CN112367000B

CN112367000B - Method and device for switching winding wiring state of motor and motor control system

Info

Publication number: CN112367000B
Application number: CN202011149000.XA
Authority: CN
Inventors: 请求不公布姓名
Original assignee: Beijing 66 Interactive Technology Co ltd
Current assignee: Beijing 66 Interactive Technology Co ltd
Priority date: 2020-02-21
Filing date: 2020-10-23
Publication date: 2023-03-24
Anticipated expiration: 2040-10-23
Also published as: CN112260610A; CN214125189U; CN112511069B; CN113300658B; CN112468054B; CN113300659B; CN112468054A; CN112511069A; CN111147000A; CN112311296A; CN113300659A; CN112311296B; CN112367000A; CN113300656B; CN112311295A; CN113300658A; CN112290852B; CN113300657B; CN113300657A; CN113300656A

Abstract

The application provides a winding wiring state switching method and device of a motor and a motor control system, wherein the method comprises the following steps: acquiring the current rotating speed of the motor; acquiring a first switching rotating speed; controlling the winding wiring state of the motor to be switched according to the current rotating speed of the motor and the first switching rotating speed; the winding wiring state comprises a star connection state and an angle connection state, and the first switching rotating speed is less than the highest no-load rotating speed of the motor in the star connection state. Therefore, the method can ensure the smooth switching of the wiring state of the motor winding and realize the speed expansion of the motor. Compared with the scheme of speed expansion through weak magnetism, the method has the advantages of high motor operation efficiency, small torque pulsation and high safety performance.

Description

Method and device for switching winding wiring state of motor and motor control system

Technical Field

The present application relates to the field of motor technologies, and in particular, to a winding connection state switching method and apparatus for a motor, and a motor control system.

Background

Related electric products mostly use permanent magnet synchronous motors or brushless motors as power motors. The motor adopts permanent magnet excitation, the magnetic potential of the excitation is difficult to change, and the counter electromotive force of the motor is higher when the speed is higher, so that the possibility of further speed expansion of the motor is limited.

Disclosure of Invention

The present application is directed to solving, at least to some extent, one of the technical problems in the related art.

To this end, a first objective of the present application is to provide a winding wiring state switching method of a motor, so as to realize motor speed expansion through switching of winding wiring states of the motor.

A second object of the present application is to provide a winding wiring state switching device of an electric machine.

A third object of the present application is to provide a motor control system.

A fourth object of the present application is to propose a computer readable storage medium.

To achieve the above object, an embodiment of the first aspect of the present application provides a winding wiring state switching method for an electric machine, including: acquiring the current rotating speed of the motor; acquiring a first switching rotating speed; controlling the winding wiring state of the motor to switch according to the current rotating speed of the motor and the first switching rotating speed; the winding wiring state comprises a star connection state and an angle connection state, and the first switching rotating speed is less than the highest no-load rotating speed of the motor in the star connection state.

According to the winding wiring state switching method of the motor, the first switching rotating speed is set to be smaller than the highest no-load rotating speed of the motor in the star connection state, and the winding wiring state of the motor is controlled to be switched based on the current rotating speed of the motor and the first switching rotating speed. Compared with the scheme of speed expansion through weak magnetism, the method has the advantages of high motor operation efficiency, small torque pulsation and high safety performance.

According to an embodiment of the application, the first switching speed is a preset fixed speed, or the first switching speed is calculated according to a current bus voltage of the motor.

According to an embodiment of the application, calculating the first switching speed from the present bus voltage of the electric machine comprises: determining the current highest no-load rotating speed of the motor in the star connection state according to the current bus voltage of the motor; and determining a first switching rotating speed of the winding wiring state of the motor according to the current highest no-load rotating speed of the motor in the star connection state.

According to one embodiment of the application, the current maximum no-load rotation speed of the motor in the star-connected state is determined by the following formula:

Nmax＝Vpp*K,

wherein Nmax is the current highest no-load rotation speed of the motor in a star connection state, vpp is the current bus voltage of the motor, and K is the motor no-load rotation speed corresponding to the unit bus voltage under the maximum output of the motor controller.

According to an embodiment of the application, the first switching speed is a difference between a highest idling speed of the electric machine in the star connected state and a first speed threshold, wherein the first speed threshold is larger than zero.

According to an embodiment of the application, after obtaining the current bus voltage of the electric machine, the method further comprises: determining a voltage variation between the current bus voltage of the motor and the bus voltage acquired last time; and when the voltage variation is larger than a preset voltage threshold, calculating the first switching speed according to the current bus voltage of the motor.

According to an embodiment of the application, after obtaining the current bus voltage of the electric machine, the method further comprises: determining the time difference between the current moment and the moment of last calculation of the first switching rotating speed; and when the time difference reaches a preset trigger time, calculating the first switching rotating speed according to the current bus voltage of the motor.

According to an embodiment of the application, the controlling of the winding wiring state of the motor to be switched according to the current rotation speed of the motor and the first switching rotation speed includes: and determining that the current rotating speed of the motor is increased to the first switching rotating speed, and controlling the winding wiring state of the motor to be switched from the star connection state to the angle connection state.

According to an embodiment of the present application, the winding connection state switching method of the motor further includes: determining that the current rotating speed of the motor is reduced to the second switching rotating speed, and controlling the winding wiring state of the motor to be switched from the angular connection state to the star connection state; the second switching rotation speed is less than or equal to the first switching rotation speed.

According to an embodiment of the present application, the winding wiring state switching method of the motor further includes: and adjusting the torque current of the motor according to the switching mode of the winding wiring state of the motor.

According to one embodiment of the application, the winding of the motor is arranged in the statorThe switching mode of the wiring state, which is used for adjusting the torque current of the motor, comprises the following steps: determining the connection state of the winding of the motor to be switched from the star connection state to the angle connection state, and adjusting the torque current of the motor to the current torque current

Doubling; determining the winding connection state of the motor to be switched from the angular connection state to the star connection state, and adjusting the torque current of the motor to the current torque current

And (4) multiplying.

To achieve the above object, an embodiment of a second aspect of the present application provides a winding wiring state switching device for an electric machine, including: the first acquisition module is used for acquiring the current rotating speed of the motor; the second acquisition module is used for acquiring the first switching rotating speed; the control module is used for controlling the winding wiring state of the motor to be switched according to the current rotating speed of the motor and the first switching rotating speed; the winding wiring state comprises a star connection state and an angle connection state, and the first switching rotating speed is less than the highest no-load rotating speed of the motor in the star connection state.

According to the winding wiring state switching device of the motor, the first switching rotating speed is set to be smaller than the highest no-load rotating speed of the motor in the star connection state, and the winding wiring state of the motor is controlled to be switched based on the current rotating speed of the motor and the first switching rotating speed, so that the device can guarantee smooth switching of the winding wiring state of the motor, and speed expansion of the motor is achieved. Compared with the scheme of speed expansion through weak magnetism, the method has the advantages of high motor operation efficiency, small torque pulsation and high safety performance.

In order to achieve the above object, a motor control system is provided in an embodiment of a third aspect of the present application, and includes a memory, a processor, and a computer program stored in the memory and executable on the processor, where the processor executes the computer program to implement the winding connection state switching method of the motor according to the above embodiment.

According to the motor control system provided by the embodiment of the application, the winding wiring state switching method of the motor is executed, so that the smooth switching of the winding wiring state of the motor can be ensured, and the speed expansion of the motor is realized. Compared with the scheme of speed expansion through weak magnetism, the method has the advantages of high motor operation efficiency, small torque pulsation and high safety performance.

To achieve the above object, a non-transitory readable storage medium is provided in a fourth aspect of the present application, and the program is stored thereon and when executed by a processor, implements the winding wiring state switching method of the motor of the above embodiment.

Additional aspects and advantages of the present application will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the present application.

Drawings

The foregoing and/or additional aspects and advantages of the present application will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

fig. 1 is a circuit schematic diagram of a winding wiring state switching circuit of an electric machine according to an embodiment of the present application;

fig. 2 is a flowchart of a winding wiring state switching method of an electric machine according to an embodiment of the present application;

fig. 3 is a block schematic diagram of a winding wiring state switching device of an electric machine according to an embodiment of the present application;

FIG. 4 is a block schematic diagram of a motor control system according to an embodiment of the present application;

fig. 5 is a first schematic diagram of a switching device for switching an operating state of a winding of a motor according to an embodiment of the present application;

fig. 6 is a schematic diagram of a switching device for switching an operating state of a winding of a motor according to an embodiment of the present application;

fig. 7 is a schematic diagram of a motor winding provided by an embodiment of the present application in a star connection state;

FIG. 8 is a schematic diagram of a motor winding in an angular connection state according to an embodiment of the present disclosure;

fig. 9 is a second schematic diagram of a switching device for switching an operating state of a winding of a motor according to an embodiment of the present application;

fig. 10 is a circuit diagram of a star driver circuit provided in an embodiment of the present application;

fig. 11 is a circuit diagram of a first electronic switch provided in an embodiment of the present application;

fig. 12 is a circuit diagram of an angular driving circuit according to an embodiment of the present application;

fig. 13 is a circuit diagram of a second electronic switch provided in an embodiment of the present application;

fig. 14 is a circuit diagram of an isolated switching power supply according to an embodiment of the present application;

fig. 15 is a circuit diagram of an arc extinguishing device according to an embodiment of the present application;

FIG. 16 is a schematic diagram of an external 84V power supply according to an embodiment of the present application;

fig. 17 is a schematic interface circuit diagram of a switching device for switching an operating state of a winding of a motor according to an embodiment of the present application;

fig. 18 is a schematic circuit diagram of a switching device for switching an operating state of a motor winding according to an embodiment of the present application;

fig. 19 is a first graph of measurement results of an oscilloscope in a circuit principle simulation diagram of a switching device for a motor winding working state according to the technical solution of the embodiment of the present application;

fig. 20 is a second graph of measurement results of an oscilloscope in a circuit principle simulation diagram of the switching device for the operating state of the motor winding provided in the technical solution of the embodiment of the present application.

