WO2024093551A1

WO2024093551A1 - Motor controller, control unit, electric drive system, and electric vehicle

Info

Publication number: WO2024093551A1
Application number: PCT/CN2023/119330
Authority: WO
Inventors: 李迎
Original assignee: 华为数字能源技术有限公司
Priority date: 2022-10-31
Filing date: 2023-09-18
Publication date: 2024-05-10
Also published as: CN115648966A

Abstract

A motor controller (2010), a control unit (2014), an electric drive system (201), and an electric vehicle (20). Three phases of windings of a drive motor (2013) and a power battery (202) can be used in conjunction to form a discharge circuit, to heat the power battery (202), and thus the heating duration can be shortened and the heating efficiency can be improved. The motor controller (2010) comprises three bridge arms, wherein two ends of each bridge arm are respectively adapted to be connected to a positive electrode and a negative electrode of the power battery (202), and operation modes of the three bridge arms comprise a heating mode and an inversion mode, wherein when the three bridge arms operate in the inversion mode, the three bridge arms are used for receiving power supplied by the power battery (202) and supplying power to U-, V- and W-phase windings of the drive motor (2013), and when the three bridge arms operate in the heating mode, an upper bridge switching transistor of one of the three bridge arms is periodically electrically connected to lower bridge switching transistors of the other two bridge arms, or a lower bridge switching transistor of one of the three bridge arms is periodically electrically connected to upper bridge switching transistors of the other two bridge arms.

Description

Motor controller, control unit, electric drive system and electric vehicle

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to the Chinese patent application filed with the Intellectual Property Office of the People's Republic of China on October 31, 2022, with application number 202211366326.7 and invention name "A motor controller, control unit, electric drive system and electric vehicle", the entire contents of which are incorporated by reference in this application.

Technical Field

The present application relates to the field of new energy vehicle technology, and in particular to a motor controller, a control unit, an electric drive system and an electric vehicle.

Background technique

In low-temperature environments, high-current discharge of power batteries is prone to lithium deposition, which can cause battery capacity decay and even lead to battery safety hazards. Therefore, when the ambient temperature is low, electric vehicles need to heat the power battery so that the power battery reaches the preset temperature before it supplies power to the drive motor to enable the electric vehicle to travel.

In the first type of battery heating method, a positive temperature coefficient (PTC) resistor is used to directly heat the water path of the power battery. In the second type of battery heating method, the heat generated by the drive motor of the electric vehicle is used to heat the water path, thereby heating the power battery.

Both of these methods heat the power battery by heating the water circuit, which has low heating efficiency and takes about 30 minutes to heat.

Summary of the invention

The present application provides a motor controller, a control unit, an electric drive system and an electric vehicle, which can reuse the three-phase winding of the drive motor and the power battery to form a discharge circuit to heat the power battery, and can shorten the heating time and improve the heating efficiency.

In the first aspect, an embodiment of the present application provides a motor controller for an electric vehicle drive motor, which may include three bridge arms, and the two ends of each bridge arm can be connected to the positive and negative poles of the power battery respectively, so that the three bridge arms are in parallel. Usually the drive motor includes three-phase windings, which are respectively recorded as U-phase winding, V-phase winding, and W-phase winding. In the motor controller, the midpoints of the three bridge arms are respectively used to connect the three-phase windings of the drive motor. The three bridge arms in the motor controller in the embodiment of the present application can have multiple operating modes. Multiple operating modes may include but are not limited to heating mode and inverter mode.

In the embodiment of the present application, when the three bridge arms are operated in the inverter mode, the three bridge arms can receive power from the power battery and power the U-phase winding, V-phase winding, and W-phase winding of the drive motor. The power battery provides direct current to the three bridge arms, and when the three bridge arms are operated in the inverter mode, they provide alternating current to the three-phase winding of the drive motor. When the three bridge arms are operated in the heating mode, the upper bridge switch tube of one of the three bridge arms and the lower bridge switch tubes in the other two bridge arms are periodically turned on, so that the power battery, the upper bridge switch tube that is turned on, the two-phase winding of the drive motor, and the two lower bridge switch tubes that are turned on can form a discharge circuit, and the internal resistance of the power battery is heated under the action of the current in the discharge circuit to achieve heating of the power battery. Alternatively, the lower bridge switch tube of one of the three bridge arms and the upper bridge switch tubes in the other two bridge arms are periodically turned on, so that the power battery, the lower bridge switch tube that is turned on, the two-phase winding of the drive motor, and the two upper bridge switch tubes that are turned on form a discharge circuit. This design does not require adding water channels to the power battery, and has a shorter heating time and higher heating efficiency.

In one possible design, the motor controller can operate the three bridge arms in a heating mode in response to the temperature of the power battery being less than a first temperature threshold; and operate the three bridge arms in an inverter mode in response to the temperature of the power battery being greater than or equal to the first temperature threshold.

In the embodiment of the present application, when the temperature of the power battery is less than the first temperature threshold, the three bridge arms operate in a heating mode, so that the internal resistance of the power battery generates heat, thereby heating the power battery. When the temperature of the power battery is greater than or equal to the first temperature threshold, the three bridge arms in the motor controller can operate in an inverter mode, providing AC current to the three-phase bridge arms, so that the drive motor can drive the wheels of the electric vehicle.

In one possible design, when the three bridge arms operate in the heating mode, according to the rotor position angle of the drive motor, the upper bridge switch tube of one of the three bridge arms and the lower bridge switch tubes in the other two bridge arms are cyclically turned on, and the rotor position angle represents the angle between the N pole of the rotor in space and a reference direction, and the reference direction is the direction in which the center of the rotor points to the U-phase winding in the three-phase stator winding.

In the embodiment of the present application, the motor controller can, according to the rotor position angle, periodically turn on the upper bridge switch tube of one of the three bridge arms and the lower bridge switch tubes in the other two bridge arms, or periodically turn on the lower bridge switch tube of one of the three bridge arms and the upper bridge switch tubes in the other two bridge arms, so that the current output by the power battery is larger, thereby improving the heating efficiency of the power battery.

In a possible design, the upper bridge switch tube of one of the three bridge arms and the lower bridge switch tubes in the other two bridge arms are turned on for the first duration in each cycle, or the lower bridge switch tube of one of the three bridge arms and the upper bridge switch tubes in the other two bridge arms are turned on for the first duration in each cycle. The first duration is less than or equal to half of the duration of each cycle, which can achieve heating of the power battery and reduce the switching losses of the three bridge arms. Optionally, when the conduction duration is equal to half of the duration of a switching cycle, the DC current output by the power battery can reach the maximum current.

In one possible design, the motor controller can respond to the rotor position angle belonging to the first angle set, and the upper bridge switch tube of the bridge arm corresponding to the U-phase winding, the lower bridge switch tube of the bridge arm corresponding to the V-phase winding, and the lower bridge switch tube in the bridge arm corresponding to the W-phase winding are periodically turned on, or the lower bridge switch tube of the bridge arm corresponding to the U-phase winding, the upper bridge switch tube of the bridge arm corresponding to the V-phase winding, and the upper bridge switch tube in the bridge arm corresponding to the W-phase winding are periodically turned on, so that the power battery outputs direct current to the V and W phase windings of the drive motor. The first angle set includes the rotor position angle belonging to any one of the angle intervals [0, θ _m ], the angle interval [0, θ _m ], the angle interval (θ _m +120, θ _m +180], and the angle interval (θ _m +300, 360), wherein θ _m is less than or equal to 60°, and θ _m is a positive number.

In an embodiment of the present application, the motor controller may compare the rotor position angle with a first angle set, and the first angle set includes one or more preset angle intervals. Optionally, the first angle set may include an angle interval [0, θ _m ], an angle interval [0, θ _m ], an angle interval (θ _m +120, θ _m +180], and an angle interval (θ _m +300, 360). The motor controller may respond to the rotor position angle belonging to the first angle set, and the upper bridge switch tube of the bridge arm corresponding to the U-phase winding, the lower bridge switch tube of the bridge arm corresponding to the V-phase winding, and the lower bridge switch tube in the bridge arm corresponding to the W-phase winding are periodically turned on, and the conduction time may be less than or equal to half of the duration of a switching cycle, which can achieve heating of the power battery and reduce the switching loss of the three bridge arms. Optionally, when the conduction time is equal to half of the duration of a switching cycle, the power battery output DC current can reach the maximum current.

In one possible design, the motor controller can respond to the rotor position angle belonging to the second angle set, and the upper bridge switch tube of the bridge arm corresponding to the W-phase winding, the lower bridge switch tube of the bridge arm corresponding to the V-phase winding, and the lower bridge switch in the bridge arm corresponding to the U-phase winding are periodically turned on, or the lower bridge switch tube of the bridge arm corresponding to the W-phase winding, the upper bridge switch tube of the bridge arm corresponding to the V-phase winding, and the upper bridge switch tube in the bridge arm corresponding to the U-phase winding are periodically turned on, so that the power battery outputs direct current to the V and W phase windings of the drive motor. The second angle set includes the rotor position angle belonging to the angle interval (θ _m , θ _m +60] and the angle interval (θ _m +180, θ _m +240], wherein θ _m is less than or equal to 60°, and θ _m is a positive number.

In an embodiment of the present application, the motor controller can compare the rotor position angle with a second angle set, and the second angle set includes one or more preset angle intervals. Optionally, the second angle set may include an angle interval (θ _m , θ _m +60] and an angle interval (θ _m +180, θ _m +240]. The motor controller may respond to the rotor position angle belonging to the second angle set, and the upper bridge switch tube of the bridge arm corresponding to the W-phase winding, the lower bridge switch tube of the bridge arm corresponding to the V-phase winding, and the lower bridge switch in the bridge arm corresponding to the U-phase winding are periodically turned on, and the conduction time may be less than or equal to half of the duration of a switching cycle, which can achieve heating of the power battery and reduce the switching loss of the three bridge arms. Optionally, when the conduction time is equal to half of the duration of a switching cycle, the power battery output DC current can reach the maximum current.

In one possible design, the motor controller can respond to the rotor position angle belonging to a third angle set, and the upper bridge switch tube of the bridge arm corresponding to the V-phase winding, the lower bridge switch tube of the bridge arm corresponding to the W-phase winding, and the lower bridge switch in the bridge arm corresponding to the U-phase winding are periodically turned on, or the lower bridge switch tube of the bridge arm corresponding to the V-phase winding, the upper bridge switch tube of the bridge arm corresponding to the W-phase winding, and the upper bridge switch tube in the bridge arm corresponding to the U-phase winding are periodically turned on, so that the power battery outputs direct current to the U and W phase windings of the drive motor. The third angle set includes the rotor position angle belonging to the angle interval (θ _m +60, θ _m +120] and the angle interval (θ _m +240, θ _m +300], wherein θ _m is less than or equal to 60°, and θ _m is a positive number.

In an embodiment of the present application, the motor controller can compare the rotor position angle with a third angle set, and the third angle set includes one or more preset angle intervals. Optionally, the third angle set may include an angle interval (θ _m +60, θ _m +120] and an angle interval (θ _m +240, θ _m +300]. The motor controller can respond to the rotor position angle belonging to the third angle set, and the upper bridge switch tube of the bridge arm corresponding to the W-phase winding, the lower bridge switch tube of the bridge arm corresponding to the V-phase winding, and the lower bridge switch in the bridge arm corresponding to the U-phase winding are periodically turned on, and the conduction time can be less than or equal to half of the duration of a switching cycle, which can achieve heating of the power battery and reduce the switching loss of the three bridge arms. Optionally, when the conduction time is equal to half of the duration of a switching cycle, the power battery output DC current can reach the maximum current.

In one possible design, the three bridge arms in the motor controller operate in a heating mode, and the motor controller can respond to the three-phase winding Any one of

The temperature of the three-phase winding is greater than the preset winding temperature threshold or the temperature of any one of the switch tubes in the three bridge arms is greater than the preset switch tube temperature threshold, the conduction time of the switch tube that is turned on is reduced in the next cycle to reduce the DC current output by the power battery and reduce the DC current in the discharge circuit, which can reduce the heat generated by the three-phase winding or the heat generated by the switch tube that is turned on.

In one possible design, the three bridge arms in the motor controller operate in a heating mode. The motor controller can respond to the temperature of the three switching tubes turned on in the three bridge arms being greater than a preset switching tube temperature threshold. The conduction time of the three switching tubes turned on in the next cycle is reduced to reduce the DC current output by the power battery and reduce the DC current in the discharge circuit, which can reduce the heat generated by the switching tubes turned on.

In the second aspect, an embodiment of the present application provides a control unit for a motor controller, the motor controller is used to receive power from a power battery and to power the three-phase winding of the drive motor. Usually, the drive motor includes a three-phase winding, which is respectively recorded as a U-phase winding, a V-phase winding, and a W-phase winding. The motor controller may include three bridge arms, and the midpoints of the bridge arms of the three bridge arms are respectively used to connect the three-phase windings of the drive motor. The three bridge arms in the motor controller in the embodiment of the present application may have multiple operating modes. Multiple operating modes may include but are not limited to heating mode and inverter mode. Among them, when the control unit controls the three bridge arms to operate in the heating mode, the control unit controls the upper bridge switch tube of one of the three bridge arms and the lower bridge switch tubes in the other two bridge arms to be turned on cyclically. When the control unit controls the three bridge arms to operate in the inverter mode, the control unit controls the three bridge arms to output alternating current to the U, V, and W phase windings of the drive motor.

In the embodiment of the present application, when the control unit can control the three bridge arms to operate in the inverter mode, the control unit controls the three bridge arms to output AC power to the U, V, and W phase windings of the drive motor, so that the drive motor can drive the wheels of the electric vehicle. The control unit can control the upper bridge switch tube of one of the three bridge arms and the lower bridge switch tubes in the other two bridge arms to be turned on periodically, or control the lower bridge switch tube of one of the three bridge arms and the upper bridge switch tubes in the other two bridge arms to be turned on periodically, so that the power battery, the upper bridge switch tube that is turned on, the two-phase windings of the drive motor, and the two lower bridge switch tubes that are turned on can form a discharge circuit, and the internal resistance of the power battery is heated under the action of the current in the discharge circuit, so as to achieve heating of the power battery, with a shorter heating time, higher heating efficiency, and no need to add a water channel at the power battery.

In a possible design, the control unit can control the three bridge arms to operate in the heating mode, and according to the rotor position angle of the drive motor, control the upper bridge switch tube of one of the three bridge arms and the lower bridge switch tubes in the other two bridge arms to be periodically turned on, and the rotor position angle represents the angle between the N pole of the rotor in space and a reference direction, and the reference direction is the direction from the center of the rotor to the U-phase winding in the three-phase stator winding.

In the embodiment of the present application, the control unit can control the upper bridge switch tube of one of the three bridge arms and the lower bridge switch tubes in the other two bridge arms to be turned on cyclically according to the rotor position angle, so that the current output by the power battery is larger, thereby improving the heating efficiency of the power battery.

In one possible design, the control unit can be used to control the upper bridge switch tube of the bridge arm corresponding to one phase winding of the U, V, and W three-phase windings and the lower bridge switch tube of the bridge arm corresponding to the other two phase windings of the U, V, and W three-phase windings to be periodically turned on in response to the comparison result of the rotor position angle with multiple angle sets, and the multiple angle sets include the angle interval [0, θ _m ], the angle interval [0, θ _m ], the angle interval (θ _m +120, θ _m +180], the angle interval (θ _m +300, 360), the angle interval (θ _m , θ _m +60], the angle interval (θ _m +180, θ _m +240], the angle interval (θ _m +60, θ _m +120] and the angle interval (θ _m +240, θ _m +300], wherein θ _m is less than or equal to 60° and θ _m is a positive number.

In some embodiments, the first angle set may include an angle interval [0, θ _m ], an angle interval [0, θ _m ], an angle interval (θ _m +120, θ _m +180], and an angle interval (θ _m +300, 360). In response to the rotor position angle belonging to the first angle set, the control unit may control the upper bridge switch tube of the bridge arm corresponding to the U-phase winding, the lower bridge switch tube of the bridge arm corresponding to the V-phase winding, and the lower bridge switch tube in the bridge arm corresponding to the W-phase winding to be periodically turned on, or control the lower bridge switch tube of the bridge arm corresponding to the U-phase winding, the upper bridge switch tube of the bridge arm corresponding to the V-phase winding, and the upper bridge switch tube in the bridge arm corresponding to the W-phase winding to be periodically turned on, so that the power battery outputs direct current to the V and W phase windings of the drive motor, which can make the power battery output a larger direct current and increase the heat generated by the power battery.

