阅读说明：本技术 一种电流信号检测方法、装置、存储介质和电机控制器 (Current signal detection method and device, storage medium and motor controller ) 是由 徐亚美 任宪丰 李强 李军营 于 2020-12-25 设计创作，主要内容包括：本申请公开了一种电流信号检测方法、装置、存储介质和电机控制器,将电机控制器的电压调节为不小于预设电压,触发电机控制器调节电机的直轴电流和交轴电流,使得直轴电流的电流值和交轴电流的电流值互不相同。基于直轴电流的电流值和交轴电流的电流值,计算得到相电流的预估电流值。获取电机的相电流的稳态电流值,并计算稳态电流值与预估电流值的差值。在确定稳态电流值与预估电流值的差值,不小于预设第一阈值的情况下,提示电机的相电流信号无效。可见,利用本申请所述的方法,能够在不对电机控制器进行改造的情况下,辅助电机控制器识别无效相电流信号。(The application discloses a current signal detection method, a current signal detection device, a storage medium and a motor controller, wherein the voltage of the motor controller is regulated to be not less than a preset voltage, and the motor controller is triggered to regulate the direct-axis current and the quadrature-axis current of a motor, so that the current values of the direct-axis current and the quadrature-axis current are different from each other. And calculating to obtain an estimated current value of the phase current based on the current value of the direct-axis current and the current value of the quadrature-axis current. And acquiring a steady-state current value of the phase current of the motor, and calculating a difference value between the steady-state current value and the estimated current value. And under the condition that the difference value between the steady-state current value and the estimated current value is not smaller than a preset first threshold value, prompting that the phase current signal of the motor is invalid. Therefore, by the method, the motor controller can be assisted to identify the invalid phase current signal without being modified.)

1. A current signal detection method, comprising:

adjusting the voltage of the motor controller to be not less than a preset voltage;

triggering the motor controller to adjust the direct axis current and the quadrature axis current of the motor, so that the current value of the direct axis current and the current value of the quadrature axis current are different;

calculating to obtain an estimated current value of the phase current based on the current value of the direct-axis current and the current value of the quadrature-axis current;

acquiring a steady-state current value of the phase current of the motor, and calculating a difference value between the steady-state current value and an estimated current value;

and prompting that the phase current signal of the motor is invalid under the condition that the difference value between the steady-state current value and the estimated current value is not smaller than a preset first threshold value.

2. The method of claim 1, wherein the triggering the motor controller to adjust a direct-axis current and a quadrature-axis current of the motor such that a current value of the direct-axis current and a current value of the quadrature-axis current are different from each other comprises:

triggering the motor controller to adjust the direct axis current and the quadrature axis current of the motor, so that the current value of the direct axis current is equal to a first numerical value, and the current value of the quadrature axis current is equal to zero;

alternatively, the first and second electrodes may be,

and triggering the motor controller to adjust the direct-axis current and the quadrature-axis current of the motor, so that the current value of the direct-axis current is equal to zero and the current value of the quadrature-axis current is equal to a second numerical value.

3. The method of claim 2, wherein the estimated current value comprises a first current value;

the first current value is a current value of the phase current calculated based on the first numerical value.

4. The method of claim 2, wherein the estimated current value comprises a second current value;

the second current value is a current value of the phase current calculated based on the second numerical value.

5. The method of claim 1, wherein calculating the difference between the steady state current value and the estimated current value comprises:

under the condition that the steady-state current value is smaller than a preset second threshold value, calculating a difference value between the steady-state current value and an estimated current value;

the method further comprises the following steps:

and prompting that the phase current signal of the motor is invalid under the condition that the steady-state current value is determined to be smaller than the preset second threshold value.

6. The method of claim 1, wherein the obtaining a steady state current value of phase currents of the electric machine comprises:

and under the condition that the response time of the motor torque is longer than the preset time, determining that the phase current of the motor is in a stable state, and taking the current value of the phase current in the stable state as a stable current value.

7. The method of claim 1, further comprising:

adjusting the voltage of the motor controller to be less than the preset voltage;

acquiring a current value of a phase current of the motor;

and prompting that the phase current signal of the motor is invalid under the condition that the current value of the phase current is smaller than a preset second threshold value.