Detailed Description

Reference will now be made in detail to embodiments of the present application, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary and intended to be used for explaining the present application and should not be construed as limiting the present application.

A winding wiring state switching method and device of a motor and a motor control system according to an embodiment of the present application are described below with reference to the drawings.

The winding wiring state switching circuit of the motor is described first. With reference to fig. 1, the winding connection state switching circuit of the motor includes a first switch group, a second switch group, a first driving unit and a second driving unit. The first change-over switch group is configured to change a winding wiring state of the motor into a star winding wiring state, the second change-over switch group is configured to change the winding wiring state of the motor into an angle winding wiring state, the first driving unit is connected with the first change-over switch group to drive the first change-over switch group to work, and the second driving unit is connected with the second change-over switch group to drive the second change-over switch group to work.

Specifically, the motor may have three-phase windings, i.e., an a-phase winding L11, a B-phase winding L12, and a C-phase winding L13, where the two ends of the a-phase winding are a11 and a12, respectively, the two ends of the B-phase winding are B11 and B12, respectively, and the two ends of the C-phase winding are C11 and C12, respectively.

The first switching switch group includes a first switch S11, a second switch S12, and a third switch S13. One end of the first switch S11 is connected to the other end a12 of the a-phase winding L11, one end of the second switch S12 is connected to the other end B12 of the B-phase winding L12, and one end of the third switch S13 is connected to the other end C12 of the C-phase winding L13. The other end of the first switch S11, the other end of the second switch S12, and the other end of the third switch S13 are connected together. The first driving unit includes a first switch Q11, a first end of the first switch Q11 is connected to control ends of the first switch S11, the second switch S12 and the third switch S13, a second end of the first switch Q11 is grounded, and the control end of the first switch Q11 is configured to receive a star control signal, for example, the star control signal may be from a motor controller.

The second group of switches includes a fourth switch S14, a fifth switch S15 and a sixth switch S16. One end of the fourth switch S14 is connected to one end a11 of the phase-a winding L11, the other end of the fourth switch S14 is connected to the other end B12 of the phase-B winding L12, one end of the fifth switch S15 is connected to one end B11 of the phase-B winding L12, the other end of the fifth switch S15 is connected to the other end C12 of the phase-C winding L13, one end of the sixth switch S16 is connected to one end C11 of the phase-C winding L13, and the other end of the sixth switch S16 is connected to the other end a12 of the phase-a winding L11. The second driving unit includes a second switch tube Q12, a first end of the second switch tube Q12 is connected to control ends of the fourth switch S14, the fifth switch S15 and the sixth switch S16, a second end of the second switch tube Q12 is grounded, and the control end of the second switch tube Q12 is configured to receive an angular control signal, for example, the angular control signal may be from a motor controller.

The first, second and third switches S11, S12 and S13 and the fourth, fifth and sixth switches S14, S15 and S16 may be powered by a preset power source, such as a 1214V power source. As a specific example, the first, second, and third switches S11, S12, and S13 and the fourth, fifth, and sixth switches S14, S15, and S16 may be relays. The first switching tube Q11 and the second switching tube Q12 may be transistors.

When the first driving unit receives the star control signal, the first switching tube Q11 is turned on, so that the first switch S11, the second switch S12 and the third switch S13 are closed, the a12 of the a-phase winding L11, the B12 of the B-phase winding L12 and the C12 of the C-phase winding L13 are connected together, and at this time, the motor windings are in star connection (i.e., star connection).

When the second driving unit receives the angle control signal, the second switching tube Q12 is turned on, so that the fourth switch S14, the fifth switch S15 and the sixth switch S16 are closed, the a11 of the a-phase winding L11 is connected with the B12 of the B-phase winding L12, the B11 of the B-phase winding L12 is connected with the C12 of the C-phase winding L13, the C11 of the C-phase winding L13 is connected with the a12 of the a-phase winding L11, and at this time, the motor windings are in angle connection (i.e., angle connection).

In this way, the switching of the winding connection state of the motor, for example, from star connection to angular connection or from angular connection to star connection, can be achieved by the first selector switch group and the second selector switch group.

Note that, in the same winding, the back electromotive force coefficient Ke of the motor in the star contact state is the back electromotive force coefficient of the motor in the angular contact state

Double, i.e. angle-connected at the same supply voltageThe rotational speed of

Therefore, the motor can be controlled to operate in a star connection state at a low speed, and the motor can be controlled to operate in an angle connection state when speed expansion is needed. />

Therefore, in the embodiment of the application, in order to realize a wider speed regulation range, the motor is controlled to work in a star connection state when the motor is in a low-speed running state, and the motor is controlled to work in an angle connection state when the motor is in a high-speed running state. Specifically, in the embodiment of the present application, the switching rotation speed of the motor is first determined, and then the winding connection state of the motor is controlled to switch according to the switching rotation speed of the motor, so as to realize speed expansion of the motor.

It should be noted that the above method can be applied to electric vehicles such as electric motorcycles, electric scooters, electric bicycles, power-assisted scooters, power-assisted bicycles, balance cars, and the like, and can also be applied to electric toys such as electric kart cars and the like.

The winding wiring state switching method of the motor of the embodiment of the present application is described in detail below.

Referring to fig. 2, a winding wiring state switching method of a motor according to an embodiment of the present application includes:

s101: and acquiring the current rotating speed of the motor.

The current rotating speed of the motor can be acquired in real time or at preset sampling time intervals. The motor can be a permanent magnet synchronous motor or a brushless motor and the like.

S102: a first switching speed is obtained.

S103: and controlling the winding wiring state of the motor to switch according to the current rotating speed of the motor and the first switching rotating speed.

The winding connection state of the motor (or referred to as a winding working state of the motor or a winding connection state of the motor) includes a star connection state and an angular connection state. The first switching speed is less than the highest no-load speed of the motor in the star connection state. The maximum idling rotation speed of the motor is the idling rotation speed reached by the motor when the counter electromotive force of the motor is equal to the bus voltage of the motor.

Therefore, according to the method for switching the winding wiring state of the motor, the first switching rotating speed is set to be smaller than the highest no-load rotating speed of the motor in the star connection state, and the winding wiring state of the motor is controlled to be switched based on the current rotating speed of the motor and the first switching rotating speed, so that the method can guarantee smooth switching of the winding wiring state of the motor, and speed expansion of the motor is achieved. Compared with the scheme of speed expansion through weak magnetism, the method has the advantages of high motor operation efficiency, small torque pulsation and high safety performance.

It is to be understood that the first switching rotational speed is used to determine the switching rotational speed for switching from the star connection state to the angle connection state and the switching rotational speed for switching from the angle connection state to the star connection state. As an example, the switching rotational speed for switching from the star connection state to the angular connection state and the switching rotational speed for switching from the angular connection state to the star connection state may be the same value, and may be set to the first switching rotational speed, for example. As an example, the switching rotational speed for switching from the star connection state to the angular connection state and the switching rotational speed for switching from the angular connection state to the star connection state may be different values, for example, the switching rotational speed for switching from the star connection state to the angular connection state may be set to a first switching rotational speed, and the switching rotational speed for switching from the angular connection state to the star connection state may be slightly lower than the first switching rotational speed, which is referred to as a second switching rotational speed.

As described above, the winding wiring state includes the star connection state and the angular connection state, and further, the controlling of the switching of the winding wiring state of the motor may include controlling of the switching of the winding wiring state of the motor from the star connection state to the angular connection state and controlling of the switching of the winding wiring state of the motor from the angular connection state to the star connection state.

And in the running process of the motor, acquiring the current rotating speed of the motor in real time or at intervals of preset sampling time, comparing the acquired current rotating speed of the motor with the corresponding switching rotating speed, and controlling the winding wiring state of the motor to be switched between a star connection state and an angle connection state according to a comparison result.

Specifically, if the switching rotation speed for switching from the star connection state to the angular connection state and the switching rotation speed for switching from the angular connection state to the star connection state are both set to be the first switching rotation speed, the current rotation speed may be compared with the first switching rotation speed, and when the current rotation speed is greater than or equal to the first switching rotation speed, the winding connection state of the motor is controlled to be switched to the angular connection state, and when the current rotation speed is less than the first switching rotation speed, the winding connection state of the motor is controlled to be switched to the star connection state.

If the switching rotating speed for switching from the star connection state to the angular connection state is set as a first switching rotating speed, and the switching rotating speed for switching from the angular connection state to the star connection state is set as a second switching rotating speed, the change trend of the current rotating speed can be further combined, the switching rotating speed to be compared is determined according to the change trend of the current rotating speed, namely when the current rotating speed is in the rising trend, the current rotating speed is compared with the first switching rotating speed, and when the current rotating speed is greater than the first switching rotating speed, the winding wiring state of the motor is controlled to be switched to the angular connection state, and when the current rotating speed is in the falling trend, the current rotating speed is compared with the second switching rotating speed, and when the current rotating speed is less than the second switching rotating speed, the winding wiring state of the motor is controlled to be switched to the star connection state.

It can be understood that when the motor is started, the windings of the motor can be controlled to be connected in a star connection state.

According to some embodiments of the present application, the first switching speed may be a difference between a highest idling speed of the motor in the star connected state and a first speed threshold, wherein the first speed threshold is greater than zero.