Exemplarily, the control unit may send a first control signal to the upper bridge switch tube of the bridge arm corresponding to the U-phase winding, the lower bridge switch tube of the bridge arm corresponding to the V-phase winding, and the lower bridge switch tube in the bridge arm corresponding to the W-phase winding in response to the rotor position angle belonging to the first angle set, or send a first control signal to the lower bridge switch tube of the bridge arm corresponding to the U-phase winding, the upper bridge switch tube of the bridge arm corresponding to the V-phase winding, and the upper bridge switch tube in the bridge arm corresponding to the W-phase winding. The first control signal is a periodic signal, and the duty cycle of the first control signal in each switching cycle is less than or equal to 0.5. The first control signal is used to drive the switch tube to turn on.

In some embodiments, the second set of angles may include an angle interval (θ _m , θ _m +60] and an angle interval (θ _m +180, θ _m +240]. The control unit can respond to the rotor position angle belonging to the second angle set, and the upper bridge switch tube of the bridge arm corresponding to the W-phase winding, the lower bridge switch tube of the bridge arm corresponding to the V-phase winding, and the lower bridge switch tube in the bridge arm corresponding to the U-phase winding are periodically turned on, or the lower bridge switch tube of the bridge arm corresponding to the W-phase winding, the upper bridge switch tube of the bridge arm corresponding to the V-phase winding, and the upper bridge switch tube in the bridge arm corresponding to the U-phase winding are periodically turned on, so that the power battery outputs direct current to the V and W phase windings of the drive motor, which can make the power battery output a larger direct current and increase the heat generated by the power battery.

Exemplarily, the control unit may send the first control signal to the upper bridge switch tube of the bridge arm corresponding to the W-phase winding, the lower bridge switch tube of the bridge arm corresponding to the V-phase winding, and the lower bridge switch tube in the bridge arm corresponding to the U-phase winding in response to the rotor position angle belonging to the second angle set, or send the first control signal to the lower bridge switch tube of the bridge arm corresponding to the W-phase winding, the upper bridge switch tube of the bridge arm corresponding to the V-phase winding, and the upper bridge switch tube in the bridge arm corresponding to the U-phase winding. The relevant introduction of the first control signal can be found in the above example and will not be repeated here.

In some embodiments, the third angle set may include an angle interval of (θ _m +60, θ _m +120] and an angle interval of (θ _m +240, θ _m +300]. The control unit may, in response to the rotor position angle belonging to the third angle set, periodically turn on the upper bridge switch tube of the bridge arm corresponding to the V-phase winding, the lower bridge switch tube of the bridge arm corresponding to the W-phase winding, and the lower bridge switch tube in the bridge arm corresponding to the U-phase winding, or periodically turn on the lower bridge switch tube of the bridge arm corresponding to the V-phase winding, the upper bridge switch tube of the bridge arm corresponding to the W-phase winding, and the upper bridge switch tube in the bridge arm corresponding to the U-phase winding, so that the power battery outputs direct current to the V and W phase windings of the drive motor, which can make the power battery output a larger direct current and increase the heat generated by the power battery.

Exemplarily, the control unit may send the first control signal to the upper bridge switch tube of the bridge arm corresponding to the V-phase winding, the lower bridge switch tube of the bridge arm corresponding to the W-phase winding, and the lower bridge switch tube in the bridge arm corresponding to the U-phase winding in response to the rotor position angle belonging to the third angle set, or send the first control signal to the lower bridge switch tube of the bridge arm corresponding to the V-phase winding, the upper bridge switch tube of the bridge arm corresponding to the W-phase winding, and the upper bridge switch tube in the bridge arm corresponding to the U-phase winding. The relevant introduction of the first control signal can be found in the above example, which will not be repeated here.

In one possible design, the control unit can send a first control signal to the upper bridge switch tube of one of the three bridge arms and the lower bridge switch tubes in the other two bridge arms in response to the temperature of the power battery being less than a first temperature threshold. The first control signal is a periodic signal, and the duty cycle of the first control signal in each switching cycle is less than or equal to 0.5, which can make the power battery output a larger DC current and increase the heat generated by the power battery.

In one possible design, the control unit may control the three bridge arms to output alternating current to the U, V, and W phase windings of the drive motor in response to the temperature of the power battery being greater than or equal to the first temperature threshold. Optionally, the control unit may control the three bridge arms to output three-phase alternating current based on space vector pulse width modulation (SVPWM) technology. Alternatively, the control unit sends a second control signal to the upper bridge switch tube in each bridge arm, and sends a third control signal to the lower bridge switch tube in each bridge arm, wherein the duration between the start times of the second control signals of the upper bridge switch tubes of any two bridge arms is one third of the duration of the switching cycle, and the duration between the start times of the third control signals of the lower bridge switch tubes of any two bridge arms is one third of the duration of the switching cycle, and the second control signal of the upper bridge switch tube and the third control signal of the lower bridge switch tube in the bridge arm are both periodic signals, and the time period corresponding to the second control signal of the upper bridge switch tube in the bridge arm does not overlap with the time period corresponding to the third control signal of the lower bridge switch tube, so that the three bridge arms can convert the DC current output by the power battery into AC current and provide it to the three-phase winding, so that the drive motor can drive the wheels of the electric vehicle.

In a possible design, the control unit may respond to the temperature of any one of the three-phase windings being greater than a preset winding temperature threshold or the temperature of the switch tubes turned on in the three bridge arms being greater than a preset switch tube temperature threshold, and the control unit may send a fourth control signal to the upper bridge switch tube of one of the three bridge arms and the lower bridge switch tubes in the other two bridge arms, or the control unit may send a fourth control signal to the lower bridge switch tube of one of the three bridge arms and the upper bridge switch tubes in the other two bridge arms. The duty cycle of the fourth control signal in each switching cycle is less than the duty cycle of the first control signal in each switching cycle. The duty cycle of the fourth control signal is less than the duty cycle of the first control signal, which can reduce the conduction time of the turned-on switch tube, reduce the DC current output by the power battery, reduce the heat generation of the three-phase winding or the heat generation of the turned-on switch tube, and protect the three-phase winding or the switch tubes of the three bridge arms.

In a third aspect, an embodiment of the present application further provides an electric drive system, which may include a drive motor and a motor controller. The motor controller may be a motor controller as in the first aspect and any design thereof. Alternatively, the motor controller may include a control unit as in the second aspect and any design thereof.

In a fourth aspect, an embodiment of the present application further provides an electric vehicle, which may include a power battery and an electric drive system as described in the third aspect.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of a scenario of an electric vehicle provided in an embodiment of the present application;

FIG2 is a schematic diagram of the structure of an electric drive system provided in an embodiment of the present application;

FIG3 is a schematic diagram of a partial chassis structure of an electric vehicle provided in an embodiment of the present application;

FIG4 is a circuit diagram of an electric drive system provided in an embodiment of the present application;

FIG5 is a schematic diagram of a process for controlling heat generation of a power battery provided in an embodiment of the present application;

FIG6 is a schematic diagram of a rotor position angle;

7a-7c are schematic diagrams of control signals when three bridge arms operate in a heating mode;

8a-8c are schematic diagrams of control signals when three bridge arms operate in a heating mode;

9a-9c are schematic diagrams of control signals when three bridge arms operate in a heating mode;

10a-10c are schematic diagrams of control signals when three bridge arms operate in a heating mode;

11a-11c are schematic diagrams of control signals when three bridge arms operate in a heating mode;

12a-12c are schematic diagrams of control signals when three bridge arms are operating in a heating mode, provided in an embodiment of the present application;

FIG13 is a schematic diagram of multiple voltage vectors in SVPWM technology;

FIG14 is a schematic diagram showing the corresponding relationship between multiple angle sets and multiple vector pairs;

FIG15 is a schematic diagram of control signals when three bridge arms operate in an inverter mode;

FIG16 is a schematic diagram of multiple voltage vectors and sectors in SVPWM technology;

FIG17 is a schematic diagram showing the relationship between a reference voltage vector and a voltage vector;

FIG. 18 is a schematic diagram of the state of each phase bridge arm and the control signal of each switch tube in each phase bridge arm.

Detailed ways

In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings. It should be noted that in the description of the present application, "at least one" refers to one or more, wherein a plurality refers to two or more. In view of this, "a plurality" may also be understood as "at least two" in the embodiments of the present application. "And/or" describes the association relationship of associated objects, indicating that three relationships may exist, for example, A and/or B may represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character "/", unless otherwise specified, generally indicates that the associated objects before and after are in an "or" relationship. In addition, it should be understood that in the description of the present application, words such as "first" and "second" are only used to distinguish the purpose of description, and cannot be understood as indicating or implying relative importance, nor can they be understood as indicating or implying order.

Obviously, the described embodiments are only some embodiments of the present application, rather than all embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application. The implementation of the technical solution of the present application is further described in detail below in conjunction with the accompanying drawings.

Please refer to Figure 1, which is a schematic diagram of a scenario of an electric vehicle provided in an embodiment of the present application. As shown in Figure 1, the electric vehicle 20 includes an electric drive system 201 and a power battery 202. Among them, the power battery 202 is connected to the electric drive system 201. The power battery 202 is discharged or charged by forming a loop with the electric drive system 201. The internal resistance of the power battery 202 generates heat under the action of the current in the loop, and the temperature of the power battery 202 increases, thereby achieving heating of the power battery 202.

The following is an exemplary description of how the electric drive system 201 generates heat and how the power battery 202 is heated in conjunction with the structure of the electric drive system 201 .

Referring to FIG. 2 , FIG. 2 is a schematic diagram of the structure of an electric drive system provided in an embodiment of the present application. As shown in FIG. 2 , the electric drive system 201 may include a motor controller 2010. The motor controller 2010 may include an inverter circuit 2011, a DC conversion circuit 2012, and a control unit 2014. The electric drive system 201 may also include at least one drive motor 2013.

One side of the inverter circuit 2011 is connected to the power battery 202. One side of the inverter circuit 2011 is connected to the drive motor 2013, specifically connected to the three-phase stator winding, or three-phase winding, of the drive motor 2013. One side of the DC conversion circuit 2012 is connected to the power battery 202, and the other side is connected to the drive motor 2013, specifically connected to the rotor winding of the drive motor 2013.

The power battery 202 may be, for example, a lithium-ion battery, a lead-acid battery, a solar cell, etc. The present application does not limit the type of the power battery.

In one embodiment, the electric drive system 201 may include at least two drive motors, and the drive motor 2013 may be any one of the drive motors in the electric drive system 201. FIG3 takes the electric drive system 201 including two drive motors as an example, for example, the electric drive system 201 includes a drive motor 2013A and a drive motor 2013B, the drive motor 2013A drives the front wheels of the electric vehicle 20, and the drive motor 2013B Drive the rear wheels of the electric vehicle 20. The drive motor 2013 involved in the present application can be any one of the drive motor 2013A and the drive motor 2013B. Exemplarily, the drive motor 2013A can be a permanent magnet synchronous motor, which is the main drive motor of the electric vehicle 20; the drive motor 2013B can be an electrically excited synchronous motor, which is the auxiliary drive motor of the electric vehicle 20.

In the embodiment of the present application, the motor controller 2010 may have multiple working modes, and the multiple working modes may include but are not limited to an inverter mode and a heating mode.

When the motor controller 2010 operates in the heating mode, the inverter circuit 2011, the drive motor 2013, and the power battery 202 can form a discharge loop. The power battery 202 outputs a DC current, which is transmitted to the power battery 202 via the inverter circuit 2011 and the drive motor 2013. Under the action of the DC current in the discharge loop, the internal resistance of the power battery 202 generates heat, thereby achieving heating of the power battery 202.

It can be understood that, taking the drive motor 2013 as the drive motor 2013B as an example, when the motor controller 2010 operates in the heating mode, the three-phase stator winding, the inverter circuit 2011, and the power battery 202 in any one of the drive motors in the electric drive system 201 can form a discharge circuit. The discharge circuit contains a direct current. Each drive motor in the electric drive system 201 may not rotate.

Optionally, when the motor controller 2010 operates in the heating mode, the calipers in the electronic parking brake (EPB) system of the electric vehicle 20 can be in a locked state, which can ensure that the wheels of the electric vehicle 20 do not move or move very little.

When the motor controller 2010 operates in the inverter mode, the power battery 202 can provide a DC current for the electric drive system 201. The inverter circuit 2011 can convert the DC current output by the power battery 202 into an AC current and output it to the drive circuit 2013, that is, the output current of the inverter circuit 2011 in the embodiment of the present application is specifically implemented as a three-phase AC current. The inverter circuit transmits the output three-phase AC power to the three-phase stator windings respectively. Under the action of the three-phase AC current, the three-phase stator windings can drive the wheels to rotate.

The DC conversion circuit 2012 can convert the DC voltage output by the power battery 202. Exemplarily, the DC conversion circuit 2012 can be specifically implemented as a DC/DC converter, such as a BUCK converter, a BOOST converter, or a BUCK-BOOST converter.

Exemplarily, the inverter circuit 2011 may include three bridge arms, as shown in FIG4 . Each bridge arm includes an upper bridge switch tube and a lower bridge switch tube connected in series. The connection point of the upper bridge switch tube and the lower bridge switch tube can be used as the midpoint of the bridge arm. The inverter circuit 2011 is connected to the power battery 202 via a DC bus, and the upper bridge switch tube and the lower bridge switch tube in each bridge arm are connected in series between the positive and negative electrodes of the DC bus.

The three bridge arms included in the inverter circuit 2011 can be respectively recorded as the U-phase bridge arm, the V-phase bridge arm and the W-phase bridge arm. As shown in FIG4 , the upper bridge switch tube in the U-phase bridge arm is the switch tube _Q51 , and the lower bridge switch tube is the switch tube _Q52 . The upper bridge switch tube in the V-phase bridge arm is the switch tube _Q53 , and the lower bridge switch tube is the switch tube _Q54 . The upper bridge switch tube in the W-phase bridge arm is the switch tube _Q55 , and the lower bridge switch tube is the switch tube _Q56 .

One end of each bridge arm is connected to the first pole of the power battery 202, that is, the collector of the switch tube _Q51 , the collector of the switch tube _Q53 , and the collector of the switch tube _Q55 are connected to the first pole of the power battery 202. The other end of each bridge arm is connected to the second pole of the power battery 202, that is, the emitter of the switch tube _Q52 , the emitter of the switch tube _Q54 , and the emitter of the switch tube _Q56 are connected to the second pole of the power battery 202. Optionally, the first pole may be the positive terminal of the power battery 202, and the second pole may be the negative terminal of the power battery 202. Alternatively, the first pole may be the negative terminal of the power battery 202, and the second pole may be the positive terminal of the power battery 202.

FIG4 shows that the first pole of the power battery 202 is the positive pole (+) of the power battery, and the second pole of the power battery 202 is the negative pole (-) of the power battery. Optionally, a capacitor unit is connected in parallel between the positive pole and the negative pole of the power battery 202. The capacitor unit includes at least one capacitor, such as capacitor _C51 . The capacitor _C51 can filter the output voltage of the power battery 202.

The midpoint of each bridge arm is connected to the corresponding stator winding, that is, the emitter of the switch tube _Q51 and the collector of the switch tube _Q52 are connected to the U-phase winding of the drive motor 2013, which is also the winding LU shown in Figure 4, the emitter of the switch tube _Q53 and the collector of the switch tube _Q54 are connected to the V-phase winding of the drive motor 2013, which is also the winding LV shown in Figure 4, and the emitter of the switch tube _Q55 and the collector of the switch tube _Q56 are connected to the W-phase winding of the drive motor 2013, which is also the winding LW shown in Figure 4.

Through the above introduction, the connection relationship and relative position of the upper bridge switch tube and the lower bridge switch tube in a bridge arm can be clarified. Optionally, the upper bridge switch tube can be an insulated gate bipolar transistor (IGBT) and its anti-parallel diode, or a metal oxide semiconductor field effect transistor (MOSFET), etc. This application does not make too many restrictions on the specific structure inside the upper bridge switch tube. Optionally, the lower bridge switch tube can be an IGBT and its anti-parallel diode or a MOSFET. This application does not make too many restrictions on the specific structure inside the lower bridge switch tube.

When the motor controller 2010 operates in the inverter mode, the three bridge arms also operate in the inverter mode. The three bridge arms in the inverter circuit 2011 can receive power from the power battery 202, and the three bridge arms supply power to the three-phase windings of the drive motor 2013, that is, the U, V, and W phase windings. In the inverter mode, the three bridge arms provide AC current to the three-phase windings of the drive motor 2013, so that the drive motor 2013 outputs torque to drive the wheels.

Optionally, when the three bridge arms operate in the inverter mode, the DC current output by the power battery 202 can be converted into AC current, and The AC current is provided to the drive motor 2013. Usually, the three bridge arms can convert the DC current into the internal AC current based on the space vector pulse width modulation (SVPWM) technology. The embodiment of the present application does not specifically limit the way in which the three bridge arms convert the DC current into the AC current.

