Motor controller for inhibiting common-mode current, power assembly and electric vehicle

Abstract

The invention provides a motor controller for inhibiting common-mode current, a power assembly and an electric vehicle, relates to the technical field of energy, and is used for effectively inhibiting the common-mode current between the motor controller and a motor and improving the driving safety. The motor controller is used for controlling the output torque of a driving motor, the motor controller comprises an inverter circuit and a control circuit, the inverter circuit comprises three phases of switch tube bridge arms, and each phase of switch tube bridge arm comprises an upper bridge arm switch tube and a lower bridge arm switch tube. The control circuit adopts a space vector pulse width modulation mode to control on or off of an upper bridge arm switch tube and a lower bridge arm switch tube of a three-phase switch tube bridge arm of the inverter circuit. Wherein in the operation process of the motor controller in a space vector pulse width modulation mode, the control circuit is used for controlling the action moments of any two switch tubes, located on different bridge arms, in the three-phase switch tube bridge arms to be different, and the action of the switch tubes refers to switch-on or switch-off of the switch tubes.

Description

Technical Field

[0001] This application relates to the field of energy technology, and more particularly to a motor controller, powertrain, and electric vehicle for suppressing common-mode current. Background Technology

[0002] With the continuous development of energy technology, in order to meet the functional requirements of intelligence and electrification, electric vehicles are gradually evolving towards higher operating voltages, faster switching speeds of power devices, higher switching frequencies of power devices, and integrated layout of motor controllers and motors. However, these factors also lead to the increasingly prominent problem of common-mode current. Common-mode current not only causes signal interference to the internal electrical system of electric vehicles, resulting in signal transmission errors, but it can also damage the motor, causing electro-corrosion of the motor bearings and degrading motor performance.

[0003] Currently, common-mode ferrite cores are commonly used to suppress common-mode current. This involves connecting the common-mode ferrite core in series with the cable between the motor controller's output and the motor windings, directly intercepting the common-mode current's conduction path. However, improving the suppression effect of the common-mode ferrite core requires increasing the number of coil turns, leading to increased core size and weight, which is unsuitable for deployment in space-constrained compact devices. Furthermore, the common-mode ferrite core needs to be used in conjunction with other filtering components for common-mode suppression, further increasing the circuit complexity of the motor controller and motor.

[0004] Therefore, how to effectively suppress common-mode current while reducing circuit complexity has become an urgent technical problem to be solved. Summary of the Invention

[0005] This application provides a motor controller, powertrain, and electric vehicle for suppressing common-mode current, which effectively suppresses the common-mode current between the motor controller and the motor, thereby improving driving safety.

[0006] To achieve the above objectives, the embodiments of this application adopt the following technical solutions:

[0007] Firstly, a motor controller for suppressing common-mode current is provided. The motor controller controls the output torque of a drive motor. The motor controller includes an inverter circuit and a control circuit. The inverter circuit includes a three-phase switching transistor bridge arm, with each phase bridge arm including an upper bridge arm switch and a lower bridge arm switch. The control circuit uses space vector pulse width modulation (SVM) to control the upper and lower bridge arm switches of the three-phase switching transistor bridge arm of the inverter circuit to be turned on or off. Specifically, during the operation of the motor controller using SVM, the control circuit controls the timing of the operation of any two switches located in different bridge arms of the three-phase switching transistor bridge arm to be different, where the switch operation refers to the switch being turned on or off.

[0008] In the above technical solution, during the operation of the motor controller via space vector pulse width modulation, the control circuit controls the two switching transistors located in different arms of the three-phase switching bridge to operate at different times. This results in any two switching bridge arms operating at different times, meaning that only one switching bridge arm operates at any given moment. This avoids the situation where the common-mode current increases abnormally due to the simultaneous operation of two or all three switching bridge arms. It can effectively reduce the amplitude and frequency of the common-mode current, thereby suppressing the common-mode current between the motor controller and the motor to a certain extent and improving driving safety.

[0009] In conjunction with the first aspect, in one implementation, when the motor controller operates by means of space vector pulse width modulation, when two of the three-phase switch bridge arms need to operate simultaneously to switch the inverter circuit from one vector state to another, the control circuit controls the timing of the operation of the two-phase switch bridge arms to be staggered by a preset time.

[0010] Based on the above scheme, only one phase switch bridge arm operates at the same time, avoiding the abnormal increase of common mode current caused by the simultaneous operation of two or three phase switch bridge arms. This can effectively reduce the amplitude and frequency of common mode current, thereby suppressing the common mode current between the motor controller and the motor to a certain extent and improving driving safety.

[0011] In conjunction with the first aspect, in one implementation, when the motor controller operates by means of space vector pulse width modulation, when the three-phase switch bridge arms need to operate simultaneously to switch the inverter circuit from one vector state to another, the timing of the operation of the three-phase switch bridge arms is staggered by a preset time interval.