It can be understood that, assuming that the maximum no-load rotation speed of the motor in the star connection state is Nmax, when the rotation speed of the motor reaches the maximum no-load rotation speed Nmax, because of voltage limitation, the counter potential of the motor is equal to the bus voltage Vpp of the motor, at this time, the motor cannot output torque to the outside, and in order to ensure that the motor is smoothly switched from star connection to angular connection, the first switching rotation speed is set to be less than Nmax, so that torque is provided by a part of fixed rotation difference, for example, the first rotation speed threshold value Nsave, that is, the first switching rotation speed may be Nmax-Nsave, so as to ensure smooth switching of the winding connection state.

The winding connection state switching method of the motor according to the embodiment of the present invention is further described in detail below by taking, as an example, a case where the switching rotational speed for switching from the star connection state to the angular connection state is set as the first switching rotational speed, and the switching rotational speed for switching from the angular connection state to the star connection state is set as the second switching rotational speed.

Specifically, the method of the embodiment of the present application further includes: and acquiring a second switching rotating speed, and further controlling the winding wiring state of the motor to switch according to the current rotating speed of the motor, the first switching rotating speed and the second switching rotating speed, wherein the second switching rotating speed is less than or equal to the first switching rotating speed.

The first switching rotating speed is a switching rotating speed for switching the star connection state to the angular connection state, the second switching rotating speed is a switching rotating speed for switching the angular connection state to the star connection state, and the second switching rotating speed is slightly smaller than the first switching rotating speed.

More specifically, controlling the winding wiring state of the motor to be switched according to the current rotation speed of the motor and a first switching rotation speed includes:

and determining that the current rotating speed of the motor is increased to a first switching rotating speed, and controlling the winding wiring state of the motor to be switched from a star connection state to an angle connection state.

Further, the winding wiring state of the motor is controlled to be switched according to the current rotating speed of the motor and the first switching rotating speed, and the method further comprises the following steps:

determining a second switching rotation speed, wherein the second switching rotation speed is less than or equal to the first switching rotation speed;

and determining that the current rotating speed of the motor is reduced to a second switching rotating speed, and controlling the winding wiring state of the motor to be switched from an angular connection state to a star connection state.

Therefore, the wiring state of the motor winding can be prevented from frequently changing around the switching rotating speed.

As described above, when the motor is started, the windings of the control motor are connected in a star connection state. The method comprises the steps of obtaining the current rotating speed of a motor in real time in the running process of the motor, determining that the motor is in a high-speed state when the current rotating speed of the motor rises and rises to a first switching rotating speed, and controlling the winding wiring state of the motor to be switched from a star connection state to an angle connection state at the moment, so that the speed regulation range of the motor is widened, and the motor can reach higher speed. And then, when the current rotating speed of the motor is reduced and is reduced to a second switching rotating speed, namely the difference between the first switching rotating speed and the preset return difference rotating speed, determining that the motor is in a low-speed state, and controlling the winding wiring state of the motor to be switched from an angular connection state to a star connection state at the moment, so that the motor can output larger torque.

In addition, it should be noted that, in the embodiment of the present application, the first switching speed may be a preset fixed speed, or the first switching speed may be calculated according to the current bus voltage of the motor.

It should be understood that, in some examples, for a scenario where the bus voltage of the motor does not change much, for example, when the power supply with a continuously stable power supply source is used for supplying power, the first switching rotation speed may be a fixed rotation speed, and may be preset according to a usage scenario of the motor.

In other examples, for a scenario where the bus voltage of the motor has a large variation, for example, when the energy storage module (such as a battery) is used for supplying power, the bus voltage of the motor decreases when the amount of power of the energy storage module decreases, and the first switching speed may be calculated according to the current bus voltage of the motor. That is to say, in practical application, in the case of battery power supply, the bus voltage Vpp of the motor will gradually decrease with the consumption of the battery power, and at this time, the preset fixed rotation speed may not be able to achieve accurate switching, and the first switching rotation speed can be calculated in real time according to the current bus voltage of the motor, thereby ensuring that the wiring state of the winding is switched at the better switching rotation speed.

It should be noted that, for the case that the first switching rotation speed is calculated according to the current bus voltage of the motor, after the first switching rotation speed is adjusted, the second switching rotation speed may be adjusted accordingly, for example, the difference between the first switching rotation speed and the second switching rotation speed is kept as the preset back difference rotation speed.

The motor can be controlled by a motor controller, the input end of the motor controller can be connected with a bus, the output end of the motor controller is connected with the motor, and the bus voltage (such as direct current bus voltage) Vpp on the bus is input into the motor controller, inverted to obtain alternating current and supplied to the motor.

Specifically, calculating the first switching speed from the current bus voltage of the electric machine includes: acquiring the current bus voltage and the current rotating speed of the motor; determining the current highest no-load rotating speed of the motor in a star connection state according to the current bus voltage of the motor; and determining a first switching rotating speed of the winding wiring state of the motor according to the current highest no-load rotating speed of the motor in the star connection state. For example, the difference between the maximum idling speed of the electric machine in the star connection state and the first speed threshold is used as the first switching speed.

The current rotating speed can be acquired in real time or at preset sampling time intervals.

It should be noted that, after the current bus voltage of the motor is obtained, the current highest no-load rotation speed is directly calculated according to the current bus voltage of the motor, so as to obtain the first switching rotation speed.

Or after the current bus voltage of the motor is obtained, the voltage variation between the current bus voltage of the motor and the bus voltage obtained last time can be judged, if the voltage variation is smaller than a preset voltage threshold, the current highest no-load rotating speed is kept unchanged, and the first switching rotating speed does not need to be recalculated; and if the voltage variation is larger than the preset voltage threshold, recalculating the highest no-load rotating speed according to the current bus voltage of the motor to obtain a new first switching rotating speed.

Or after the current bus voltage of the motor is obtained, whether the time difference between the current time and the time when the first switching rotating speed is calculated last time reaches the preset trigger time or not can be judged, if the time difference does not reach the preset trigger time, the current highest no-load rotating speed is kept unchanged, and the first switching rotating speed does not need to be recalculated; and if the preset trigger time is reached, recalculating the highest no-load rotating speed according to the current bus voltage of the motor to obtain a new first switching rotating speed.

Specifically, the first switching rotational speed may be recalculated according to the current bus voltage, and then the winding wiring state of the motor may be controlled to be switched according to the recalculated first switching rotational speed.

Wherein, the first switching speed may be recalculated based on the current bus voltage when:

1) The current bus voltage (namely the direct-current bus voltage on the bus) can be obtained in real time or at preset sampling time intervals or at preset trigger time intervals, and when the current bus voltage is collected every time, the current highest no-load rotating speed is directly calculated according to the current bus voltage of the motor, so that the first switching rotating speed of the wiring state of the motor winding is obtained, and therefore, the first switching rotating speed is calculated once when the current bus voltage is collected every time.

2) The method can acquire the current bus voltage (namely the direct current bus voltage on the bus) in real time or at intervals of preset sampling time, and after the current bus voltage is acquired each time, judge whether the voltage variation of the bus voltage is greater than a preset voltage threshold, namely, the difference between the current bus voltage of the motor and the bus voltage acquired last time is used as the voltage variation of the bus voltage, if the voltage variation is less than the preset voltage threshold, the current highest no-load rotating speed is kept unchanged, and the switching rotating speed does not need to be recalculated; and if the voltage variation is larger than the preset voltage threshold, recalculating the highest no-load rotating speed according to the current bus voltage of the motor to obtain a new switching rotating speed. Therefore, the first switching rotating speed is calculated once when the voltage change quantity of the bus voltage is judged to be larger than the preset voltage threshold value each time.

3) The current bus voltage (namely the direct current bus voltage on the bus) can be obtained in real time or at intervals of preset sampling time, and after the current bus voltage is obtained every time, whether the rotating speed calculation time interval reaches the preset trigger time or not is judged, namely, the time difference between the current time and the last time when the first switching rotating speed is calculated is used as the rotating speed calculation time interval, if the rotating speed calculation time interval does not reach the preset trigger time, the current highest no-load rotating speed is kept unchanged, and the switching rotating speed does not need to be recalculated; if the time interval of the rotation speed calculation reaches the preset trigger time, the highest no-load rotation speed is recalculated according to the current bus voltage of the motor to obtain a new switching rotation speed, and therefore, the first switching rotation speed is calculated every other preset trigger time, wherein the preset trigger time can be greater than or equal to the preset sampling time, for example, the preset sampling time is an integral multiple of the preset trigger time.

According to one embodiment of the present application, the current maximum no-load rotation speed of the motor in the star-connected state can be determined by the following formula:

Nmax＝Vpp*K,

wherein, nmax is the current highest no-load rotation speed of the motor in the star connection state, vpp is the current bus voltage of the motor, and K is the motor no-load rotation speed corresponding to the unit bus voltage under the maximum output of the motor controller.

That is, when it is determined that the maximum no-load rotation speed needs to be calculated, the current maximum no-load rotation speed Nmax of the motor in the star connection state can be calculated through the calculation formula Vpp × K, so that the maximum no-load rotation speed Nmax corresponding to the current bus voltage can be accurately calculated, and the winding connection state is ensured to be switched at a preferred switching point.

According to another embodiment of the application, the current highest no-load rotation speed of the motor in the star connection state can be determined through a preset relation table, wherein the preset relation table is used for indicating the corresponding relation between a plurality of bus voltage regions and the plurality of highest no-load rotation speeds respectively.

That is, the correspondence between the plurality of bus voltage zones and the plurality of maximum no-load rotation speeds may be preset, for example, a plurality of points are taken at equal intervals on a curve corresponding to the above formula Nmax = Vpp × K (for example, the maximum rotation speed corresponding to the voltage zone of U1 to U1+ Δ U is U1/K), and then, according to the correspondence, the voltage zone to which the current bus voltage of the motor belongs is determined, and further, the current maximum no-load rotation speed of the motor in the star connection state is determined.