When the motor controller 2010 operates in the heating mode, the three bridge arms also operate in the heating mode. The upper bridge switch tube of one of the three bridge arms and the lower bridge switch tubes in the other two bridge arms can be turned on periodically, so that the power battery 202, the turned-on upper bridge switch tube, the two turned-on lower bridge switch tubes, and the three-phase winding of the drive motor 2013 form a discharge circuit. The discharge circuit is all direct current, and the internal resistance of the power battery 202 is heated under the action of the direct current to achieve heating of the power battery 202. Optionally, the upper bridge switch tube of one of the three bridge arms and the lower bridge switch tubes in the other two bridge arms can be turned on for a first duration in each cycle, wherein the first duration is less than or equal to half of the duration of each cycle. Among them, the greater the synchronous conduction duration of the switch tubes forming the discharge circuit, the greater the output current of the power battery 202.

In a possible scenario, FIG5 shows a schematic diagram of a working process of a motor controller. The motor controller 2010 may execute the steps shown in FIG5. As shown in FIG5, the execution steps of the motor controller 2010 may include:

Step S600: The motor controller 2010 detects whether the temperature of the power battery 202 is less than a first temperature threshold. If so, the motor controller 2010 executes step S601a; otherwise, the motor controller 2010 executes step S601b.

In one embodiment, the motor controller 2010 may obtain the temperature of the power battery 202 through a battery management system (BMS). Alternatively, the motor controller 2010 may obtain the temperature of the power battery 202 through a vehicle control unit (VCU).

The motor controller 2010 compares the temperature of the power battery 202 with a first temperature threshold, which may be any one of the optimal operating temperature ranges of the power battery 202. The first temperature threshold may be adjusted according to the actual operating conditions of the power battery 202, for example, according to the usage time or remaining power of the power battery 202.

Step S601a: In response to the temperature of the power battery 202 being lower than a first temperature threshold, the motor controller 2010 operates the three bridge arms in a heating mode.

The motor controller 2010 operates in a heating mode when the temperature of the power battery 202 is less than the first temperature threshold. When the three bridge arms operate in the heating mode, the upper bridge switch tube of one of the three bridge arms and the lower bridge switch tubes in the other two bridge arms are circumferentially turned on, so that the power battery, the upper bridge switch tube that is turned on, the two-phase winding of the drive motor, and the two lower bridge switch tubes that are turned on form a discharge circuit, and the internal resistance of the power battery 202 generates heat under the action of the current in the discharge circuit, so that the power battery 202 can be heated. Alternatively, when the three bridge arms operate in the heating mode, the lower bridge switch tube of one of the three bridge arms and the upper bridge switch tubes in the other two bridge arms are circumferentially turned on, so that the power battery, the lower bridge switch tube that is turned on, the two-phase winding of the drive motor, and the two upper bridge switch tubes that are turned on form a discharge circuit, and the internal resistance of the power battery 202 generates heat under the action of the current in the discharge circuit, so that the power battery 202 can be heated. In such a design, the three bridge arms and the three-phase winding are reused to achieve self-heating of the power battery 202 , which is beneficial to improving the performance of the power battery 202 and avoiding damage to the power battery 202 .

Step S601b: In response to the temperature of the power battery 202 being greater than or equal to a preset battery temperature, the motor controller 2010 operates the three bridge arms in the inverter mode.

In the scenario where the power battery 202 supplies power to the load, the motor controller 2010 can normally start the drive motor 2013 in response to the temperature of the power battery 202 being greater than or equal to the first temperature threshold. The three bridge arms in the inverter circuit 2011 can convert the DC current provided by the power battery 202 into AC current, and provide the AC current to the drive motor 2013, so that the drive motor 2013 outputs torque to drive the wheels of the electric vehicle.

It should be noted that step S601b in FIG. 5 is only introduced as an example, and the operation of the motor controller 2010 in step S601b can be configured according to the actual application scenario. Optionally, in step S601b, the motor controller 2010 may not start the drive motor 2013. For example, in the scenario of charging the power battery 202, the motor controller 2010 may not start the drive motor 2013 in response to the temperature of the power battery 202 being greater than or equal to the first temperature threshold. So that the external power supply charges the power battery 202. Exemplarily, in this case, the three bridge arms in the inverter circuit 2011 may not output current. In the scenario of charging the power battery 202 with an external power supply, the motor controller 2010 performs the operations in steps S600 and S601a to realize self-heating of the power battery 202, improve the performance of the power battery 202, and help improve the charging efficiency of the power battery 202 in a low temperature environment.

In the embodiment of the present application, the three bridge arms can be configured with a variety of operating modes, and the three bridge arms can implement the aforementioned heating mode in each operating mode.

In one embodiment, the first operation mode of the three bridge arms may be that the switch tube _Q51 in the U-phase bridge arm, the switch tube _Q54 in the V-phase bridge arm, and the switch tube _Q56 in the W-phase bridge arm are periodically turned on, so that the power battery 202, the switch tube _Q51 , the U-phase winding, the V-phase winding, and the W-phase winding are turned on. The phase winding, the switch tube _Q54 and the switch tube _Q56 form a discharge loop. In this case, the U phase winding, the V phase winding and the W phase winding are all direct currents. In the formed discharge loop, the V phase winding and the W phase winding are in parallel.

Optionally, the switch tube _Q51 in the U-phase bridge arm, the switch tube _Q54 in the V-phase bridge arm, and the switch tube _Q56 in the W-phase bridge arm are periodically turned on, and are continuously turned on for a first duration in each switching cycle. In the first switching cycle, when the switch tube _Q51 in the U-phase bridge arm, the switch tube _Q54 in the V-phase bridge arm, and the switch tube _Q56 in the W-phase bridge arm are turned on for a first duration, the power battery 202, the switch tube _Q51 , the U-phase winding, the V-phase winding, the W-phase winding, the switch tube _Q54 , and the switch tube _Q56 form a discharge loop, the power battery 202 is discharged, and the three-phase winding can store electrical energy. After the switch tube _Q51 in the U-phase bridge arm, the switch tube _Q54 in the V-phase bridge arm, and the switch tube _Q56 in the W-phase bridge arm are in the open-circuit state, the power battery 202, the anti-parallel diode of the switch tube _Q52 , the anti-parallel diode of the switch tube _Q53 , the anti-parallel diode of the switch tube _Q55 , the U-phase winding, the V-phase winding, and the W-phase winding can form a charging circuit, which can enable the three-phase winding to release electrical energy to the power battery 202, and the current in the three-phase winding is reduced to zero.

Optionally, the first operation mode of the three bridge arms may be that the switch tube _Q51 in the U-phase bridge arm, the switch tube _Q54 in the V-phase bridge arm, and the switch tube _Q56 in the W-phase bridge arm are periodically turned on, and are continuously turned on for a first duration in the first half of each switching cycle. In each switching cycle, when the switch tube _Q51 in the U-phase bridge arm, the switch tube _Q54 in the V-phase bridge arm, and the switch tube _Q56 in the W-phase bridge arm are turned on for the first duration, the power battery 202, the switch tube _Q51 , the U-phase winding, the V-phase winding, the W-phase winding, the switch tube _Q54 , and the switch tube _Q56 form a discharge loop, the power battery 202 is discharged, and the three-phase winding can store electrical energy. In the second half of each switching cycle, the switch tube _Q52 in the U-phase bridge arm, the switch tube _Q53 in the V-phase bridge arm, and the switch tube _Q55 in the W-phase bridge arm can be turned on for a first period of time, and the power battery 202, the switch tube _Q52 in the U-phase bridge arm, the U-phase winding, the V-phase winding, the W-phase winding, the switch tube _Q53 in the V-phase bridge arm, and the switch tube _Q55 in the W-phase bridge arm can form a charging circuit, and the three-phase winding releases electrical energy to charge the power battery 202.

In one embodiment, the second operation mode of the three bridge arms may be that the switch tube _Q52 in the U-phase bridge arm, the switch tube _Q53 in the V-phase bridge arm, and the switch tube _Q55 in the W-phase bridge arm are periodically turned on, so that the power battery 202, the switch tube _Q52 , the U-phase winding, the V-phase winding, the W-phase winding, the switch tube _Q53 , and the switch tube _Q55 form a discharge loop. In this case, the U-phase winding, the V-phase winding, and the W-phase winding are all direct currents. In the formed discharge loop, the V-phase winding and the W-phase winding are in parallel.

Optionally, the switch tube _Q52 in the U-phase bridge arm, the switch tube _Q53 in the V-phase bridge arm, and the switch tube _Q55 in the W-phase bridge arm are periodically turned on, and are continuously turned on for a first duration in each switching cycle. In the first switching cycle, when the switch tube _Q52 in the U-phase bridge arm, the switch tube _Q53 in the V-phase bridge arm, and the switch tube _Q55 in the W-phase bridge arm are turned on for a first duration, the power battery 202, the switch tube _Q52 , the U-phase winding, the V-phase winding, the W-phase winding, the switch tube _Q53 , and the switch tube _Q55 form a discharge loop, the power battery 202 is discharged, and the three-phase winding can store electrical energy. After the switch tube _Q52 in the U-phase bridge arm, the switch tube _Q53 in the V-phase bridge arm, and the switch tube _Q55 in the W-phase bridge arm are in the open-circuit state, the power battery 202, the anti-parallel diode of the switch tube _Q51 , the anti-parallel diode of the switch tube _Q54 , the anti-parallel diode of the switch tube _Q56 , the U-phase winding, the V-phase winding, and the W-phase winding can form a charging circuit, which can enable the three-phase winding to release electrical energy to the power battery 202, and the current in the three-phase winding is reduced to zero.

Optionally, the second operation mode of the three bridge arms may be that the switch tube _Q52 in the U-phase bridge arm, the switch tube _Q53 in the V-phase bridge arm, and the switch tube _Q55 in the W-phase bridge arm are periodically turned on, and are continuously turned on for a first duration in the first half of each switching cycle. In each switching cycle, when the switch tube _Q52 in the U-phase bridge arm, the switch tube _Q53 in the V-phase bridge arm, and the switch tube _Q55 in the W-phase bridge arm are turned on for the first duration, the power battery 202, the switch tube _Q52 , the U-phase winding, the V-phase winding, the W-phase winding, the switch tube _Q53 , and the switch tube _Q55 form a discharge loop, the power battery 202 is discharged, and the three-phase winding can store electrical energy. In the second half of each switching cycle, the switch tube Q ₅₁ in the U-phase bridge arm, the switch tube Q ₅₄ in the V-phase bridge arm, and the switch tube Q ₅₆ in the W-phase bridge arm can be turned on for a first period of time, and the power battery 202, the switch tube Q ₅₁ in the U-phase bridge arm, the U-phase winding, the V-phase winding, the W-phase winding, the switch tube Q ₅₄ in the V-phase bridge arm, and the switch tube Q ₅₆ in the W-phase bridge arm can form a charging circuit, and the three-phase winding releases electrical energy to charge the power battery 202.

In one embodiment, the third operation mode of the three bridge arms may be that the switch tube _Q53 in the V-phase bridge arm, the switch tube _Q52 in the U-phase bridge arm, and the switch tube _Q56 in the W-phase bridge arm are periodically turned on, so that the power battery 202, the switch tube _Q53 , the U-phase winding, the V-phase winding, the W-phase winding, the switch tube _Q52 , and the switch tube _Q56 form a discharge loop. In this case, the U-phase winding, the V-phase winding, and the W-phase winding are all direct currents. In the formed discharge loop, the U-phase winding and the W-phase winding are in parallel.

Optionally, the switch tube _Q53 in the V-phase bridge arm, the switch tube _Q52 in the U-phase bridge arm, and the switch tube _Q56 in the W-phase bridge arm are periodically turned on, and are continuously turned on for a first duration in each switching cycle. In the first switching cycle, when the switch tube _Q53 in the V-phase bridge arm, the switch tube _Q52 in the U-phase bridge arm, and the switch tube _Q56 in the W-phase bridge arm are turned on for a first duration, the power battery 202, the switch tube _Q52 , the U-phase winding, the V-phase winding, the W-phase winding, the switch tube _Q53 , and the switch tube _Q56 form a discharge loop, the power battery 202 is discharged, and the three-phase winding can store electrical energy. After the switch tube _Q53 in the V-phase bridge arm, the switch tube _Q52 in the U-phase bridge arm, and the switch tube _Q56 in the W-phase bridge arm are in the open circuit state, the power battery 202, the reverse parallel diode of the switch tube _Q51 , the reverse parallel diode of the switch tube _Q54 , the reverse parallel diode of the switch tube _Q55 , the U-phase winding, and the V-phase The winding and the W-phase winding can form a charging circuit, which can enable the three-phase winding to release electrical energy to the power battery 202, and the current in the three-phase winding is reduced to zero.

Optionally, the third operation mode of the three bridge arms may be that the switch tube _Q52 in the U-phase bridge arm, the switch tube _Q53 in the V-phase bridge arm, and the switch tube _Q56 in the W-phase bridge arm are periodically turned on, and are continuously turned on for a first duration in the first half of each switching cycle. In each switching cycle, when the switch tube _Q52 in the U-phase bridge arm, the switch tube _Q53 in the V-phase bridge arm, and the switch tube _Q56 in the W-phase bridge arm are turned on for the first duration, the power battery 202, the switch tube _Q52 , the U-phase winding, the V-phase winding, the W-phase winding, the switch tube _Q53 , and the switch tube _Q56 form a discharge loop, the power battery 202 is discharged, and the three-phase winding can store electrical energy. In the second half of each switching cycle, the switch tube Q ₅₁ in the U-phase bridge arm, the switch tube Q ₅₄ in the V-phase bridge arm, and the switch tube Q ₅₅ in the W-phase bridge arm can be turned on for a first period of time, and the power battery 202, the switch tube Q ₅₁ in the U-phase bridge arm, the U-phase winding, the V-phase winding, the W-phase winding, the switch tube Q ₅₄ in the V-phase bridge arm, and the switch tube Q ₅₅ in the W-phase bridge arm can form a charging circuit, and the three-phase winding releases electrical energy to charge the power battery 202.

In one embodiment, the fourth operation mode of the three bridge arms may be that the switch tube _Q54 in the V-phase bridge arm, the switch tube _Q51 in the U-phase bridge arm, and the switch tube _Q55 in the W-phase bridge arm are periodically turned on, so that the power battery 202, the switch tube _Q54 , the U-phase winding, the V-phase winding, the W-phase winding, the switch tube _Q51 , and the switch tube _Q55 form a discharge loop. In this case, the U-phase winding, the V-phase winding, and the W-phase winding are all direct currents. In the formed discharge loop, the U-phase winding and the W-phase winding are in parallel.

In a possible scenario, the switch tube _Q54 in the V-phase bridge arm, the switch tube _Q51 in the U-phase bridge arm, and the switch tube _Q55 in the W-phase bridge arm are periodically turned on, and are continuously turned on for a first duration in each switching cycle. In the first switching cycle, when the switch tube _Q54 in the V-phase bridge arm, the switch tube _Q51 in the U-phase bridge arm, and the switch tube _Q55 in the W-phase bridge arm are turned on for a first duration, the power battery 202, the switch tube _Q51 , the U-phase winding, the V-phase winding, the W-phase winding, the switch tube _Q54 , and the switch tube _Q55 form a discharge loop, the power battery 202 is discharged, and the three-phase winding can store electrical energy. After the switch tube _Q54 in the V-phase bridge arm, the switch tube _Q51 in the U-phase bridge arm, and the switch tube _Q55 in the W-phase bridge arm are in the open-circuit state, the power battery 202, the anti-parallel diode of the switch tube _Q52 , the anti-parallel diode of the switch tube _Q53 , the anti-parallel diode of the switch tube _Q56 , the U-phase winding, the V-phase winding, and the W-phase winding can form a charging circuit, which can enable the three-phase winding to release electrical energy to the power battery 202, and the current in the three-phase winding is reduced to zero.

Optionally, the fourth operation mode of the three bridge arms may be that the switch tube _Q51 in the U-phase bridge arm, the switch tube _Q54 in the V-phase bridge arm, and the switch tube _Q55 in the W-phase bridge arm are periodically turned on, and are continuously turned on for a first duration in the first half of each switching cycle. In each switching cycle, when the switch tube _Q51 in the U-phase bridge arm, the switch tube _Q52 in the V-phase bridge arm, and the switch tube _Q55 in the W-phase bridge arm are turned on for the first duration, the power battery 202, the switch tube _Q51 , the U-phase winding, the V-phase winding, the W-phase winding, the switch tube _Q54 , and the switch tube _Q55 form a discharge loop, the power battery 202 is discharged, and the three-phase winding can store electrical energy. In the second half of each switching cycle, the switch tube _Q52 in the U-phase bridge arm, the switch tube _Q53 in the V-phase bridge arm, and the switch tube _Q56 in the W-phase bridge arm can be turned on for a first period of time, and the power battery 202, the switch tube _Q52 in the U-phase bridge arm, the U-phase winding, the V-phase winding, the W-phase winding, the switch tube _Q53 in the V-phase bridge arm, and the switch tube _Q56 in the W-phase bridge arm can form a charging circuit, and the three-phase winding releases electrical energy to charge the power battery 202.

