of the other capacitor. The mid - point of each phase of the bridge arm is also connected to the second ends of the two capacitors through one of the three - phase control switches. And, the control device can control the mid - points of the three - phase bridge arms to output three - phase currents. During the process of the mid - points of the three - phase bridge arms outputting three - phase currents, the control device is used to respond to an open - circuit fault in any one of the three - phase bridge arms. Before the magnitude of the phase current output at the mid - point of the any one phase bridge arm drops to zero, the control device turns off the upper - arm switch tube and the lower - arm switch tube of the any one phase bridge arm and disconnects the corresponding control switch of the any one phase bridge arm. And, the control device is further used to respond to an open - circuit fault in any one of the three - phase bridge arms, control the mid - points of the other two - phase bridge arms to output fault - tolerant currents, generate drive currents on the three - phase windings of the motor through the fault - tolerant currents, and drive the drive motor to output torque with the drive currents to continue driving the vehicle. With this setting, by outputting fault - tolerant currents through the non - faulty phase bridge arms, performing open - phase control, controlling the drive motor to continue rotating, and enabling the electric vehicle to drive to a safe location or a repair shop and then stop during this period, the safety hazard is reduced, especially effectively protecting people's lives at critical moments.

[0005] In some embodiments, the control device can be used to respond to the absolute value of the current residual of the phase current output at the mid - point of any one of the three - phase bridge arms being greater than the absolute value of the current residuals of the phase currents output at the mid - points of the other two - phase bridge arms, and can determine that there is an open - circuit fault in this phase bridge arm. Then, before the magnitude of the phase current output at the mid - point of the any one phase bridge arm drops to zero, the control device turns off the upper - arm switch tube and the lower - arm switch tube of the any one phase bridge arm and disconnects the corresponding control switch of the any one phase bridge arm, and controls the mid - points of the other two - phase bridge arms to output fault - tolerant currents. Among them, the current residual is the difference between the phase current output at the mid - point of one phase of the three - phase bridge arm and a preset current.

[0006] In some embodiments, a sensor is also provided in the powertrain. During the process of the control device controlling the mid - points of the three - phase bridge arms to output three - phase currents, the sensor collects the phase currents actually output at the mid - points of the three - phase bridge arms and sends the collected phase currents to the control device.

[0007] In some embodiments, the process of the inverter circuit outputting a fault-tolerant current includes a first fault-tolerant stage and a second fault-tolerant stage. Among them, in the first fault-tolerant stage, the difference between the driving current of the winding corresponding to any phase leg and the preset current is greater than the difference threshold, indicating that the driving current is quite different from the corresponding preset current. And, in the second fault-tolerant stage, the difference between the driving current of the winding corresponding to any phase leg and the preset current is less than or equal to the difference threshold, indicating that the driving current is less different from the corresponding preset current.

[0008] In some embodiments, the control device is further configured to receive a torque signal and control the three-phase current to be output at the midpoints of the three-phase legs through the torque signal. Then, during the process of the three-phase current being output at the midpoints of the three-phase legs, the motor controller is configured to control the driving motor to output the torque indicated by the torque signal. And, in the second fault-tolerant stage, the control device is also configured to receive the torque signal, and the motor controller is also configured to control the driving motor to output the torque indicated by the torque signal. Also, in the first fault-tolerant stage, the control device is also configured to receive the torque signal, and the torque output by the motor controller controlling the driving motor is less than the torque indicated by the torque signal.

[0009] In some embodiments, during the process of the motor controller outputting a fault-tolerant current, the motor controller is configured to control the rotational speed of the driving motor to be less than or equal to a set speed threshold, so as to reduce the load of the driving motor and further reduce potential safety hazards.

[0010] In some embodiments, during the process of the motor controller outputting a fault-tolerant current, the motor controller is configured to control the torque output by the driving motor to be less than or equal to a set torque threshold, so as to reduce the load of the driving motor and further reduce potential safety hazards.

[0011] In some embodiments, since the driving motor cannot be controlled to rotate in a single-phase open state all the time and in order to reduce losses, the control device is further configured to control the inverter circuit to stop outputting current after a preset duration of the inverter circuit outputting a fault-tolerant current. With this setting, after entering the preset duration of single-phase open control, it is required that the driver of the electric vehicle drive the electric vehicle to a safe location or a repair shop and then automatically stop outputting.

[0012] In some embodiments, the control device is further configured to issue an alarm signal in response to the absolute value of the current residual corresponding to any one of the three-phase legs being greater than the absolute values of the current residuals corresponding to the other two-phase legs. The alarm signal is used to indicate that there is an open-circuit fault in the motor controller, so as to be able to give a warning to the driver of the electric vehicle. Exemplarily, the ways of issuing the alarm signal include but are not limited to image display, indicator light display, voice broadcast, etc.

[0013] In some embodiments, the control device is further configured to determine that the upper-arm switch of any one phase leg is open in response to the current residual corresponding to any one phase leg being non-positive. Exemplarily, a fault feedback message may also be sent, and the fault feedback message carries information that the upper-arm switch in this phase leg has an open-circuit fault.

[0014] In some embodiments, the control device is further configured to determine that the lower-arm switch of any one phase leg is open in response to the current residual corresponding to any one phase leg being non-negative. Exemplarily, a fault feedback message may also be sent, and the fault feedback message carries information that the lower-arm switch in this phase leg has an open-circuit fault.

[0015] In some embodiments, the control device is further configured to determine that both the upper-arm switch and the lower-arm switch of any one phase leg are open in response to the current residual corresponding to any one phase leg being in an alternating state. Exemplarily, a fault feedback message may also be sent, and the fault feedback message carries information that both switches in this phase leg have open-circuit faults.

[0016] In some embodiments, the control device is further configured to, in response to the absolute value of the current residual of the phase current output at the midpoint of any one phase leg among the three-phase legs being twice the absolute value of the current residuals of the phase currents output at the midpoints of the other two phase legs, and the direction of the current residual of the phase current output at the midpoint of any one phase leg being opposite to the directions of the current residuals of the phase currents output at the midpoints of the other two phase legs, before the magnitude of the phase current output at the midpoint of any one phase leg drops to zero, control the upper-arm switch and the lower-arm switch of any one phase leg to turn off and the control switch corresponding to any one phase leg to disconnect, and control the other two phase legs to output fault-tolerant currents at their midpoints.

[0017] In some embodiments, during the process of the motor controller outputting fault-tolerant currents, the control device is further configured to control the power of the fault-tolerant currents to be less than or equal to a preset power, so as to reduce the load on the drive motor and further reduce potential safety hazards.

[0018] This application can calculate a preset current based on a Mixed Logic Dynamic (MLD) model to improve positioning accuracy. Exemplarily, the preset currents corresponding to the three-phase legs satisfy the following formula:

[0019]

[0020]

[0021]

[0022] Wherein, respectively represent the current change amounts corresponding to the three-phase bridge arms, ia1, ib1, and ic1 respectively represent the preset currents corresponding to the three-phase bridge arms, R represents the resistance of the winding, L represents the inductance of the winding, ω s represents the electrical angular velocity of the rotor, ψf represents the magnetic flux of the rotor permanent magnet, θ represents the electrical angle of the rotor. S1, S2, S3, S4, S5, and S6 respectively represent the switching signals of the three-phase bridge arms, σ a 、σ b represents the current logic quantity of the output current at the midpoint of the bridge arm of the other two-phase bridge arms, σ c represents the current logic quantity of the output current at the midpoint of the bridge arm of any one-phase bridge arm.