Therefore, dynamic adjustment of the switching rotating speed is realized, the maximum no-load rotating speed Nmax corresponding to the current bus voltage can be accurately calculated, and the winding wiring state is ensured to be switched at a better switching point.

In other embodiments of the present application, a counter electromotive force coefficient of the motor may be further considered, and the maximum no-load rotation speed Nmax corresponding to the current bus voltage may be calculated in real time according to the counter electromotive force coefficient of the motor and the current bus voltage Vpp.

It is understood that when the current maximum idling rotational speed Nmax at which the electric machine is determined to be in the star connected state, the first switching rotational speed may be set to a rotational speed which is less than Nmax, for example, the first switching rotational speed may be Nmax — Nsave.

Note that, the back electromotive force coefficient Ke of the motor in the star connection state is the back electromotive force coefficient of the motor in the angular connection state

Multiple according to formula K _t ＝K _e +104.7 (where Kt is the torque coefficient in Nm/A and Ke is the back EMF coefficient in V/KRPM), it can be seen that the torque coefficient of the motor in the star-connected state is based on ^ or greater than the torque coefficient of the motor in the angular-connected state for the same winding>

The torque output by the electric motor in the star-connected state is greater than or equal to the torque output by the electric motor in the angular-connected state for the same winding and the same current>

And (4) doubling. Therefore, after the wiring state of the winding of the motor is switched, the torque output by the motor can be adjusted.

Specifically, the winding wiring state switching method of the motor further comprises the following steps:

and adjusting the torque current of the motor according to the switching mode of the winding wiring state of the motor.

More specifically, the method for adjusting the torque current of the motor according to the switching mode of the winding wiring state of the motor comprises the following steps:

determining the switching of the winding connection state of the machine from a star connection state to an angle connection state, and regulating the torque current of the machine to the current torque current

Doubling;

determining a switching of a winding connection state of an electrical machine from an angular connection state to a star connection stateFor adjusting the torque current of the motor to the present torque current

And (4) doubling.

It will be appreciated that, in accordance with the foregoing analysis, the torque output by the motor in the star-connected state is the torque output by the motor in the angular-connected state at the same winding and the same current

The torque can also be adapted when switching between star connection and angle connection, i.e. the torque current of the electric machine can be adapted to the greater or lesser of the original torque current after the winding connection of the electric machine has been switched from star connection to angle connection>

Doubling; when the winding connection state of the electric machine is switched from the angle connection state to the star connection state, the torque current of the electric machine can be adapted to the ^ or ^ of the original torque current>

And (4) doubling.

Therefore, the fluctuation of the rotating speed and the torque in the switching process of the winding wiring state when the motor operates can be effectively reduced, and the smooth transition of the motor in the switching process of the winding wiring state is ensured.

Further, according to an embodiment of the present application, the winding wiring state switching method of the motor further includes: determining that the winding wiring state of the motor changes, and timing the time when the motor enters the changed winding wiring state; and determining that the timing time is less than the preset dead time, and controlling the motor to keep the changed winding wiring state unchanged.

And further, determining that the timing time is greater than or equal to the preset dead time, and controlling the winding wiring state of the motor to switch according to the rotating speed of the motor.

That is, after the winding connection state is switched, the winding connection state of the motor is maintained constant regardless of the change of the rotation speed of the motor within the preset dead time tdeat, and after the preset dead time tdeat is exceeded, the winding connection state of the motor is controlled to be switched according to the current rotation speed of the motor in the above-mentioned method.

When the wiring state of the motor winding is switched from an angular connection state to a star connection state or the star connection state is switched to the angular connection state, the wiring state of the winding of the motor is determined to be changed.

As an example, the preset dead time may range from, but is not limited to, 100ms to 2s.

Therefore, by setting a proper dead time such as 100 ms-2 s, the real rotating speed of the motor can be ensured not to change greatly in the dead time.

Specifically, the preset dead time may be determined based on the rotation speed fluctuation width of the motor. That is, the preset dead time is affected by the application and the fluctuation range of the rotation speed signal.

The fluctuation range of the rotation speed of the motor may refer to a fluctuation range of the rotation speed of the motor after the change relative to the rotation speed of the motor before the change, for example, a difference value obtained by subtracting the rotation speed of the motor after the change from the rotation speed of the motor before the change is the rotation speed fluctuation range of the motor.

More specifically, the fluctuation width of the rotation speed of the motor after the change relative to the rotation speed of the motor before the change is in a positive correlation with the preset dead time. That is, the larger the fluctuation width is, the larger the preset dead time is, and conversely, the smaller the fluctuation width is, the smaller the preset dead time is.

It should be understood that the motor does not output in the winding wiring state switching process, the rotating speed of the motor is reduced when the winding wiring state is switched, the time length of the dead time is set to ensure that the switching cannot be triggered again due to the short-time speed reduction after the motor winding wiring state is switched, and the robustness is improved.

Therefore, by setting the dead time of switching, after the winding wiring state is switched, the winding wiring state is not changed any more in the preset dead time Tdefault no matter how the rotating speed of the motor changes, so that the winding wiring state switching is prevented from being triggered again due to the speed reduction caused by the interruption of the torque in the winding wiring state switching process, the fluctuation of the rotating speed and the torque in the winding wiring state switching process when the motor operates is effectively reduced, and the smooth transition of the motor in the winding wiring state switching process is ensured.

And the switching rotating speed switched to the angular connection state and the switching rotating speed switched to the star connection state are set to different values, and meanwhile, the wiring state of the motor winding can be effectively prevented from frequently changing near the switching rotating speed by setting the preset dead time, so that the robustness can be further improved.

Further, according to an embodiment of the present application, the winding wiring state switching method of the motor further includes:

determining the switching process of the winding wiring state of the motor, and controlling a motor controller to stop controlling the motor; acquiring preset delay time; and controlling the winding wiring state of the motor to be switched to a target wiring state according to the preset delay time, and controlling a motor controller to start controlling the motor.

As mentioned above, the winding connection state of the motor includes a star connection state and an angular connection state, and the process of the motor entering the winding connection state switching process includes a process of the motor entering the switching from the star connection state to the angular connection state, or a process of the motor entering the switching from the angular connection state to the star connection state. Specifically, it may be determined that the motor enters the winding connection state switching process according to the current rotation speed of the motor, for example, when the current rotation speed of the motor is increased to a first switching rotation speed, the motor enters the process of switching from the star connection state to the angular connection state, and when the current rotation speed of the motor is decreased to a second switching rotation speed, the motor enters the process of switching from the angular connection state to the star connection state.

And a short time delay exists in the switching process, so that the reliable switching of the wiring state of the motor winding is ensured.

Specifically, the preset delay time includes a first preset delay time, and controlling the winding connection state of the motor to be switched to the target connection state according to the preset delay time includes: after the motor controller is controlled to stop controlling the motor, delaying the first preset delay time, and controlling the winding wiring state of the motor to be switched to the target wiring state.

That is to say, when the motor enters the switching process of the winding wiring state, the motor controller can be controlled to stop outputting the PWM signal, so as to control the PWM output of the motor controller to be turned off, so that the motor controller stops controlling the motor, and maintain the state for a first preset delay time, so that the winding of the motor discharges through the freewheeling circuit, after the first preset delay time is delayed, the winding of the motor discharges to 0 substantially, and at this time, the winding wiring state of the motor is controlled to be switched to a target wiring state, for example, to a star connection state, or to an angle connection state.

Further, the preset delay time includes a second preset delay time, and controlling the motor controller to start controlling the motor according to the preset delay time includes:

and after the target wiring state is switched, delaying a second preset delay time, and controlling the motor controller to start controlling the motor.

That is to say, after the target wiring state is switched, the second preset delay time is delayed, and the PWM output of the motor controller is controlled to be turned on, so that the motor controller is controlled to start outputting a PWM signal, and the motor controller starts to control the motor. By delaying the second predetermined delay time, a reliable connection of the switches, for example, the first switch groups S1 to S3 or the second switch groups S4 to S6 in fig. 1, can be ensured.

As an example, when the first switch group S1 to S3 or the second switch group S4 to S6 employs a relay, the overall delay (the sum of the first preset delay time and the second preset delay time) is about 100 ms. When the first switch group S1-S3 or the second switch group S4-S6 adopts MOSFET tubes, the integral delay (the sum of the first preset delay time and the second preset delay time) is 10 ms-40 ms.

In order to realize the above embodiments, the embodiments of the present application further provide a winding wiring state switching device of a motor.

Fig. 3 is a block schematic diagram of a winding wiring state switching device of a motor according to an embodiment of the present application. It is noted that the apparatus 1 may be comprised in or realized as a motor controller. As shown in fig. 3, the winding wiring state switching device 1 of the motor includes: a first acquisition module 310, a second acquisition module 320, and a control module 330.

The first obtaining module 310 is configured to obtain a current rotation speed of the motor; the second obtaining module 320 is configured to obtain a first switching speed; the control module 330 is configured to control the winding connection state of the motor to be switched according to the current rotation speed of the motor and the first switching rotation speed.

The winding wiring state comprises a star connection state and an angle connection state, and the first switching rotating speed is less than the highest no-load rotating speed of the motor in the star connection state.

For example, the control module 330 may send a star connection control signal to the winding connection state switching circuit of the motor shown in fig. 1 when determining that the winding connection state of the motor is to be switched to the star connection state, and the control module 30 may send an angle connection control signal to the winding connection state switching circuit of the motor shown in fig. 1 when determining that the winding connection state of the motor is to be switched to the angle connection state.

According to an embodiment of the application, the first switching speed is a difference between a highest idling speed of the electric machine in the star connected state and a first speed threshold, wherein the first speed threshold is greater than zero.

