阅读说明：本技术 永磁同步电机的启动方法、装置及电机 (Starting method and device of permanent magnet synchronous motor and motor ) 是由 唐婷婷 王声纲 朱绯 任艳华 潘军 陈跃 杨正 王璠 于 2019-11-05 设计创作，主要内容包括：本发明提供了一种永磁同步电机的启动方法、装置及电机,在接收到上位机发送的启动指令时,采用电流闭环、速度开环的方式对所述永磁同步电机进行第一控制；在进行所述第一控制的时长达到设定时间阈值时,采用电流闭环、速度闭环的方式对所述永磁同步电机进行第二控制。本方案,在接收到启动指令时,采用电流闭环给电机一个电流,让转子开始转起来,在达到设定时间阈值时,转子会有一个转动的惯性,此时,直接切换到速度闭环对电极进行控制,省去了定位时间,从而可以快速实现永磁同步电机的启动。(The invention provides a starting method and a starting device of a permanent magnet synchronous motor and the motor, wherein when a starting instruction sent by an upper computer is received, the permanent magnet synchronous motor is subjected to first control in a current closed loop and speed open loop mode; and when the duration of the first control reaches a set time threshold, performing second control on the permanent magnet synchronous motor in a current closed-loop and speed closed-loop mode. According to the scheme, when a starting instruction is received, the current closed loop is adopted to supply the current to the motor, the rotor starts to rotate, when a set time threshold is reached, the rotor has rotating inertia, at the moment, the speed closed loop is directly switched to control the electrode, the positioning time is saved, and therefore the permanent magnet synchronous motor can be quickly started.)

1. A starting method of a permanent magnet synchronous motor is characterized by comprising the following steps:

when a starting instruction sent by an upper computer is received, performing first control on the permanent magnet synchronous motor in a current closed-loop and speed open-loop mode;

and when the duration of the first control reaches a set time threshold, performing second control on the permanent magnet synchronous motor in a current closed-loop and speed closed-loop mode.

2. The starting method of a permanent magnet synchronous motor according to claim 1,

the starting instruction carries acceleration and a target rotating speed;

adopt the mode of electric current closed loop, speed closed loop to control PMSM includes: when the acceleration is greater than a first rotating speed, a rotating speed command starts from an initial speed value, and the rotating speed is increased once every set time interval until the permanent magnet synchronous motor reaches the target rotating speed; when the acceleration is not greater than the first rotating speed, a rotating speed command starts from an initial speed value, and the rotating speed of a set step length is increased every time until the permanent magnet synchronous motor reaches the target rotating speed; and the error value of the rotating speed command and the rotating speed feedback is used as the input end of the speed PI loop regulation.

3. The method of starting a permanent magnet synchronous motor according to claim 2,

further comprising: determining a current working mode of the washing machine, wherein the working mode comprises a washing mode or a dehydration mode;

when the working mode is a washing mode, if the current rotating speed corresponding to the rotating speed command is less than or equal to a second rotating speed, the initial speed value of the rotating speed command is the second rotating speed, and if the current rotating speed corresponding to the rotating speed command is greater than the second rotating speed, the initial speed value of the rotating speed command is the current rotating speed;

and when the working mode is the dehydration mode, if the current rotating speed corresponding to the rotating speed command is less than or equal to a third rotating speed, the initial speed value of the rotating speed command is the third rotating speed, and if the current rotating speed corresponding to the rotating speed command is greater than the third rotating speed, the initial speed value of the rotating speed command is the current rotating speed.

4. The method of claim 3, wherein the second rotational speed is greater than the third rotational speed.

5. A starting apparatus of a permanent magnet synchronous motor, comprising:

the first control unit is used for performing first control on the permanent magnet synchronous motor in a current closed loop and speed open loop mode when receiving a starting instruction sent by an upper computer;

and the second control unit is used for performing second control on the permanent magnet synchronous motor in a current closed-loop and speed closed-loop mode when the duration of the first control reaches a set time threshold.

6. The starting apparatus of a permanent magnet synchronous motor according to claim 5,

the starting instruction carries acceleration and a target rotating speed;

the second control unit is specifically configured to, when the acceleration is greater than the first rotation speed, instruct a rotation speed command to increase the rotation speed once every set time interval from an initial speed value until the permanent magnet synchronous motor reaches the target rotation speed; when the acceleration is not greater than the first rotating speed, a rotating speed command starts from an initial speed value, and the rotating speed of a set step length is increased every time until the permanent magnet synchronous motor reaches the target rotating speed; and the error value of the rotating speed command and the rotating speed feedback is used as the input end of the speed PI loop regulation.