[0023] In a second aspect, the embodiments of the present application further provide an open-circuit fault location and fault-tolerant control method, which is applied to a powertrain. The powertrain includes a motor controller and a drive motor. The motor controller includes an inverter circuit and a control device. The inverter circuit includes three-phase bridge arms, three-phase control switches, and two capacitors; the three-phase bridge arms are connected between the first pole and the second pole of the power battery. Each phase bridge arm in the three-phase bridge arms includes an upper-bridge-arm switch tube and a lower-bridge-arm switch tube. The midpoint of each phase bridge arm is connected to one phase winding of the three-phase windings of the drive motor. One end of one of the two capacitors is used to connect to the first pole of the power battery, and one end of the other capacitor is used to connect to the second pole of the power battery. The second end of one capacitor is used to connect to the second end of the other capacitor. The midpoint of each phase bridge arm is also connected to the second ends of one capacitor and the other capacitor through one phase control switch in the three-phase control switches.

[0024] Moreover, the method includes: during the process that the midpoints of the three-phase bridge arms are used to output three-phase currents, in response to an open-circuit fault existing in any one-phase bridge arm among the three-phase bridge arms, before the magnitude of the phase current output at the midpoint of any one-phase bridge arm drops to zero, control the upper-bridge-arm switch tube and the lower-bridge-arm switch tube of any one-phase bridge arm to turn off and the control switch corresponding to any one-phase bridge arm to disconnect, and control the midpoints of the other two-phase bridge arms to output fault-tolerant currents. The fault-tolerant currents are used to generate drive currents on the three-phase windings of the motor, and the drive currents are used to drive the drive motor to output torque.

[0025] In some embodiments, the control method includes:

[0026] In response to the absolute value of the current residual of the phase current output at the midpoint of any one-phase bridge arm among the three-phase bridge arms being greater than the absolute value of the current residual of the phase currents output at the midpoints of the other two-phase bridge arms, before the magnitude of the phase current output at the midpoint of any one-phase bridge arm drops to zero, control the upper-bridge-arm switch tube and the lower-bridge-arm switch tube of any one-phase bridge arm to turn off and the control switch corresponding to any one-phase bridge arm to disconnect, and control the midpoints of the other two-phase bridge arms to output fault-tolerant currents;

[0027] The current residual is the difference between the phase current output at the midpoint of one of the three-phase bridge arms and the preset current.

[0028] In some embodiments, the process of the inverter circuit outputting the fault-tolerant current includes a first fault-tolerant stage and a second fault-tolerant stage;

[0029] In the first fault-tolerant stage, the difference between the drive current of the winding corresponding to any one of the phase bridge arms and the preset current is greater than the difference threshold;

[0030] In the second fault-tolerant stage, the difference between the drive current of the winding corresponding to any one of the phase bridge arms and the preset current is less than or equal to the difference threshold.

[0031] In a third aspect, an embodiment of the present application further provides an electric vehicle, which includes: a vehicle body, wheels, and a power assembly. The power assembly and the wheels are installed on the vehicle body, and the power assembly is used to drive the wheels to rotate. Among them, the power assembly is the power assembly described in the first aspect or any possible implementation manner of the first aspect.

[0032] In addition, the technical effects of the corresponding solutions in the second aspect and the third aspect can be referred to the technical effects that can be obtained from the corresponding solutions in the first aspect, and the repeated parts will not be elaborated. Description of the Drawings

[0033] Figure 1 It is a schematic structural diagram of an electric vehicle in an embodiment of the present application;

[0034] Figure 2 It is a framework diagram of a power assembly in an embodiment of the present application;

[0035] Figure 3 It is a schematic structural diagram of a power assembly in an embodiment of the present application;

[0036] Figure 4 It is a signal timing diagram of a three-phase current in an embodiment of the present application;

[0037] Figure 5 It is a current residual vector diagram of the c-phase bridge arm in different states in an embodiment of the present application;

[0038] Figure 6 It is an equivalent circuit schematic diagram of an inverter circuit in an embodiment of the present application;

[0039] Figure 7 It is another equivalent circuit schematic diagram of an inverter circuit in an embodiment of the present application;

[0040] Figure 8 It is a voltage vector diagram corresponding to the 00 switching state of the inverter circuit in an embodiment of the present application;

[0041] Figure 9 It is the SVPWM modulation flowchart of the three-phase four-switch in the embodiment of the present application;

[0042] Figure 10 It is the basic voltage vector diagram when there is an open-circuit fault in the a-phase bridge arm in the embodiment of the present application;

[0043] Figure 11 It is the basic voltage vector diagram when there is an open-circuit fault in the b-phase bridge arm in the embodiment of the present application.

[0044] Reference numerals

[0045] 100 - Vehicle body; 200 - Wheel; 300 - Transmission mechanism; 400 - Powertrain; 410 - Motor controller; 420 - Drive motor; 411 - Inverter circuit; 411a - a-phase bridge arm; 411b - b-phase bridge arm; 411c - c-phase bridge arm; 412 - Control device; 500 - Power battery; Ka - a-phase thyristor; Kb - b-phase thyristor; Kc - c-phase thyristor; M - Intermediate node; Ssa - a-phase winding; Ssb - b-phase winding; Ssc - c-phase winding; C1 / C2 - Capacitor. Detailed implementation manners

[0046] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings. The specific operation methods in the method embodiments can also be applied to the device embodiments or system embodiments. It is worth mentioning that in the description of the present application, "a plurality of" can be understood as "at least two". In addition, it should be understood that in the description of the present application, terms such as "first" and "second" are only used for the purpose of distinguishing descriptions, and cannot be understood as indicating or implying relative importance, nor can they be understood as indicating or implying an order.

[0047] It should be noted that the same reference numerals in the accompanying drawings of the present application represent the same or similar structures, so repeated descriptions thereof will be omitted. The words expressing positions and directions described in the present application are all illustrated with reference to the accompanying drawings, but can be changed according to needs, and all changes made are included in the protection scope of the present application. The accompanying drawings of the present application are only used to illustrate the relative position relationship and do not represent the true proportion.

[0048] To facilitate the understanding of the powertrain, open-circuit fault location and fault-tolerant control method and vehicle provided in the embodiments of the present application, the application scenario thereof will be introduced first below.

[0049] The powertrain in the embodiments of this application can be applied to different types of electric devices. For example, the electric device can be various types of electric vehicles such as electric vehicles (EV), pure electric vehicles (PEV / BEV), hybrid electric vehicles (HEV), range extended electric vehicles (REEV), plug-in hybrid electric vehicles (PHEV), and new energy vehicles. In addition, the above-mentioned electric device can also be a battery management device, a motor & driver device, a power converter device, a reducer, an elevator, or an aircraft, etc. In some embodiments, from the perspective of the application scenario or function, the above-mentioned electric vehicles include passenger vehicles and various special operation vehicles with specific functions, such as engineering rescue vehicles, sprinkler trucks, sewage suction trucks, cement mixer trucks, crane trucks, medical vehicles, etc.

[0050] The technical solution of this application will be introduced below in conjunction with the accompanying drawings, taking the electric device as an electric vehicle as an example.