According to an embodiment of the application, the first switching speed is a predetermined fixed speed, or the first switching speed is calculated according to a current bus voltage of the motor.

According to an embodiment of the present application, the second obtaining module 320 is further configured to determine a current maximum no-load rotation speed of the motor in the star connection state according to a current bus voltage of the motor; and determining a first switching rotating speed of the winding wiring state of the motor according to the current highest no-load rotating speed of the motor in the star connection state.

According to an embodiment of the present application, the second obtaining module 20 determines the current maximum no-load rotation speed of the motor in the star-connected state by the following formula:

Nmax＝Vpp*K,

According to an embodiment of the present application, the control module 30 is further configured to determine that the current rotation speed of the motor is increased to a first switching rotation speed, and control the winding connection state of the motor to switch from the star connection state to the angular connection state.

According to an embodiment of the application, the control module 30 is further configured to determine a second switching rotational speed, wherein the second switching rotational speed is less than or equal to the first switching rotational speed; and determining that the current rotating speed of the motor is reduced to a second switching rotating speed, and controlling the winding wiring state of the motor to be switched from an angular connection state to a star connection state.

According to an embodiment of the present application, the control module 30 is further configured to adjust the torque current of the motor according to a switching manner of the winding connection state of the motor.

According to an embodiment of the present application, the control module 30 is further configured to determine that the winding connection state of the motor is switched from a star connection state to an angle connection state, and adjust the torque current of the motor to the current torque current

Doubling; or the control module is also used for determining that the winding wiring state of the motor is switched from the angle connection state to the star connection state, and adjusting the torque current of the motor to be greater than or equal to the current torque current>

And (4) doubling.

It should be noted that the foregoing explanation on the winding connection state switching method embodiment of the motor is also applicable to the winding connection state switching device of the motor in this embodiment, and details are not repeated here.

In order to realize the above embodiments, the embodiment of the present application further provides a motor control system.

Fig. 4 is a block schematic diagram of a motor control system according to an embodiment of the present application. As shown in fig. 4, the motor control system 100 includes a memory 101, a processor 102, and a computer program 103 stored in the memory 101 and executable on the processor, and when the processor 102 executes the program, the winding wiring state switching method of the motor of the foregoing embodiment is implemented.

In order to implement the foregoing embodiments, the present application also proposes a non-transitory readable storage medium on which a computer program is stored, which when executed by a processor implements the winding wiring state switching method of the motor of the foregoing embodiments.

A specific embodiment of the present application is described in detail below.

Fig. 5 is a first schematic diagram of a switching device for an operating state of a winding of a motor according to an embodiment of the present application. As shown in fig. 5, the switching device for the operating state of the motor winding comprises: a drive circuit 10, a first electronic switch 11 and a second electronic switch 12; wherein,

the driving circuit 10 is connected to the first electronic switch 11 and the second electronic switch 12, and is configured to input a first driving signal to the first electronic switch 11 or input a second driving signal to the second electronic switch 12; if the first electronic switch 11 receives the first driving signal, the first electronic switch 11 is in a working state; if the second electronic switch 12 receives the second driving signal, the second electronic switch 12 is in a working state;

the first electronic switch 11 and the second electronic switch 12 are respectively connected with a motor winding 13; if the first electronic switch 11 is in a working state, the motor windings 13 are in star connection; if the second electronic switch 12 is in a working state, the motor windings 13 are connected in an angular shape.

The first electronic switch or the second electronic switch is respectively driven and controlled to be in the working state through the driving circuit, and when different electronic switches are in the working state, the connection states of the motor windings are different, so that the connection states of the motor windings can be switched through controlling the electronic switches, the windings of the motor can be switched into a more appropriate connection mode under different conditions, and the motor is guaranteed to have larger torsion, speed and efficiency while running stably.

In an optional embodiment of the present application, the driving circuit includes: a controller, a star drive circuit, and an angle drive circuit; wherein,

the controller is respectively connected with the star drive circuit and the angular drive circuit and is used for inputting star control signals to the star drive circuit or inputting angular control signals to the angular drive circuit; if the star drive circuit receives the star control signal, the star drive circuit inputs a first drive signal to the first electronic switch; and if the angular driving circuit receives the angular control signal, the angular driving circuit inputs a second driving signal to the second electronic switch.

Specifically, the driving circuit of the embodiment of the present application includes a controller, a star driving circuit, and an angle driving circuit. The controller is used for outputting a control signal, wherein the controller can be an embedded chip, the star drive circuit or the angular drive circuit is respectively connected with two pins of the embedded chip, and the star drive circuit is used for receiving the star control signal output by the controller by controlling different pins of the embedded chip to output a level signal, so that a first drive signal is input to the first electronic switch; or the angle driving circuit receives the angle driving signal and further inputs a second driving signal to the second electronic switch. It should be noted that the star drive signal and the angular drive signal may be the same or different, for example, the star drive signal may be set to be a 5V square wave signal, the angular drive signal may be a 3.3V square wave signal, or both the star drive signal and the angular drive signal may be set to be a 3.3V square wave signal. Preferably, an optical isolation circuit may be further disposed between the controller and the star driver circuit, and an optical isolation circuit may be further disposed between the controller and the angular driver circuit, so that when the controller switches to output the star control signal or the angular driver signal, the star control signal and the angular driver signal are isolated, and interference between the two signals is avoided.

This application embodiment makes star drive circuit work through star control signal through divideing into star drive circuit and angular form drive circuit respectively, and then to the first drive signal of first electronic switch input, makes angular form drive circuit work through angular form control signal, and then inputs second drive signal to second electronic switch, so realize the switching to first electronic switch and second electronic switch, and then reach the purpose that changes motor winding connection status.

Fig. 6 is a schematic diagram of a switching device for operating states of a winding of a motor according to an embodiment of the present application, as shown in fig. 6, in an alternative embodiment of the present application, the star driver circuit (not shown in the figure) has an output terminal, and the first electronic switch 11 includes a first switch unit 111, a second switch unit 112, and a third switch unit 113;

one output end of the star-shaped driving circuit is connected to the first switch unit 111, the second switch unit 112, and the third switch unit 113, respectively, and is configured to input a first driving signal to the first switch unit 111, the second switch unit 112, and the third switch unit 113, where the first driving signal is used to control the first switch unit 111, the second switch unit 112, and the third switch unit 113 to be in a conducting state; when the first switch unit 111, the second switch unit 112, and the third switch unit 113 are in the on state, the first electronic switch 11 is in the operating state.

Here, the first electronic switch includes three switch units, and the three switch units are respectively connected to the output terminals of the star drive circuit, so that the star drive circuit can simultaneously drive the three switch units to be in a conducting state after outputting the first drive signal, and when all of the three switch units are in the conducting state, the first electronic switch is in the conducting state. It should be noted that one switch unit in the embodiments of the present application may include only one switch element, or may be a switch unit composed of two or more switch elements. In the embodiment of the present application, the type of the selected switching element is not specifically limited, and one or more switching elements of a Metal-Oxide-Semiconductor Field Effect Transistor (MOSFET), a silicon controlled rectifier (scr), an Insulated Gate Bipolar Transistor (IGBT), or the like may be selected to form a switching unit in the embodiment of the present application. When the three switch units are connected to the star drive circuit, the gate of each switch element in each switch unit needs to be connected to the output end of the star drive circuit, so that the star drive circuit drives each switch element in each switch unit to be in a conducting state.

As a preferred embodiment, as shown in fig. 6, the motor winding includes a first coil 211, a second coil 212, and a third coil 213; one end of the first switching unit 111 is connected to the first coil 211, one end of the second switching unit 112 is connected to the second coil 212, and one end of the third switching unit 113 is connected to the third coil 213; the other end of the first switching unit 111 is connected to the other end of the second switching unit 112 and the other end of the third switching unit 113; wherein,

under the condition that the three switch units of the first electronic switch 11 are in a conducting state, the three coils of the motor winding are in star connection.

Specifically, in fig. 6, A1 and A2 represent first and second ends of the first coil, respectively, B1 and B2 represent first and second ends of the second coil, respectively, and C1 and C2 represent first and second ends of the third coil, respectively. Each of the three switch units of the embodiment of the application comprises three terminals, wherein each of the three switch units has one terminal connected with the output end of the star-shaped driving circuit, the other terminal of each of the three switch units is connected with one end of the other two switch units, one end of each of the three switch units is connected with different coils, and when the three switch units of the first electronic switch are all in a conducting state, 3 coils of the motor winding have a common end which is connected together, and the three coils of the motor winding are in a star-shaped connection mode. In fig. 6, when the electronic switches Q1, Q2 and Q3 are all in the on state, the terminals A2, B2 and C2 of the three windings of the motor are connected together, so that the motor windings are in the star connection state. Here, the three coils of the motor winding are also respectively connected with a motor controller, and the motor controller realizes the control of the motor running state. In general, a motor controller is also referred to as a motor driver.

In an alternative embodiment of the present application, as shown in fig. 6, the angular driving circuit (not shown) has a first output terminal, a second output terminal, and a third output terminal; the second electronic switch 12 includes a first group of switch units 121, a second group of switch units 122, and a third group of switch units 123; when the first group of switch units 121, the second group of switch units 122, and the third group of switch units 123 are in the on state, the second electronic switch 12 is in the working state;

a first output end of the angular driving circuit is connected to the first group of switch units 121, and is configured to input a first path of signal to the first group of switch units 121;

a second output end of the angular driving circuit is connected to the second group of switch units 122, and is used for inputting a second signal to the second group of switch units 122;

a third output end of the angular driving circuit is connected to the third group of switch units 123, and is configured to input a third signal to the third group of switch units 123;

the first path of signal, the second path of signal and the third path of signal belong to the second driving signal.