[0012] Based on the above scheme, only one phase switch bridge arm operates at the same time, avoiding the abnormal increase of common mode current caused by the simultaneous operation of two or three phase switch bridge arms. This can effectively reduce the amplitude and frequency of common mode current, thereby suppressing the common mode current between the motor controller and the motor to a certain extent and improving driving safety.

[0013] In conjunction with the first aspect, in one implementation, during the operation of the motor controller via space vector pulse width modulation, the control circuit responds to the zero torque output of the drive motor and the zero speed of the drive motor. Specifically, the control circuit is used to control the timing of the operation of two switching transistors located in different arms of the three-phase switching transistor bridge.

[0014] Based on the above solution, the motor controller for suppressing common-mode current provided in this application embodiment can control the drive motor using the above modulation strategy when the drive motor outputs zero torque and the speed of the drive motor is zero. This can effectively reduce the amplitude and frequency of the common-mode current, thereby suppressing the common-mode current between the motor controller and the motor to a certain extent and improving driving safety.

[0015] In conjunction with the first aspect, in one implementation, during the operation of the motor controller via space vector pulse width modulation, the control circuit responds to the fact that the torque output by the drive motor is greater than zero and the speed of the drive motor is zero. Specifically, the control circuit controls the timing of the operation of two switching transistors located in different arms of the three-phase switching transistor bridge arm.

[0016] Based on the above solution, the motor controller for suppressing common-mode current provided in this application embodiment can control the drive motor using the above modulation strategy when the torque output by the drive motor is greater than zero and the speed of the drive motor is zero. This can effectively reduce the amplitude and frequency of the common-mode current, thereby suppressing the common-mode current between the motor controller and the motor to a certain extent and improving driving safety.

[0017] In conjunction with the first aspect, in one implementation, during the operation of the motor controller via space vector pulse width modulation, the control circuit responds to the torque output by the drive motor being greater than zero and the speed of the drive motor being less than a preset speed. Specifically, the control circuit controls the timing of the operation of two switching transistors located in different arms of the three-phase switching transistor bridge arm.

[0018] Based on the above solution, the motor controller for suppressing common-mode current provided in this application embodiment can control the drive motor by adopting the above modulation strategy when the torque output by the drive motor is greater than zero and the speed of the drive motor is less than a preset speed, for example, when the drive motor rotates at a speed greater than zero and less than the preset speed. This can effectively reduce the amplitude and frequency of the common-mode current, thereby suppressing the common-mode current between the motor controller and the motor to a certain extent and improving driving safety.

[0019] Secondly, a powertrain is provided, comprising a drive motor and a motor controller. The motor controller controls the output torque of the drive motor and includes an inverter circuit and a control circuit. The inverter circuit includes a three-phase switch bridge arm, each phase switch bridge arm including an upper bridge arm switch and a lower bridge arm switch. The midpoint of each phase switch bridge arm is connected to one phase winding of the drive motor. The control circuit uses space vector pulse width modulation to control the upper and lower bridge arm switches of the three-phase switch bridge arm of the inverter circuit to be turned on or off. During the operation of the motor controller using space vector pulse width modulation, the control circuit controls any two switches located in different bridge arms of the three-phase switch bridge arm to operate at different times. Switch operation refers to the switching of the switch to be turned on or off.

[0020] In conjunction with the second aspect, in one implementation, when the motor controller operates by means of space vector pulse width modulation, when two of the three-phase switch bridge arms need to operate simultaneously to switch the inverter circuit from one vector state to another, the control circuit controls the timing of the operation of the two-phase switch bridge arms to be staggered by a preset time.

[0021] In conjunction with the second aspect, in one implementation, when the motor controller operates via space vector pulse width modulation, and when the three-phase switch bridge arms need to operate simultaneously to switch the inverter circuit from one vector state to another, the control circuit controls the timing of the operation of the three-phase switch bridge arms to be staggered by a preset time interval.

[0022] Thirdly, an electric vehicle is provided, the electric vehicle including a power battery and a powertrain as provided in the second aspect or any implementation thereof, the power battery being used to supply power to the powertrain.

[0023] Understandably, the beneficial effects that any of the powertrains and electric vehicles provided above can achieve can be referred to in the beneficial effects of the motor controllers provided above, and will not be repeated here. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of an electric vehicle provided in an embodiment of this application;

[0025] Figure 2 A circuit topology diagram of a motor controller provided in an embodiment of this application;

[0026] Figure 3 This is a schematic diagram of a voltage space vector in a space vector pulse width modulation scheme.

[0027] Figure 4This is a schematic diagram of the output common-mode voltage and common-mode current of a motor controller using space vector pulse width modulation.

[0028] Figure 5 This is a schematic diagram of a dual-wave region for space vector pulse width modulation.

[0029] Figure 6 This is a schematic diagram of a synthesized vector sequence and common-mode voltage for a modulation strategy.