In one embodiment, the fifth operation mode of the three bridge arms may be that the switch tube _Q52 in the U-phase bridge arm, the switch tube _Q54 in the V-phase bridge arm, and the switch tube _Q55 in the W-phase bridge arm are periodically turned on, so that the power battery 202, the switch tube _Q52 , the U-phase winding, the V-phase winding, the W-phase winding, the switch tube _Q54 , and the switch tube _Q55 form a discharge loop. In this case, the U-phase winding, the V-phase winding, and the W-phase winding are all direct currents. In the formed discharge loop, the V-phase winding and the W-phase winding are in parallel.

Optionally, the switch tube _Q52 in the U-phase bridge arm, the switch tube _Q54 in the V-phase bridge arm, and the switch tube _Q55 in the W-phase bridge arm are periodically turned on, and are continuously turned on for a first duration in each switching cycle. In the first switching cycle, when the switch tube _Q52 in the U-phase bridge arm, the switch tube _Q54 in the V-phase bridge arm, and the switch tube _Q55 in the W-phase bridge arm are turned on for a first duration, the power battery 202, the switch tube _Q52 , the U-phase winding, the V-phase winding, the W-phase winding, the switch tube _Q54 , and the switch tube _Q55 form a discharge loop, the power battery 202 is discharged, and the three-phase winding can store electrical energy. After the switch tube _Q52 in the U-phase bridge arm, the switch tube _Q54 in the V-phase bridge arm, and the switch tube _Q55 in the W-phase bridge arm are in the open-circuit state, the power battery 202, the anti-parallel diode of the switch tube _Q51 , the anti-parallel diode of the switch tube _Q53 , the anti-parallel diode of the switch tube _Q56 , the U-phase winding, the V-phase winding, and the W-phase winding can form a charging circuit, which can enable the three-phase winding to release electrical energy to the power battery 202, and the current in the three-phase winding is reduced to zero.

Optionally, the fifth operation mode of the three bridge arms may be that the switch tube _Q52 in the U-phase bridge arm, the switch tube _Q54 in the V-phase bridge arm, and the switch tube _Q55 in the W-phase bridge arm are periodically turned on, and are continuously turned on for a first duration in the first half of each switching cycle. In each switching cycle, when the switch tube _Q52 in the U-phase bridge arm, the switch tube _Q54 in the V-phase bridge arm, and the switch tube _Q55 in the W-phase bridge arm are turned on for a first duration, the power battery 202, the switch tube _Q52 , the U-phase winding, the V-phase winding, the W-phase winding, the switch tube Q54, and the switch tube _Q55 form a discharge loop, the power battery 202 discharges, and the three-phase winding can store electrical energy. In the second half of each switching cycle, the switch tube Q51 in the U-phase bridge arm, the switch tube _Q53 in the V-phase bridge arm, and the switch tube _Q56 in the W-phase bridge arm can be turned on for a first duration, and the power battery 202, the U-phase winding, the V-phase winding, the W-phase winding, the switch tube _Q54 , and the switch tube _Q55 form a discharge loop, the power battery 202 discharges, and the three-phase winding can store electrical energy. The switch tube Q ₅₁ in the phase bridge arm, the U-phase winding, the V-phase winding, the W-phase winding, the switch tube Q ₅₃ in the V-phase bridge arm, and the switch tube Q ₅₆ in the W-phase bridge arm can form a charging circuit, and the three-phase winding releases electrical energy to charge the power battery 202 .

In one embodiment, the sixth operation mode of the three bridge arms may be that the switch tube _Q51 in the U-phase bridge arm, the switch tube _Q53 in the V-phase bridge arm, and the switch tube _Q56 in the W-phase bridge arm are periodically turned on, so that the power battery 202, the switch tube _Q51 , the U-phase winding, the V-phase winding, the W-phase winding, the switch tube _Q53 , and the switch tube _Q56 form a discharge loop. In this case, the U-phase winding, the V-phase winding, and the W-phase winding are all direct currents. In the formed discharge loop, the V-phase winding and the W-phase winding are in parallel.

Optionally, the switch tube _Q51 in the U-phase bridge arm, the switch tube _Q53 in the V-phase bridge arm, and the switch tube _Q56 in the W-phase bridge arm are periodically turned on, and are continuously turned on for a first duration in each switching cycle. In the first switching cycle, when the switch tube _Q51 in the U-phase bridge arm, the switch tube _Q53 in the V-phase bridge arm, and the switch tube _Q56 in the W-phase bridge arm are turned on for a first duration, the power battery 202, the switch tube _Q51 , the U-phase winding, the V-phase winding, the W-phase winding, the switch tube _Q53 , and the switch tube _Q56 form a discharge loop, the power battery 202 is discharged, and the three-phase winding can store electrical energy. After the switch tube _Q51 in the U-phase bridge arm, the switch tube _Q53 in the V-phase bridge arm, and the switch tube _Q56 in the W-phase bridge arm are in the open-circuit state, the power battery 202, the anti-parallel diode of the switch tube _Q52 , the anti-parallel diode of the switch tube _Q54 , the anti-parallel diode of the switch tube _Q55 , the U-phase winding, the V-phase winding, and the W-phase winding can form a charging circuit, which can enable the three-phase winding to release electrical energy to the power battery 202, and the current in the three-phase winding is reduced to zero.

Optionally, the sixth operation mode of the three bridge arms may be that the switch tube _Q51 in the U-phase bridge arm, the switch tube _Q53 in the V-phase bridge arm, and the switch tube _Q56 in the W-phase bridge arm are periodically turned on, and are continuously turned on for a first duration in the first half of each switching cycle. In each switching cycle, when the switch tube _Q51 in the U-phase bridge arm, the switch tube _Q53 in the V-phase bridge arm, and the switch tube _Q56 in the W-phase bridge arm are turned on for the first duration, the power battery 202, the switch tube _Q51 , the U-phase winding, the V-phase winding, the W-phase winding, the switch tube _Q53 , and the switch tube _Q56 form a discharge loop, the power battery 202 is discharged, and the three-phase winding can store electrical energy. In the second half of each switching cycle, the switch tube _Q52 in the U-phase bridge arm, the switch tube _Q54 in the V-phase bridge arm, and the switch tube _Q55 in the W-phase bridge arm can be turned on for a first period of time, and the power battery 202, the switch tube _Q52 in the U-phase bridge arm, the U-phase winding, the V-phase winding, the W-phase winding, the switch tube _Q54 in the V-phase bridge arm, and the switch tube _Q55 in the W-phase bridge arm can form a charging circuit, and the three-phase winding releases electrical energy to charge the power battery 202.

In a possible design, in order to reduce the torque of the drive motor 2013 when the three bridge arms are operating in the heating mode, the motor controller 2010 can use the operation mode of the three bridge arms corresponding to the rotor position angle according to the rotor position angle of the drive motor 2013 to realize the three bridge arms operating in the heating mode.

The electric vehicle 20 may be provided with a rotor position sensor, which may provide information about the rotor position to the motor controller 2010, so that the motor controller 2010 may determine or obtain the rotor position angle in each drive motor. Please refer to FIG. 6. In the field of motor control, the three-phase stator winding in the motor includes a U-phase stator winding, a V-phase stator winding, and a W-phase stator winding. In space, the angle between the direction from the center of the rotor to the U-phase stator winding and the direction from the center of the rotor to the V-phase stator winding is 120°. The angle between the direction from the center of the rotor to the V-phase stator winding and the direction from the center of the rotor to the W-phase stator winding is 120°. The angle between the direction from the center of the rotor to the U-phase stator winding and the direction from the center of the rotor to the W-phase stator winding is 120°. The rotor position angle θ _r represents the angle between the N pole of the rotor in space and the reference direction, and the reference direction is the direction from the center of the rotor to the U-phase winding among the three stator windings.

Exemplarily, the motor controller 2010 may pre-store a correspondence between a plurality of angle sets and the operating modes of the three bridge arms. The plurality of angle sets may include a first angle set, a second angle set, and a third angle set. The first angle set may include any one of the angle intervals [0, θ _m ], the angle interval (θ _m +120, θ _m +180], and the angle interval (θ _m +300, 360), wherein θ _m is less than or equal to 60°, and θ _m is a positive number. The second angle set may include the angle interval (θ _m , θ _m +60] and the angle interval (θ _m +180, θ _m +240]. The third angle set may include the angle interval (θ _m +60, θ _m +120] and the angle interval (θ _m +240, θ _m +300]. The specific value of θ _m may be configured in combination with the actual application scenario. For example, θ _m may be an angle value such as 25°, 30°, 35°, 40°, 45°, 50°, 55°, etc. Typically, θ _m may be configured to 30°.

In the correspondence between the multiple angle sets and the operation modes of the three bridge arms, the operation mode of the three bridge arms corresponding to the first angle set may be the first operation mode or the second operation mode of the aforementioned three bridge arms. The operation mode of the three bridge arms corresponding to the second angle set may be the third operation mode or the fourth operation mode of the aforementioned three bridge arms. The operation mode of the three bridge arms corresponding to the third angle set may be the fifth operation mode or the sixth operation mode of the aforementioned three bridge arms.

The motor controller 2010 can respond to the rotor position angle of the drive motor 2013 belonging to the first angle set, and the three bridge arms can be the aforementioned first operation mode or the second operation mode, so that the three bridge arms operate in the heating mode. The rotor position angle of the drive motor 2013 is an angle value in any angle interval in the first angle set, which can be regarded as the rotor position angle of the drive motor 2013 belonging to the first angle set.

In some examples, the motor controller 2010 may respond to the rotor position angle of the drive motor 2013 belonging to the first angle set, The upper bridge switch tube of the bridge arm corresponding to the phase winding, the lower bridge switch tube of the bridge arm corresponding to the V phase winding, and the lower bridge switch tube in the bridge arm corresponding to the W phase winding are periodically turned on, so that the power battery outputs direct current to the V and W phase windings of the drive motor. In such a design, when the rotor position angle of the drive motor 2013 belongs to the first angle set, when the three bridge arms are in the first operating mode, the internal resistance of the power battery 202 can be heated, and the drive motor 2013 has a small torque.

In other examples, the motor controller 2010 can respond to the rotor position angle of the drive motor 2013 belonging to the first angle set, and the lower bridge switch tube of the bridge arm corresponding to the U-phase winding, the upper bridge switch tube of the bridge arm corresponding to the V-phase winding, and the upper bridge switch tube in the bridge arm corresponding to the W-phase winding are periodically turned on, so that the power battery outputs direct current to the V and W phase windings of the drive motor. In such a design, when the rotor position angle of the drive motor 2013 belongs to the first angle set, when the three bridge arms are in the second operating mode, the internal resistance of the power battery 202 can be heated, and the drive motor 2013 has a small torque.

The motor controller 2010 can respond to the rotor position angle of the drive motor 2013 belonging to the second angle set, and the three bridge arms can be the aforementioned third operation mode or fourth operation mode, so that the three bridge arms operate in the heating mode. The rotor position angle of the drive motor 2013 is an angle value in any angle interval in the second angle set, which can be regarded as the rotor position angle of the drive motor 2013 belonging to the second angle set.

In some examples, the motor controller 2010 can periodically conduct the upper bridge switch tube of the bridge arm corresponding to the W-phase winding, the lower bridge switch tube of the bridge arm corresponding to the V-phase winding, and the lower bridge switch tube in the bridge arm corresponding to the U-phase winding in response to the rotor position angle belonging to the second angle set, so that the power battery outputs direct current to the V and W phase windings of the drive motor. In such a design, when the rotor position angle of the drive motor 2013 belongs to the second angle set, when the three bridge arms are in the third operating mode, the internal resistance of the power battery 202 can be heated, and the drive motor 2013 has a small torque.

In other examples, the motor controller 2010 can respond to the rotor position angle belonging to the second angle set, and the lower bridge switch tube of the bridge arm corresponding to the W phase winding, the upper bridge switch tube of the bridge arm corresponding to the V phase winding, and the upper bridge switch tube in the bridge arm corresponding to the U phase winding are periodically turned on, so that the power battery outputs direct current to the V and W phase windings of the drive motor. In such a design, when the rotor position angle of the drive motor 2013 belongs to the second angle set, when the three bridge arms are in the fourth operation mode, the internal resistance of the power battery 202 can be heated, and the drive motor 2013 has a small torque.

The motor controller 2010 can respond to the rotor position angle of the drive motor 2013 belonging to the second angle set, and the three bridge arms can be the aforementioned fifth operation mode or sixth operation mode, so that the three bridge arms operate in the heating mode. The rotor position angle of the drive motor 2013 is an angle value in any angle interval in the third angle set, which can be regarded as the rotor position angle of the drive motor 2013 belonging to the third angle set.

In some examples, the motor controller 2010 can respond to the rotor position angle belonging to the third angle set, and the upper bridge switch tube of the bridge arm corresponding to the V-phase winding, the lower bridge switch tube of the bridge arm corresponding to the W-phase winding, and the lower bridge switch tube in the bridge arm corresponding to the U-phase winding are periodically turned on so that the power battery outputs direct current to the U and W phase windings of the drive motor. In such a design, when the rotor position angle of the drive motor 2013 belongs to the third angle set, when the three bridge arms are in the fifth operating mode, the internal resistance of the power battery 202 can be heated, and the drive motor 2013 has a small torque.

In some examples, the motor controller 2010 can periodically conduct the lower bridge switch tube of the bridge arm corresponding to the V-phase winding, the upper bridge switch tube of the bridge arm corresponding to the W-phase winding, and the upper bridge switch tube in the bridge arm corresponding to the U-phase winding in response to the rotor position angle belonging to the third angle set, so that the power battery outputs direct current to the U and W phase windings of the drive motor. In such a design, when the rotor position angle of the drive motor 2013 belongs to the third angle set, when the three bridge arms are in the sixth operating mode, the internal resistance of the power battery 202 can be heated, and the drive motor 2013 has a small torque.

Based on the motor controller 2010 adopted in any of the above embodiments, in some embodiments, when the three bridge arms operate in the heating mode, the motor controller 2010 can respond to the temperature of any one of the three-phase windings being greater than a preset winding temperature threshold, and the conduction time of the turned-on switch tube in the next cycle is reduced, so as to reduce the DC current output by the power battery and avoid overheating and damage of the three-phase windings.

In some embodiments, when the three bridge arms operate in the heating mode, the motor controller 2010 can respond to the temperature of any one of the switch tubes in the three bridge arms being greater than a preset switch tube temperature threshold, and the conduction time of the turned-on switch tube in the next cycle is reduced, so as to reduce the DC current output by the power battery and avoid overheating and damage to the switch tubes in the three bridge arms.

Exemplarily, the motor controller 2010 can reduce the conduction time of the three switched tubes in the next cycle in response to the temperature of any one of the three switched tubes turned on in the three bridge arms being greater than a preset switched tube temperature threshold, so as to reduce the DC current output by the power battery.

Based on any of the electric drive systems 201 provided in the above embodiments, the embodiments of the present application further provide a control unit 2014, which can control the inverter circuit 2011, that is, the operation mode of the three bridge arms. Please refer to FIG. 2 again. The control unit 2014 is connected to the control end of the inverter circuit 2011 and the control end of the DC conversion circuit 2012. Then, the control unit 2014 can send control signals to the inverter circuit 2011 and the DC conversion circuit 2012, thereby controlling the output current of the inverter circuit 2011 and the output current of the DC conversion circuit 2012. Exemplarily, the control The unit 2014 may include, but is not limited to, a central processing unit (CPU), other general-purpose processors, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The control unit 2014 may control the switches in each bridge arm to be turned on or off by outputting a control signal to each bridge arm of the inverter circuit 2011. The control signal may be a pulse width modulation (PWM) signal.

Exemplarily, the control unit 2014 may be connected to the gates of the switch tubes of the three bridge arms in the inverter circuit 2011 to control the on or off of the switch tubes in the inverter circuit 2011 so as to adjust the working modes of the three bridge arms.

In one embodiment, the control unit 2014 may detect whether the temperature of the power battery 202 is less than a first temperature threshold. In response to the temperature of the power battery 202 being less than the first temperature threshold, the control unit 2014 may control the three bridge arms to operate in a heating mode. Alternatively, in response to the temperature of the power battery 202 being greater than or equal to the first temperature threshold, the control unit 2014 may control the three bridge arms to operate in an inverter mode so as to drive the motor to drive the wheels to rotate.

First, the control unit 2014 controlling the three bridge arms to operate in the heating mode is introduced.