As a preferred embodiment, as shown in fig. 6, the motor winding includes a first coil 211, a second coil 212, and a third coil 213; a first end of the first coil 211 is connected to a first end of the first group of switching units 121, a second end of the first coil 211 is connected to a second end of the second group of switching units 122, a first end of the second coil 212 is connected to a first end of the third group of switching units 123, a second end of the second coil 212 is connected to a second end of the first group of switching units 121, a first end 213 of the third coil is connected to a first end of the second group of switching units 122, and a second end of the third coil 213 is connected to a second end of the third group of switching units 123; wherein,

when the three groups of switch units of the second electronic switch 12 are in a conducting state, the three coils of the motor winding are connected in an angular shape.

Specifically, each of the three groups of switch units in the embodiment of the present application includes three terminals, where each of the three groups of switch units has one terminal connected to the output terminal of the angular driving circuit, the angular driving circuit has a first output terminal, a second output terminal, and a third output terminal, and each group of switch units is connected to different output terminals of the angular driving circuit, so that the angular driving circuit is used to supply power to different groups of switch units.

In the embodiment of the present application, the connection order of the three sets of switch units and the coils is not particularly limited, as long as the coils are connected in a delta connection manner finally.

In an alternative embodiment of the present application, the first group of switch units 121 includes a fourth switch unit and a fifth switch unit; wherein the fourth switching unit and the fifth switching unit are connected in series;

the second group switching unit 122 includes a sixth switching unit and a seventh switching unit; wherein the sixth switching unit and the seventh switching unit are connected in series;

the third group switching unit 123 includes an eighth switching unit and a ninth switching unit; wherein the eighth switching unit and the ninth switching unit are connected in series.

Specifically, as shown in fig. 6, each group of switch units in the embodiment of the present application includes two switch units, and two switch units in one group of switch units are connected in series, so that when the direction of the current in the coil changes, under the action of the angular driving signal, three groups of switch units of the second electronic switch can be in a conducting state. Taking the first group of switch units 121 as an example, the first group of switch units 121 includes a fourth switch unit (i.e., Q4) and a fifth switch unit (i.e., Q7), the two switch units are connected in series, and by connecting the two switch units in one group in series, the first group of switch units 121 formed by the fourth switch unit (i.e., Q4) and the fifth switch unit (i.e., Q7) can be in a conducting state under the action of the angular driving signal when the direction of the current in the coil changes. Here, taking the example that Q4 and Q7 are both MOS transistors, Q4 and Q7 are connected in series by a common source stage (i.e., S stage), and when the first group of switch units is in the on state, the current flow direction in the first group of switch units is: drain of Q4 (i.e., D pole) → S pole of Q4 → S pole of Q7 → D pole of Q7, or: pole D of Q7 → pole S of Q4 → pole D of Q4.

As shown in fig. 6, when the electronic switches Q4 to Q9 are all in the on state, A1 of the electronic winding is connected to B2, B1 is connected to C2, C1 is connected to A2, and the motor winding is in delta connection.

Fig. 7 is a schematic view of a motor winding in a star connection state provided in an embodiment of the present application, and fig. 8 is a schematic view of a motor winding in an angle connection state provided in an embodiment of the present application, as shown in fig. 7 and 8, in an alternative embodiment of the present application, the apparatus further includes: an isolation switching power supply 31; the isolation switch power supply 31 is connected with the driving circuit and used for supplying power to the driving circuit; wherein, the output of the isolated switching power supply 31 comprises a first output signal, a second output signal, a third output signal and a fourth output signal; the first output signal is used to power the star driver circuit 32, and the second, third and fourth output signals are used to power the corner driver circuit 33.

As shown in fig. 7, the isolated switching power supply can output a first output signal to power the star driving circuit, and the star circuit drives the three switching units in the first electronic switch to be in a conducting state by receiving the star driving signal output by the controller, so that the windings of the motor are connected in a star shape.

As shown in fig. 8, the isolation switch power supply can output the second output signal, the third output signal and the fourth output signal respectively to supply power to the angular driving circuit, and the angular driving circuit drives the three groups of switch units in the second electronic switch to be in a conducting state by receiving the angular control signal output by the controller, so that the windings of the motor are connected in an angular shape.

As shown in fig. 7 and fig. 8, in the embodiment of the present application, the external power source 34 provides power to the motor controller 215 and the isolated switch power source 31, and the isolated switch power source 31 outputs a first output signal to power the star driver 32 by processing the received external power source 34 signal, and outputs a second output signal, a third output signal and a fourth output signal to power the angle driver 41, so as to drive the first electronic switch 11 or the second electronic switch 12 to be in a conducting state.

In an optional embodiment of the present application, the isolation switch power supply includes a rectifying circuit, configured to rectify an external power signal received by the isolation switch power supply.

Specifically, when the isolating switch power supply is designed, the rectifying circuit can be arranged at the input end of the isolating switch power supply, so that the isolating switch power supply in the switching device of the working state of the motor winding can receive external signal input of wide voltage, the common bus operation of the isolating switch power supply and the motor controller is realized, power supply for the motor controller and the isolating switch power supply can be realized through one external power supply, and an additional electric energy conversion device is not required to be arranged. For example, when the switching device for the working state of the motor winding, the motor and the motor controller are used in a vehicle, the power supply provided by the vehicle can be used for supplying power to the isolation switch power supply and the motor controller at the same time, so that the switching of the connection mode of the motor winding is realized, and the operation of the motor is ensured.

Fig. 9 is a second schematic diagram of a switching device for switching an operating state of a winding of a motor according to an embodiment of the present application, and as a preferred implementation, as shown in fig. 9, the switching device further includes: a first arc extinguishing device 51, a second arc extinguishing device 52, and a third arc extinguishing device 53; wherein,

the first arc extinguishing device 51 is connected with a second end of the first coil 211; the second arc extinguishing device 52 is connected to a second end of the second coil 212; the third arc extinguishing device 53 is connected to a second end of the third coil 213.

Specifically, the arc control device of this application embodiment is the clamp arc control device, through set up the clamp arc control device between every coil of motor winding and switch module, can absorb the high pressure that produces when the inductive load cuts off in the relevant circuit when the motor operation.

The switching device of the working state of the motor winding provided by the embodiment of the application can realize a star connection mode and a triangular connection mode of the motor winding through an electronic circuit device. According to the star drive circuit, when the star drive circuit receives a star control signal, the first electronic switch connected with the star drive circuit is driven, the motor works in a state that the winding is in star connection, similarly, when the angle drive circuit receives an angle control signal, the second electronic switch connected with the angle drive circuit is driven, the motor works in a state that the winding is in angle connection, different drive signals are output through different control signals to realize switching of the first electronic switch and the second electronic switch, the whole switching time is below 10 microseconds, and the motor power interruption time in the switching process can be obviously shortened. Under different conditions, the connection mode of the motor winding is switched by switching the electronic switch, so that the motor can stably run and has higher torque, speed and efficiency.

The circuit design of the switching device for the operating state of the motor winding provided by the embodiment of the present application is described below with reference to a specific embodiment, and the circuit of the present embodiment is used for switching the operating state of the winding of a permanent magnet synchronous motor on a vehicle. It should be noted that the circuit composition of the switching device for switching the operating state of the motor winding according to the embodiment of the present application is not limited to the specific circuit according to the embodiment of the present application.

Fig. 10 to 17 are circuit diagrams of an implementation manner of the switching device for the operating state of the motor winding according to the embodiment of the present application. The switching of the connection mode of the motor winding can be realized by the circuit of the switching device of the motor winding working state designed by fig. 10 to 17.

Fig. 10 is a circuit diagram of a star driver circuit according to an embodiment of the present invention, in fig. 10, a star control signal is input to the star driver circuit from an input terminal (i.e., IO 1) of the star driver circuit, and is input to the optocoupler chip ACPL-P314 after passing through the optoelectronic isolation circuit 61, where the chip ACPL-P314 includes a power stage output circuit, and can be used for driving an electronic switch in the circuit. Here, when actually designing the driving circuit, the selected driving chip is not limited to ACPL-P314, and other driving chips or driving circuits capable of achieving the same function may be selected.

Fig. 11 is a circuit diagram of a first electronic switch according to an embodiment of the present application, in fig. 11, each of a first switch unit 111, a second switch unit 112, and a third switch unit 113 is composed of two switch elements, and the two switch elements are connected in series to form one switch unit, so that power of the one switch unit can be increased. Here, the gate of each switching element is connected to the output STAR-C of the STAR driver circuit in fig. 10. In the figure, PA2 is connected to the second end of the first coil of the motor, PB2 is connected to the second end of the second coil of the motor, and PC2 is connected to the second end of the third coil of the motor.

Fig. 12 is a circuit diagram of an angle driving circuit according to an embodiment of the present invention, in fig. 12, an angle control signal is input into the angle driving circuit from an input terminal (i.e., IO 2) of the angle driving circuit, and is input into three photocoupler chips ACPL-P314 after passing through the optoelectronic isolation circuit 81, and the chips ACPL-P314 include power stage output circuits, which can be used for driving electronic switches in the circuit. The corner drive circuit has three outputs for providing drive signals to the first, second and third groups of switch units in fig. 13, respectively.

Fig. 13 is a circuit diagram of a second electronic switch provided in the embodiment of the present application, in fig. 13, the first group of switch units 121 is composed of 4 switch elements Q8, Q11, Q14, and Q17, where Q8 and Q17 constitute a fourth switch unit in the embodiment of the present application, and Q11 and Q14 constitute a seventh switch unit in the embodiment of the present application; the second group of switching units 122 is composed of 4 switching elements Q9, Q12, Q15, and Q18, where Q9 and Q18 constitute the fifth switching unit of the embodiment of the present application, and Q12 and Q15 constitute the eighth switching unit of the embodiment of the present application; the third group of switching units 123 is composed of 4 switching elements Q10, Q13, Q16, and Q19, where Q10 and Q19 constitute a sixth switching unit and Q13 and Q16 constitute a ninth switching unit in the embodiments of the present application.