[0030] Figure 7 This is a schematic diagram of a synthesized vector sequence of a modulation strategy provided in an embodiment of this application;

[0031] Figure 8 A schematic diagram of a synthesized vector sequence for another modulation strategy provided in this application embodiment;

[0032] Figure 9 This is a schematic diagram of a synthesized vector sequence for another modulation strategy provided in an embodiment of this application. Detailed Implementation

[0033] The following sections will discuss the fabrication and use of various embodiments in detail. However, it should be understood that many applicable inventive concepts provided in this application can be implemented in a variety of specific environments. The specific embodiments discussed are merely illustrative of specific ways to implement and use this application and technology, and do not limit the scope of this application.

[0034] Unless otherwise defined, all technical terms used herein have the same meaning as commonly known to one of ordinary skill in the art.

[0035] Before introducing the embodiments of this application, the application scenarios involved in this application will be introduced first.

[0036] Figure 1 This is a schematic diagram of an electric vehicle provided as an embodiment of this application. Figure 1 As shown, the electric vehicle 01 includes a powertrain 10 and a power battery 20. The powertrain 10 can also be referred to as a drive system. The powertrain 10 includes a motor controller 11 and a drive motor 12. During the operation of the electric vehicle 01, the motor controller 11 converts the direct current supplied by the power battery 20 into three-phase alternating current. This three-phase alternating current is used to control the output torque of the drive motor 12 to drive the wheels, thereby propelling the electric vehicle 01. The power battery 20 provided in this embodiment can be a lithium-ion battery, a nickel-metal hydride battery, a lead-acid battery, a sodium battery, etc., and this embodiment does not specifically limit its type.

[0037] Figure 2 An example of a motor controller circuit topology is shown. For example... Figure 2As shown, the motor controller 11 includes an inverter circuit 111. The inverter circuit 111 includes three-phase switch bridge arms. For ease of description, the first phase switch bridge arm will be referred to as phase A, the second phase switch bridge arm as phase B, and the third phase switch bridge arm as phase C. The midpoint of each phase switch bridge arm is used to connect to one phase winding of the drive motor 12, and the two ends of each phase switch bridge arm are used to connect to the power battery 20.

[0038] Specifically, phase A bridge arm includes a first switch Q1 and a second switch Q2 connected in series; phase B bridge arm includes a third switch Q3 and a fourth switch Q4 connected in series; and phase C bridge arm includes a fifth switch Q5 and a sixth switch Q6 connected in series. The aforementioned first to sixth switches Q1 may include metal-oxide-semiconductor field-effect transistors (MOSFETs), also simply referred to as MOS transistors. Each MOS transistor includes a reverse-biased body diode. Alternatively, each switch may include an insulated-gate bipolar transistor (IGBT) and a diode D, with the collector of the IGBT connected to the cathode of the diode D, and the emitter of the IGBT connected to the anode of the diode D. By way of example and not limitation, this embodiment is illustrated using the example of each switch being a MOS transistor.

[0039] Further, such as Figure 2 As shown, the motor controller 11 also includes a control circuit 112, which is used to control the conduction state of the three-phase switch bridge arm in the inverter circuit 111 so that the midpoint of the bridge arm of the three-phase switch bridge arm outputs a three-phase voltage. This three-phase voltage is used to generate a corresponding three-phase current on the drive motor 12 to control the output torque of the drive motor 12.

[0040] The aforementioned control circuit 112 may be a central processing unit (CPU), a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a programmable logic device (PLD), a transistor logic device, a discrete hardware component, or other general-purpose processors.

[0041] Currently, the control circuit 112 typically uses space vector pulse width modulation (SVPWM) to output a control signal to the inverter circuit 111 to control the on or off of each switch in the inverter circuit 111. SVPWM controls the state of each switch in the inverter circuit 111 to synthesize a voltage space vector with a specific direction and magnitude, thereby generating an approximately circular rotating magnetic field to control the drive motor 12. For example, this control signal can be a pulse width modulation (PWM) signal.

[0042] The following combination Figure 3 Further explanation of SVPWM is provided below. Figure 3 As shown, SVPWM includes two zero vectors and six non-zero vectors. The two zero vectors can also be called invalid vectors, and the six non-zero vectors can also be called valid vectors. The six valid vectors divide the space into six sectors, which can be denoted as sector I (represented by the number "I"), sector II (represented by the number "II"), sector III (represented by the number "III"), sector IV (represented by the number "IV"), sector V (represented by the number "V"), and sector VI (represented by the number "VI"). The sectors do not overlap and all have an angle of 60°.

[0043] like Figure 3 As shown, the two zero vectors can be denoted as 000 and 111, and they are located at the center of the vector diagram. The six non-zero vectors are denoted as Ua 100, Ub 010, Uc 001, Ua'011, Ub'101, and Uc'110. Taking Ua100 as an example, combined with... Figure 2 In the circuit topology shown, the first bit "1" indicates that the first switch Q1 in phase A is turned on and the second switch Q2 is turned off; the second bit "0" indicates that the third switch Q3 in phase B is turned off and the fourth switch Q4 is turned on; and the third bit "0" indicates that the fifth switch Q5 in phase C is turned off and the sixth switch Q6 is turned on. In other words, "0" controls the upper switch in a given phase arm to be turned on and the lower switch to be turned off, while "1" controls the upper switch to be turned off and the lower switch to be turned on.