8. A current signal detecting device, comprising:

the adjusting unit is used for adjusting the voltage of the motor controller to be not less than the preset voltage;

the trigger unit is used for triggering the motor controller to adjust the direct-axis current and the quadrature-axis current of the motor, so that the current value of the direct-axis current and the current value of the quadrature-axis current are different;

the first calculation unit is used for calculating and obtaining an estimated current value of the phase current based on the current value of the direct-axis current and the current value of the quadrature-axis current;

the second calculation unit is used for acquiring a steady-state current value of the phase current of the motor and calculating a difference value between the steady-state current value and an estimated current value;

and the first prompting unit is used for prompting that the phase current signal of the motor is invalid under the condition that the difference value between the steady-state current value and the estimated current value is determined to be not smaller than a preset first threshold value.

9. A computer-readable storage medium, characterized in that the computer-readable storage medium includes a stored program, wherein the program executes the current signal detection method according to any one of claims 1 to 7.

10. A motor controller, comprising: a processor, a memory, and a bus; the processor and the memory are connected through the bus;

the memory is used for storing a program, and the processor is used for running the program, wherein the program is used for executing the current signal detection method according to any one of claims 1 to 7.

Technical Field

The present disclosure relates to the field of electrical control, and in particular, to a method and an apparatus for detecting a current signal, a storage medium, and a motor controller.

Background

Vector control is the mainstream control mode of the current permanent magnet synchronous motor, and under the existing development level, three-phase current of the motor needs to be collected and used as a feedback signal of the control strategy to form a closed loop. In practical applications, a sensor generally collects a phase current signal (i.e., a current value of a phase current), and sends the phase current signal to a motor controller, and then the motor controller controls and manages the motor according to the phase current signal.

However, the phase current signals sent by the sensors are not all valid, and the existing motor controller cannot identify the validity of the phase current signals, so that the control effect of the motor controller on the motor is reduced. Therefore, how to detect the effectiveness of the phase current signal is a problem to be solved urgently.

Disclosure of Invention

The application provides a current signal detection method, a current signal detection device, a storage medium and a motor controller, and aims to assist the motor controller in identifying invalid phase current signals under the condition that the motor controller is not modified.

In order to achieve the above object, the present application provides the following technical solutions:

a current signal detection method, comprising:

adjusting the voltage of the motor controller to be not less than a preset voltage;

triggering the motor controller to adjust the direct axis current and the quadrature axis current of the motor, so that the current value of the direct axis current and the current value of the quadrature axis current are different;

calculating to obtain an estimated current value of the phase current based on the current value of the direct-axis current and the current value of the quadrature-axis current;

acquiring a steady-state current value of the phase current of the motor, and calculating a difference value between the steady-state current value and an estimated current value;

and prompting that the phase current signal of the motor is invalid under the condition that the difference value between the steady-state current value and the estimated current value is not smaller than a preset first threshold value.

Optionally, the triggering the motor controller to adjust a direct-axis current and a quadrature-axis current of the motor, so that a current value of the direct-axis current and a current value of the quadrature-axis current are different from each other, includes:

triggering the motor controller to adjust the direct axis current and the quadrature axis current of the motor, so that the current value of the direct axis current is equal to a first numerical value, and the current value of the quadrature axis current is equal to zero;

alternatively, the first and second electrodes may be,

and triggering the motor controller to adjust the direct-axis current and the quadrature-axis current of the motor, so that the current value of the direct-axis current is equal to zero and the current value of the quadrature-axis current is equal to a second numerical value.

Optionally, the estimated current value includes a first current value;

the first current value is a current value of the phase current calculated based on the first numerical value.

Optionally, the estimated current value includes a second current value;

the second current value is a current value of the phase current calculated based on the second numerical value.

Optionally, the calculating the difference between the steady-state current value and the estimated current value includes:

under the condition that the steady-state current value is smaller than a preset second threshold value, calculating a difference value between the steady-state current value and an estimated current value;

the method further comprises the following steps:

and prompting that the phase current signal of the motor is invalid under the condition that the steady-state current value is determined to be smaller than the preset second threshold value.

Optionally, the obtaining the steady-state current value of the phase current of the motor includes:

and under the condition that the response time of the motor torque is longer than the preset time, determining that the phase current of the motor is in a stable state, and taking the current value of the phase current in the stable state as a stable current value.

Optionally, the method further includes:

adjusting the voltage of the motor controller to be less than the preset voltage;

acquiring a current value of a phase current of the motor;

and prompting that the phase current signal of the motor is invalid under the condition that the current value of the phase current is smaller than a preset second threshold value.