In fig. 13, the fourth to ninth switching units are each composed of two switching elements, and the two switching elements are connected in series to form one switching unit, so that the power of the one switching unit can be increased. Here, the gate of each switching element in the first group of switching units 121 is connected to the output terminal PA-PB of the corner drive circuit of fig. 10, the gate of each switching element in the second group of switching units 122 is connected to the output terminal PB-PC of the corner drive circuit of fig. 10, and the gate of each switching element in the third group of switching units 123 is connected to the output terminal PC-PA of the corner drive circuit of fig. 10. In the figure, PA1 is connected to a first end of a first coil of the motor, PB1 is connected to a first end of a second coil of the motor, and PC1 is connected to a first end of a third coil of the motor; in the figure, PA2 is connected to the second end of the first coil of the motor, PB2 is connected to the second end of the second coil of the motor, and PC2 is connected to the second end of the third coil of the motor.

Fig. 14 is a circuit diagram of an isolation switch power supply according to an embodiment of the present application, and as shown in fig. 14, a rectifier bridge is disposed at an input end of the isolation switch power supply circuit, and is capable of rectifying an external power supply signal input to the isolation switch power supply, so that the isolation switch power supply can receive input of the external power supply signal in a wide voltage range, and the external power supply signal may be a direct current signal or an alternating current signal. The isolation switch power supply is provided with four paths of output signals, wherein one path of output signal supplies power for the star drive circuit, and the other three paths of output signals supply power for the angle drive circuit, so that an isolated drive power supply can be provided for each switch element in the first electronic switch and the second electronic switch. The four 12V outputs of the isolating switch power supply are isolated from each other, so that the anti-interference capability of the power supply can be improved, and no mutual influence exists among the four paths of signals output by the isolating switch power supply. Here, the circuit of the isolated switching power supply further includes a feedback circuit 102, which can monitor the output voltage of the isolated switching power supply in real time, and ensure that the output of the isolated switching power supply is stabilized at a target output value.

Fig. 15 is a circuit diagram of an arc extinguishing apparatus according to an embodiment of the present application, and as shown in fig. 15, the first arc extinguishing apparatus 51, the second arc extinguishing apparatus 52, and the third arc extinguishing apparatus 53 all have the same composition, taking the first arc extinguishing apparatus 51 as an example, the first arc extinguishing apparatus 51 includes two diodes D1 and D2 connected in series, a negative electrode of D2 is connected to a positive electrode of D1, and a positive electrode of D2 is connected to a negative electrode of an external 84V power supply. FIG. 16 is a schematic diagram of an external 84V power supply, which may be an on-board power supply, according to an embodiment of the present application. Here, the external power source is selected according to the actual application scenario and is not limited to 84V. The negative pole of D1 is connected with the positive pole of the 84V power supply, the positive pole of D1 is also connected with the phase winding of the motor winding A, namely the first arc-extinguishing device is connected with the second end of the first winding in the embodiment of the application, if the conduction voltage drop of the diodes D1 and D2 is 0.7V, the voltage of the second end of the first winding can be ensured to be in the range of-0.7V-84.7V through the clamping arc-extinguishing device arranged in the embodiment of the application, and the electric arc generated when the inductive load in the circuit is turned off is avoided. Similarly, the arc extinguishing devices are arranged at the second ends of the motor B-phase winding and the motor C-phase winding, so that an electric arc generated when the inductive load is turned off in a circuit can be avoided, and the damage to the switching device of the working state of the motor winding and the load of the embodiment of the application caused by the electric arc is avoided.

Fig. 17 is a schematic diagram of an interface circuit of a switching device for switching an operating state of a motor winding according to an embodiment of the present invention, and as shown in fig. 17, the switching device further includes a first interface circuit 1301, a second interface circuit 1302, and a third interface circuit 1303, where PA1 of the first interface circuit 1301 is connected to PA1 of fig. 11 and fig. 13, P3 is connected to a first end of a first coil of the motor winding, that is, to a first end of an a-phase winding of the motor, and P5 is connected to an a-phase output end of the motor controller; PB1 of the second interface circuit 1302 is connected to the output terminals PB1 of fig. 11 and 13, P6 is connected to the first end of the second coil of the motor winding, i.e. to the first end of the B-phase winding of the motor, and P8 is connected to the B-phase output terminal of the motor controller; the PC1 of the third interface circuit 1303 is connected to the output terminals PC1 of fig. 11 and 13, P9 is connected to the first end of the third coil of the motor winding, i.e., to the first end of the C-phase winding of the motor, and P11 is connected to the C-phase output terminal of the motor controller.

Here, by providing an interface circuit, the interface can be set to 1 to 2, and the output terminals of the electronic switches are connected to the second terminal of one of the three coils of the motor winding and the output terminal of the motor controller corresponding to the coil, respectively.

In the circuit of the switching device for the operating state of the motor winding composed of fig. 10 to 17, the star control signal is input to the star drive circuit in fig. 10 by switching the control signal, or the angle control signal is input to the angle drive circuit in fig. 12, so that the switching of the star or delta connection state of the motor winding can be realized by changing the conduction state of the electronic switching element in the circuit.

Fig. 18 is a circuit principle simulation diagram of a switching device for motor winding operating states according to the technical solution of the embodiment of the present application. As shown in fig. 18, L1, L2 and L3 represent a first coil, a second coil and a third coil of a motor winding, respectively, V7 represents an output signal of a motor controller, the voltage of the first coil is measured by XSC1, and switching of a star control signal and an angle control signal input in the device is realized by a switch S1. In fig. 18, U1, U2, U3, and U4 are all driving circuits, where U1, U2, and U3 are angular driving circuits, and when an angular control signal is input to U1, U2, and U3, a first driving signal is output to the first group of switching units Q6 and Q9 through U1, and Q6 and Q9 are both driven to be in a conducting state; outputting a second path of signals to a second group of switch units Q5 and Q8 through U2, and driving Q5 and Q8 to be in a conducting state; outputting a third path of signal to a third group of switching units Q4 and Q7 through U3, and driving Q4 and Q7 to be in a conducting state; as shown in fig. 15, when Q4 to Q9 are all in the on state, L1, L2, and L3 are in the angle connection state, the peak-to-peak voltage (i.e., vpp) of the first coil measured using an oscilloscope is about 84V, the height of each cell on the vertical axis in fig. 19 represents 50V, and each cell on the horizontal axis represents 100us.

In fig. 18, when a star-shaped driving signal is input to U4, U4 simultaneously outputs a first driving signal to Q1 of the first switching unit, Q2 of the second switching unit, and Q3 of the third switching unit, so that Q1, Q2, and Q3 are all in a turned-on state; as shown in fig. 20, when Q1, Q2 and Q3 are all in the on state, L1, L2 and L3 are in the star connection state, the peak-to-peak voltage (i.e., vpp) of the first coil measured using an oscilloscope is about 42V, the height of each cell on the vertical axis in fig. 20 represents 50V, and each cell on the horizontal axis represents 100us.

The voltages at two ends of the L1 are measured by an oscilloscope in the simulation circuit when the L1, the L2 and the L3 are in an angular connection mode and a star connection mode, and the characteristic that the voltage at two ends of the L1 is greater than the voltage at two ends of the L1 in the star connection mode in the triangular connection mode is met.

1. A device for switching the operating state of a winding of an electric machine, said device comprising: the circuit comprises a driving circuit, a first electronic switch and a second electronic switch; wherein,

the driving circuit is connected with the first electronic switch and the second electronic switch and is used for inputting a first driving signal to the first electronic switch or inputting a second driving signal to the second electronic switch; if the first electronic switch receives the first driving signal, the first electronic switch is in a working state; if the second electronic switch receives the second driving signal, the second electronic switch is in a working state;

the first electronic switch and the second electronic switch are respectively connected with a motor winding; if the first electronic switch is in a working state, the motor windings are in star connection; and if the second electronic switch is in a working state, the motor windings are connected in an angle shape.

2. The apparatus of claim 1, wherein the drive circuit comprises: a controller, a star drive circuit, and an angle drive circuit; wherein,

3. The apparatus of claim 2, wherein the star driver circuit has an output, and the first electronic switch comprises a first switch unit, a second switch unit, and a third switch unit;

one output end of the star drive circuit is connected with the first switch unit, the second switch unit and the third switch unit respectively, and is used for inputting a first drive signal to the first switch unit, the second switch unit and the third switch unit, wherein the first drive signal is used for controlling the first switch unit, the second switch unit and the third switch unit to be in a conducting state; under the condition that the first switch unit, the second switch unit and the third switch unit are in a conducting state, the first electronic switch is in a working state.

4. The apparatus of claim 3, wherein the motor winding comprises a first coil, a second coil, and a third coil; one end of the first switching unit is connected with the first coil, one end of the second switching unit is connected with the second coil, and one end of the third switching unit is connected with the third coil; the other end of the first switch unit is connected with the other end of the second switch unit and the other end of the third switch unit; wherein,

and under the condition that the three switch units of the first electronic switch are in a conducting state, three coils of the motor winding are in star connection.