[0051] Figure 1 It is a schematic structural diagram of an electric vehicle in the embodiments of this application. Referring to Figure 1 , the electric vehicle in the embodiments of this application includes: a vehicle body 100, wheels 200, a transmission mechanism 300, a powertrain 400, and a power battery 500. Among them, the wheels 200, the transmission mechanism 300, the power battery 500, and the powertrain 400 are installed on the vehicle body 100, and the powertrain 400 is connected to the wheels 200 through the transmission mechanism 300. In actual application, the powertrain 400 can convert the electrical energy of the power battery 500 into mechanical energy, and the transmission mechanism 300 transmits the mechanical energy converted by the powertrain 400 to the wheels 200 to drive the wheels 200 to rotate. Exemplarily, the electric vehicle may further include a power supply module (not shown in the figure). The power supply module is connected to the power battery. The power supply module can receive the power supply from an external power source and charge the power battery. In addition, the power supply module is also used to supply power to in-vehicle loads. It can be understood that the external power source can be an AC power grid, an AC charging pile, or a DC charging pile. And the power supply module can be a power distribution unit or an on-vehicle charger. Moreover, the in-vehicle loads include, but are not limited to, one or more of a compressor, a battery heating module, a seat heating module, and a DC low-voltage power supply.

[0052] Figure 2 This is a framework diagram of the powertrain in the embodiments of the present application. Referring to Figure 2 , the powertrain 400 includes a motor controller 410 and a drive motor 420. The motor controller 410 is connected to the power battery 500 and can convert the direct current provided by the power battery 500 into alternating current to supply power to the drive motor 420. The drive motor 420 receives the alternating current to drive the wheels 200 to rotate. Exemplarily, the drive motor 420 is a permanent magnet synchronous motor (PMSM).

[0053] Figure 3 This is a schematic structural diagram of the powertrain in the embodiments of the present application. Referring to Figure 3 , the powertrain 400 includes: a motor controller 410 and a drive motor 420. The motor controller 410 includes an inverter circuit 411 and a control device 412. Among them, the drive motor 420 includes three-phase windings (for example: phase-a winding SSa, phase-b winding SSb, phase-c winding SSc). The inverter circuit 411 includes three-phase bridge arms (for example: phase-a bridge arm 411a, phase-b bridge arm 411b, and phase-c bridge arm 411c), and two capacitors C1, C2. Among them, the phase-a bridge arm 411a, phase-b bridge arm 411b, and phase-c bridge arm 411c are respectively connected between the first pole (for example, the positive pole) and the second pole (for example, the negative pole) of the power battery 500. The midpoint of the phase-a bridge arm 411a is connected to the phase-a winding SSa of the drive motor 420, the midpoint of the phase-b bridge arm 411b is connected to the phase-b winding SSb of the drive motor 420, and the midpoint of the phase-c bridge arm 411c is connected to the phase-c winding SSc of the drive motor 420. And, the two capacitors C1, C2 are connected in series between the first pole (for example, the positive pole) and the second pole (for example, the negative pole) of the power battery 500. Specifically, the first end of the capacitor C1 is connected to the first pole (for example, the positive pole) of the power battery 500, and the first end of the capacitor C2 is connected to the second pole (for example, the negative pole) of the power battery 500. And, the second end of the capacitor C1 is connected to the second end of the capacitor C2 at the intermediate node M.

[0054] The inverter circuit 411 in the embodiments of this application further includes three-phase control switches. Exemplarily, the control switch can be one or more of various types of switching devices such as a relay, a metal oxide semiconductor field effect transistor (MOSFET), a bipolar junction transistor (BJT), an insulated gate bipolar transistor (IGBT), a silicon carbide (SiC) MOSFET, a thyristor, etc. The embodiments of this application will not list them one by one. Moreover, each control switch can include a first electrode, a second electrode, and a control electrode. Among them, the control electrode is used to control the closing or turning off of the control switch. When the control switch is closed, current can be transmitted between the first electrode and the second electrode of the control switch. When the control switch is turned off, current cannot be transmitted between the first electrode and the second electrode of the control switch. The following takes the thyristor as the control switch as an example for specific illustration. Refer to Figure 3 , the control switch corresponding to the a-phase bridge arm 411a is the a-phase thyristor Ka, the control switch corresponding to the b-phase bridge arm 411b is the b-phase thyristor Kb, and the control switch corresponding to the c-phase bridge arm 411c is the c-phase thyristor Kc. Among them, the midpoint of the a-phase bridge arm 411a is connected to the middle node M of the two capacitors through the a-phase thyristor Ka, the midpoint of the b-phase bridge arm 411b is also connected to the middle node M of the two capacitors through the b-phase thyristor Kb, and the midpoint of the c-phase bridge arm 411c is also connected to the middle node M of the two capacitors through the c-phase thyristor Kc.

[0055] Generally, the structure of the inverter circuit 411 has various topological forms, which are not limited in this application. In some embodiments of this application, the inverter circuit 411 in this application can be an inverter with a two-level structure, an inverter with a three-level structure, an inverter with a five-level structure, an inverter with a seven-level structure, and an inverter with a nine-level structure. The following takes the inverter circuit 411 as an example of an inverter with a two-level structure for illustration. Exemplarily, refer to Figure 3, the phase-a bridge arm 411a includes two switching tubes T1 and T4. The control electrode of the switching tube T1 is connected to the control device 412. The first electrode of the switching tube T1 is connected to the positive electrode of the power battery 500. The second electrode of the switching tube T1 is connected to the midpoint of the bridge arm of the phase-a bridge arm 411a. The control electrode of the switching tube T2 is connected to the control device 412. The second electrode of the switching tube T2 is connected to the negative electrode of the power battery 500. The first electrode of the switching tube T2 is connected to the midpoint of the bridge arm of the phase-a bridge arm 411a. And, the phase-b bridge arm 411b includes two switching tubes T3 and T6. The control electrode of the switching tube T3 is connected to the control device 412. The first electrode of the switching tube T3 is connected to the positive electrode of the power battery 500. The second electrode of the switching tube T3 is connected to the midpoint of the bridge arm of the phase-b bridge arm 411b. The control electrode of the switching tube T6 is connected to the control device 412. The second electrode of the switching tube T6 is connected to the negative electrode of the power battery 500. The first electrode of the switching tube T6 is connected to the midpoint of the bridge arm of the phase-b bridge arm 411b. And, the phase-c bridge arm 411c includes two switching tubes T5 and T2. The control electrode of the switching tube T5 is connected to the control device 412. The first electrode of the switching tube T5 is connected to the positive electrode of the power battery 500. The second electrode of the switching tube T5 is connected to the midpoint of the bridge arm of the phase-c bridge arm 411c. The control electrode of the switching tube T2 is connected to the control device 412. The second electrode of the switching tube T2 is connected to the negative electrode of the power battery 500. The first electrode of the switching tube T2 is connected to the midpoint of the bridge arm of the phase-c bridge arm 411c. It can be understood that the switching tubes T1, T3, and T5 are all upper-bridge-arm switching tubes, and the switching tubes T2, T4, and T6 are lower-bridge-arm switching tubes. Exemplarily, each of the above switching tubes can be one or more of various types of switching devices such as a relay, a metal oxide semiconductor field effect transistor (MOSFET), a bipolar junction transistor (BJT), an insulated gate bipolar transistor (IGBT), a silicon carbide (SiC) MOSFET, a thyristor, etc., and the embodiments of the present application will not list them one by one. And, each switching tube can include a first electrode, a second electrode, and a control electrode. Among them, the control electrode is used to control the closing or turning off of the switching tube. When the switching tube is closed, current can be transmitted between the first electrode and the second electrode of the switching tube. When the switching tube is turned off, current cannot be transmitted between the first electrode and the second electrode of the switching tube.