A current signal detecting device comprising:

the adjusting unit is used for adjusting the voltage of the motor controller to be not less than the preset voltage;

the trigger unit is used for triggering the motor controller to adjust the direct-axis current and the quadrature-axis current of the motor, so that the current value of the direct-axis current and the current value of the quadrature-axis current are different;

the first calculation unit is used for calculating and obtaining an estimated current value of the phase current based on the current value of the direct-axis current and the current value of the quadrature-axis current;

the second calculation unit is used for acquiring a steady-state current value of the phase current of the motor and calculating a difference value between the steady-state current value and an estimated current value;

and the first prompting unit is used for prompting that the phase current signal of the motor is invalid under the condition that the difference value between the steady-state current value and the estimated current value is determined to be not smaller than a preset first threshold value.

A computer-readable storage medium including a stored program, wherein the program executes the current signal detection method.

A motor controller comprising: a processor, a memory, and a bus; the processor and the memory are connected through the bus;

the memory is used for storing a program, and the processor is used for running the program, wherein the program is run for executing the current signal detection method.

The technical scheme that this application provided, with motor controller's voltage regulation for being not less than predetermineeing voltage, trigger motor controller and adjust the direct axis electric current and the quadrature axis electric current of motor for the current value of direct axis electric current and the current value mutually different of quadrature axis electric current. And calculating to obtain an estimated current value of the phase current based on the current value of the direct-axis current and the current value of the quadrature-axis current. And acquiring a steady-state current value of the phase current of the motor, and calculating a difference value between the steady-state current value and the estimated current value. And under the condition that the difference value between the steady-state current value and the estimated current value is not smaller than a preset first threshold value, prompting that the phase current signal of the motor is invalid. Therefore, by the method, the motor controller can be assisted to identify the invalid phase current signal without being modified.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic diagram of a current signal detection method according to an embodiment of the present disclosure;

FIG. 2 is a schematic diagram of another current signal detection method according to an embodiment of the present disclosure;

fig. 3 is a schematic structural diagram of a current signal detection device according to an embodiment of the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

The process described herein is applied to a motor system, and in particular, can be executed by a motor controller to assist the motor controller in identifying an invalid phase current signal without modifying the motor controller.

As shown in fig. 1, taking an example that a motor controller is applied to a whole vehicle, a schematic diagram of a current signal detection method provided in the embodiment of the present application includes the following steps:

s101: and regulating the voltage of the motor controller to be less than the preset voltage, and triggering the motor controller to regulate the rotating speed of the motor, so that the rotating speed of the motor is less than the preset rotating speed.

And when the voltage of the motor controller is smaller than the preset voltage, determining that the motor controller is in a low-voltage state. When the rotating speed of the motor is smaller than the preset rotating speed, the motor is determined to be in a locked-rotor state (the whole vehicle can be understood to be in a stationary state).

The whole vehicle comprises a motor system, and the motor system comprises a motor and a motor controller. Specifically, the motor controller is used for controlling the work of the motor, and the motion of the whole vehicle is provided by the motor, namely the motor and the motor controller jointly form a motion control system of the whole vehicle.

S102: and acquiring the current value of the phase current of the motor, and judging whether the current value of the phase current is smaller than a preset second threshold value.

If the current value of the phase current is smaller than the preset second threshold value, executing S103, otherwise, determining that the phase current signal of the motor is invalid, and executing S112.

Wherein the phase current comprises a U-phase current i_aPhase i of V-phase_bAnd W-phase current i_c. In practical applications, the current value of the phase current on the motor is usually detected by a current sensor.

It should be noted that, although an error occurs in the current value of the phase current due to adverse effects such as accuracy and null shift of the current sensor, the error is within a preset range, and when the error exceeds the preset range, it is determined that the current sensor is distorted, and at this time, the phase current signal collected by the current sensor is invalid. Therefore, if the current value of the phase current is not less than the preset second threshold, it can be determined that the error exceeds the preset range, and the phase current signal of the motor is invalid.

S103: and regulating the voltage of the motor controller to be not less than the preset voltage, and triggering the motor controller to regulate the rotating speed of the motor, so that the rotating speed of the motor is less than the preset rotating speed.

And when the voltage of the motor controller is not less than the preset voltage, determining that the motor controller is in a high-voltage state.

S104: the trigger motor controller adjusts direct-axis current and quadrature-axis current of the motor so that the current value of the direct-axis current is equal to a first value and the current value of the quadrature-axis current is equal to zero.

