阅读说明：本技术 电机制动方法、洗衣机、计算机可读存储介质 (Motor braking method, washing machine, and computer-readable storage medium ) 是由 王凯 任敬芝 杨湘木 曾锦泉 于 2021-09-03 设计创作，主要内容包括：本发明公开了一种电机制动方法、洗衣机、计算机可读存储介质。其中电机制动方法,包括：基于电机的反电动势获取电机的电压偏差值；将所述电压偏差值作为PI调节器的输入量；基于PI调节器的输出量来输出对应的电参数对电机进行控制,直至电机停机。本发明使得电机的转速平滑下降,既可以缩短电机制动的时间,又可以确保电机运行的稳定性。(The invention discloses a motor braking method, a washing machine and a computer readable storage medium. The motor braking method comprises the following steps: acquiring a voltage deviation value of the motor based on the back electromotive force of the motor; taking the voltage deviation value as the input quantity of a PI regulator; and outputting corresponding electrical parameters to control the motor based on the output quantity of the PI regulator until the motor stops. The invention enables the rotating speed of the motor to be smoothly reduced, not only can shorten the braking time of the motor, but also can ensure the running stability of the motor.)

1. A method of braking an electric machine, comprising:

acquiring a voltage deviation value of the motor based on the back electromotive force of the motor;

taking the voltage deviation value as the input quantity of a PI regulator;

and outputting corresponding electrical parameters to control the motor based on the output quantity of the PI regulator until the motor stops.

2. The motor braking method of claim 1, wherein the PI regulator is an incremental PI regulator.

3. The motor braking method of claim 2, wherein the obtaining the voltage deviation value of the motor based on the back electromotive force of the motor specifically comprises:

sampling the current back electromotive force of the motor;

and respectively subtracting the reference level from the back electromotive force obtained by the last two times of sampling to obtain the voltage deviation value of the last two times of sampling.

4. A method of braking an electric motor as claimed in claim 3, characterised in that the expression of the incremental PI regulator is，

Δ f (k) is the output quantity of the incremental PI regulator, E (k) is the current voltage deviation value, E (k-1) is the previous voltage deviation value, Kp is the proportional coefficient, and Ki is the integral coefficient.

5. The motor braking method of claim 3, wherein the sampling is two samples of the current back EMF of the motor.

6. The motor braking method according to claim 1, wherein the outputting of the corresponding electrical parameter based on the output of the PI regulator to control the motor specifically comprises:

subtracting the reference level from the back electromotive force obtained by the latest sampling of the motor, and adding the output quantity of the PI regulator to obtain an output result;

comparing the output result with a reference value;

and when the output result is greater than the reference value, controlling the motor by adopting the phase and the duty ratio of the brake torque increasing state, otherwise, controlling the motor by sampling the phase and the duty ratio of the brake torque decreasing state.

7. The motor braking method according to claim 6, wherein the duty ratio of the braking torque increase is obtained by a formula of 100% - (X1-X0)/K, wherein X1 is the output result, X0 is the reference value, and K is an empirical value of voltage.

8. The motor braking method according to claim 6, characterized in that the duty cycle of the braking torque reduction state is specifically 100%.

9. The motor braking method of claim 1, further comprising: the method comprises the steps of thickening the outer diameter of a bus of the motor to be larger than or equal to an outer diameter threshold value, increasing the capacitance of a capacitor on the bus of the motor to be a capacitance threshold value, increasing an energy consumption resistor and consuming the energy of the motor in at least one mode of a relay which can connect the energy consumption resistor and the bus.

10. A washing machine comprising a controller, a motor controlled by the controller, wherein the controller controls braking of the motor by using the motor braking method according to any one of claims 1 to 8.

11. A computer-readable storage medium for storing a computer program, wherein the computer program is operative to perform a motor braking method according to any one of claims 1 to 8.

Technical Field

The invention relates to the technical field of motor control, in particular to a motor braking method.

Background

With the progress of new technologies and the application of new technologies, the manufacturing level of clothes treatment devices, such as washing machines, is continuously improved, and meanwhile, under the driving of innovation taking user requirements as starting points, intelligent washing and protection, healthy washing and protection and convenient washing and protection are more and more emphasized.

However, if the dewatering process of the washing machine does not have a braking function, namely the rotating speed of the motor is freely reduced after the program of the washing machine is completed, the braking speed of the motor is relatively long due to inertia, and in consideration of safety reasons, the motor of some washing machines cannot be opened when the speed of the motor is reduced to the safe rotating speed, so that the door opening time is relatively long after the program operation is completed, and inconvenience is brought to users. And the motor can produce the counter electromotive force when moving, and the counter electromotive force that the rotational speed is big produced is also big more, if when high-speed dehydration, washing machine judges that the lock is opened unusually, and the motor can't slow down, then can bring great potential safety hazard.