The control unit 2014 can control the upper bridge switch tube of one of the three bridge arms and the lower bridge switch tubes in the other two bridge arms to be turned on periodically. For example, the control unit 2014 can send a first control signal to the upper bridge switch tube of one of the three bridge arms and the lower bridge switch tubes in the other two bridge arms, or send a first control signal to the lower bridge switch tube of one of the three bridge arms and the upper bridge switch tubes in the other two bridge arms. The first control signal is a periodic signal, and the duty cycle of the first control signal in each switching cycle is less than or equal to 0.5, so as to control the three bridge arms to operate in the heating mode.

In one embodiment, when the control unit 2014 controls the three bridge arms to operate in the heating mode, any one of the aforementioned six operating modes may be adopted.

In some examples, when the control unit 2014 controls the three bridge arms to operate in the heating mode, the control unit 2014 can control the three bridge arms in the aforementioned first operation mode. Specifically, the control unit 2014 can control the switch tube _Q51 in the U-phase bridge arm, the switch tube _Q54 in the V-phase bridge arm, and the switch tube _Q56 in the W-phase bridge arm to be periodically turned on.

In some examples, the control unit 2014 can control the three bridge arms in the aforementioned second operation mode. Specifically, the control unit 2014 can control the switch tube _Q52 in the U phase bridge arm, the switch tube _Q53 in the V phase bridge arm, and the switch tube _Q55 in the W phase bridge arm to be periodically turned on.

In some examples, when the control unit 2014 controls the three bridge arms to operate in the heating mode, the control unit 2014 can control the three bridge arms in the aforementioned third operation mode. Specifically, the control unit 2014 can control the switch tube _Q53 in the V phase bridge arm, the switch tube _Q52 in the U phase bridge arm, and the switch tube _Q56 in the W phase bridge arm to be periodically turned on.

In some examples, when the control unit 2014 controls the three bridge arms to operate in the heating mode, the control unit 2014 can control the three bridge arms in the aforementioned fourth operation mode. Specifically, the control unit 2014 can control the switch tube _Q54 in the V phase bridge arm, the switch tube _Q51 in the U phase bridge arm, and the switch tube _Q55 in the W phase bridge arm to be periodically turned on.

In some examples, when the control unit 2014 controls the three bridge arms to operate in the heating mode, the control unit 2014 controls the three bridge arms in the fifth operation mode. Specifically, the control unit 2014 can control the switch tube _Q52 in the U phase bridge arm, the switch tube _Q54 in the V phase bridge arm, and the switch tube _Q55 in the W phase bridge arm to be periodically turned on.

In some examples, when the control unit 2014 controls the three bridge arms to operate in the heating mode, the control unit 2014 controls the three bridge arms in the aforementioned sixth operation mode. Specifically, the control unit 2014 can control the switch tube _Q51 in the U-phase bridge arm, the switch tube _Q53 in the V-phase bridge arm, and the switch tube _Q56 in the W-phase bridge arm to be periodically turned on.

In one embodiment, to improve the heating efficiency of the heating power battery 202, the control unit 2014 can select one operating mode from the six operating modes of the three bridge arms according to the rotor position angle to control the three bridge arms, so that the three bridge arms operate in the heating mode.

The control unit 2014 may obtain a plurality of pre-configured angle sets. The plurality of angle sets may include a first angle set, a second angle set, and a third angle set. Among the plurality of angle sets, any two sets do not overlap, that is, any two sets have no intersection. Each angle set may include one or more angles. In a possible implementation, the first angle set includes angle intervals [0, θ _m ], (θ _m +120, θ _m +180], and (θ _m +300, 360]. Optionally, θ _m is less than or equal to 60°, and θ _m is a positive number. The second angle set includes angle intervals (θ _m , θ _m +60], and (θ _m +180, θ _m +240]; the third angle set includes angle intervals (θ _m +60, θ _m +120], (θ _m +240, θ _m +300]. The specific value of θ _m can be configured in combination with actual application scenarios. For example, θ _m can be angle values such as 25°, 30°, 35°, 40°, 45°, 50°, 55°, etc. Typically θ _m can be configured to 30°.

Each angle set has corresponding operation modes of three bridge arms. Exemplarily, the first angle set corresponds to the first operation mode and The second operating mode corresponds to one or more of the second operating mode, the second angle set corresponds to one or more of the third operating mode and the fourth operating mode, and the third angle set corresponds to one or more of the fifth operating mode and the sixth operating mode.

The control unit 214 can adopt one of the operation modes of the three bridge arms corresponding to the angle set to which the rotor position angle of the drive motor 2013 belongs, control the three bridge arms, and adjust the output current of the power battery 202. The angle set to which the rotor position angle belongs can be understood as the angle set to which the rotor position angle is located, or if there is an angle value equal to the rotor position angle in the angle values included in the angle set, it can also be regarded as that the rotor position angle belongs to the angle set. The control unit 214 can compare the rotor position angle of the drive motor 2013 with each angle set, and determine the angle set to which the rotor position angle belongs by comparison.

In a possible scenario, the control unit 2014 may detect that the rotor position angle belongs to a first angle set, and adopt a first operating mode or a second operating mode corresponding to the first angle set.

In one embodiment, the control unit 2014 can detect that the rotor position angle belongs to the first angle set, and adopt the first operation mode corresponding to the first angle set. In response to the rotor position angle belonging to the first angle set, the control unit 2014 can control the switch tube _Q51 in the U phase bridge arm, the switch tube _Q54 in the V phase bridge arm, and the switch tube _Q56 in the W phase bridge arm to be periodically turned on.

Exemplarily, the control unit 2014 can send a first control signal to the upper bridge switch tube of the U phase bridge arm, the V phase bridge arm, and the lower bridge switch tube in the W phase bridge arm, wherein the first control signal is a periodic signal, wherein the first control signal is a periodic signal, and the duty cycle of the first control signal in each switching cycle is less than or equal to 0.5. Referring to FIG. 4 , the control unit 2014 can output the switch tube _Q51 in the U phase bridge arm to send a duty cycle of PWM signal, where _t1 represents the first duration, _Tz represents the duration of a switching cycle, The control unit 2014 can output the switch tube _Q54 in the V-phase bridge arm to send a duty cycle of The control unit 2014 can output the switch tube _Q56 in the W-phase bridge arm to send a PWM signal with a duty cycle of PWM signal. Optionally, the control unit 2014 may also respond to the temperature of any one of the three-phase windings in the drive motor 2013 being greater than a preset winding temperature threshold or the temperature of the upper bridge switch tube of the U-phase bridge arm, the lower bridge switch tube in the V-phase bridge arm and the W-phase bridge arm being greater than a preset switch tube temperature threshold. The control unit 2014 may send a fourth control signal to the upper bridge switch tube of the U-phase bridge arm, the lower bridge switch tube in the V-phase bridge arm and the W-phase bridge arm starting from the next switching cycle, wherein the duty cycle of the fourth control signal in each switching cycle is less than the duty cycle of the first control signal in each switching cycle. For example, the control unit 2014 may output the switch tube _Q51 in the U-phase bridge arm to send a fourth control signal with a duty cycle of PWM signal, wherein _t4 represents the second duration, _Tz represents the duration of a switching cycle, Less than the above The control unit 2014 can output the switch tube _Q54 in the V-phase bridge arm to send a duty cycle of The control unit 2014 can output the switch tube _Q56 in the W-phase bridge arm to send a PWM signal with a duty cycle of Such a design can reduce the output current of the power battery 202, reduce the heat generated by the three-phase winding, the heat generated by the three-phase bridge arm, and protect the drive motor 2013 and the three-phase bridge arm.

For ease of introduction, in the present application, level V1 represents the level that can drive the switch tube to conduct, and level V2 represents the level that drives the switch tube to disconnect. Among them, the control unit 2014 can also drive the switch tube to disconnect by not providing a control signal to the switch, which can reduce switching losses. The control signal of the switch tube _Q51 in the U-phase bridge arm is PWM_S1, and the control signal of the switch tube _Q52 is PWM_S2. The control signal of the switch tube _Q53 in the V-phase bridge arm is PWM_S3, the control signal of the switch tube _Q54 is PWM_S4, the control signal of the switch tube _Q55 in the W-phase bridge arm is PWM_S5, and the control signal of the switch tube _Q56 is PWM_S6.

In a possible implementation, FIG7a shows the control signals of the switch tubes of the three bridge arms when the rotor position angle belongs to the first angle set. The control unit 2014 can control the upper bridge switch tube of the U-phase bridge arm, the lower bridge switch tubes in the V-phase bridge arm and the W-phase bridge arm to be turned on for the first duration in the first half of each switching cycle. When the rotor position angle belongs to the first angle set, the control unit 2014 sends corresponding signals to the switch tubes of the three bridge arms, such as PWM_S1, PWM_S2, PWM_S3, PWM_S4, PWM_S5, and PWM_S6 shown in FIG7a. The control signal with a level of V1 can be implemented as the aforementioned first control signal. Among them, in the signals PWM_S1, PWM_S4, and PWM_S6, in the first half of each switching cycle, the control signal with a level of V1 lasts for a first duration, which is recorded as _t1 . The duration of each switching cycle is recorded as _Tz , and the duty cycle of the control signal with a level of V1 is Less than or equal to 0.5.

Optionally, the control unit 2014 may control the lower bridge switch of the U phase bridge arm, the upper bridge switch in the V phase bridge arm and the W phase bridge arm to be turned on for a first duration in the second half of each switching cycle. As shown in FIG7a , in the second half of each switching cycle T, the control signal with a level of V1 in the signals PWM_S2, PWM_S3, and PWM_S5 lasts for a duration of _t1 .

Alternatively, as shown in FIG7b, the control unit 2014 may not output control signals to each switch in the second half of each switching cycle. The control unit 2014 may control the upper bridge switch tube of the U-phase bridge arm, the lower bridge switch tubes in the V-phase bridge arm and the W-phase bridge arm to conduct for a first period of time and then seal the wave, that is, not output control signals to the switches in each three-phase bridge arm. The control unit 2014 may not output control signals to each switch in the three-phase bridge arm in the second half of each switching cycle, and each switch in the three-phase bridge arm is in an open circuit state. At this time, the freewheeling diode in the lower bridge switch tube of the U-phase bridge arm, the upper bridge switch tube in the V-phase bridge arm, and the lower bridge switch tube in the W-phase bridge arm are in an open circuit state. The freewheeling diode in the switch tube, the freewheeling diode in the upper bridge switch tube in the W-phase bridge arm, the drive motor 2013, and the power battery 202 form a freewheeling loop. Under the action of the current in the freewheeling loop, the power battery 202 can continue to heat. Such a design can reduce the switching loss of the three bridge arms in the inverter circuit 2011.

In another possible implementation, Fig. 7c shows the control signals of the switch tubes of the three bridge arms when the rotor position angle belongs to the first angle set. The control unit 2014 can control the upper bridge switch tube of the U-phase bridge arm, the lower bridge switch tubes in the V-phase bridge arm and the W-phase bridge arm to be turned on for the first duration in the second half of each switching cycle.

In one embodiment, the control unit 2014 can detect that the rotor position angle belongs to the first angle set, and adopt the second operation mode corresponding to the first angle set. In response to the rotor position angle belonging to the first angle set, the control unit 2014 can control the switch tube _Q52 in the U phase bridge arm, the switch tube _Q53 in the V phase bridge arm, and the switch tube _Q55 in the W phase bridge arm to be periodically turned on.

Exemplarily, the control unit 2014 can send a first control signal to the lower bridge switch tube of the U phase bridge arm, the upper bridge switch tube in the V phase bridge arm and the W phase bridge arm, wherein the first control signal is a periodic signal, wherein the first control signal is a periodic signal, and the duty cycle of the first control signal in each switching cycle is less than or equal to 0.5. Referring to FIG. 4 , the control unit 2014 can output the switch tube _Q52 in the U phase bridge arm to send a duty cycle of PWM signal, where _t1 represents the first duration, _Tz represents the duration of a switching cycle, The control unit 2014 can output the switch tube _Q53 in the V-phase bridge arm to send a duty cycle of The control unit 2014 can output the switch tube _Q55 in the W-phase bridge arm to send a PWM signal with a duty cycle of PWM signal. Optionally, the control unit 2014 can also respond to the temperature of any one of the three-phase windings in the drive motor 2013 being greater than a preset winding temperature threshold or the temperature of the lower bridge switch tube of the U-phase bridge arm, the upper bridge switch tube in the V-phase bridge arm and the W-phase bridge arm being greater than a preset switch tube temperature threshold. The control unit 2014 can send a fourth control signal to the lower bridge switch tube of the U-phase bridge arm, the upper bridge switch tube in the V-phase bridge arm and the W-phase bridge arm starting from the next switching cycle, wherein the duty cycle of the fourth control signal in each switching cycle is less than the duty cycle of the first control signal in each switching cycle. For example, the control unit 2014 can output the switch tube _Q52 in the U-phase bridge arm to send a fourth control signal with a duty cycle of PWM signal, wherein _t4 represents the second duration, _Tz represents the duration of a switching cycle, Less than the above The control unit 2014 can output the switch tube _Q53 in the V-phase bridge arm to send a duty cycle of The control unit 2014 can output the switch tube _Q55 in the W-phase bridge arm to send a PWM signal with a duty cycle of Such a design can reduce the output current of the power battery 202, reduce the heat generated by the three-phase winding, the heat generated by the three-phase bridge arm, and protect the drive motor 2013 and the three-phase bridge arm.

In a possible implementation, FIG8a shows the control signals of the switch tubes of the three bridge arms when the rotor position angle belongs to the first angle set. The control unit 2014 can control the lower bridge switch tube of the U-phase bridge arm, the upper bridge switch tubes in the V-phase bridge arm and the W-phase bridge arm to be turned on for the first duration in the first half of each switching cycle. When the rotor position angle belongs to the first angle set, the control unit 2014 sends corresponding signals to the switch tubes of the three bridge arms, such as PWM_S1, PWM_S2, PWM_S3, PWM_S4, PWM_S5, and PWM_S6 shown in FIG8a. The control signal with a level of V1 can be implemented as the aforementioned first control signal. Among them, in the signals PWM_S2, PWM_S3, and PWM_S5, in the first half of each switching cycle, the control signal with a level of V1 lasts for a first duration, which is recorded as _t1 . The duration of each switching cycle is recorded as _Tz , and the duty cycle of the control signal with a level of V1 is Less than or equal to 0.5.

Optionally, the control unit 2014 may control the upper bridge switch of the U-phase bridge arm, the lower bridge switch in the V-phase bridge arm and the W-phase bridge arm to be turned on for a first duration in the second half of each switching cycle. As shown in FIG8a , in the second half of each switching cycle T, the control signal with a level of V1 in the signals PWM_S1, PWM_S4, and PWM_S6 lasts for a duration of _t1 .

Alternatively, as shown in FIG8b, the control unit 2014 may not output a control signal to each switch in the second half of each switching cycle. The control unit 2014 may control the lower bridge switch tube of the U-phase bridge arm, the upper bridge switch tube in the V-phase bridge arm and the W-phase bridge arm to conduct for the first time length and then seal the wave, that is, not output a control signal to the switch in each three-phase bridge arm. The control unit 2014 may not output a control signal to each switch in the three-phase bridge arm in the second half of each switching cycle, and each switch in the three-phase bridge arm is in an open circuit state. At this time, the freewheeling diode in the upper bridge switch tube of the U-phase bridge arm, the freewheeling diode in the lower bridge switch tube in the V-phase bridge arm, the freewheeling diode in the lower bridge switch tube in the W-phase bridge arm, the drive motor 2013, and the power battery 202 form a freewheeling loop, and under the action of the current in the freewheeling loop, the power battery 202 can continue to heat. Such a design can reduce the switching losses of the three bridge arms in the inverter circuit 2011.

In another possible implementation, Fig. 8c shows the control signals of the switch tubes of the three bridge arms when the rotor position angle belongs to the first angle set. The control unit 2014 can control the lower bridge switch tube of the U-phase bridge arm, the upper bridge switch tubes in the V-phase bridge arm and the W-phase bridge arm to be turned on for the first duration in the second half of each switching cycle.

In a possible scenario, the control unit 2014 may detect that the rotor position angle belongs to the second angle set, and adopt the third operating mode or the fourth operating mode corresponding to the first angle set.

In one embodiment, the control unit 2014 can detect that the rotor position angle belongs to the second angle set, and adopt the third operation mode corresponding to the second angle set. In response to the rotor position angle belonging to the second angle set, the control unit 2014 can control the switch tube _Q54 in the V phase bridge arm, the switch tube _Q52 in the U phase bridge arm, and the switch tube _Q55 in the W phase bridge arm to be periodically turned on.