[0044] Taking the angle θ of the target vector voltage as an example, when θ is located in sector I, i.e., 0°≤θ<60°, the target vector voltage can be synthesized by controlling the non-zero vectors Ua 100 and Uc'110, as well as the zero vectors 000 and 111. Specifically, when θ=0°, i.e., when the direction of the target vector voltage is consistent with the direction of the non-zero vector Ua 100, the target vector voltage can be synthesized by controlling the non-zero vector Ua 100, as well as the zero vectors 000 and 111. Therefore, by using six non-zero vectors and two zero vectors to control the different conduction states of the three-phase switching bridge arms in the inverter circuit 111, the inverter circuit 111 can be driven to output the target vector voltage to the drive motor 12.

[0045] With the continuous development of energy technology, in order to meet the functional requirements of intelligence and electrification, electric vehicles are gradually evolving towards higher operating voltage, faster switching speed of power devices (i.e., the switching transistors in the inverter circuit 111), higher switching frequency of power devices, and integrated arrangement of motor controller 11 and drive motor 12.

[0046] However, the gradual increase in operating voltage increases the potential difference of inverter circuit 111, creating more favorable conditions for the generation of common-mode current. The faster switching speed and higher switching frequency of the switching transistors lead to more frequent state switching in inverter circuit 111, easily causing electromagnetic interference and consequently generating common-mode current. Meanwhile, while the integrated arrangement of motor controller 11 and drive motor 12 offers significant advantages in terms of space utilization and system integration, it also results in a more complex circuit structure and enhanced electromagnetic coupling between different components, further exacerbating the common-mode current problem. Common-mode current not only affects the normal operation of the electrical system in electric vehicles, causing signal transmission errors and equipment performance degradation, but it can also interfere with surrounding electronic equipment and even pose safety hazards.

[0047] Figure 4 This is a schematic diagram of the common-mode voltage and common-mode current output by a motor controller using SVPWM. Figure 4 As shown, located Figure 4 The waveform above is used to illustrate the common-mode current, located at... Figure 4 The waveform at the bottom center is used to illustrate the common-mode voltage. The common-mode voltage refers to the voltage between the neutral point of the three-phase windings of the drive motor 12 and the reference potential.

[0048] like Figure 4 As shown, at some modulation points of SVPWM, i.e. Figure 4 Within the dashed box, it is clear that the common-mode current has increased abnormally and the common-mode voltage has changed from the original four levels to three levels. This is because two or all three phases of the three-phase switch bridge arms in the inverter circuit are operating simultaneously.

[0049] Currently, to reduce common-mode current, a three-phase common-mode magnetic ring is typically added between the connection path of the inverter circuit 111 and the drive motor winding 12. However, during these periods of abnormally high common-mode current, not only does the thermal stress on the three-phase magnetic ring increase significantly, accelerating its aging process and reducing its reliability, but it also exacerbates the electromagnetic compatibility (EMC) issues of the electronic control system, thereby interfering with the normal operation of other electronic devices within the vehicle system.

[0050] For ease of description, the waveform generated by the simultaneous operation of the switching transistors in the two or three switching arms of the bridge is called a double wave, and the region where the double wave appears is simply referred to as the double wave region. For example, the double wave region is as follows: Figure 5 As shown. For example, at the edges of two sectors, double waves are more likely to occur if the target vector voltage is aligned with the direction of the non-zero vector.

[0051] See Figure 5 When using SVPWM control, multiple double waves will appear within one fundamental cycle, meaning that multiple passes of double waves will occur. Figure 5 The dual-wave region in the text. The fundamental frequency refers to the period corresponding to the electrical fundamental frequency during the operation of the drive motor 12. This fundamental frequency is the main frequency used to control the sinusoidal voltage or sinusoidal current of the stator winding in the drive motor 12, and is directly related to the desired speed of the drive motor 12.

[0052] For example, such as Figure 6 As shown, during the entire modulation process, the vector states output by the three-phase switching bridge arms are sequentially: "000", "100", "111", "111", "111", "100", and "000". At time T0, the three-phase switching bridge arms switch from vector state "100" to vector state "111", with the upper bridge arm switches of phase B and phase C simultaneously turning on and the lower bridge arm switches simultaneously turning off. At time T1, the three-phase switching bridge arms switch from vector state "111" to vector state "100", with the lower bridge arm switches of phase B and phase C simultaneously turning on and the upper bridge arm switches simultaneously turning off. Time T0 and T1 are the times when phase B and phase C operate simultaneously, respectively. At times T0 and T1, the common-mode current of the inverter circuit will increase abnormally.

[0053] In view of this, embodiments of this application provide a motor controller, powertrain, and electric vehicle for suppressing common-mode current. Based on the generation mechanism of common-mode current, the amplitude and frequency of common-mode current are effectively reduced by controlling the on and off of the three-phase switch bridge arms in the inverter circuit 111, thereby avoiding problems caused by excessive common-mode current.