[0056] Generally, components such as an accelerator pedal are also installed on the vehicle body 100. The communication end of the control device 412 is connected to the communication bus, so that the control device 412 can communicate with components such as the accelerator pedal and the brake pedal through the communication bus, enabling the control device 412 to obtain signals from the communication bus. For example, it can obtain an accelerator signal generated due to the triggering of the accelerator pedal from the communication bus. After the control device 412 obtains the accelerator signal, it can generate a torque signal based on the accelerator signal, and this torque signal is used to indicate the torque demand of the electric vehicle. Based on this, referring to Figure 4 , Figure 4 is a signal timing diagram of a three-phase current in an embodiment of the present application. Among them, Figure 4 (a) represents the phase current output at the midpoint of the bridge arm of the three-phase bridge arm, Figure 4 (b) represents the drive current flowing through the three-phase winding. Specifically, the control device 412 can respond to this torque signal and control the thyristors Ka of phase a, Kb of phase b, and Kc of phase c to be all closed, and conduct the midpoint M of the two capacitors to the midpoints of the bridge arms of phase a bridge arm 411a, phase b bridge arm 411b, and phase c bridge arm 411c respectively. Moreover, the control device 412 also controls the operation of the phase a bridge arm 411a, phase b bridge arm 411b, and phase c bridge arm 411c, so that the phase a bridge arm 411a outputs a phase current ia1, the phase b bridge arm 411b outputs a phase current ib1, and the phase c bridge arm 411c outputs a phase current ic1. Through the phase currents ia1 to ic1, a drive current ia2 is generated on the phase a winding SSa, a drive current ib2 is generated on the phase b winding SSb, and a drive current ic2 is generated on the phase c winding SSc. Based on this, during the process that the phase a bridge arm 411a outputs the phase current ia1, the phase b bridge arm 411b outputs the phase current ib1, and the phase c bridge arm 411c outputs the phase current ic1, the motor controller can control the drive motor 420 to output the torque indicated by the torque signal, and then drive the vehicle to run. In some embodiments of the present application, the control device 412 can control the phase a bridge arm 411a, phase b bridge arm 411b, and phase c bridge arm 411c to output three-phase alternating current based on the combined space vector pulse width modulation (SVPWM) technology.

[0057] However, when the A-phase bridge arm 411a, B-phase bridge arm 411b, and C-phase bridge arm 411c are working, their performance will change due to various factors, resulting in faults in the switching tubes. Generally, the faults that occur in the switching tubes generally include two types: open-circuit faults and short-circuit faults. If a short-circuit fault occurs in the switching tube, the protection device in the motor controller 410 will directly stop switching the switching tube with the short-circuit fault to a continuously open state, so that the short-circuit fault changes to an open-circuit fault. After the switching tube fails, directly controlling the drive motor to stop running will cause the electric vehicle to suddenly stop like an "emergency brake". If the electric vehicle is driving on the road, it may cause traffic accidents and pose potential safety hazards. Therefore, enabling the power assembly 400 to have an open-circuit fault location and fault-tolerant control function can switch the original three-phase six-switch control mode to a three-phase four-switch fault-tolerant control mode after a fault occurs in the bridge arm where the switching tube is located, and output a fault-tolerant current through the non-faulty phase bridge arm to generate a drive current in each phase winding, so as to control the drive motor to continue rotating through the drive current, and enable the electric vehicle to drive to a safe location or repair shop and then stop during this period, reducing potential safety hazards, especially effectively protecting people's lives at critical moments. For this reason, the embodiment of the present application provides a power assembly 400 with open-circuit fault location and fault-tolerant control, which can timely locate the fault point of the open-circuit fault of the motor controller 410 and implement fault-tolerant control, thereby reducing potential safety hazards.

[0058] Continue to refer to Figure 4, during the process of outputting three-phase currents at the midpoints of the phase A arm 411a, phase B arm 411b, and phase C arm 411c respectively, if an open-circuit fault occurs in the phase C arm, the control device can respond to the open-circuit fault in the phase C arm 411c, and before the magnitude of the phase current ic1 output at the midpoint of the phase C arm 411c drops to zero, control the upper-bridge switch tube T5 and the lower-bridge switch tube T2 of the phase C arm 411c to turn off and control the thyristor Kc corresponding to the phase C arm 411c to switch from closed to off. Also, the control device 412 also continues to control the phase A thyristor and the phase B thyristor to be closed before the magnitude of the phase current ic1 output at the midpoint of the phase C arm 411c drops to zero, and control the midpoint of the phase A arm 411a to output the fault-tolerant current iar in a timely manner, and control the midpoint of the phase B arm 411b to output the fault-tolerant current ibr in a timely manner, so as to generate a driving current ia3 on the phase A winding SSa through the fault-tolerant currents iar and ibr, generate a driving current ib3 on the phase B winding SSb, and generate a driving current ic3 on the phase C winding SSc, thereby continuing to control the driving motor to output torque through the driving current and continue to drive the vehicle to run. With this setting, the fault-tolerant current is output through the non-faulty phase arm, the open-phase control is executed, the driving motor is controlled to continue rotating, and during this period, the electric vehicle can be driven to a safe position or a repair shop and then stopped, reducing potential safety hazards, especially effectively ensuring people's lives at critical moments.

[0059] Since the driving motor cannot be controlled to rotate in the open-phase state all the time, and in order to reduce losses, the control device is also used to control the inverter circuit to stop outputting current after a preset duration of outputting the fault-tolerant current by the inverter circuit. With this setting, after entering the preset duration of open-phase control, it is required that the driver of the electric vehicle drive the electric vehicle to a safe position or a repair shop and then automatically stop outputting.

[0060] In specific implementation, sensors are usually also provided in the powertrain 400. During the process of the control device 412 controlling the phase currents ia1 to ic1 output at the midpoints of the armatures of the a-phase armature 411a, b-phase armature 411b, and c-phase armature 411c, the sensors collect the actual phase currents ia1 output at the midpoint of the a-phase armature 411a, the actual phase current ib1 output at the midpoint of the b-phase armature 411b, and the actual phase current ic1 output at the midpoint of the c-phase armature 411b, and send the collected phase currents ia1 to ic1 to the control device 412. During the process of the control device 412 controlling the phase currents ia1 to ic1 output at the midpoints of the armatures of the a-phase armature 411a, b-phase armature 411b, and c-phase armature 411c, it obtains the actually output phase currents ia1 to ic1 from the sensors. The control device 412 subtracts the preset current ia0 corresponding to the a-phase armature 411a from the actually output phase current ia1 to obtain the current residual ia1 - ia0 corresponding to the a-phase armature 411a. Similarly, the preset current ib0 corresponding to the b-phase armature 411b is subtracted from the actually output phase current ib1 to obtain the current residual ib1 - ib0 corresponding to the b-phase armature 411b. And the preset current ic0 corresponding to the c-phase armature 411c is subtracted from the actually output phase current ic1 to obtain the current residual ic1 - ic0 corresponding to the c-phase armature 411c. Based on this, the control device 412 compares the absolute values of the current residuals corresponding to the a-phase armature 411a, |ia1 - ia0|, the absolute value of the current residual corresponding to the b-phase armature 411b, |ib1 - ib0|, and the absolute value of the current residual corresponding to the c-phase armature 411c, |ic1 - ic0| with each other. If |ic1 - ic0| > |ia1 - ia0| and |ic1 - ic0| > |ib1 - ib0|, it indicates that there is an open-circuit fault in the c-phase armature 411c. Therefore, before the magnitude of the phase current ic1 output at the midpoint of the c-phase armature 411c drops to zero, the control device 412 controls the upper-arm switch tube T5 and the lower-arm switch tube T2 of the c-phase armature 411c to turn off and controls the thyristor Kc corresponding to the c-phase armature 411c to switch from closed to off. And, before the magnitude of the phase current ic1 output at the midpoint of the c-phase armature 411c drops to zero, the control device 412 also continues to control the a-phase thyristor and the b-phase thyristor to be closed, and controls the midpoints of the a-phase armature 411a and the b-phase armature 411b to output fault-tolerant currents in a timely manner, so as to generate driving currents on the a-phase winding SSa, b-phase winding SSb, and c-phase winding SSc respectively through the fault-tolerant currents, thereby continuing to control the driving motor to output torque through the driving currents and continuing to drive the vehicle to run. With this setting, the fault-tolerant current is output through the non-faulty phase armature, and the driving motor is continuously controlled to rotate. During this period, the electric vehicle can be driven to a safe location or a repair shop and then stopped, reducing potential safety hazards, especially effectively ensuring people's lives at critical moments.