The braking control method of the variable frequency motor of the washing machine provided in the prior art is characterized in that the braking is carried out by suddenly cutting off the power supply, and the rotating speed of the motor is gradually reduced in a deceleration level increasing mode after the washing machine is dehydrated at a high speed, so that the speed reduction of the motor is not smooth enough and the noise is large.

Disclosure of Invention

The invention provides a motor braking method, a washing machine and a computer readable storage medium, aiming at solving the technical problem that motor braking is not smooth enough in the prior art.

The invention provides a motor braking method, which comprises the following steps:

acquiring a voltage deviation value of the motor based on the back electromotive force of the motor;

taking the voltage deviation value as the input quantity of a PI regulator;

and outputting corresponding electrical parameters to control the motor based on the output quantity of the PI regulator until the motor stops.

Further, the PI regulator is an incremental PI regulator.

Further, the obtaining of the voltage deviation value of the motor based on the back electromotive force of the motor specifically includes:

sampling the current back electromotive force of the motor;

and respectively subtracting the reference level from the back electromotive force obtained by the last two times of sampling to obtain the voltage deviation value of the last two times of sampling.

Further, the expression of the incremental PI regulator isΔ f (k) is the output quantity of the incremental PI regulator, E (k) is the current voltage deviation value, E (k-1) is the previous voltage deviation value, Kp is the proportional coefficient, and Ki is the integral coefficient.

Further, the sampling is to sample the current back electromotive force of the motor twice.

Further, the outputting a corresponding electrical parameter based on the output quantity of the PI regulator to control the motor specifically includes:

subtracting the reference level from the back electromotive force obtained by the latest sampling of the motor, and adding the output quantity of the PI regulator to obtain an output result;

comparing the output result with a reference value;

and when the output result is greater than the reference value, controlling the motor by adopting the phase and the duty ratio of the brake torque increasing state, otherwise, controlling the motor by sampling the phase and the duty ratio of the brake torque decreasing state.

Further, the duty ratio of the brake torque increase is obtained by a formula of 100% - (X1-X0)/K, wherein X1 is the output result, X0 is the reference value, and K is an empirical voltage value.

Further, the duty ratio of the braking torque reduction state is specifically 100%.

The washing machine provided by the invention comprises a controller and a motor controlled by the controller, wherein the controller adopts the motor braking method in the technical scheme to control the braking of the motor.

The computer-readable storage medium is used for storing a computer program, and the computer program executes the motor braking method in the above technical scheme when running.

Further, the motor braking method of the present invention further includes: the method comprises the steps of thickening the outer diameter of a bus of the motor to be larger than or equal to an outer diameter threshold value, increasing the capacitance of a capacitor on the bus of the motor to be a capacitance threshold value, increasing an energy consumption resistor and consuming the energy of the motor in at least one mode of a relay which can connect the energy consumption resistor and the bus.

The invention adopts increment type PI regulation, inputs voltage deviation signals and outputs PWM control signals with different pulse phases and pulse duty ratios, so that the washing machine can self-adaptively regulate a braking mode, realizes the continuous, automatic and real-time switching of the braking mode of the washing machine, ensures the safety and stability of the high-speed operation of the washing machine and the reliability of braking control, ensures the user experience, solves the problems of long door opening time and inconvenience for users after the program operation of the washing machine is finished, and also solves the potential safety hazard caused by the fact that a motor cannot decelerate during high-speed dehydration.

Drawings

The invention is described in detail below with reference to examples and figures, in which:

FIG. 1 is a flow chart of an embodiment of the present invention.

Detailed Description

In order to make the technical problems, technical solutions and advantageous effects to be solved by the present invention more clearly apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Thus, a feature indicated in this specification will serve to explain one of the features of one embodiment of the invention, and does not imply that every embodiment of the invention must have the stated feature. Further, it should be noted that this specification describes many features. Although some features may be combined to show a possible system design, these features may also be used in other combinations not explicitly described. Thus, the combinations illustrated are not intended to be limiting unless otherwise specified.

The principles of the present invention will be described in detail below with reference to the accompanying drawings and embodiments.

As shown in fig. 1, in the motor braking method of the present invention, a voltage deviation value of the motor is obtained based on the back electromotive force of the motor, the voltage deviation value is used as an input quantity of the PI regulator, and finally, a corresponding electrical parameter is output based on an output quantity of the PI regulator to control the motor until the motor is stopped.