[0054] This application provides a motor controller for suppressing common-mode current, the topology of which is as follows: Figure 2 As shown.

[0055] In one embodiment, the motor controller 11 includes an inverter circuit 111 and a control circuit 112. The inverter circuit 111 includes three-phase switching transistor bridge arms, each phase including an upper bridge arm switch and a lower bridge arm switch. The control circuit 112 uses space vector pulse width modulation to control the upper and lower bridge arm switches of the three-phase switching transistor bridge arms of the inverter circuit 111 to be turned on or off. For example, the control circuit 112 can generate drive signals for each switch using space vector pulse width modulation and output the drive signals to each switch to drive each switch.

[0056] During the operation of the motor controller 11 using space vector pulse width modulation, the control circuit 112 controls the timing of the action of any two switching transistors located in different arms of the three-phase switching transistor bridge. The action of the switching transistor refers to the switching transistor being turned on or off.

[0057] The following combination Figure 2 The topology of the motor controller 11 shown illustrates that the timing of operation of the two switching transistors located in different arms of the three-phase switching transistor bridge is different.

[0058] For example, when control circuit 112 outputs drive signals to the upper and lower bridge arm switches of phase A to change the conduction state of phase A, the switches in phase B and phase C remain in their previous states to avoid operating simultaneously with the switches in phase A. Similarly, when control circuit 112 outputs drive signals to the upper and lower bridge arm switches of phase B to change the conduction state of phase B, the switches in phase A and phase C remain in their previous states to avoid operating simultaneously with the switches in phase B. Likewise, when control circuit 112 outputs drive signals to the upper and lower bridge arm switches of phase C to change the conduction state of phase C, the switches in phase A and phase B remain in their previous states to avoid operating simultaneously with the switches in phase C. As can be seen from the above, at the same time, only the switch tube on one of the three-phase switch tube bridge arms will operate.

[0059] In this embodiment, during the operation of the motor controller 11 via space vector pulse width modulation, the control circuit 112 controls the timing of the operation of two switches located in different arms of the three-phase switch bridge arm. This results in the timing of the operation of any two switches in the three-phase switch bridge arm being different, meaning that only one switch bridge arm operates at any given time. This avoids the situation where the common-mode current increases abnormally due to the simultaneous operation of two or three switches bridge arms, effectively reducing the amplitude and frequency of the common-mode current. Consequently, it suppresses the common-mode current between the motor controller 11 and the motor to a certain extent, improving driving safety.

[0060] In one embodiment, during the operation of the motor controller 11 using space vector pulse width modulation, when two phase switching bridge arms in the three-phase switching bridge arm need to operate simultaneously to switch the inverter circuit 111 from one vector state to another, the control circuit 112 controls the timing of the two phase switching bridge arms to be staggered by a preset time t. For example, the preset time t can be 1 microsecond (μs). The preset time t can be used to indicate the duration of the double wave stagger, and this embodiment of the application does not specifically limit it in this way.

[0061] The staggered timing of the two phase switch bridge arms indicates that one phase switch bridge arm operates first, followed by the other phase switch bridge arm.

[0062] In one example, combining Figure 6 ,like Figure 7 As shown. At time T0, both phase B and phase C of the inverter circuit need to operate simultaneously to switch the inverter circuit 111 from vector state "100" to vector state "111". The control circuit 112 controls the timing of the operation of phase B and phase C to be staggered by a preset time t, that is, phase B operates at time T0, and phase C operates at time T0+t after a preset time t. At time T1, both phase B and phase C of the inverter circuit need to operate simultaneously to switch the inverter circuit 111 from vector state "111" to vector state "100". The control circuit 112 controls the timing of the operation of phase B and phase C to be staggered by a preset time t, that is, phase B operates at time T1, and phase C operates at time T1+t after a preset time t.

[0063] Continue reading Figure 7During the process of inverter circuit 111 switching from vector state "100" to vector state "111", at time T0, inverter circuit 111 first switches from vector state "100" to vector state "110", and at time T0+t, inverter circuit 111 then switches from vector state "110" to vector state "111", thus completing the process of switching from vector state "100" to vector state "111". During the process of inverter circuit 111 switching from vector state "111" to vector state "100", at time T1, inverter circuit 111 first switches from vector state "111" to vector state "101", and at time T1+t, inverter circuit 111 then switches from vector state "101" to vector state "111", thus completing the process of switching from vector state "111" to vector state "100".

[0064] Depend on Figure 3 As shown in the voltage space vector diagram, Uc'110 and Ub'101 are two adjacent non-zero vectors of Ua 100. Furthermore, by controlling the duration of action of vector Uc'110 and vector Ub'101 to be the same, Uc'110 and Ub'101 can be combined to form vector Ua 100. Therefore, during the switching process of inverter circuit 111 from vector state "100" to vector state "111", Uc'110 is inserted and its duration is controlled to a preset duration t. Similarly, during the switching process of inverter circuit 111 from vector state "111" to vector state "100", Ub'101 is inserted and its duration is controlled to a preset duration t. In this way, only one phase switch bridge arm operates at any given time, and the effect is the same as if both phase switch bridge arms operated simultaneously.