[0061] In some embodiments, to further accurately locate the fault, when the control device 412 determines that the current residual corresponding to any phase bridge arm is non-positive, it can determine that the upper-arm switch tube of that phase bridge arm is open. For example, when the current residual corresponding to the c-phase bridge arm 411a is non-positive, the control device 412 can determine that the upper-arm switch tube T5 of the c-phase bridge arm 411a has an open-circuit fault. Further, a fault feedback message can be sent, and the fault feedback message carries information that the upper-arm switch tube in that phase bridge arm has an open-circuit fault.

[0062] In some other embodiments, when the control device 412 determines that the current residual corresponding to any phase bridge arm is non-negative, it can determine that the lower-arm switch tube of that phase bridge arm is open. For example, when the current residual corresponding to the c-phase bridge arm 411a is non-negative, the control device 412 can determine that the lower-arm switch tube T2 of the c-phase bridge arm 411a has an open-circuit fault. Further, a fault feedback message can be sent, and the fault feedback message carries information that the lower-arm switch tube in that phase bridge arm has an open-circuit fault.

[0063] In some other embodiments, when the control device 412 determines that the current residual corresponding to any phase bridge arm is in an alternating state, it can determine that both the upper-arm switch tube and the lower-arm switch tube of that phase bridge arm are open. For example, when the current residual corresponding to the c-phase bridge arm 411a is in an alternating state, the control device 412 can determine that the upper-arm switch tube T5 and the lower-arm switch tube T2 of the c-phase bridge arm 411a have open-circuit faults. Further, a fault feedback message can be sent, and the fault feedback message carries information that both switch tubes in that phase bridge arm have open-circuit faults.

[0064] To further prompt the driver of the electric vehicle that there is an open-circuit fault in the c-phase bridge arm 411c of the inverter circuit 411, the control device 412 also issues an alarm signal in response to the absolute value of the current residual corresponding to the c-phase bridge arm 411c being greater than the absolute values of the current residuals corresponding to the b-phase bridge arm 411b and the a-phase bridge arm 411a, so as to indicate through the alarm signal that there is an open-circuit fault in the motor controller, thereby being able to give a warning to the driver of the electric vehicle. Exemplarily, the ways of issuing the alarm signal include but are not limited to image display, indicator light display, voice broadcast, etc.

[0065] Exemplarily, the control device 412 can send the above-mentioned fault feedback message to a superior controller, an external controller, or a vehicle controller.

[0066] This application can calculate preset currents \(i_{a0}\sim i_{c0}\) based on a Mixed Logic Dynamic (MLD) model to improve positioning accuracy. Exemplarily, the preset currents corresponding to the three-phase bridge arms satisfy the following formula:

[0067]

[0068]

[0069]

[0070] Among them, respectively represent the current change amounts corresponding to the three-phase bridge arms, \(i_{a0}\), \(i_{b0}\), and \(i_{c0}\) respectively represent the preset currents corresponding to the three-phase bridge arms, \(R\) represents the resistance of the winding, \(L\) represents the inductance of the winding, \(\omega\) s represents the electrical angular velocity of the rotor, \(\psi_f\) represents the magnetic flux of the rotor permanent magnet, \(\theta\) represents the electrical angle of the rotor, \(S_1\) represents the switching signal of the upper-arm switch transistor \(T_1\) of the a-phase bridge arm \(411a\), \(S_4\) represents the switching signal of the lower-arm switch transistor \(T_4\) of the a-phase bridge arm \(411a\), \(S_3\) represents the switching signal of the upper-arm switch transistor \(T_3\) of the b-phase bridge arm \(411b\), \(S_6\) represents the switching signal of the lower-arm switch transistor \(T_6\) of the b-phase bridge arm \(411b\), \(S_5\) represents the switching signal of the upper-arm switch transistor \(T_5\) of the c-phase bridge arm \(411c\), \(S_2\) represents the switching signal of the lower-arm switch transistor \(T_2\) of the c-phase bridge arm \(411c\), \(\sigma\) a represents the current logic quantity of the output current at the midpoint of the a-phase bridge arm \(411a\), \(\sigma\) b represents the current logic quantity of the output current at the midpoint of the b-phase bridge arm \(411b\), \(\sigma\) c represents the current logic quantity of the output current at the midpoint of the c-phase bridge arm \(411c\).

[0071] In some embodiments of the present application, taking the open - circuit fault of the C - phase bridge arm 411c as an example, when the absolute value of the current residual corresponding to the C - phase bridge arm 411c is greater than the absolute values of the current residuals corresponding to the A - phase bridge arm 411a and the B - phase bridge arm 411b, the following relationship may also exist: the absolute value of the current residual |ic1 - ic0| corresponding to the C - phase bridge arm 411c is twice the absolute value of the current residual |ia1 - ia0| corresponding to the A - phase bridge arm 411a and the absolute value of the current residual |ib1 - ib0| corresponding to the B - phase bridge arm 411b respectively. And the current residual c1 - ic0 corresponding to the C - phase bridge arm 411c is in the opposite direction to the current residual ia1 - ia0 corresponding to the A - phase bridge arm 411a and the current residual ib1 - ib0 corresponding to the B - phase bridge arm 411b respectively. Based on this relationship, it can be shown that there is an open - circuit fault in the C - phase bridge arm 411c. Therefore, before the magnitude of the phase current ic1 output at the mid - point of the C - phase bridge arm 411c drops to zero, the control device 412 controls the upper - arm switch tube T5 and the lower - arm switch tube T2 of the C - phase bridge arm 411c to turn off and controls the thyristor Kc corresponding to the C - phase bridge arm 411c to switch from closed to off. And, before the magnitude of the phase current ic1 output at the mid - point of the C - phase bridge arm 411c drops to zero, the control device 412 also continues to control the A - phase thyristor and the B - phase thyristor to be closed, and controls the mid - points of the A - phase bridge arm 411a and the B - phase bridge arm 411b to output fault - tolerant currents in a timely manner respectively, so as to generate drive currents on the A - phase winding SSa, the B - phase winding SSb and the C - phase winding SSc respectively through the fault - tolerant currents, thereby continuing to control the drive motor to output torque through the drive currents and continuing to drive the vehicle to run. With this setting, the fault - tolerant current is output through the non - fault phase bridge arms, the drive motor is continuously controlled to rotate, and during this period, the electric vehicle can drive to a safe position or a repair shop and then stop, reducing potential safety hazards, especially effectively ensuring people's life safety at critical moments.

[0072] Taking the C - phase bridge arm as an example, referring to Figure 5 , Figure 5 is the current residual vector diagram of the C - phase bridge arm in different states in the embodiments of the present application. Among them, Figure 5 in (a) is the current residual vector diagram when there is no fault in the C - phase bridge arm 411c, Figure 5 in (b) is the current residual vector diagram when the upper - arm switch tube T5 in the C - phase bridge arm 411c fails, Figure 5 in (c) is the current residual vector diagram when the lower - arm switch tube T2 in the C - phase bridge arm 411c fails, Figure 5 in (d) is the current residual vector diagram when both the upper - arm switch tube T5 and the lower - arm switch tube T2 in the C - phase bridge arm 411c fail.