Wherein the direct axis is also called d axis, and the quadrature axis is also called q axis, which are actually coordinate axes rather than actual axes. In the control of the permanent magnet synchronous motor, in order to obtain the control characteristic similar to a direct current motor, a coordinate system is established on a motor rotor, the coordinate system and the rotor rotate synchronously, the direction of a rotor magnetic field is taken as a d axis, the direction vertical to the rotor magnetic field is taken as a q axis, and a mathematical model of the motor is converted into the coordinate system, so that the decoupling of d axis current and q axis current can be realized, and the good control characteristic can be obtained.

It should be noted that, when the current value of the direct-axis current is equal to the first value and the current value of the quadrature-axis current is equal to zero, the rotation speed of the motor does not change, that is, the motor is still in the locked-rotor state.

S105: and acquiring a steady-state current value of the phase current, and calculating a difference value between the steady-state current value and the first current value.

The first current value is a current value of the phase current calculated based on a current value (i.e., a first value) of the direct-axis current. In the embodiment of the present application, the process of calculating the current value of the obtained phase current based on the current value of the direct-axis current is as shown in formula (1).

In the formula (1), i_dRepresents the direct-axis current of the motor, and θ represents the rotor position of the motor (which can be understood as a constant, in the prior art, the measurement and control software is usually used to analyze the rotation signal of the rotor to obtain the rotor position).

It should be noted that the above formula (1) is derived based on the constraint condition that the phase current amplitude of the motor does not change. According to the constraint condition that the phase current amplitude of the motor is not changed, the current transformation relation between the synchronous rotation coordinate system and the natural coordinate system can be obtained, and as shown in the formula (2), the formula (2) is analyzed, so that the formula (1) can be obtained.

In the formula (2), i_qRepresenting the quadrature current of the motor.

Optionally, when the response time of the motor torque is longer than the preset time, it is determined that the phase current of the motor is in a steady state, and a current value of the phase current in the steady state is taken as a steady-state current value. Specifically, the response time of the motor torque of the whole vehicle is usually in the order of milliseconds, and when the response time is greater than 1s, it is determined that the phase current of the motor enters a steady state.

S106: and judging whether the difference value between the steady-state current value and the first current value is smaller than a preset first threshold value.

If the difference between the steady-state current value and the first current value is smaller than the preset first threshold, S107 is executed, otherwise S112 is executed.

It should be noted that, no matter whether the voltage controller is in the high-voltage state, the first current value is not affected, and it is determined whether a difference between the steady-state current value and the first current value is smaller than a preset first threshold, substantially, the steady-state current value is compared with the first current value, if the difference between the steady-state current value and the first current value is smaller than the preset first threshold, it is determined that the steady-state current value is real and valid, that is, the phase current signal is valid, and if the difference is not smaller than the preset first threshold, it is determined that the steady-state current value is not real and valid, that is, the phase. It follows that the present embodiment is able to assist the motor controller in identifying invalid phase current signals.

S107: and judging whether the steady-state current value is smaller than a preset second threshold value.

If the steady-state current value is smaller than the preset second threshold value, S108 is executed, otherwise, S112 is executed.

It should be noted that, although an error occurs in the current value of the phase current due to adverse effects such as accuracy and null shift of the current sensor, the error is within a preset range, and when the error exceeds the preset range, it is determined that the current sensor is distorted, and at this time, the phase current signal collected by the current sensor is invalid. Therefore, when the motor is in a high-voltage state, if the steady-state current value of the phase current is not less than the preset second threshold, it may be determined that the error exceeds the preset range, and the phase current signal of the motor is invalid, thereby assisting the motor controller to identify an invalid phase current signal.

S108: and triggering the motor controller to adjust the direct-axis current and the quadrature-axis current of the motor, so that the current value of the direct-axis current is equal to zero and the current value of the quadrature-axis current is equal to a second value.

After execution of S108, execution of S109 is continued.

It should be noted that, when the current value of the direct-axis current is equal to zero and the current value of the quadrature-axis current is equal to the second value, the rotation speed of the motor does not change, that is, the motor is still in the locked-rotor state.

S109: and acquiring a steady-state current value of the phase current, and calculating a difference value between the steady-state current value and the second current value.