The PI regulator adopts the incremental PI regulator, so that the voltage deviation value of the motor at the last two times needs to be obtained, the current counter electromotive force of the motor needs to be sampled firstly when the voltage deviation value of the motor is obtained based on the counter electromotive force of the motor, in one embodiment, the counter electromotive force of the motor at the two times only needs to be sampled when the motor is ready to brake, and the method can obtain the result only by keeping the deviation value at the last 2 times, so that the stability of the system is greatly improved. In other embodiments, the back emf of the motor may be sampled periodically and the back emf sampled the last two times is selected. And then subtracting the reference level from the back electromotive force obtained by the last two times of sampling respectively to obtain the voltage deviation value of the last two times of sampling. The reference level of the present invention is obtained from the development experience of the skilled person and/or the experimental data related to the corresponding model of motor.

And taking the voltage deviation value of the last two times of sampling as the input quantity of the incremental PI regulator. The expression for the incremental PI regulator isWherein Δ f (k) is the output of the incremental PI regulator, E (k) is the current voltage deviation value, E (k-1) is the previous voltage deviation value, Kp is the proportional coefficient, and Ki is the integral coefficient. The PI control of the incremental PI regulator is actually a control process for the deviation. If the deviation is 0, the proportional link does not work, and only if the deviation exists, the proportional link works. The integration step is mainly used for eliminating the static error, namely the difference between the output value and the set value after the system is stabilized, and the integration step is actually the process of deviation accumulation, and the accumulated error is added to the original system to counteract the static error caused by the system.

The output quantity of the incremental PI regulator can be obtained through the expression, the output quantity of the incremental PI regulator is added with the current voltage deviation value to obtain an output result, namely the back electromotive force obtained by the last sampling of the motor is subtracted from a reference level, the output quantity of the PI regulator is added to obtain an output result, the output result is compared with a reference value, when the output result is larger than the reference value, the motor is controlled by adopting the phase and duty ratio of the brake torque increasing state, and otherwise, the phase and duty ratio of the brake torque decreasing state are adopted for control.

Specifically, when the output result is greater than the reference value, the motor is controlled by using the a-type duty ratio, where the a-type duty ratio =100% - (X1-X0)/K, X1 is the output result, that is, the output result obtained by adding the output quantity of the incremental PI regulator to the current voltage deviation value, X0 is the reference value, and K is the voltage empirical value, in a specific embodiment, the value of K may be 400 according to the empirical value, which means that the input voltage of the motor is higher at this time, and the input voltage of the motor needs to be further reduced. When the output result is light rain equal to the reference value, the motor is controlled by using the B-type duty ratio, and the B-type duty ratio =100%, which means that the input voltage of the motor is not very high at this time.

The principle of the duty ratio of the braking torque increasing state and the duty ratio of the braking torque decreasing state can be explained by the following formulas.

The formula of the braking torque of the motor is。

Derived from the result of the derivation。

In the above formula, Te is the electromagnetic torque of the motor,the derivation of Te, wherein Ki is the electromagnetic torque coefficient; ke is the electromotive force coefficient; w is the rotating speed of the motor,derivation for the motor speed; d is the duty cycle of the pulse width modulation,is the derivation of the duty cycle; ud is the supply voltage. When in useWhen is at timeThe duty ratio of the brake torque increasing state, i.e., the type a duty ratio is used. When in useWhen is at timeThe duty ratio in the braking torque reduction state, i.e., the B-type duty ratio is used.

The invention also protects a washing machine, which comprises a controller and a motor controlled by the controller, wherein the controller adopts the motor braking method in the technical scheme to control the braking of the motor. Meanwhile, because the motor braking method is mainly realized through a computer program, the invention also protects a computer readable storage medium for storing the computer program, and when the computer program runs, the motor braking method in the technical scheme is executed.

The invention adopts the braking method to brake and control the motor, and simultaneously can also adopt at least one mode of thickening the outer diameter of the bus of the motor to be more than or equal to the outer diameter threshold value, increasing the capacitance of the capacitor on the bus of the motor to be the capacitance threshold value, increasing the energy consumption resistor and a relay which can connect the energy consumption resistor and the bus to consume the energy of the motor, thereby ensuring the stability and the reliability of the motor braking. That is to say, except the above-mentioned form that adopts software, utilize corresponding logic to reach the braking deceleration to the motor, can also select to add thick generating line, improve the withstand voltage value of generating line, increase the corresponding electric capacity on the generating line, can be with the unnecessary energy consumption of motor like this, still add corresponding resistance and relay of consuming energy on the generating line, control the relay during braking, connect resistance of consuming energy to the circuit, form the return circuit, consume the energy of motor.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.