[0073] Continuing with the example where there is an open circuit fault in the C-phase bridge arm 411c, when there is an open circuit fault in the C-phase bridge arm 411c, the control device can adopt fault-tolerant control so that the drive motor 420 can still drive the wheel 200 to rotate, and during this period, the electric vehicle can be driven to a safe position or a repair shop and then stop, reducing potential safety hazards. Continuing to refer to Figure 4 , in the T0 stage, the drive currents ia2 to ic2 of the windings are the same as the corresponding phase currents ia1 to ic1 respectively, indicating that no open circuit fault has occurred in this stage. After that, fault-tolerant control is entered, and the inverter circuit is controlled to output fault-tolerant currents iar and ibr. The process of the inverter circuit outputting the fault-tolerant currents iar and ibr can include two fault-tolerant stages, namely the first fault-tolerant stage T1 and the second fault-tolerant stage T2. Among them, in the first fault-tolerant stage T1, before the magnitude of the phase current ic1 output at the midpoint of the C-phase bridge arm 411c is reduced to zero, the fault-tolerant current iar output at the midpoint of the A-phase bridge arm 411a is controlled, and the fault-tolerant current ibr output at the midpoint of the B-phase bridge arm 411b is controlled, so as to generate drive currents ia3 to ic3. Moreover, the difference between the drive current ia3 and the corresponding preset current ia0, the difference between the drive current ib3 and the corresponding preset current ib0, and the difference between the drive current ic3 and the corresponding preset current ic0 are all greater than the difference threshold. This shows that the drive currents ia3 to ic3 are quite different from the corresponding preset currents ia0 to ic0. Further, in the first fault-tolerant stage T1, the control device 412 can also receive a torque signal, and by outputting the fault-tolerant currents iar and ibr through the motor controller 410, it can control the torque output by the drive motor 420 to be less than the torque indicated by the torque signal.

[0074] Continuing to refer to Figure 4 , in the second fault-tolerant stage T2, the fault-tolerant current iar output at the midpoint of the A-phase bridge arm 411a is continuously controlled, and the fault-tolerant current ibr output at the midpoint of the B-phase bridge arm 411b is controlled, so as to generate drive currents ia3 to ic3. Moreover, the difference between the drive current ia3 and the corresponding preset current ia0, the difference between the drive current ib3 and the corresponding preset current ib0, and the difference between the drive current ic3 and the corresponding preset current ic0 are all less than or equal to the difference threshold. This shows that the drive currents ia3 to ic3 are as close as possible to the corresponding preset currents ia0 to ic0 respectively. Further, in the second fault-tolerant stage T2, the control device 412 can also receive a torque signal, and by outputting the fault-tolerant currents iar and ibr through the motor controller 410, it can control the drive motor 420 to output the torque indicated by the torque signal.

[0075] It is understandable that the difference threshold can be set to 0 + Δi, where Δi can be a value within the allowable error range or a value set according to experience. Moreover, the specific value of Δi can be determined according to the requirements of the actual application scenario and is not limited herein.

[0076] Taking the case where there is a switching fault in the C-phase bridge arm 411c as an example, the switching states of the inverter circuit 411 will be described. For example, referring to Figure 6 , Figure 6 which is an equivalent circuit schematic diagram of the inverter circuit in an embodiment of the present application, the C-phase bridge arm 411c will be replaced by two series-connected capacitors CT5 and CT2, and only the switching tubes of the A-phase bridge arm 411a and the B-phase bridge arm 411b can perform the actions of closing and turning off. Based on this, referring to Figure 7 , Figure 7 which is another equivalent circuit schematic diagram of the inverter circuit in an embodiment of the present application, if it is stipulated that when the upper-bridge-arm switching tube is turned on, it is 1, and when the lower-bridge-arm switching tube is turned on, it is 0, at this time, the inverter circuit 411 has four switching states: 00, 10, 11, and 01. Among them, Figure 7 in (a) represents the 00 switching state, the first 0 represents the switching state of the A-phase bridge arm 411a, and the second 0 represents the switching state of the B-phase bridge arm 411b. Figure 7 in (b) represents the 10 switching state, 1 represents the switching state of the A-phase bridge arm 411a, and 0 represents the switching state of the B-phase bridge arm 411b. Figure 7 in (c) represents the 11 switching state, the first 1 represents the switching state of the A-phase bridge arm 411a, and the second 1 represents the switching state of the B-phase bridge arm 411b. Figure 7 in (d) represents the 01 switching state, 0 represents the switching state of the A-phase bridge arm 411a, and 1 represents the switching state of the B-phase bridge arm 411b. And, Ra represents the resistance of the A-phase winding SSa, Rb represents the resistance of the B-phase winding SSb, and Rc represents the resistance of the C-phase winding SSc.

[0077] Continuing to take the case where there is a switching fault in the C-phase bridge arm 411c as an example, the voltage vector of the inverter circuit 411 in the 00 switching state will be analyzed. Referring to Figure 7 , if the voltage fluctuations of the capacitors are ignored, the following can be obtained:

[0078]

[0079] Among them, u an represents the phase voltage of the A-phase winding SSa, u bn represents the phase voltage of the B-phase winding SSb, u cn represents the phase voltage of the C-phase winding SSc, and V dc represents the voltage of the power battery 500.

[0080] Moreover, the relationship between the three-phase phase voltages of the driving electrodes and the switching states sa and sb is as follows:

[0081]

[0082] where s a represents the switching state of phase-a bridge arm 411a, and s b represents the switching state of phase-b bridge arm 411b.

[0083] By performing Clarke transformation on the three-phase phase voltages in formula (8), the expression of the space voltage vector in the α-β coordinate system can be obtained:

[0084]

[0085] By synthesizing the u α and u β vectors, the voltage vector corresponding to the 00 switching state of the inverter circuit 411 can be obtained. Similarly, the voltage vectors of the inverter circuit 411 in the 10, 11, and 01 switching states can be obtained, as shown in Table 1. Presenting it in the form of a vector diagram, reference can be made to Figure 8 , Figure 8 which is the voltage vector diagram corresponding to the 00 switching state of the inverter circuit in the embodiment of the present application.

[0086] Table 1

[0087]

[0088] The control device 412 in the present application adopts SVPWM technology. According to the voltage vector diagram obtained from the voltage vectors u α and u β , it controls the phase-a bridge arm 411a and the phase-b bridge arm 411b to output fault-tolerant currents. Exemplarily, referring to Figure 9 , Figure 9 which is the SVPWM modulation flowchart of the three-phase four-switch in the embodiment of the present application. After the control device 412 determines the space voltage vector expression (9), according to the u α and u β in the space voltage vector expression (9), the voltage vector diagram obtained is used for sector division, and with the goal of reducing device losses, a suitable switching sequence is selected in each sector for the synthesis of the target vector. Moreover, according to the u α and u β in the space voltage vector expression (9), the obtained voltage vector diagram, and applying the sine theorem of a triangle, based on T PWMThe action time of each voltage vector is calculated, and the duty cycle is obtained according to the action time of the voltage vector and the sector division result. Then, pulse width modulation (PWM) is performed based on the obtained duty cycle and the triangular carrier wave, and the switching signals S1, S4, S3, and S6 can be output. Among them, S1 is used to control the conduction and cutoff of the switching transistor T1, S4 is used to control the conduction and cutoff of the switching transistor T4, S3 is used to control the conduction and cutoff of the switching transistor T3, and S6 is used to control the conduction and cutoff of the switching transistor T16.