Exemplarily, the control unit 2014 can send a first control signal to the upper bridge switch tube of the W phase bridge arm, the V phase bridge arm, and the lower bridge switch tube in the U phase bridge arm, wherein the first control signal is a periodic signal, wherein the first control signal is a periodic signal, and the duty cycle of the first control signal in each switching cycle is less than or equal to 0.5. In the operation of the first duration of conduction, please refer to FIG. 4, the control unit 2014 can output the switch tube _Q55 in the W phase bridge arm to send a duty cycle of PWM signal, where _t1 represents the first duration, _Tz represents the duration of a switching cycle, The control unit 2014 can output the switch tube _Q54 in the V-phase bridge arm to send a duty cycle of The control unit 2014 can output the switch tube _Q52 in the U-phase bridge arm to send a PWM signal with a duty cycle of PWM signal. Optionally, the control unit 2014 can also respond to the temperature of any one of the three-phase windings in the drive motor 2013 being greater than a preset winding temperature threshold or the temperature of the upper bridge switch tube of the W-phase bridge arm, the lower bridge switch tube in the V-phase bridge arm and the U-phase bridge arm being greater than a preset switch tube temperature threshold. The control unit 2014 can send a fourth control signal to the upper bridge switch tube of the W-phase bridge arm, the lower bridge switch tube in the V-phase bridge arm and the U-phase bridge arm starting from the next switching cycle, wherein the duty cycle of the fourth control signal in each switching cycle is less than the duty cycle of the first control signal in each switching cycle. For example, the control unit 2014 can output the switch tube _Q55 in the W-phase bridge arm to send a fourth control signal with a duty cycle of PWM signal, wherein _t4 represents the second duration, _Tz represents the duration of a switching cycle, Less than the above The control unit 2014 can output the switch tube _Q54 in the V-phase bridge arm to send a duty cycle of The control unit 2014 can output the switch tube _Q52 in the U-phase bridge arm to send a PWM signal with a duty cycle of Such a design can reduce the output current of the power battery 202, reduce the heat generated by the three-phase winding, the heat generated by the three-phase bridge arm, and protect the drive motor 2013 and the three-phase bridge arm.

In a possible implementation, Fig. 9a shows the control signals of the switch tubes of the three bridge arms when the rotor position angle belongs to the second angle combination. The control unit 2014 can control the upper bridge switch tube of the W-phase bridge arm, the lower bridge switch tubes in the V-phase bridge arm and the U-phase bridge arm to be turned on for the first duration in the first half of each switching cycle.

As shown in FIG9a, PWM_S1, PWM_S2, PWM_S3, PWM_S4, PWM_S5, and PWM_S6, the control signal with a level of V1 can be implemented as the aforementioned first control signal. Among them, in the first half of each switching cycle of the signals PWM_S5, PWM_S2, and PWM_S4, the control signal with a level of V1 lasts for a first duration, which is recorded as _t1 . The duration of each switching cycle is recorded as _Tz , and the duty cycle of the control signal with a level of V1 is Less than or equal to 0.5.

Optionally, the control unit 2014 may control the lower bridge switch of the W-phase bridge arm, the upper bridge switch in the V-phase bridge arm and the U-phase bridge arm to be turned on for a first duration in the second half of each switching cycle. As shown in FIG9a , in the second half of each switching cycle, the control signal with a level of V1 in the signals PWM_S6, PWM_S1, and PWM_S3 lasts for a duration of t ₁ . The duration of each switching cycle is denoted as T _z , and the duty cycle of the control signal with a level of V1 is Less than or equal to 0.5.

Alternatively, as shown in FIG9b, the control unit 2014 may not output a control signal to each switch in the second half of each switching cycle. The control unit 2014 may control the lower bridge switch tube of the W-phase bridge arm, the upper bridge switch tube in the V-phase bridge arm and the U-phase bridge arm to conduct for the first time length and then seal the wave, that is, not output a control signal to the switch in each three-phase bridge arm. The control unit 2014 may not output a control signal to each switch in the three-phase bridge arm in the second half of each switching cycle, and each switch in the three-phase bridge arm is in an open circuit state. That is, not output a control signal to the switch in each three-phase bridge arm. The control unit 2014 may not output a control signal to each switch in the three-phase bridge arm in the second half of each switching cycle, and each switch in the three-phase bridge arm is in an open circuit state. At this time, the freewheeling diode in the lower bridge switch tube of the W-phase bridge arm, the freewheeling diode in the upper bridge switch tube of the V-phase bridge arm, the freewheeling diode in the upper bridge switch tube of the U-phase bridge arm, the drive motor 2013, and the power battery 202 form a freewheeling loop, and the power battery 202 can continue to be heated under the action of the current in the freewheeling loop. Such a design can reduce the switching loss of the three bridge arms in the inverter circuit 2011.

In another possible implementation, Fig. 9c shows the control signals of the switch tubes of the three bridge arms when the rotor position angle belongs to the second angle set. The control unit 2014 can control the lower bridge switch tube of the W-phase bridge arm, the upper bridge switch tubes in the V-phase bridge arm and the U-phase bridge arm to be turned on for the first duration in the second half of each switching cycle.

In one embodiment, the control unit 2014 can detect that the rotor position angle belongs to the second angle set, and adopt the fourth operation mode corresponding to the second angle set. In response to the rotor position angle belonging to the second angle set, the control unit 2014 can control the switch tube _Q53 in the V phase bridge arm, the switch tube _Q51 in the U phase bridge arm, and the switch tube _Q56 in the W phase bridge arm to be periodically turned on.

Exemplarily, the control unit 2014 may provide a control signal to the lower bridge switch tube of the W phase bridge arm, the V phase bridge arm and the U phase bridge arm. The upper bridge switch tube sends a first control signal, the first control signal is a periodic signal, wherein the first control signal is a periodic signal, and the duty cycle of the first control signal in each switching cycle is less than or equal to 0.5. In the operation of the first duration of conduction, please refer to FIG. 4, the control unit 2014 can output the switch tube _Q56 in the W phase bridge arm to send a duty cycle of PWM signal, where _t1 represents the first duration, _Tz represents the duration of a switching cycle, The control unit 2014 can output the switch tube _Q53 in the V-phase bridge arm to send a duty cycle of The control unit 2014 can output the switch tube _Q51 in the U-phase bridge arm to send a PWM signal with a duty cycle of PWM signal. Optionally, the control unit 2014 can also respond to the temperature of any one of the three-phase windings in the drive motor 2013 being greater than a preset winding temperature threshold or the temperature of the lower bridge switch tube of the W-phase bridge arm, the upper bridge switch tube in the V-phase bridge arm and the U-phase bridge arm being greater than a preset switch tube temperature threshold. The control unit 2014 can send a fourth control signal to the lower bridge switch tube of the W-phase bridge arm, the upper bridge switch tube in the V-phase bridge arm and the U-phase bridge arm starting from the next switching cycle, wherein the duty cycle of the fourth control signal in each switching cycle is less than the duty cycle of the first control signal in each switching cycle. For example, the control unit 2014 can output the switch tube _Q56 in the W-phase bridge arm to send a duty cycle of PWM signal, wherein _t4 represents the second duration, _Tz represents the duration of a switching cycle, Less than the above The control unit 2014 can output the switch tube _Q53 in the V-phase bridge arm to send a duty cycle of The control unit 2014 can output the switch tube _Q51 in the U-phase bridge arm to send a PWM signal with a duty cycle of Such a design can reduce the output current of the power battery 202, reduce the heat generated by the three-phase winding, the heat generated by the three-phase bridge arm, and protect the drive motor 2013 and the three-phase bridge arm.

In a possible implementation, Fig. 10a shows the control signals of the switch tubes of the three bridge arms when the rotor position angle belongs to the second angle combination. The control unit 2014 can control the lower bridge switch tube of the W-phase bridge arm, the upper bridge switch tubes in the V-phase bridge arm and the U-phase bridge arm to be turned on for the first duration in the first half of each switching cycle.

As shown in FIG. 10a, PWM_S1, PWM_S2, PWM_S3, PWM_S4, PWM_S5, and PWM_S6, the control signal with a level of V1 can be implemented as the aforementioned first control signal. Among them, in the first half of each switching cycle of the signals PWM_S6, PWM_S1, and PWM_S3, the control signal with a level of V1 lasts for a first duration, which is recorded as _t1 . The duration of each switching cycle is recorded as _Tz , and the duty cycle of the control signal with a level of V1 is Less than or equal to 0.5.

Optionally, the control unit 2014 may control the upper bridge switch of the W-phase bridge arm, the lower bridge switch in the V-phase bridge arm and the U-phase bridge arm to be turned on for a first duration in the second half of each switching cycle. As shown in FIG10a , in the second half of each switching cycle, the control signal with a level of V1 in the signals PWM_S5, PWM_S2, and PWM_S4 lasts for a duration of t ₁ . The duration of each switching cycle is denoted as T _z , and the duty cycle of the control signal with a level of V1 is Less than or equal to 0.5.

Alternatively, as shown in FIG10b, the control unit 2014 may not output a control signal to each switch in the second half of each switching cycle. The control unit 2014 may control the upper bridge switch tube of the W-phase bridge arm, the V-phase bridge arm, and the lower bridge switch tube in the U-phase bridge arm to conduct for the first time length and then seal the wave, that is, not output a control signal to the switch in each three-phase bridge arm. The control unit 2014 may not output a control signal to each switch in the three-phase bridge arm in the second half of each switching cycle, and each switch in the three-phase bridge arm is in an open circuit state. That is, not output a control signal to the switch in each three-phase bridge arm. The control unit 2014 may not output a control signal to each switch in the three-phase bridge arm in the second half of each switching cycle, and each switch in the three-phase bridge arm is in an open circuit state. At this time, the freewheeling diode in the upper bridge switch tube of the W-phase bridge arm, the freewheeling diode in the lower bridge switch tube in the V-phase bridge arm, the freewheeling diode in the lower bridge switch tube in the U-phase bridge arm, the drive motor 2013, and the power battery 202 form a freewheeling loop, and the power battery 202 can continue to be heated under the action of the current in the freewheeling loop. Such a design can reduce the switching loss of the three bridge arms in the inverter circuit 2011.

In another possible implementation, Fig. 10c shows the control signals of the switch tubes of the three bridge arms when the rotor position angle belongs to the second angle set. The control unit 2014 can control the upper bridge switch tube of the W-phase bridge arm, the lower bridge switch tubes in the V-phase bridge arm and the U-phase bridge arm to be turned on for the first duration in the second half of each switching cycle.

In another possible scenario, the control unit 2014 may detect that the rotor position angle belongs to the third angle set, and adopt the fifth operating mode or the sixth operating mode corresponding to the third angle set.

In one embodiment, the control unit 2014 can detect that the rotor position angle belongs to the third angle set, and adopt the fifth operation mode corresponding to the third angle set. In response to the rotor position angle belonging to the third angle set, the control unit 2014 can control the switch tube _Q52 in the U phase bridge arm, the switch tube _Q53 in the V phase bridge arm, and the switch tube _Q56 in the W phase bridge arm to be periodically turned on.

Exemplarily, the control unit 2014 may send a first control signal to the upper bridge switch tube of the V-phase bridge arm, the U-phase bridge arm, and the lower bridge switch tube in the W-phase bridge arm, wherein the first control signal is a periodic signal, wherein the first control signal is a periodic signal, and the duty cycle of the first control signal in each switching cycle is less than or equal to 0.5. The switch tube _Q53 in the V-phase bridge arm can output a duty cycle of PWM signal, where _t1 represents the first duration, _Tz represents the duration of a switching cycle, The control unit 2014 can output the switch tube _Q52 in the U-phase bridge arm to send a duty cycle of The control unit 2014 can output the switch tube _Q56 in the W-phase bridge arm to send a PWM signal with a duty cycle of PWM signal. Optionally, the control unit 2014 can also respond to the temperature of any one of the three-phase windings in the drive motor 2013 being greater than a preset winding temperature threshold or the temperature of the upper bridge switch tube of the V-phase bridge arm, the lower bridge switch tube in the U-phase bridge arm and the W-phase bridge arm being greater than a preset switch tube temperature threshold. The control unit 2014 can send a fourth control signal to the upper bridge switch tube of the V-phase bridge arm, the lower bridge switch tube in the U-phase bridge arm and the W-phase bridge arm starting from the next switching cycle, wherein the duty cycle of the fourth control signal in each switching cycle is less than the duty cycle of the first control signal in each switching cycle. For example, the control unit 2014 can output the switch tube _Q53 in the V-phase bridge arm to send a fourth control signal with a duty cycle of PWM signal, wherein _t4 represents the second duration, _Tz represents the duration of a switching cycle, Less than the above The control unit 2014 can output the switch tube _Q52 in the U-phase bridge arm to send a duty cycle of The control unit 2014 can output the switch tube _Q56 in the W-phase bridge arm to send a PWM signal with a duty cycle of Such a design can reduce the output current of the power battery 202, reduce the heat generated by the three-phase winding, the heat generated by the three-phase bridge arm, and protect the drive motor 2013 and the three-phase bridge arm.

In a possible implementation, FIG11a shows the control signals of the switch tubes of the three bridge arms when the rotor position angle belongs to the third angle set. The control unit 2014 can control the upper bridge switch tube of the V-phase bridge arm, the lower bridge switch tubes in the U-phase bridge arm and the W-phase bridge arm to be turned on for the first duration in the first half of each switching cycle. When the rotor position angle belongs to the third angle set, the control unit 2014 sends corresponding signals to the switch tubes of the three bridge arms, such as PWM_S1, PWM_S2, PWM_S3, PWM_S4, PWM_S5, and PWM_S6 shown in FIG11a. The control signal with a level of V1 can be implemented as the aforementioned first control signal. Among them, in the signals PWM_S2, PWM_S3, and PWM_S6, in the first half of each switching cycle, the control signal with a level of V1 lasts for a first duration, and the first duration is recorded as _t1 . The duration of each switching cycle is recorded as _Tz , and the duty cycle of the control signal with a level of V1 is Less than or equal to 0.5.

Optionally, the control unit 2014 may control the lower bridge switch of the V-phase bridge arm, the upper bridge switch in the U-phase bridge arm and the W-phase bridge arm to be turned on for a first duration in the second half of each switching cycle. As shown in FIG11a , in the signals PWM_S1, PWM_S4, and PWM_S5, in the second half of each switching cycle T, the control signal with a level of V1 lasts for a duration of t ₁ .

Alternatively, as shown in FIG11b, the control unit 2014 may not output a control signal to each switch in the second half of each switching cycle. The control unit 2014 may control the upper bridge switch tube of the V-phase bridge arm, the lower bridge switch tube in the U-phase bridge arm and the W-phase bridge arm to conduct for the first time length and then seal the wave, that is, not output a control signal to the switch in each three-phase bridge arm. The control unit 2014 may not output a control signal to each switch in the three-phase bridge arm in the second half of each switching cycle, and each switch in the three-phase bridge arm is in an open circuit state. At this time, the freewheeling diode in the lower bridge switch tube of the V-phase bridge arm, the freewheeling diode in the upper bridge switch tube in the U-phase bridge arm, the freewheeling diode in the upper bridge switch tube in the W-phase bridge arm, the drive motor 2013, and the power battery 202 form a freewheeling loop, and under the action of the current in the freewheeling loop, the power battery 202 can continue to heat. Such a design can reduce the switching loss of the three bridge arms in the inverter circuit 2011.

In another possible implementation, FIG11c shows the control signals of the switch tubes of the three bridge arms when the rotor position angle belongs to the third angle set. The control unit 2014 can control the upper bridge switch tube of the V-phase bridge arm, the lower bridge switch tubes in the U-phase bridge arm and the W-phase bridge arm to be turned on for the first duration in the second half of each switching cycle.

In one embodiment, the control unit 2014 can detect that the rotor position angle belongs to the third angle set, and adopt the sixth operation mode corresponding to the third angle set. In response to the rotor position angle belonging to the third angle set, the control unit 2014 can control the switch tube _Q51 in the U phase bridge arm, the switch tube _Q54 in the V phase bridge arm, and the switch tube _Q55 in the W phase bridge arm to be periodically turned on.