7. The starting apparatus of a permanent magnet synchronous motor according to claim 6,

further comprising: a mode determining unit for determining a current operation mode of the washing machine, the operation mode including a washing mode or a dehydrating mode;

when the working mode is a washing mode, if the current rotating speed corresponding to the rotating speed command is less than or equal to a second rotating speed, the initial speed value of the rotating speed command is the second rotating speed, and if the current rotating speed corresponding to the rotating speed command is greater than the second rotating speed, the initial speed value of the rotating speed command is the current rotating speed;

and when the working mode is the dehydration mode, if the current rotating speed corresponding to the rotating speed command is less than or equal to a third rotating speed, the initial speed value of the rotating speed command is the third rotating speed, and if the current rotating speed corresponding to the rotating speed command is greater than the third rotating speed, the initial speed value of the rotating speed command is the current rotating speed.

8. The PMSM startup device of claim 7, wherein the second rotational speed is greater than the third rotational speed.

9. An electric machine, comprising: a starting apparatus of a permanent magnet synchronous machine according to any of claims 5 to 8.

10. A pulsator washing machine, comprising: the electric machine of claim 9.

Technical Field

The invention relates to the technical field of motor control, in particular to a starting method and device of a permanent magnet synchronous motor and the motor.

Background

When the permanent magnet synchronous motor operates, the actual speed and the position of a rotor need to be detected to realize the commutation of a winding, generally, the speed and the position of the rotor are estimated by detecting the back electromotive force or the harmonic wave of the motor, however, when the permanent magnet synchronous motor is at zero speed or low speed, the back electromotive force is small and difficult to detect, so that the permanent magnet synchronous motor needs to be started by adopting a special method when being started.

The conventional starting method is divided into the following processes:

1. initial positioning of a rotor: energizing a direct current to the motor winding such that the rotor is positioned at an angle;

2. speed open loop (current closed loop) control: while the electronic winding is conducted in sequence according to a preset phase sequence by using the current with a preset amplitude, the commutation frequency is gradually increased, and the motor is accelerated to a set rotating speed (also called as a synchronous operation mode);

3. speed open closed loop switching to speed closed loop (current closed loop): when the commutation frequency is larger than a preset value, namely sufficient back electromotive force exists, the speed is switched to speed closed-loop control (also called a sensorless operation mode), and the starting of the permanent magnet synchronous motor is completed.

Disclosure of Invention

The embodiment of the invention provides a method and a device for starting a permanent magnet synchronous motor and the motor, so as to realize the starting rapidity of the permanent magnet synchronous motor.

In a first aspect, the present invention provides a method for starting a permanent magnet synchronous motor, including:

when a starting instruction sent by an upper computer is received, performing first control on the permanent magnet synchronous motor in a current closed-loop and speed open-loop mode;

and when the duration of the first control reaches a set time threshold, performing second control on the permanent magnet synchronous motor in a current closed-loop and speed closed-loop mode.

Preferably, the first and second electrodes are formed of a metal,

the starting instruction carries acceleration and a target rotating speed;

adopt the mode of electric current closed loop, speed closed loop to control PMSM includes: when the acceleration is greater than a first rotating speed, a rotating speed command starts from an initial speed value, and the rotating speed is increased once every set time interval until the permanent magnet synchronous motor reaches the target rotating speed; when the acceleration is not greater than the first rotating speed, a rotating speed command starts from an initial speed value, and the rotating speed of a set step length is increased every time until the permanent magnet synchronous motor reaches the target rotating speed; and the error value of the rotating speed command and the rotating speed feedback is used as the input end of the speed PI loop regulation.

Preferably, the first and second electrodes are formed of a metal,

further comprising: determining a current working mode of the washing machine, wherein the working mode comprises a washing mode or a dehydration mode;

when the working mode is a washing mode, if the current rotating speed corresponding to the rotating speed command is less than or equal to a second rotating speed, the initial speed value of the rotating speed command is the second rotating speed, and if the current rotating speed corresponding to the rotating speed command is greater than the second rotating speed, the initial speed value of the rotating speed command is the current rotating speed;

and when the working mode is the dehydration mode, if the current rotating speed corresponding to the rotating speed command is less than or equal to a third rotating speed, the initial speed value of the rotating speed command is the third rotating speed, and if the current rotating speed corresponding to the rotating speed command is greater than the third rotating speed, the initial speed value of the rotating speed command is the current rotating speed.