The second current value is a current value of the phase current calculated based on a current value (i.e., a second value) of the quadrature axis current. In the embodiment of the present application, the process of calculating the current value of the obtained phase current based on the current value of the quadrature axis current is as shown in formula (3).

It should be noted that the above equation (3) is derived based on the constraint condition that the phase current amplitude of the motor does not change. According to the constraint condition that the phase current amplitude of the motor is not changed, the current transformation relation between the synchronous rotation coordinate system and the natural coordinate system can be obtained, and as shown in the formula (2), the formula (2) is analyzed, so that the formula (3) can be obtained.

S110: and judging whether the difference value between the steady-state current value and the second current value is smaller than a preset first threshold value.

If the difference between the steady-state current value and the second current value is smaller than the preset first threshold, S111 is executed, otherwise S112 is executed.

It should be noted that, no matter whether the voltage controller is in the high-voltage state, the second current value is not affected, and it is determined whether a difference between the steady-state current value and the second current value is smaller than a preset first threshold, substantially, the steady-state current value is compared with the second current value, if the difference between the steady-state current value and the second current value is smaller than the preset first threshold, it is determined that the steady-state current value is real and valid, that is, the phase current signal is valid, and if the difference is not smaller than the preset first threshold, it is determined that the steady-state current value is not real and valid, that is, the phase. It follows that the present embodiment is able to assist the motor controller in identifying invalid phase current signals.

S111: the phase current signal of the motor is determined to be valid.

S112: and prompting that the phase current signal of the motor is invalid.

In summary, with the method of the present embodiment, the motor controller can be assisted to identify the invalid phase current signal without modifying the motor controller.

It should be noted that, in the above embodiments, the above-mentioned S101 and S102 are used for verifying the phase current signal of the motor with respect to the voltage controller in the voltage state, and since the voltage controller is a power device with high voltage and low voltage coexisting, the S101 and S102 may be regarded as an optional implementation manner of the current signal detection method described in this application. In addition, S104 and S108 mentioned in the above embodiments are also an optional implementation manner of the current signal detection method described in this application. For this reason, the flow mentioned in the above embodiment can be summarized as the method shown in fig. 2.

As shown in fig. 2, a schematic diagram of another current signal detection method provided in the embodiment of the present application includes the following steps:

s201: the voltage of the motor controller is regulated to be not less than a preset voltage.

S202: the trigger motor controller adjusts direct-axis current and quadrature-axis current of the motor so that current values of the direct-axis current and the quadrature-axis current are different from each other.

S203: and calculating to obtain an estimated current value of the phase current based on the current value of the direct-axis current and the current value of the quadrature-axis current.

The first current value and the second current value mentioned in the above embodiments are a specific implementation manner of the estimated current value.

S204: and acquiring a steady-state current value of the phase current of the motor, and calculating a difference value between the steady-state current value and the estimated current value.

S205: and under the condition that the difference value between the steady-state current value and the estimated current value is not smaller than a preset first threshold value, prompting that the phase current signal of the motor is invalid.

In summary, with the method of the present embodiment, the motor controller can be assisted to identify the invalid phase current signal without modifying the motor controller.

Corresponding to the current signal detection method provided by the embodiment of the application, the application also provides a current signal detection device.

As shown in fig. 3, a schematic structural diagram of a current signal detecting device provided in an embodiment of the present application includes:

and an adjusting unit 100 for adjusting the voltage of the motor controller to be not less than a preset voltage.

The trigger unit 200 is configured to trigger the motor controller to adjust a direct-axis current and a quadrature-axis current of the motor, so that a current value of the direct-axis current and a current value of the quadrature-axis current are different from each other.

The trigger unit 200 is specifically configured to: triggering a motor controller to adjust direct-axis current and quadrature-axis current of a motor, so that the current value of the direct-axis current is equal to a first numerical value and the current value of the quadrature-axis current is equal to zero; or triggering the motor controller to adjust the direct-axis current and the quadrature-axis current of the motor, so that the current value of the direct-axis current is equal to zero and the current value of the quadrature-axis current is equal to a second value.

The first calculating unit 300 is configured to calculate an estimated current value of the phase current based on a current value of the direct-axis current and a current value of the quadrature-axis current. The estimated current value includes a first current value and a second current value, the first current value is a current value of the phase current calculated based on the first value, and the second current value is a current value of the phase current calculated based on the second value.

The second calculating unit 400 is configured to obtain a steady-state current value of the phase current of the motor, and calculate a difference between the steady-state current value and the estimated current value.