Exemplarily, the control unit 2014 can send a first control signal to the lower bridge switch tube of the V phase bridge arm, the upper bridge switch tube in the U phase bridge arm and the W phase bridge arm, wherein the first control signal is a periodic signal, wherein the first control signal is a periodic signal, and the duty cycle of the first control signal in each switching cycle is less than or equal to 0.5. Referring to FIG. 4 , the control unit 2014 can output the switch tube _Q54 in the V phase bridge arm to send a duty cycle of PWM signal, where _t1 represents the first duration, _Tz represents the duration of a switching cycle, The control unit 2014 can output the switch tube _Q51 in the U-phase bridge arm to send a duty cycle of The control unit 2014 can output the switch tube _Q55 in the W-phase bridge arm to send a PWM signal with a duty cycle of Optionally, the control unit 2014 may also respond to the temperature of any one of the three-phase windings in the drive motor 2013 being greater than a preset winding temperature threshold or the temperature of the lower bridge switch tube of the V-phase bridge arm, the upper bridge switch tube in the U-phase bridge arm and the W-phase bridge arm being greater than a preset switch tube temperature threshold, and the control unit 2014 may send a fourth control signal to the lower bridge switch tube of the V-phase bridge arm, the upper bridge switch tube in the U-phase bridge arm and the W-phase bridge arm from the next switching cycle, wherein the fourth control signal is within each switching cycle. The duty cycle is less than the duty cycle of the first control signal in each switching cycle. For example, the control unit 2014 can output the switch tube _Q54 in the V-phase bridge arm to send a duty cycle of PWM signal, wherein _t4 represents the second duration, _Tz represents the duration of a switching cycle, Less than the above The control unit 2014 can output the switch tube _Q51 in the U-phase bridge arm to send a duty cycle of The control unit 2014 can output the switch tube _Q55 in the W-phase bridge arm to send a PWM signal with a duty cycle of Such a design can reduce the output current of the power battery 202, reduce the heat generated by the three-phase winding, the heat generated by the three-phase bridge arm, and protect the drive motor 2013 and the three-phase bridge arm.

In a possible implementation, FIG12a shows the control signals of the switch tubes of the three bridge arms when the rotor position angle belongs to the third angle set. The control unit 2014 can control the lower bridge switch tube of the V-phase bridge arm, the upper bridge switch tubes in the U-phase bridge arm and the W-phase bridge arm to be turned on for the first duration in the first half of each switching cycle. When the rotor position angle belongs to the third angle set, the control unit 2014 sends corresponding signals to the switch tubes of the three bridge arms, such as PWM_S1, PWM_S2, PWM_S3, PWM_S4, PWM_S5, and PWM_S6 shown in FIG12a. The control signal with a level of V1 can be implemented as the aforementioned first control signal. Among them, in the signals PWM_S1, PWM_S4, and PWM_S5, in the first half of each switching cycle, the control signal with a level of V1 lasts for a first duration, and the first duration is recorded as _t1 . The duration of each switching cycle is recorded as _Tz , and the duty cycle of the control signal with a level of V1 is Less than or equal to 0.5.

Optionally, the control unit 2014 may control the upper bridge switch of the V-phase bridge arm, the lower bridge switch in the U-phase bridge arm and the W-phase bridge arm to be turned on for a first duration in the second half of each switching cycle. As shown in FIG12a , in the second half of each switching cycle T, the control signal with a level of V1 in the signals PWM_S2, PWM_S3, and PWM_S6 lasts for a duration of _t1 .

Alternatively, as shown in FIG. 12b, the control unit 2014 may not output a control signal to each switch in the second half of each switching cycle. The control unit 2014 may control the lower bridge switch tube of the V-phase bridge arm, the upper bridge switch tube in the U-phase bridge arm and the W-phase bridge arm to conduct for the first time length and then seal the wave, that is, not output a control signal to the switch in each three-phase bridge arm. The control unit 2014 may not output a control signal to each switch in the three-phase bridge arm in the second half of each switching cycle, and each switch in the three-phase bridge arm is in an open circuit state. At this time, the freewheeling diode in the upper bridge switch tube of the V-phase bridge arm, the freewheeling diode in the lower bridge switch tube in the U-phase bridge arm, the freewheeling diode in the lower bridge switch tube in the W-phase bridge arm, the drive motor 2013, and the power battery 202 form a freewheeling loop, and under the action of the current in the freewheeling loop, the power battery 202 can continue to heat. Such a design can reduce the switching losses of the three bridge arms in the inverter circuit 2011.

In another possible implementation, FIG12c shows the control signals of the switch tubes of the three bridge arms when the rotor position angle belongs to the third angle set. The control unit 2014 can control the lower bridge switch tube of the V-phase bridge arm, the upper bridge switch tubes in the U-phase bridge arm and the W-phase bridge arm to be turned on for the first duration in the second half of each switching cycle.

In some application scenarios, when the control unit 2014 controls the three bridge arms to operate in the heating mode, the control unit 2014 can combine the SVPWM technology to generate control signals for each switch of the three bridge arms, so that the control unit 2014 controls the upper bridge switch tube of one of the three bridge arms and the lower bridge switch tubes of the other two bridge arms to be cyclically turned on.

In the SVPWM technology, the state of the upper bridge switch tube of a bridge arm is opposite to that of the lower bridge switch tube, that is, in a bridge arm, when the upper bridge switch tube is in the on state, the lower bridge switch tube is in the off state; when the lower bridge switch tube is in the on state, the upper bridge switch tube is in the off state. As shown in FIG13 , 8 voltage vectors are set in the SVPWM technology, namely, zero vector VS0 (000), VS7 (111) and basic voltage vectors VS1 (100), VS2 (110), VS3 (010), VS4 (011), VS5 (001), and VS6 (101). Each voltage vector represents the state of the upper bridge switch tube of the three-phase bridge arm, and "0" in each voltage vector represents the switch off, and "1" represents the switch on. For example, the voltage vector VS1 is 100, which represents that the state of the upper bridge switch tube of the U phase is on, the state of the upper bridge switch tube of the V phase is off, and the state of the upper bridge switch tube of the W phase is off.

Among them, voltage vector VS1 (100) and voltage vector VS4 (011) are a pair of opposite voltage vectors. In the embodiment of the present application, voltage vector VS1 (100) and voltage vector VS4 (011) are recorded as a first vector pair. Voltage vector VS2 (110) and voltage vector VS5 (001) are a pair of opposite voltage vectors. In the embodiment of the present application, voltage vector VS2 (110) and voltage vector VS5 (001) are recorded as a second vector pair. Voltage vector VS3 (010) and voltage vector VS6 (101) are a pair of opposite voltage vectors. In the embodiment of the present application, voltage vector VS3 (010) and voltage vector VS6 (101) are recorded as a third vector pair.

The control unit 2014 can obtain the correspondence between multiple pre-configured angle sets and multiple vector pairs. The multiple angle sets may include a first angle set, a second angle set, and a third angle set. Among the multiple angle sets, any two sets do not overlap, that is, any two sets have no intersection. Each angle set may include one or more angles. In a possible implementation, as shown in Figure 14, the first angle set includes angle intervals [0, θ _m ], (θ _m +120, θ _m +180], and (θ _m +300, 360). Optionally, θ _m is less than or equal to 60°, and θ _m is a positive number. The second angle set includes angle intervals (θ _m , θ _m +60], and (θ _m +180, θ _m +240]; the third angle set includes angle intervals (θ _m +60, θ _m +120], (θ _m +240, θ _m +300]. The specific value of θ _m can be combined with the actual The actual application scenario is configured. For example, θ _m can be 25°, 30°, 35°, 40°, 45°, 50°, 55°, etc. Usually, θ _m can be configured to 30°.

For example, please refer to Fig. 14, in the correspondence between the multiple angle sets and the multiple vector pairs, the first angle set corresponds to the first vector pair, the second angle set corresponds to the second vector pair, and the third angle set corresponds to the third vector pair. The control unit 2014 can output a control signal for the switch in each of the three bridge arms in the inverter circuit 2011 based on the vector pair corresponding to the angle set to which the rotor position angle belongs.

The control unit 2014 can control the three bridge arms in the inverter circuit 2011 according to the vector pair corresponding to the angle set to which the rotor position angle belongs, that is, according to the first vector pair. Exemplarily, the control unit 2014 can control the three bridge arms in the inverter circuit 2011 according to a voltage vector in the vector pair corresponding to the angle set described by the rotor position angle in the first time period of each switching cycle; and in the second time period of each switching cycle, control the three bridge arms in the inverter circuit 2011 according to another voltage vector in the vector pair corresponding to the angle set to which the rotor position angle belongs, or do not provide control signals to each switch in the three bridge arms, so that each switch in the three bridge arms is in an open circuit state. Among them, the first time period and the second time period do not overlap. The duration of the first time period is the same as the duration of the second time period.

In some examples, the duration of the first time period may be half of a switching cycle. Optionally, in each switching cycle, the first time period is the first half of the switching cycle, and the second time period is the second half of the switching cycle. Alternatively, in each switching cycle, the second time period is the first half of the switching cycle, and the first time period is the second half of the switching cycle.

In some other examples, the duration of the first time period is less than half of a switching cycle, and the control unit 2014 can control the three bridge arms in the inverter circuit 2011 according to the voltage vector VS0 (000) or the voltage vector VS7 (111) in each switching cycle except the first time period and the second time period. Optionally, in each switching cycle, the end time point of the first time period can be before the start time point of the second time period. Or, the end time point of the second time period is before the start time point of the first time period.

Since the tooth gap of the transmission chain from the wheel end to the powertrain input shaft in electric vehicles is generally around 70°, which is larger than the angle of 60° between two adjacent basic voltage vectors, after the high-frequency charging and discharging begins, even if the resolver position angle changes, the wheel end may not move or move slightly.

In a possible scenario, the control unit 2014 may control the three bridge arms in the inverter circuit 2011 according to the vector pair corresponding to the first angle set in response to the rotor position angle belonging to the first angle set, that is, control the three bridge arms in the inverter circuit 2011 according to the first vector pair. Exemplarily, the control unit 2014 may control the three bridge arms in the inverter circuit 2011 according to a voltage vector in the first vector pair in the first time period of each switching cycle in response to the rotor position angle belonging to the first angle set; control the three bridge arms in the inverter circuit 2011 according to another voltage vector in the first vector pair in the second time period of each switching cycle, or not provide control signals to the switches in the three bridge arms, so that the switches in the three bridge arms are in an open circuit state. The first time period and the second time period do not overlap.

Optionally, the duration of the first time period may be half of a switching cycle. Or if the duration of the first time period is less than half of a switching cycle, the control unit 2014 may control the three bridge arms in the inverter circuit 2011 according to the voltage vector VS0 (000) or the voltage vector VS7 (111) in each switching cycle except the first time period and the second time period.

In one embodiment, the control unit 2014 may control the three bridge arms in the inverter circuit 2011 according to the voltage vector VS1 (100) in the first vector pair in response to the rotor position angle belonging to the first angle set in the first time period of each switching cycle; and control the three bridge arms in the inverter circuit 2011 according to the voltage vector VS4 (011) in the first vector pair in the second time period of each switching cycle, or not provide control signals to the switches in the three bridge arms, so that the switches in the three bridge arms are in an open circuit state. The length of the first time period may be half of a switching cycle.

In one embodiment, the control unit 2014 may control the three bridge arms in the inverter circuit 2011 according to the voltage vector VS4 (011) in the first vector pair in response to the rotor position angle belonging to the first angle set in the first time period of each switching cycle; and control the three bridge arms in the inverter circuit 2011 according to the voltage vector VS1 (100) in the first vector pair in the second time period of each switching cycle, or not provide control signals to the switches in the three bridge arms, so that the switches in the three bridge arms are in an open circuit state. The length of the first time period may be half of a switching cycle.

In another possible scenario, the control unit 2014 may control the three bridge arms in the inverter circuit 2011 according to the vector pair corresponding to the second angle set in response to the rotor position angle belonging to the second angle set, that is, control the three bridge arms in the inverter circuit 2011 according to the second vector pair. Exemplarily, the control unit 2014 may control the three bridge arms in the inverter circuit 2011 according to a voltage vector in the second vector pair in the first time period of each switching cycle in response to the rotor position angle belonging to the second angle set; control the three bridge arms in the inverter circuit 2011 according to another voltage vector in the second vector pair in the second time period of each switching cycle, or not provide control signals to each switch in the three bridge arms, so that each switch in the three bridge arms is in an open circuit state. The first time period and the second time period do not overlap. The duration of the first time period is the same as the duration of the second time period.

Optionally, the duration of the first time period may be half of a switching cycle. Or if the duration of the first time period is less than half of a switching cycle, the control unit 2014 may control the switching time period in each switching cycle except the first time period and the second time period according to the voltage vector VS0 (000) or voltage vector VS7 (111) controls the three bridge arms in the inverter circuit 2011.

In one embodiment, the control unit 2014 may control the three bridge arms in the inverter circuit 2011 according to the voltage vector VS2 (110) in the second vector pair in the first period of each switching cycle in response to the rotor position angle belonging to the second angle set; and control the three bridge arms in the inverter circuit 2011 according to the voltage vector VS5 (001) in the second vector pair in the second period of each switching cycle, or not provide control signals to the switches in the three bridge arms, so that the switches in the three bridge arms are in an open circuit state. The length of the first period may be half of a switching cycle.

In one embodiment, the control unit 2014 may control the three bridge arms in the inverter circuit 2011 according to the voltage vector VS5 (001) in the second vector pair in the first period of each switching cycle in response to the rotor position angle belonging to the second angle set; and control the three bridge arms in the inverter circuit 2011 according to the voltage vector VS2 (110) in the second vector pair in the second period of each switching cycle, or not provide control signals to the switches in the three bridge arms, so that the switches in the three bridge arms are in an open circuit state. The length of the first period may be half of a switching cycle.

In another possible scenario, the control unit 2014 may control the three bridge arms in the inverter circuit 2011 according to the vector pair corresponding to the third angle set in response to the rotor position angle belonging to the third angle set, that is, control the three bridge arms in the inverter circuit 2011 according to the third vector pair. Exemplarily, the control unit 2014 may control the three bridge arms in the inverter circuit 2011 according to a voltage vector in the third vector pair in the first time period of each switching cycle in response to the rotor position angle belonging to the third angle set; control the three bridge arms in the inverter circuit 2011 according to another voltage vector in the third vector pair in the second time period of each switching cycle, or not provide a control signal to each switch in the three bridge arms, so that each switch in the three bridge arms is in an open circuit state. The first time period and the second time period do not overlap. The duration of the first time period is the same as the duration of the second time period.

In one embodiment, the control unit 2014 may control the three bridge arms in the inverter circuit 2011 according to the voltage vector VS3 (010) in the third vector pair in response to the rotor position angle belonging to the third angle set in the first period of each switching cycle; and control the three bridge arms in the inverter circuit 2011 according to the voltage vector VS6 (101) in the third vector pair in the second period of each switching cycle, or not provide control signals to the switches in the three bridge arms, so that the switches in the three bridge arms are in an open circuit state. The length of the first period may be half of a switching cycle.

In one embodiment, the control unit 2014 may control the three bridge arms in the inverter circuit 2011 according to the voltage vector VS6 (101) in the third vector pair in response to the rotor position angle belonging to the third angle set in the first period of each switching cycle; and control the three bridge arms in the inverter circuit 2011 according to the voltage vector VS3 (010) in the third vector pair in the second period of each switching cycle, or not provide control signals to the switches in the three bridge arms, so that the switches in the three bridge arms are in an open circuit state. The length of the first period may be half of a switching cycle.

The following describes how the control unit 2014 controls the three bridge arms to operate in the inverter mode. When the control unit 2014 controls the three bridge arms to operate in the inverter mode, the control unit 2014 can control the three bridge arms to output AC power to the U, V, and W phase windings of the drive motor.

In some embodiments, the control unit 2014 can send a second control signal to the upper bridge switch tube in each bridge arm, and send a third control signal to the lower bridge switch tube in each bridge arm. Among them, the duration between the start times of the second control signals of the upper bridge switch tubes of any two bridge arms is one-third of the duration Tz of the switching cycle, and the duration between the start times of the third control signals of the lower bridge switch tubes of any two bridge arms is one-third of the duration of the switching cycle, and the second control signal of the upper bridge switch tube and the third control signal of the lower bridge switch tube in the bridge arm are both periodic signals, and the time period corresponding to the second control signal of the upper bridge switch tube in the bridge arm does not overlap with the time period corresponding to the third control signal of the lower bridge switch tube. Such a design can realize that the three bridge arms output three-phase alternating current to the U, V, and W phase windings of the drive motor.

The control signal of each switch tube in the three bridge arms is shown in Figure 15. The duration of a switching cycle is Tz. The control unit 2014 sends a control signal with a level of V1 to the upper bridge switch tube of each bridge arm, which is also the second control signal to the upper bridge switch tube of each bridge arm. The duty cycle of the second control signal can be less than or equal to 0.5. The control unit 2014 sends a control signal with a level of V1 to the lower bridge switch tube of each bridge arm, which is also the third control signal to the lower bridge switch tube of each bridge arm. The duty cycle of the third control signal can be less than or equal to 0.5. In any switching cycle, the time period corresponding to the second control signal of the upper bridge switch tube of a bridge arm does not overlap with the time period corresponding to the third control signal of the lower switch tube of the bridge arm. In other words, the upper bridge switch tube and the lower bridge switch tube of a bridge arm are not turned on at the same time.