Preferably, the second rotational speed is greater than the third rotational speed.

In a second aspect, the present invention provides a starting apparatus for a permanent magnet synchronous motor, including:

the first control unit is used for performing first control on the permanent magnet synchronous motor in a current closed loop and speed open loop mode when receiving a starting instruction sent by an upper computer;

and the second control unit is used for performing second control on the permanent magnet synchronous motor in a current closed-loop and speed closed-loop mode when the duration of the first control reaches a set time threshold.

Preferably, the first and second electrodes are formed of a metal,

the starting instruction carries acceleration and a target rotating speed;

the second control unit is specifically configured to, when the acceleration is greater than the first rotation speed, instruct a rotation speed command to increase the rotation speed once every set time interval from an initial speed value until the permanent magnet synchronous motor reaches the target rotation speed; when the acceleration is not greater than the first rotating speed, a rotating speed command starts from an initial speed value, and the rotating speed of a set step length is increased every time until the permanent magnet synchronous motor reaches the target rotating speed; and the error value of the rotating speed command and the rotating speed feedback is used as the input end of the speed PI loop regulation.

Preferably, the first and second electrodes are formed of a metal,

further comprising: a mode determining unit for determining a current operation mode of the washing machine, the operation mode including a washing mode or a dehydrating mode;

when the working mode is a washing mode, if the current rotating speed corresponding to the rotating speed command is less than or equal to a second rotating speed, the initial speed value of the rotating speed command is the second rotating speed, and if the current rotating speed corresponding to the rotating speed command is greater than the second rotating speed, the initial speed value of the rotating speed command is the current rotating speed;

and when the working mode is the dehydration mode, if the current rotating speed corresponding to the rotating speed command is less than or equal to a third rotating speed, the initial speed value of the rotating speed command is the third rotating speed, and if the current rotating speed corresponding to the rotating speed command is greater than the third rotating speed, the initial speed value of the rotating speed command is the current rotating speed.

Preferably, the second rotational speed is greater than the third rotational speed.

In a third aspect, the present invention provides an electric machine comprising: a starting apparatus for a permanent magnet synchronous motor according to any of the preceding claims.

In a fourth aspect, the present invention provides a pulsator washing machine, comprising: the motor is described above.

The embodiment of the invention provides a starting method and device of a permanent magnet synchronous motor and the motor, wherein when a starting instruction sent by an upper computer is received, the permanent magnet synchronous motor is subjected to first control in a current closed loop and speed open loop mode; when the duration of the first control reaches a set time threshold, the permanent magnet synchronous motor is controlled in a current closed loop and speed closed loop mode, when a starting instruction is received, the current closed loop is adopted to supply current to the motor, the rotor starts to rotate, when the set time threshold is reached, the rotor has rotating inertia, and at the moment, the speed closed loop is directly switched to control the electrode, so that the positioning time is saved, and the permanent magnet synchronous motor can be quickly started.

Drawings

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

FIG. 1 is a flow chart of a boot method provided by one embodiment of the present invention;

FIG. 2 is a schematic structural diagram of an actuating apparatus according to an embodiment of the present invention;

FIG. 3 is a schematic structural diagram of another starting apparatus provided in an embodiment of the present invention;

fig. 4 is a control block diagram of a permanent magnet synchronous motor according to an embodiment of the present invention;

fig. 5 is a flowchart of another startup method according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer and more complete, the technical solutions in the embodiments of the present invention will be described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention, and based on the embodiments of the present invention, all other embodiments obtained by a person of ordinary skill in the art without creative efforts belong to the scope of the present invention.

As shown in fig. 1, an embodiment of the present invention provides a method for starting a permanent magnet synchronous motor, where the method may include the following steps:

step 01, when a starting instruction sent by an upper computer is received, performing first control on the permanent magnet synchronous motor in a current closed loop and speed open loop mode;

and 02, when the time length for performing the first control reaches a set time threshold, performing second control on the permanent magnet synchronous motor in a current closed-loop and speed closed-loop mode.

In the embodiment of the invention, when a starting instruction is received, a current is supplied to the motor by adopting a current closed loop, so that the rotor starts to rotate, when a set time threshold is reached, the rotor has a rotating inertia, and at the moment, the speed closed loop is directly switched to control the electrode, so that the positioning time is saved, and the starting of the permanent magnet synchronous motor can be quickly realized.