5. The apparatus of claim 2, wherein the angular drive circuit has a first output, a second output, and a third output; the second electronic switch comprises a first group of switch units, a second group of switch units and a third group of switch units; under the condition that the first group of switch units, the second group of switch units and the third group of switch units are in a conducting state, the second electronic switch is in a working state;

the first output end of the angular driving circuit is connected with the first group of switch units and is used for inputting a first path of signal to the first group of switch units;

the second output end of the angular driving circuit is connected with the second group of switch units and is used for inputting a second path of signals to the second group of switch units;

a third output end of the angular driving circuit is connected with the third group of switch units and is used for inputting a third path of signals to the third group of switch units;

6. The apparatus of claim 5, wherein the motor winding comprises a first coil, a second coil, and a third coil; the first end of the first coil is connected with the first ends of the first group of switch units, the second end of the first coil is connected with the second ends of the second group of switch units, the first end of the second coil is connected with the first ends of the third group of switch units, the second end of the second coil is connected with the second ends of the first group of switch units, the first end of the third coil is connected with the first ends of the second group of switch units, and the second end of the third coil is connected with the second ends of the third group of switch units; wherein,

and under the condition that the three groups of switch units of the second electronic switch are in a conducting state, three coils of the motor winding are connected in an angle shape.

7. The apparatus of

claim

5 or 6,

the first group of switch units comprises a fourth switch unit and a fifth switch unit; wherein the fourth switching unit and the fifth switching unit are connected in series;

the second group of switch units comprises a sixth switch unit and a seventh switch unit; wherein the sixth switching unit and the seventh switching unit are connected in series;

the third group of switch units comprises an eighth switch unit and a ninth switch unit; wherein the eighth switching unit and the ninth switching unit are connected in series.

8. The apparatus of claim 2, further comprising: an isolated switching power supply; the isolation switch power supply is connected with the drive circuit and used for supplying power to the drive circuit; wherein the output of the isolated switching power supply comprises a first output signal, a second output signal, a third output signal and a fourth output signal; the first output signal is used for supplying power to the star drive circuit, and the second output signal, the third output signal and the fourth output signal are used for supplying power to the angular drive circuit.

9. The apparatus of claim 8, wherein the isolated switching power supply comprises a rectifying circuit for rectifying an external power signal received by the isolated switching power supply.

10. The apparatus of claim 4 or 6, further comprising: a first arc extinguishing device, a second arc extinguishing device and a third arc extinguishing device; wherein,

the first arc extinguishing device is connected with the second end of the first coil; the second arc extinguishing device is connected with the second end of the second coil; the third arc extinguishing device is connected with the second end of the third coil.

In the description of the present specification, reference to the description of "one embodiment," "some embodiments," "an example," "a specific example," or "some examples" or the like means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present application. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the feature. In the description of the present application, "plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

Any process or method descriptions in flow charts or otherwise described herein may be understood as representing modules, segments, or portions of code which include one or more executable instructions for implementing steps of a custom logic function or process, and alternate implementations are included within the scope of the preferred embodiment of the present application in which functions may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order, depending on the functionality involved, as would be understood by those reasonably skilled in the art of the present application.

The logic and/or steps represented in the flowcharts or otherwise described herein, e.g., an ordered listing of executable instructions that can be considered to implement logical functions, can be embodied in any computer-readable medium for use by or in connection with an instruction execution system, apparatus, or device, such as a computer-based system, processor-containing system, or other system that can fetch the instructions from the instruction execution system, apparatus, or device and execute the instructions. For the purposes of this description, a "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of the computer-readable medium would include the following: an electrical connection (electronic device) having one or more wires, a portable computer diskette (magnetic device), a Random Access Memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). Additionally, the computer-readable medium could even be paper or another suitable medium upon which the program is printed, as the program can be electronically captured, via for instance optical scanning of the paper or other medium, then compiled, interpreted or otherwise processed in a suitable manner if necessary, and then stored in a computer memory.

It should be understood that portions of the present application may be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, various steps or methods may be implemented in software or firmware stored in a memory and executed by a suitable instruction execution system. If implemented in hardware, as in another embodiment, any one or combination of the following techniques, which are known in the art, may be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application specific integrated circuit having an appropriate combinational logic gate circuit, a Programmable Gate Array (PGA), a Field Programmable Gate Array (FPGA), or the like.

It will be understood by those skilled in the art that all or part of the steps carried by the method for implementing the above embodiments may be implemented by hardware related to instructions of a program, which may be stored in a computer readable storage medium, and when the program is executed, the program includes one or a combination of the steps of the method embodiments.

In addition, functional units in the embodiments of the present application may be integrated into one processing module, or each unit may exist alone physically, or two or more units are integrated into one module. The integrated module can be realized in a hardware mode, and can also be realized in a software functional module mode. The integrated module, if implemented in the form of a software functional module and sold or used as a stand-alone product, may also be stored in a computer readable storage medium.

The storage medium mentioned above may be a read-only memory, a magnetic or optical disk, etc. Although embodiments of the present application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present application, and that variations, modifications, substitutions and alterations may be made to the above embodiments by those of ordinary skill in the art within the scope of the present application.

Claims

1. A method for switching a winding wiring state of a motor, comprising:

acquiring the current rotating speed of the motor;

acquiring a first switching rotating speed;

controlling the winding wiring state of the motor to be switched according to the current rotating speed of the motor and the first switching rotating speed;

the winding wiring state comprises a star connection state and an angle connection state, and the first switching rotating speed is less than the highest no-load rotating speed of the motor in the star connection state;

wherein, the first switching speed is calculated according to the current bus voltage of the motor, and comprises the following steps: determining the current highest no-load rotation speed of the motor in the star connection state according to the current bus voltage of the motor, wherein the highest no-load rotation speed is the no-load rotation speed reached by the motor when the counter potential of the motor is equal to the bus voltage of the motor;

determining a first switching rotating speed of a winding wiring state of the motor according to the current highest no-load rotating speed of the motor in the star connection state; wherein the first switching speed is a difference between a highest no-load speed of the motor in the star connection state and a first speed threshold, wherein the first speed threshold is greater than zero;

the method further comprises the following steps:

determining that the winding wiring state of the motor changes, and timing the time when the motor enters the current winding wiring state; determining that the timing time is less than the preset dead time, and controlling a motor to keep the current winding wiring state unchanged; determining that the timing time is greater than or equal to the preset dead time, and controlling the winding wiring state of the motor to switch according to the rotating speed of the motor; the preset dead time is determined based on the fluctuation range of the rotating speed of the motor;

2. The winding connection state switching method of an electric machine according to claim 1, wherein the current highest no-load rotation speed of the electric machine in a star connection state is determined by the following formula:

Nmax＝Vpp*K,

3. The winding wiring state switching method of an electric machine according to claim 1, characterized in that after acquiring the current bus voltage of the electric machine, the method further comprises:

determining a voltage variation between the current bus voltage of the motor and the bus voltage acquired last time;

and when the voltage variation is larger than a preset voltage threshold, calculating the first switching rotating speed according to the current bus voltage of the motor.

4. The winding wiring state switching method of an electric machine according to claim 1, characterized in that after acquiring the current bus voltage of the electric machine, the method further comprises:

determining the time difference between the current moment and the moment of last calculation of the first switching rotating speed;

and when the time difference reaches the preset trigger time, calculating the first switching rotating speed according to the current bus voltage of the motor.

5. The winding wiring state switching method of an electric motor according to claim 1, wherein said controlling the winding wiring state of the electric motor to be switched in accordance with the current rotation speed of the electric motor and the first switching rotation speed includes:

and determining that the current rotating speed of the motor is increased to the first switching rotating speed, and controlling the winding wiring state of the motor to be switched from the star connection state to the angle connection state.

6. The winding wiring state switching method of an electric machine according to claim 1 or 5, characterized by further comprising:

determining that the current rotating speed of the motor is reduced to a second switching rotating speed, and controlling the winding wiring state of the motor to be switched from the angular connection state to the star connection state; the second switching rotational speed is less than or equal to the first switching rotational speed.

7. The winding wiring state switching method of an electric machine according to claim 1, characterized by further comprising:

8. The winding wiring state switching method of an electric motor according to claim 7, wherein adjusting the torque current of the electric motor according to the switching manner of the winding wiring state of the electric motor includes:

determining the connection state of the winding of the motor to be switched from the star connection state to the angle connection state, and adjusting the torque current of the motor to the current torque current

Doubling;

determining the winding connection state of the motor to be switched from the angular connection state to the star connection state, and adjusting the torque current of the motor to the current torque current

And (4) doubling.

9. A winding wiring state switching device of an electric motor, characterized by comprising:

the first acquisition module is used for acquiring the current rotating speed of the motor;

the second acquisition module is used for acquiring the first switching rotating speed;

the control module is used for controlling the winding wiring state of the motor to be switched according to the current rotating speed of the motor and the first switching rotating speed;

wherein, the first switching speed is calculated according to the current bus voltage of the motor, and comprises the following steps: determining the current highest no-load rotating speed of the motor in the star connection state according to the current bus voltage of the motor, wherein the highest no-load rotating speed is the no-load rotating speed reached by the motor when the counter potential of the motor is equal to the bus voltage of the motor;

the control module is also used for determining that the winding wiring state of the motor changes and timing the time when the motor enters the current winding wiring state; determining that the timing time is less than the preset dead time, and controlling a motor to keep the current winding wiring state unchanged; determining that the timing time is greater than or equal to the preset dead time, and controlling the winding wiring state of the motor to switch according to the rotating speed of the motor; the preset dead time is determined based on the fluctuation range of the rotating speed of the motor;

10. A motor control system comprising a memory, a processor and a computer program stored on the memory and executable on the processor, the processor implementing the method of switching winding wiring states of a motor according to any one of claims 1 to 8 when executing the program.

11. A non-transitory readable storage medium on which a computer program is stored, the program, when executed by a processor, implementing a winding wiring state switching method of an electric machine according to any one of claims 1 to 8.