The control signal of the switch tube _Q51 in the U phase bridge arm is PWM_S1, and the control signal of the switch tube _Q52 is PWM_S2. The control signal of the switch tube _Q53 is PWM_S3, the control signal of the switch tube _Q54 is PWM_S4, the control signal of the switch tube _Q55 in the W-phase bridge arm is PWM_S5, and the control signal of the switch tube _Q56 is PWM_S6.

In a switching cycle, the starting time when the level of the control signal of the switch tube is V1 can become the conduction angle of the control signal PWM_S1. In this embodiment, the duration between the conduction angle of the control signal PWM_S1 of the switch tube _Q51 in the U-phase bridge arm and the conduction angle of the control signal PWM_S3 of the switch tube _Q53 in the V-phase bridge arm is one third of the duration of the switching cycle, that is, It can also be understood that the phase difference between the conduction angle of the control signal PWM_S1 of the switch tube _Q51 in the U-phase bridge arm and the conduction angle of the control signal PWM_S3 of the switch tube _Q53 in the V-phase bridge arm is 120°.

The duration between the conduction angle of the control signal PWM_S5 of the switch tube _Q55 in the W phase bridge arm and the conduction angle of the control signal PWM_S3 of the switch tube _Q53 in the V phase bridge arm is one third of the duration of the switching cycle, that is, It can also be understood that the phase difference between the conduction angle of the control signal PWM_S5 of the switch tube _Q55 in the W-phase bridge arm and the conduction angle of the control signal PWM_S3 of the switch tube _Q53 in the V-phase bridge arm is 120°.

The duration between the conduction angle of the control signal PWM_S1 of the switch tube _Q51 in the U-phase bridge arm and the conduction angle of the control signal PWM_S5 of the switch tube _Q55 in the W-phase bridge arm is one third of the duration of the switching cycle, that is, It can also be understood that the phase difference between the conduction angle of the control signal PWM_S1 of the switch tube _Q51 in the U-phase bridge arm and the conduction angle of the control signal PWM_S5 of the switch tube _Q55 in the W-phase bridge arm is 120°.

In other embodiments, the control unit 2014 can control the three bridge arms to output AC power based on the existing SVPWM technology. The following briefly describes the working process of the control unit 2014 controlling the three bridge arms to output AC power based on the existing SVPWM technology.

Please refer to Figure 16. Eight voltage vectors are provided in the SVPWM technology, which can form six large sectors, and the angle of each sector is 60°. As shown in Figure 16, in the two-phase orthogonal coordinate system (αβ coordinate system), the sectors do not overlap each other, and each sector has a corresponding α-axis coordinate range and a β-axis coordinate range. Exemplarily, the control unit 2014 can use the basic voltage vectors corresponding to the eight output states of the three bridge arms to synthesize a reference voltage vector, and the reference voltage vector is determined based on the current expected value of the drive motor and the current sampling value of the drive motor. The control unit 2014 can first determine the sector to which the reference voltage vector V _ref belongs. The control unit 2014 can adopt the method of determining the sector to which it belongs in the existing SVPWM, and the embodiment of the present application will not be described in detail.

The control unit 2014 can calculate the action duration of two basic effective vectors and the zero vector corresponding to the sector to which the reference voltage vector V _ref belongs according to the volt-second balance principle. The switching cycle duration Tz and the reference voltage vector V _ref , the basic effective vector corresponding to the sector to which the reference voltage vector V _ref belongs, the zero vector and the action duration of each vector satisfy the following relationship:
V _ref × TS = W1 × k1 + W2 × k2 + W3 × k3

W1 and W2 are two basic effective vectors corresponding to the sector to which the reference voltage vector V _ref belongs, respectively, and W3 is a zero vector. For ease of explanation, as shown in FIG17 , it is assumed that the reference voltage vector V _ref belongs to sector 3, and the vectors corresponding to sector 3 include the basic voltage vector VS1 (100), the basic voltage vector VS2 (110) and the zero vector, that is, the basic voltage vector VS1 (100) can be used as W1, the basic voltage vector VS2 (110) can be used as W2, and the zero vector can be used as W3. Among them, the corresponding action time length k1 of W1 and the corresponding action time length k2 of W2 satisfy the following relationship:
V _α × TS = | W1 | × k1 + | W2 | × k2 × cos60°
V _β × TS = | W2 | × k2 × sin60°

Wherein, V _α is the component of the reference voltage vector V _ref on the α-axis, and V _β is the component of the reference voltage vector V _ref on the β-axis.

Since the magnitude of a non-zero vector is Vdc, the corresponding action duration k1 of W1 and the corresponding action duration k2 of W2 can be expressed by using the component of the reference voltage vector V _ref on the α-axis and the component on the β-axis, the switching cycle duration Tz and the input voltage Vdc of the three bridge arms, as shown below:

Then, after determining k1 and k2, the control unit 2014 can determine the action duration k3 of the zero vector, where k3=1S-k1-k2.

In some examples, after determining the corresponding action duration of each vector, the control unit 2014 can adopt a seven-segment symmetrical PWM mode and the principle that the control signal levels of the switches in only one bridge arm between two adjacent segments are different (that is, following the principle of switching only one switch in the bridge arm at a time) to determine the basic voltage vector corresponding to each vector and the corresponding action duration of each basic voltage vector.

The following is an example of the control unit 2014 using a seven-segment symmetrical PWM mode to generate control signals for each switch. As shown in FIG18 , the PWM waveform corresponding to the output state of each bridge arm in a switching cycle. The PWM waveform of the output state of each bridge arm is symmetrical about the middle moment of the switching cycle. Among them, a switching cycle can be divided into 7 segments, and the first segment, the fourth segment (middle segment) and the last segment are zero vectors. Following the principle of the minimum number of switching times, the control unit 2014 can determine the basic voltage vector corresponding to each segment and the action time of each basic voltage vector in each segment.

As an example, FIG18 shows the state of each phase bridge arm and the control signal of the switch in each direction bridge arm. In one switching cycle, the zero vector VS0 (000) corresponding to the first section, the basic voltage vector VS1 (100) corresponding to the second section, the basic voltage vector VS2 (110) corresponding to the third section, the zero vector VS7 (111) corresponding to the fourth section, the basic voltage vector VS2 (110) corresponding to the fifth section, the basic voltage vector VS1 (100) corresponding to the sixth section, and the zero vector VS0 (000) corresponding to the seventh section. The action time of each bridge arm in the first section is 0.25k3, that is, the time when the output voltage of each bridge arm is -Vdc/2 is 0.25k3. The action time of each bridge arm in the second section is 0.5k1, the time when the output voltage of the U-phase bridge arm is +Vdc/2 is 0.5k1, and the time when the output voltage of the V-phase bridge arm and the W-phase bridge arm is -Vdc/2 is 0.5k1. The action duration of each bridge arm in the third section is 0.5k2, the duration of the output voltage of the U-phase bridge arm and the V-phase bridge arm is Vdc/2 is 0.5k2, and the duration of the output voltage of the W-phase bridge arm is -Vdc/2 is 0.5k2. The action duration of each bridge arm in the fourth section can be determined based on the duration of the switching cycle and the action duration of other sections. Since the PWM waveform of the output state of each bridge arm is symmetrical about the middle moment of the switching cycle within a switching cycle. The state of each bridge arm in the fifth section is the same as the state of each bridge arm in the third section, the state of each bridge arm in the sixth section is the same as the state of each bridge arm in the second section, and the state of each bridge arm in the seventh section is the same as the state of each bridge arm in the first section, which will not be repeated here.

In addition, the embodiment of the present application further provides a motor drive system, which may include a drive motor and a motor controller. Optionally, the motor controller may be a drive motor controller provided in any of the above embodiments. Or the motor controller may include a control unit provided in any of the above embodiments.

In addition, an embodiment of the present application also provides an electric vehicle, which may include the motor drive system in any one of the above embodiments.

The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art who is familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

A motor controller for an electric vehicle drive motor, the motor controller comprising three bridge arms, the two ends of each bridge arm being respectively used to connect the positive electrode and the negative electrode of a power battery, the midpoints of the three bridge arms being respectively used to connect the three-phase windings of the drive motor, characterized in that the operation modes of the three bridge arms include a heating mode and an inverter mode, wherein:

When the three bridge arms operate in the inverter mode, the three bridge arms are used to receive power from the power battery to supply power to the U, V, and W phase windings of the drive motor;

When the three bridge arms operate in the heating mode, the upper bridge switch tube of one of the three bridge arms and the lower bridge switch tubes in the other two bridge arms are periodically turned on, so that the power battery, the turned-on upper bridge switch tube, the two-phase windings of the drive motor, and the turned-on two lower bridge switch tubes form a discharge circuit, or the lower bridge switch tube of one of the three bridge arms and the upper bridge switch tubes in the other two bridge arms are periodically turned on, so that the power battery, the turned-on lower bridge switch tube, the two-phase windings of the drive motor, and the turned-on two upper bridge switch tubes form a discharge circuit.
The motor controller as described in claim 1 is characterized in that when the three bridge arms operate in the heating mode, according to the rotor position angle of the drive motor, the upper bridge switch tube of one of the three bridge arms and the lower bridge switch tubes in the other two bridge arms are periodically turned on, or the lower bridge switch tube of one of the three bridge arms and the upper bridge switch tubes in the other two bridge arms are periodically turned on, and the rotor position angle represents the angle between the N pole of the rotor in space and a reference direction, and the reference direction is the direction in which the center of the rotor points to the U-phase winding in the three-phase stator winding.
The motor controller according to claim 1, characterized in that, in response to the rotor position angle belonging to the first angle set, the upper bridge switch tube of the bridge arm corresponding to the U-phase winding, the lower bridge switch tube of the bridge arm corresponding to the V-phase winding, and the lower bridge switch tube in the bridge arm corresponding to the W-phase winding are periodically turned on, or the lower bridge switch tube of the bridge arm corresponding to the U-phase winding, the upper bridge switch tube of the bridge arm corresponding to the V-phase winding, and the upper bridge switch tube in the bridge arm corresponding to the W-phase winding are periodically turned on, so that the power battery outputs direct current to the V and W phase windings of the drive motor;

Among them, the first angle set includes the rotor position angle belonging to any angle interval among the angle interval [0, θ m ], the angle interval (θ m +120, θ m +180], and the angle interval (θ m +300, 360), wherein θ m is less than or equal to 60° and θ m is a positive number.
The motor controller according to claim 1 is characterized in that, in response to the rotor position angle belonging to a second angle set, the upper bridge switch tube of the bridge arm corresponding to the W-phase winding, the lower bridge switch tube of the bridge arm corresponding to the V-phase winding, and the lower bridge switch tube in the bridge arm corresponding to the U-phase winding are periodically turned on, or the lower bridge switch tube of the bridge arm corresponding to the W-phase winding, the upper bridge switch tube of the bridge arm corresponding to the V-phase winding, and the upper bridge switch tube in the bridge arm corresponding to the U-phase winding are periodically turned on, so that the power battery outputs direct current to the V and W phase windings of the drive motor, and the second angle set includes the rotor position angle belonging to the angle interval (θ m , θ m +60] and the angle interval (θ m +180, θ m +240], wherein θ m is less than or equal to 60°, and θ m is a positive number.
The motor controller according to claim 1 is characterized in that, in response to the rotor position angle belonging to a third angle set, the upper bridge switch tube of the bridge arm corresponding to the V-phase winding, the lower bridge switch tube of the bridge arm corresponding to the W-phase winding, and the lower bridge switch tube in the bridge arm corresponding to the U-phase winding are periodically turned on, or the lower bridge switch tube of the bridge arm corresponding to the V-phase winding, the upper bridge switch tube of the bridge arm corresponding to the W-phase winding, and the upper bridge switch tube in the bridge arm corresponding to the U-phase winding are periodically turned on, so that the power battery outputs direct current to the U and W phase windings of the drive motor, and the third angle set includes the rotor position angle belonging to the angle interval (θ m +60, θ m +120] and the angle interval (θ m +240, θ m +300], wherein θ m is less than or equal to 60°, and θ m is a positive number.
The motor controller as described in claim 1 is characterized in that the upper bridge switch tube of one of the three bridge arms and the lower bridge switch tubes in the other two bridge arms are turned on for a first time period in each cycle, and the first time period is less than or equal to half of the time period of each cycle; or, the lower bridge switch tube of one of the three bridge arms and the upper bridge switch tubes in the other two bridge arms are turned on for the first time period in each cycle.
The motor controller according to any one of claims 1 to 6, characterized in that:

In response to the temperature of the power battery being less than a first temperature threshold, the three bridge arms operate in a heating mode;

In response to the temperature of the power battery being greater than or equal to the first temperature threshold, the three bridge arms operate in an inverter mode.
The motor controller according to any one of claims 1 to 7, characterized in that:

In response to the temperature of any one of the three-phase windings being greater than a preset winding temperature threshold or the temperature of any one of the switch tubes in the three bridge arms being greater than a preset switch tube temperature threshold, the conduction time of the turned-on switch tube is reduced in the next cycle to reduce the DC current output by the power battery.
The motor controller according to any one of claims 1 to 8, characterized in that:

In response to the temperature of the three switched tubes in the three bridge arms being greater than a preset switch tube temperature threshold, the conduction time of the three switched tubes is reduced in the next cycle to reduce the DC current output by the power battery.
A control unit for a motor controller, the motor controller is used to receive power from a power battery to power the U, V, and W phase windings of the drive motor, the motor controller includes three bridge arms, the two ends of each bridge arm are respectively used to connect the positive electrode and the negative electrode of the power battery, and the midpoints of the three bridge arms are respectively used to connect the U, V, and W phase windings of the drive motor, characterized in that the operating modes of the three bridge arms include a heating mode and an inverter mode, and the control unit is used to control the operating modes of the three bridge arms, wherein:

When the control unit controls the three bridge arms to operate in a heating mode, the control unit controls the upper bridge switch tube of one of the three bridge arms and the lower bridge switch tubes in the other two bridge arms to be turned on cyclically;

When the control unit controls the three bridge arms to operate in the inverter mode, the control unit controls the three bridge arms to output alternating current to the U, V, and W phase windings of the drive motor.
The control unit as claimed in claim 10 is characterized in that when the control unit controls the three bridge arms to operate in the heating mode, according to the rotor position angle of the drive motor, the upper bridge switch tube of one of the three bridge arms and the lower bridge switch tubes in the other two bridge arms are controlled to be periodically turned on, or the lower bridge switch tube of one of the three bridge arms and the upper bridge switch tubes in the other two bridge arms are controlled to be periodically turned on, and the rotor position angle represents the angle between the N pole of the rotor in space and a reference direction, and the reference direction is the direction in which the center of the rotor points to the U-phase winding in the three-phase stator winding.
The control unit according to claim 10 or 11, characterized in that

In response to the temperature of the power battery being less than a first temperature threshold, the control unit sends a first control signal to the upper bridge switch tube of one of the three bridge arms and the lower bridge switch tubes in the other two bridge arms, or sends a first control signal to the lower bridge switch tube of one of the three bridge arms and the upper bridge switch tubes in the other two bridge arms, wherein the first control signal is a periodic signal, and a duty cycle of the first control signal in each switching cycle is less than or equal to 0.5.
The control unit according to claim 12, characterized in that

In response to the temperature of the power battery being greater than or equal to the first temperature threshold, the control unit sends a second control signal to the upper bridge switch tube in each bridge arm, and sends a third control signal to the lower bridge switch tube of each bridge arm, wherein the duration between the start times of the second control signals of the upper bridge switch tubes of any two bridge arms is one third of the duration of the switching cycle, and the duration between the start times of the third control signals of the lower bridge switch tubes of any two bridge arms is one third of the duration of the switching cycle, and the second control signal of the upper bridge switch tube and the third control signal of the lower bridge switch tube in the bridge arm are both periodic signals, and the time period corresponding to the second control signal of the upper bridge switch tube in the bridge arm does not overlap with the time period corresponding to the third control signal of the lower bridge switch tube.
The control unit according to claim 12, characterized in that

In response to the temperature of any one of the three-phase windings being greater than a preset winding temperature threshold or the temperature of the switch tubes turned on in the three bridge arms being greater than a preset switch tube temperature threshold, the control unit sends a fourth control signal to the upper bridge switch tube of one of the three bridge arms and the lower bridge switch tubes in the other two bridge arms, or the control unit sends the fourth control signal to the lower bridge switch tube of one of the three bridge arms and the upper bridge switch tubes in the other two bridge arms, wherein the duty cycle of the fourth control signal in each switching cycle is less than the duty cycle of the first control signal in each switching cycle.
An electric drive system, characterized in that the electric drive system includes a drive motor and a motor controller, the motor controller is the motor controller as described in any one of claims 1-9, or the motor controller includes the control unit as described in any one of claims 10-14.
An electric vehicle, characterized in that the electric vehicle comprises a power battery and the electric drive system as claimed in claim 15.