In one embodiment of the invention, because the operating modes of the washing machine are different and the accelerations sent by the upper computer are also different, in the second control stage, the speed open loop is switched to the speed closed loop, if the fluctuation of the speed amplitude is large, the starting success rate is reduced, therefore, in order to make the starting smoother, the increasing modes of the rotating speed command are different according to different accelerations, wherein the starting command carries the acceleration and the target rotating speed;

adopt the mode of electric current closed loop, speed closed loop to control PMSM includes: when the acceleration is greater than a first rotating speed, a rotating speed command starts from an initial speed value, and the rotating speed is increased once every set time interval until the permanent magnet synchronous motor reaches the target rotating speed; when the acceleration is not greater than the first rotating speed, a rotating speed command starts from an initial speed value, and the rotating speed of a set step length is increased every time until the permanent magnet synchronous motor reaches the target rotating speed; and the error value of the rotating speed command and the rotating speed feedback is used as the input end of the speed PI loop regulation.

Preferably, the first rotation speed ω₁Can be 400-600 rpm; the set time period is 3-7 ms; the set step length is 0.5-1.5 revolutions per minute.

Assume that the initial velocity value is ω₀First rotational speed ω₁500 rpm, a set time period of 5ms, and a set step size of 1 rpm, if the acceleration carried by the start command is greater than 500 rpm, the rotation speed command is from the initial speed value ω₀Initially, the rotation speed command is increased once every 5ms, wherein the rotation speed of each increase can be 0.5-1.5 rpm, for example, 1 rpm, and at 5ms, the rotation speed command is ω₀+1, 10ms, the speed command is ω₀+2 … … repeating until the permanent magnet synchronous motor reaches the target rotation speed; if the acceleration carried by the start command is not greater than 500 revolutions per minute, then the speed command ω₀At the beginning, when the rotation speed of the permanent magnet synchronous motor reaches omega₀Then increase 1 revolution, the rotation speed command is omega₀+1, when the rotation speed of the permanent magnet synchronous motor reaches omega₀When +1, increase 1 rotation, the rotation speed command is omega₀+2, when the rotation speed of the permanent magnet synchronous motor reaches omega₀At +2, the rotation speed is increased by 1 revolution again and the rotation speed command is omega₀+3……, until the PMSM reaches the target speed.

Therefore, the speed change of the permanent magnet synchronous motor can be ensured to be smooth in the speed closed-loop control process, the starting process of the permanent magnet synchronous motor is smoother, and the starting success rate is improved.

Wherein the rotational speed feedback can be estimated by estimating the back emf.

In an embodiment of the present invention, since the user selects different operation modes of the washing machine, the upper computer may generate different accelerations, and the position estimation algorithm is inaccurate in estimating at a low speed, in order to ensure successful start of the permanent magnet synchronous motor, the method further includes, when entering the second control stage: determining a current working mode of the washing machine, wherein the working mode comprises a washing mode or a dehydration mode;

when the working mode is a washing mode, if the current rotating speed corresponding to the rotating speed command is less than or equal to a second rotating speed, the initial speed value of the rotating speed command is the second rotating speed, and if the current rotating speed corresponding to the rotating speed command is greater than the second rotating speed, the initial speed value of the rotating speed command is the current rotating speed;

and when the working mode is the dehydration mode, if the current rotating speed corresponding to the rotating speed command is less than or equal to a third rotating speed, the initial speed value of the rotating speed command is the third rotating speed, and if the current rotating speed corresponding to the rotating speed command is greater than the third rotating speed, the initial speed value of the rotating speed command is the current rotating speed.

After the speed open loop is switched to the speed closed loop, the rotating speed commands are accumulated from 0, and if the rotating speed commands are at the initial stage of the speed closed loop, the current rotating speed corresponding to the rotating speed commands is less than or equal to a second rotating speed omega according to the washing mode or the dehydration mode of the washing machine₂Or third rotational speed ω₃Then the initial speed value of the speed command is ω₂Or ω₃Otherwise, the initial speed value of the rotating speed command is the current rotating speed.

In one embodiment of the invention, the second rotational speed is greater than the third rotational speed.