[0089] In some examples, during the process of the motor controller 410 outputting the fault-tolerant current, the motor controller 410 can also control the rotational speed of the drive motor 420 to be less than or equal to the set rotational speed threshold, so as to reduce the load of the drive motor 420 and further reduce the potential safety hazard. Exemplarily, the set rotational speed threshold can be 1000 r / min to 3000 r / min. For example, the set rotational speed threshold can be 1000 r / min, 2000 r / min, 3000 r / min, etc. Of course, the specific value of the set rotational speed threshold can be determined according to the requirements of the actual application scenario and is not limited herein.

[0090] In some other examples, during the process of the motor controller 410 outputting the fault-tolerant current, the motor controller 410 can also control the torque output by the drive motor 420 to be less than or equal to the set torque threshold, so as to reduce the load of the drive motor 420 and further reduce the potential safety hazard. Exemplarily, the set torque threshold can be 200 N*m to 400 N*m. For example, the set torque threshold can be 200 N*m, 300 N*m, 400 N*m, etc. Of course, the specific value of the set torque threshold can be determined according to the requirements of the actual application scenario and is not limited herein.

[0091] In some other examples, during the process of the motor controller 410 outputting the fault-tolerant current, the control device 412 can also control the power of the fault-tolerant current to be less than or equal to the preset power, so as to reduce the load of the drive motor 420 and further reduce the potential safety hazard. Exemplarily, the preset power can be 350 W to 400 W. For example, the preset power can be 350 W, 370 W, 400 W, etc. Of course, the specific value of the preset power can be determined according to the requirements of the actual application scenario and is not limited herein.

[0092] Similarly, in the embodiments of the present application, the basic voltage vector diagram when the a-phase bridge arm has an open-circuit fault and the basic voltage vector diagram when the b-phase bridge arm has an open-circuit fault can also be obtained. For example, referring to Figure 10 And Figure 11 , Figure 10 is the basic voltage vector diagram when the a-phase bridge arm in the embodiments of the present application has an open-circuit fault, Figure 11This is the basic voltage vector diagram when an open - circuit fault occurs in the B - phase bridge arm in the embodiments of this application. Moreover, for the open - circuit fault location and fault - tolerant control process when an open - circuit fault occurs in the A - phase bridge arm 411a or the B - phase bridge arm 411b, it can refer to the open - circuit fault location and fault - tolerant control process when an open - circuit fault occurs in the C - phase bridge arm 411c, and the repeated parts will not be elaborated.

[0093] It is worth mentioning that due to process conditions or other factors, in actual processes, there may be some deviations or errors, resulting in the "same" described above not being completely accurate. For example, the "same" described above can be the same within the allowable error range. Of course, the "same" can also be understood as "substantially the same" or "completely the same". Therefore, as long as the "same" relationship described above generally meets the above conditions, it falls within the protection scope of this application.

[0094] It can be understood that the control device 412 can be a field - programmable gate array (FPGA), a general - purpose central processing unit (CPU), a general - purpose processor, a digital signal processing (DSP), an application - specific integrated circuit (ASIC), or other programmable logic devices, transistor - logic devices, hardware components, or any combination thereof. It can implement or execute various exemplary logic blocks, modules, and circuits described in conjunction with the disclosure of this application. The above - mentioned control device 412 can also be a combination for realizing computing functions, such as including a combination of one or more microprocessors, a combination of DSP and microprocessors, etc.

[0095] Based on this, the embodiments of this application also provide an open - circuit fault location and fault - tolerant control method. This method is applied to a powertrain. The powertrain includes a motor controller and a drive motor. The motor controller includes an inverter circuit and a control device. The inverter circuit includes three - phase bridge arms, three - phase control switches, and two capacitors. The three - phase bridge arms are connected between the first pole and the second pole of the power battery. Each phase bridge arm in the three - phase bridge arms includes an upper - bridge - arm switch tube and a lower - bridge - arm switch tube. The mid - point of each phase bridge arm is connected to one of the three - phase windings of the drive motor. The first end of one of the two capacitors is used to connect to the first pole of the power battery, and the first end of the other capacitor is used to connect to the second pole of the power battery. The second end of one capacitor is used to connect to the second end of the other capacitor. The mid - point of each phase bridge arm is also connected to the second end of one capacitor and the second end of the other capacitor through one of the three - phase control switches.

[0096] The method includes:

[0097] During the process of outputting three-phase currents at the midpoints of the three-phase bridge arms, in response to an open-circuit fault existing in any one of the three-phase bridge arms, before the magnitude of the phase current output at the midpoint of any one of the three-phase bridge arms drops to zero, control the upper and lower bridge arm switching tubes of any one of the three-phase bridge arms to turn off and the corresponding control switch of any one of the three-phase bridge arms to disconnect, and control the midpoints of the other two-phase bridge arms to output a fault-tolerant current, and the fault-tolerant current is used to generate a driving current on the three-phase windings of the motor, and the driving current is used to drive the driving motor to output torque.

[0098] In one embodiment, the control method includes:

[0099] In response to the absolute value of the current residual of the phase current output at the midpoint of any one of the three-phase bridge arms being greater than the absolute value of the current residuals of the phase currents output at the midpoints of the other two-phase bridge arms, before the magnitude of the phase current output at the midpoint of any one of the three-phase bridge arms drops to zero, control the upper and lower bridge arm switching tubes of any one of the three-phase bridge arms to turn off and the corresponding control switch of any one of the three-phase bridge arms to disconnect, and control the midpoints of the other two-phase bridge arms to output a fault-tolerant current;

[0100] The current residual is the difference between the phase current output at the midpoint of one of the three-phase bridge arms and a preset current.

[0101] In one embodiment, the process of the inverter circuit outputting a fault-tolerant current includes a first fault-tolerant stage and a second fault-tolerant stage;

[0102] In the first fault-tolerant stage, the difference between the driving current of the winding corresponding to any one of the three-phase bridge arms and the preset current is greater than a difference threshold;

[0103] In the second fault-tolerant stage, the difference between the driving current of the winding corresponding to any one of the three-phase bridge arms and the preset current is less than or equal to the difference threshold.

[0104] The above content is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application can easily think of changes or substitutions, and all should be covered within the protection scope of the present application.

Claims

1. A powertrain with a fault tolerance control function, characterized in that, The powertrain includes a motor controller and a drive motor. The motor controller includes an inverter circuit and a control device. The inverter circuit includes three-phase bridge arms, three-phase control switches, and two capacitors. The three-phase bridge arms are connected between the first pole and the second pole of the power battery. Each phase of the three-phase bridge arms includes an upper-bridge-arm switch tube and a lower-bridge-arm switch tube. The midpoint of each phase of the bridge arms is connected to one phase winding of the three-phase windings of the drive motor. The first end of one of the two capacitors is used to connect to the first pole of the power battery, and the first end of the other capacitor is used to connect to the second pole of the power battery. The second end of the one capacitor is used to connect to the second end of the other capacitor. The midpoint of each phase of the bridge arms is also connected to the second ends of the one capacitor and the other capacitor through one of the three-phase control switches. During the process that the midpoints of the three-phase bridge arms are used to output three-phase currents, the control device is configured to: In response to an open-circuit fault existing in any one of the three-phase bridge arms, before the magnitude of the phase current output at the midpoint of the any one of the three-phase bridge arms drops to zero, control the upper-bridge-arm switch tube and the lower-bridge-arm switch tube of the any one of the three-phase bridge arms to turn off and the corresponding control switch of the any one of the three-phase bridge arms to disconnect, and control the midpoints of the other two-phase bridge arms to output a fault-tolerant current, where the fault-tolerant current is used to generate a drive current on the three-phase windings of the motor, and the drive current is used to drive the drive motor to output torque.