[0065] In another example, combining Figure 6 ,like Figure 8 As shown. At time T0, both phase B and phase C of the inverter circuit need to operate simultaneously to switch the inverter circuit 111 from vector state "100" to vector state "111". The control circuit 112 controls the timing of the operation of phase B and phase C to be staggered by a preset time t, that is, phase B operates at time T0, and phase C operates a preset time t in advance at time T0-t. At time T1, both phase B and phase C of the inverter circuit need to operate simultaneously to switch the inverter circuit 111 from vector state "111" to vector state "100". The control circuit 112 controls the timing of the operation of phase B and phase C to be staggered by a preset time t, that is, phase B operates at time T1, and phase C operates a preset time t in advance at time T1-t.

[0066] See Figure 7 and Figure 8During the process of the inverter circuit 111 switching from vector state "100" to vector state "111" or from vector state "111" to vector state "100", the timing of the action of the B-phase bridge arm and the C-phase bridge arm can be staggered by a preset time t. This can control the B-phase bridge arm to act ahead of the C-phase bridge arm, or control the C-phase bridge arm to act ahead of the B-phase bridge arm.

[0067] In one embodiment, when the motor controller 11 is operating in a space vector pulse width modulation manner, and when the three-phase switch bridge arms need to operate simultaneously to switch the inverter circuit 111 from one vector state to another, the control circuit 112 controls the timing of the operation of the three-phase switch bridge arms to be staggered by a preset time t.

[0068] For example, such as Figure 9 As shown, at time T2, phase A, phase B, and phase C bridge arms need to operate simultaneously to switch inverter circuit 111 from vector state "000" to vector state "111". Control circuit 112 controls the timing of the operation of phase A, phase B, and phase C bridge arms to be staggered by a preset time t. That is, phase A bridge arm operates at time T2, phase B bridge arm operates at time T2+t after a preset time t delay, and phase C bridge arm operates at time T2+2t after another preset time t delay. Similarly, at time T3, phase A, phase B, and phase C bridge arms need to operate simultaneously to switch inverter circuit 111 from vector state "111" to vector state "000". The control circuit 112 is used to control the timing of the operation of the A-phase bridge arm, the B-phase bridge arm and the C-phase bridge arm to be staggered by a preset time t. That is, the A-phase bridge arm operates at time T3, the B-phase bridge arm operates at time T3+t after a preset time t, and the C-phase bridge arm operates at time T3+2t after a further preset time t.

[0069] Depend on Figure 3As shown in the voltage space vector diagram, Ua 100 and Ua'011 are two non-zero vectors with opposite directions, and Uc 001 and Uc'110 are also two non-zero vectors with opposite directions. By controlling the duration of action of Ua 100 and Ua'011 to be the same, Ua 100 and Ua'011 can be made to combine into a zero vector. Similarly, by controlling the duration of action of Uc 001 and Uc'110 to be the same, Uc 001 and Uc'110 can also be made to combine into a zero vector. Therefore, during the transition of inverter circuit 111 from vector state "000" to vector state "111", Ua 100 and Uc'110 are inserted, and their durations are controlled to be a preset duration t. Furthermore, during the transition of inverter circuit 111 from vector state "111" to vector state "000", Ua'011 and Uc 001 are inserted, and their durations are controlled to be a preset duration t. Thus, although only one phase switch bridge arm operates at any given time, the effect is the same as if all three phase switch bridge arms operated simultaneously.

[0070] This is an example, not a limitation. Figure 9 The example only illustrates the case where phase B and phase C arms lag behind phase A arms in sequence. In practical applications, phase B and phase C arms can also move ahead of phase A arms in sequence. This application does not specifically limit this.

[0071] Furthermore, if t1 represents the preset time for the A-phase bridge arm and the B-phase bridge arm to be staggered, and t2 represents the preset time for the B-phase bridge arm and the C-phase bridge arm to be staggered, then t1 and t2 can be equal or unequal. This application does not specifically limit this. Figure 9 The example shown is t1 = t2 = t.

[0072] The operation of the motor controller 11 provided in the embodiments of this application has been described above with reference to the accompanying drawings. The actual application scenarios of the embodiments of this application will be further described below in conjunction with the operating conditions of electric vehicles.

[0073] In the first example, during the operation of the motor controller 11 by space vector pulse width modulation, the control circuit 112 responds to the zero torque output of the drive motor 12 and the zero speed of the drive motor 12. Specifically, the control circuit 112 is used to control the timing of the operation of two switching tubes located in different arms of the three-phase switching tube bridge.

[0074] Specifically, when the drive motor 12 outputs zero torque and its speed is zero, the electric vehicle is in a parked state. At this time, the electric vehicle is in neutral or the driver has not pressed the accelerator or brake pedal. The control circuit 112 is used to control the A-phase bridge arm, B-phase bridge arm, and C-phase bridge arm to be in vector state "000", or in vector state "111", or to switch between vector state "111" and vector state "000".