The specific process of the second calculating unit 400 for obtaining the steady-state current value of the phase current of the motor includes: and under the condition that the response time of the motor torque is longer than the preset time, determining that the phase current of the motor is in a stable state, and taking the current value of the phase current in the stable state as a stable current value.

The second computing unit 400 is specifically configured to: and under the condition that the steady-state current value is smaller than the preset second threshold value, calculating the difference value between the steady-state current value and the estimated current value.

The first prompting unit 500 is configured to prompt that a phase current signal of the motor is invalid when a difference value between the steady-state current value and the estimated current value is determined to be not smaller than a preset first threshold.

And the second prompting unit 600 is used for prompting that the phase current signal of the motor is invalid under the condition that the steady-state current value is determined to be smaller than the preset second threshold value.

And a third prompting unit 700, configured to adjust a voltage of the motor controller to be smaller than a preset voltage, obtain a current value of a phase current of the motor, and prompt that a phase current signal of the motor is invalid when it is determined that the current value of the phase current is smaller than a preset second threshold.

In summary, with the method of the present embodiment, the motor controller can be assisted to recognize the invalid phase current signal without modifying the motor controller.

The present application also provides a computer-readable storage medium including a stored program, wherein the program performs the current signal detection method provided by the present application.

The present application further provides a motor controller, including: a processor, a memory, and a bus. The processor is connected with the memory through a bus, the memory is used for storing programs, the processor is used for running the programs, and when the programs are run, the current signal detection method provided by the application is executed, and the method comprises the following steps:

adjusting the voltage of the motor controller to be not less than a preset voltage;

triggering the motor controller to adjust the direct axis current and the quadrature axis current of the motor, so that the current value of the direct axis current and the current value of the quadrature axis current are different;

calculating to obtain an estimated current value of the phase current based on the current value of the direct-axis current and the current value of the quadrature-axis current;

acquiring a steady-state current value of the phase current of the motor, and calculating a difference value between the steady-state current value and an estimated current value;

and prompting that the phase current signal of the motor is invalid under the condition that the difference value between the steady-state current value and the estimated current value is not smaller than a preset first threshold value.

Optionally, the triggering the motor controller to adjust a direct-axis current and a quadrature-axis current of the motor, so that a current value of the direct-axis current and a current value of the quadrature-axis current are different from each other, includes:

triggering the motor controller to adjust the direct axis current and the quadrature axis current of the motor, so that the current value of the direct axis current is equal to a first numerical value, and the current value of the quadrature axis current is equal to zero;

alternatively, the first and second electrodes may be,

and triggering the motor controller to adjust the direct-axis current and the quadrature-axis current of the motor, so that the current value of the direct-axis current is equal to zero and the current value of the quadrature-axis current is equal to a second numerical value.

Optionally, the estimated current value includes a first current value;

the first current value is a current value of the phase current calculated based on the first numerical value.

Optionally, the estimated current value includes a second current value;

the second current value is a current value of the phase current calculated based on the second numerical value.

Optionally, the calculating the difference between the steady-state current value and the estimated current value includes:

under the condition that the steady-state current value is smaller than a preset second threshold value, calculating a difference value between the steady-state current value and an estimated current value;

the method further comprises the following steps:

and prompting that the phase current signal of the motor is invalid under the condition that the steady-state current value is determined to be smaller than the preset second threshold value.

Optionally, the obtaining the steady-state current value of the phase current of the motor includes:

and under the condition that the response time of the motor torque is longer than the preset time, determining that the phase current of the motor is in a stable state, and taking the current value of the phase current in the stable state as a stable current value.

Optionally, the method further includes:

adjusting the voltage of the motor controller to be less than the preset voltage;

acquiring a current value of a phase current of the motor;

and prompting that the phase current signal of the motor is invalid under the condition that the current value of the phase current is smaller than a preset second threshold value.

The functions described in the method of the embodiment of the present application, if implemented in the form of software functional units and sold or used as independent products, may be stored in a storage medium readable by a computing device. Based on such understanding, part of the contribution to the prior art of the embodiments of the present application or part of the technical solution may be embodied in the form of a software product stored in a storage medium and including several instructions for causing a computing device (which may be a personal computer, a server, a mobile computing device or a network device) to execute all or part of the steps of the method described in the embodiments of the present application. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.

The embodiments are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same or similar parts among the embodiments are referred to each other.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.