2. The powertrain according to claim 1, wherein The control device is configured to: In response to the absolute value of the current residual of the phase current output at the midpoint of any one of the three-phase bridge arms being greater than the absolute value of the current residual of the phase currents output at the midpoints of the other two-phase bridge arms, before the magnitude of the phase current output at the midpoint of the any one of the three-phase bridge arms drops to zero, control the upper-bridge-arm switch tube and the lower-bridge-arm switch tube of the any one of the three-phase bridge arms to turn off and the corresponding control switch of the any one of the three-phase bridge arms to disconnect, and control the midpoints of the other two-phase bridge arms to output the fault-tolerant current; The current residual is the difference between the phase current output at the midpoint of one of the three-phase bridge arms and a preset current.

3. The powertrain according to claim 1 or 2, characterized in that, The process of the inverter circuit outputting the fault-tolerant current includes a first fault-tolerant stage and a second fault-tolerant stage; In the first fault-tolerant stage, the difference between the drive current of the winding corresponding to the any one of the three-phase bridge arms and the preset current is greater than a difference threshold; In the second fault-tolerant stage, the difference between the drive current of the winding corresponding to the any one of the three-phase bridge arms and the preset current is less than or equal to the difference threshold.

4. The powertrain according to claim 3, characterized in that, The control device is further configured to: receive a torque signal; During the process that the midpoints of the three-phase bridge arms are used to output three-phase currents and in the second fault-tolerant stage, the motor controller is configured to control the drive motor to output the torque indicated by the torque signal; In the first fault-tolerant stage, the motor controller controls the drive motor to output a torque less than the torque indicated by the torque signal.

5. The powertrain according to any one of claims 1-4, characterized in that, During the process that the motor controller outputs the fault-tolerant current, the motor controller is configured to: Control the rotational speed of the drive motor to be less than or equal to a set rotational speed threshold, or control the torque output by the drive motor to be less than or equal to a set torque threshold.

6. The powertrain according to any one of claims 1-5, characterized in that, The control device is further configured to: After the inverter circuit outputs the fault-tolerant current for a preset duration, control the inverter circuit to stop outputting current.

7. The powertrain according to any one of claims 2-6, characterized in that, The control device is further configured to: In response to the absolute value of the current residual corresponding to any one of the three-phase bridge arms being greater than the absolute values of the current residuals corresponding to the other two-phase bridge arms, issue an alarm signal, where the alarm signal is used to indicate that the motor controller has an open-circuit fault.

8. The powertrain according to any one of claims 2-7, characterized in that, The control device is further configured to: If the current residual corresponding to any one of the bridge arms is non-positive, determine that the upper-arm switch tube of the any one of the bridge arms is open-circuited; If the current residual corresponding to any one of the bridge arms is non-negative, determine that the lower-arm switch tube of the any one of the bridge arms is open-circuited; If the current residual corresponding to any one of the bridge arms is in an alternating state, determine that both the upper-arm switch tube and the lower-arm switch tube of the any one of the bridge arms are open-circuited.

9. The powertrain according to any one of claims 2-8, characterized in that, The control device is further configured to: In response to the absolute value of the current residual of the phase current output at the midpoint of any one of the three-phase bridge arms being twice the absolute values of the current residuals of the phase currents output at the midpoints of the other two-phase bridge arms, and the direction of the current residual of the phase current output at the midpoint of any one of the three-phase bridge arms being opposite to the directions of the current residuals of the phase currents output at the midpoints of the other two-phase bridge arms, before the magnitude of the phase current output at the midpoint of any one of the bridge arms drops to zero, control the upper-arm switch tube and the lower-arm switch tube of the any one of the bridge arms to turn off and the corresponding control switch of the any one of the bridge arms to disconnect, and control the midpoints of the other two-phase bridge arms to output the fault-tolerant current.

10. The powertrain according to any one of claims 1-9, characterized in that, During the process of the motor controller outputting the fault-tolerant current, the control device is further configured to: Control the power of the fault-tolerant current to be less than or equal to a preset power.

11. The powertrain according to any one of claims 2-10, characterized in that, The preset currents corresponding to the three-phase bridge arms satisfy the following formula: Among them, respectively represent the current change amounts corresponding to the three-phase bridge arms, ia1, ib1, and ic1 respectively represent the preset currents corresponding to the three-phase bridge arms, R represents the resistance of the winding, L represents the inductance of the winding, ω s represents the electrical angular velocity of the rotor, ψf represents the magnetic flux of the rotor permanent magnet, θ represents the electrical angle of the rotor. S1, S2, S3, S4, S5, and S6 respectively represent the switching signals of the three-phase bridge arms, σ a , σ b represents the current logic quantity of the output current at the midpoint of the bridge arm of the other two-phase bridge arms, σ c represents the current logic quantity of the output current at the midpoint of the bridge arm of any one-phase bridge arm.

12. An open - circuit fault location and fault - tolerant control method, characterized in that, The method is applied to a powertrain, the powertrain includes a motor controller and a drive motor, the motor controller includes an inverter circuit and a control device, the inverter circuit includes three-phase bridge arms, three-phase control switches, and two capacitors; the three-phase bridge arms are connected between the first pole and the second pole of the power battery, each phase bridge arm of the three-phase bridge arms includes an upper-arm switch tube and a lower-arm switch tube, the midpoint of each phase bridge arm is connected to one phase winding of the three-phase windings of the drive motor, the first end of one of the two capacitors is used to connect to the first pole of the power battery, the first end of the other capacitor is used to connect to the second pole of the power battery, the second end of the one capacitor is used to connect to the second end of the other capacitor, and the midpoint of each phase bridge arm is further connected to the second ends of the one capacitor and the other capacitor through one of the three-phase control switches; The method includes: During the process of outputting three-phase currents at the midpoints of the three-phase bridge arms, in response to an open-circuit fault existing in any one of the three-phase bridge arms, before the magnitude of the phase current output at the midpoint of the any one of the bridge arms drops to zero, control the upper and lower arm switching transistors of the any one of the bridge arms to turn off and the control switch corresponding to the any one of the bridge arms to disconnect, and control the midpoints of the other two-phase bridge arms to output a fault-tolerant current, where the fault-tolerant current is used to generate a driving current on the three-phase windings of the motor, and the driving current is used to drive the drive motor to output torque.

13. The control method according to claim 12, wherein The control method includes: In response to the absolute value of the current residual of the phase current output at the midpoint of any one of the three-phase bridge arms being greater than the absolute value of the current residuals of the phase currents output at the midpoints of the other two-phase bridge arms, before the magnitude of the phase current output at the midpoint of the any one of the bridge arms drops to zero, control the upper and lower arm switching transistors of the any one of the bridge arms to turn off and the control switch corresponding to the any one of the bridge arms to disconnect, and control the midpoints of the other two-phase bridge arms to output the fault-tolerant current; The current residual is the difference between the phase current output at the midpoint of one of the three-phase bridge arms and a preset current.

14. The control method according to claim 12 or 13, characterized in that, The process of the inverter circuit outputting the fault-tolerant current includes a first fault-tolerant stage and a second fault-tolerant stage; In the first fault-tolerant stage, the difference between the driving current of the winding corresponding to the any one of the bridge arms and the preset current is greater than a difference threshold; In the second fault-tolerant stage, the difference between the driving current of the winding corresponding to the any one of the bridge arms and the preset current is less than or equal to the difference threshold.

15. An electric vehicle, characterized in that, It includes a vehicle body, wheels, and a powertrain as described in any one of claims 1-11, where the powertrain and the wheels are mounted on the vehicle body, and the powertrain is used to drive the wheels to rotate.

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