[0075] On the one hand, in order to avoid switching losses and maintain the stability of DC bus voltage, the A-phase bridge arm, B-phase bridge arm and C-phase bridge arm can be controlled to maintain a fixed switching state, such as the lower bridge arm switch of all bridge arms being turned on (i.e., in the "000" vector state), or the upper bridge arm switch of all bridge arms being turned on (i.e., in the "111" vector state).

[0076] On the other hand, in order to ensure the continuity of the transmission timing and the balance of the bridge arm switching, the vector state "000" and the vector state "111" can be used alternately. When the three-phase switching bridge arms need to operate simultaneously to switch the inverter circuit 111 from one vector state (e.g., vector state "000") to another vector state (e.g., vector state "111"), the control circuit 112 controls the timing of the operation of the three-phase switching bridge arms to be staggered by a preset time t.

[0077] In the second example, during the operation of the motor controller 11 by space vector pulse width modulation, the control circuit 112 responds to the torque output by the drive motor 12 being greater than zero and the speed of the drive motor 12 being zero. Specifically, the control circuit 112 is used to control the timing of the operation of two switching tubes located in different arms of the three-phase switching tube bridge arm.

[0078] Specifically, when the torque output by the drive motor 12 is greater than zero and the speed of the drive motor 12 is zero, the drive motor 12 is in a stalled state. At this time, the electric vehicle may start on a slope, and the drive motor 12 needs to output the maximum static torque. Based on the effective vector of the sector where the angle θ of the target vector voltage is located, the control circuit 112 is used to control the synthesis of the target voltage vector by the two adjacent effective vectors of that sector, and to ensure the maximization of the target voltage vector amplitude.

[0079] When angle θ approximately coincides with the angles of the six non-zero vectors, that is, when the vector direction of the target vector voltage is located at... Figure 5 In the dual-wave region shown, when two of the three-phase switch bridge arms need to operate simultaneously to switch the inverter circuit 111 from one vector state to another, the control circuit 112 controls the timing of the operation of the two switches located in different bridge arms to be different, so that the timing of the operation of the two-phase switch bridge arms is staggered by a preset time t.

[0080] In the third example, during the operation of the motor controller 11 by space vector pulse width modulation, the control circuit 112 responds to the torque output by the drive motor 12 being greater than zero and the speed of the drive motor 12 being less than the preset speed. Specifically, the control circuit 112 is used to control the timing of the operation of two switching tubes located in different arms of the three-phase switching tube bridge arm.

[0081] When the torque output by the drive motor 12 is greater than zero and the speed of the drive motor 12 is less than the preset speed, the electric vehicle may be in a low-speed driving state, or it may be in a high-speed driving state or an emergency acceleration state.

[0082] When an electric vehicle is traveling at low speed, more zero vectors need to be inserted into the effective vector to reduce the proportion of the effective vector, thereby reducing the amplitude of the equivalent drive voltage. When an electric vehicle is traveling at high speed or accelerating suddenly, fewer zero vectors need to be inserted into the effective vector to increase the proportion of the effective vector, thereby increasing the amplitude of the equivalent drive voltage. The control circuit 112 is used to control the synthesis of the target voltage vector from two adjacent effective vectors in the sector containing the angle θ of the target vector voltage.

[0083] When angle θ approximately coincides with the angles of the six non-zero vectors, that is, when the vector direction of the target vector voltage is located at... Figure 5 In the dual-wave region shown, when two of the three-phase switch bridge arms need to operate simultaneously to switch the inverter circuit 111 from one vector state to another, the control circuit 112 controls the timing of the operation of the two switches located in different bridge arms to be different, so that the timing of the operation of the two-phase switch bridge arms is staggered by a preset time t.

[0084] Furthermore, when the torque output by the drive motor 12 is greater than zero and the speed of the drive motor 12 is less than a preset speed, the electric vehicle may also be in a braking and generating state. In this case, it is necessary to select a vector opposite to the back electromotive force of the drive motor 12, that is, to select the effective vector of the reverse sector, and insert a zero vector into the effective vector to adjust the rate of energy feedback. At this time, the control circuit 112 controls the target voltage vector output by the inverter circuit 111 to be opposite to the back electromotive force of the drive motor 12, forming a reverse magnetic field, causing the motor to operate as a generator. When there is a need for two phase switching bridge arms in the three-phase switching bridge to operate simultaneously to switch the inverter circuit 111 from one vector state to another, the control circuit 112 controls the timing of the two phase switching bridge arms to be staggered by a preset time t.

[0085] As can be seen from the above, the motor controller 11 for suppressing common-mode current provided in this application embodiment can use the above modulation strategy to control the drive motor 12 under different operating conditions of electric vehicles, thereby effectively reducing the amplitude and frequency of common-mode current, and thus suppressing the common-mode current between the motor controller 11 and the motor to a certain extent, thereby improving driving safety.

[0086] This application also provides a powertrain, the structure of which can be referred to... Figure 1 and Figure 2 The system includes a drive motor and a motor controller. The motor controller controls the output torque of the drive motor and includes an inverter circuit and a control circuit. The inverter circuit includes three-phase switch bridge arms, with the midpoint of each bridge arm connected to one phase winding of the drive motor. The control circuit uses space vector pulse width modulation (SVM) to control the upper and lower bridge arm switches of the three-phase switch bridge arms of the inverter circuit to turn on or off. Specifically, during the operation of the motor controller using SVM, the control circuit controls the timing of the actions of any two switches located in different bridge arms of the three-phase switch bridge arms; switch action refers to the switching on or off of the switch.

[0087] This application also provides an electric vehicle, the structure of which can be referred to... Figure 1 Electric vehicles include a power battery and a powertrain, the power battery supplying power to the powertrain. The structure of the powertrain can be found in [reference needed]. Figure 1 and Figure 2 .

[0088] The above detailed description of the motor controller and the analysis of its beneficial effects can be applied to powertrains and electric vehicles, and will not be repeated here in the embodiments of this application.

[0089] Finally, it should be noted that the above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A motor controller for suppressing common-mode current, characterized in that, The motor controller is used to control the output torque of the drive motor. The motor controller includes an inverter circuit and a control circuit. The inverter circuit includes three-phase switching transistor bridge arms, each phase of which includes an upper bridge arm switch and a lower bridge arm switch. The control circuit uses space vector pulse width modulation to control the upper and lower bridge arm switches of the three-phase switching transistor bridge arms of the inverter circuit to turn on or off, wherein: During the operation of the motor controller via space vector pulse width modulation, the control circuit controls any two switching transistors located in different arms of the three-phase switching transistor bridge to operate at different times. The operation of the switching transistors refers to the switching transistors being turned on or off.

2. The motor controller according to claim 1, characterized in that, During the operation of the motor controller via space vector pulse width modulation, when two of the three-phase switch bridge arms need to operate simultaneously to switch the inverter circuit from one vector state to another, the control circuit controls the timing of the operation of the two-phase switch bridge arms to be staggered by a preset time.

3. The motor controller according to claim 1, characterized in that, During the operation of the motor controller using space vector pulse width modulation, when the three-phase switch bridge arms need to operate simultaneously to switch the inverter circuit from one vector state to another, the control circuit controls the timing of the operation of the three-phase switch bridge arms to be staggered by a preset time interval.

4. The motor controller according to any one of claims 1-3, characterized in that, During the operation of the motor controller using space vector pulse width modulation, the control circuit is specifically used for: In response to the drive motor outputting zero torque and the drive motor rotating at zero speed, the timing of the operation of the two switching transistors located in different arms of the three-phase switching transistor bridge is controlled to be different.

5. The motor controller according to any one of claims 1-3, characterized in that, During the operation of the motor controller using space vector pulse width modulation, the control circuit is specifically used for: In response to the torque output by the drive motor being greater than zero and the speed of the drive motor being zero, the timing of the operation of the two switching transistors located in different arms of the three-phase switching transistor bridge is controlled to be different.

6. The motor controller according to any one of claims 1-3, characterized in that, During the operation of the motor controller using space vector pulse width modulation, the control circuit is specifically used for: In response to the torque output by the drive motor being greater than zero and the speed of the drive motor being less than a preset speed, the operating times of the two switching transistors located in different arms of the three-phase switching transistor bridge are controlled to be different.

7. A powertrain, characterized in that, The powertrain includes a drive motor and a motor controller. The motor controller controls the output torque of the drive motor. The motor controller includes an inverter circuit and a control circuit. The inverter circuit includes three-phase switch arms, each phase of which includes an upper switch arm and a lower switch arm. The midpoint of each phase switch arm is connected to one phase winding of the drive motor. The control circuit uses space vector pulse width modulation to control the upper and lower switch arms of the three-phase switch arms of the inverter circuit to turn on or off. During the operation of the motor controller via space vector pulse width modulation, the control circuit controls any two switching transistors located in different arms of the three-phase switching transistor bridge to operate at different times. The operation of the switching transistors refers to the switching transistors being turned on or off.

8. The powertrain according to claim 7, characterized in that, During the operation of the motor controller via space vector pulse width modulation, when two of the three-phase switch bridge arms need to operate simultaneously to switch the inverter circuit from one vector state to another, the control circuit controls the timing of the operation of the two-phase switch bridge arms to be staggered by a preset time.

9. The powertrain according to claim 8, characterized in that, During the operation of the motor controller using space vector pulse width modulation, when the three-phase switch bridge arms need to operate simultaneously to switch the inverter circuit from one vector state to another, the control circuit controls the timing of the operation of the three-phase switch bridge arms to be staggered by a preset time interval.

10. An electric vehicle, characterized in that, The electric vehicle includes a power battery and a powertrain as described in any one of claims 7-9, wherein the power battery is used to supply power to the powertrain.

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