Referring to fig. 2, an embodiment of the present invention further provides a starting apparatus for a permanent magnet synchronous motor, including:

the first control unit 201 is configured to perform first control on the permanent magnet synchronous motor in a current closed-loop and speed open-loop manner when receiving a start instruction sent by an upper computer;

and the second control unit 202 is configured to perform second control on the permanent magnet synchronous motor in a current closed-loop and speed closed-loop manner when the duration of performing the first control reaches a set time threshold.

In one embodiment of the present invention, the start instruction carries an acceleration and a target rotation speed;

the second control unit 202 is specifically configured to, when the acceleration is greater than the first rotation speed, instruct a rotation speed command to start from an initial speed value, and increase the rotation speed once every set time interval until the permanent magnet synchronous motor reaches the target rotation speed; when the acceleration is not greater than the first rotating speed, a rotating speed command starts from an initial speed value, and the rotating speed of a set step length is increased every time until the permanent magnet synchronous motor reaches the target rotating speed; and the error value of the rotating speed command and the rotating speed feedback is used as the input end of the speed PI loop regulation.

In an embodiment of the present invention, referring to fig. 3, the starting apparatus of the permanent magnet synchronous motor may further include: a mode determining unit 203 for determining a current operation mode of the washing machine, the operation mode including a washing mode or a dehydrating mode;

when the working mode is a washing mode, if the current rotating speed corresponding to the rotating speed command is less than or equal to a second rotating speed, the initial speed value of the rotating speed command is the second rotating speed, and if the current rotating speed corresponding to the rotating speed command is greater than the second rotating speed, the initial speed value of the rotating speed command is the current rotating speed;

and when the working mode is the dehydration mode, if the current rotating speed corresponding to the rotating speed command is less than or equal to a third rotating speed, the initial speed value of the rotating speed command is the third rotating speed, and if the current rotating speed corresponding to the rotating speed command is greater than the third rotating speed, the initial speed value of the rotating speed command is the current rotating speed.

In one embodiment of the invention, the second rotational speed is greater than the third rotational speed.

An embodiment of the present invention further provides a motor, including: the starting device of the permanent magnet synchronous motor in any one of the above embodiments.

The embodiment of the invention also provides a pulsator washing machine, which comprises: the motor is provided.

Taking a pulsator washing machine as an example, please refer to fig. 4 and 5 for describing a starting process of a permanent magnet synchronous motor, wherein fig. 4 is a control block diagram of the permanent magnet synchronous motor, fig. 5 is a flow chart of the starting process, and the starting process includes the following steps:

step 501, a time threshold is preset.

The time threshold is set as a control duration of the current closed-loop speed open-loop control mode, so that the permanent magnet synchronous motor moves and has a rotational inertia, and preferably, the time threshold can be 80-150 ms.

Step 502, the user selects a corresponding working mode on the pulsator washing machine, and after the start of clicking, the upper computer generates a starting instruction according to the selection of the user.

The motor in the pulsator washing machine needs to be started in both a washing mode and a dewatering mode, so that the upper computer can generate a starting instruction according to the selection of a user, wherein the starting instruction carries acceleration and a target rotating speed.

It should be noted that, in the washing mode and the dewatering mode, the corresponding acceleration and the target rotation speed of the pulsator washing machine are different, and the corresponding acceleration and the target rotation speed are preset values.

And 503, when receiving a starting instruction sent by the upper computer, the first control unit performs first control on the permanent magnet synchronous motor in the pulsator washing machine in a current closed-loop and speed open-loop mode.

In the context of figure 4, it is shown,

is the q-axis (cross)Axis) current set point,

is the d-axis (straight axis) current set point. i.e. i_u、i_v、i_wThe sampling currents of the U-phase, the V-phase and the W-phase can be obtained by AD sampling directly, two phases of the sampling currents are usually sampled directly, and the formula i is utilized_u+i_v+i_wThe third phase is calculated as 0. Electric angle

Can be calculated by reading the values of the magnetic encoder in real time.

In the case of current closed loop, speed open loop, FIG. 4

The speed PI ring disconnection in the place ahead, after obtaining three phase current and electric angle, can carry out having executed of electric current ring: three-phase current i_u、i_v、i_wObtaining i through Clark transformation_α,i_β(ii) a Then obtaining i through Park conversion_q,i_d(ii) a Then respectively corresponding to their set values

Calculating an error value; then substituting the q-axis current error value into the q-axis current PI loop to obtain V_qSubstituting the d-axis current error value into the d-axis current PI loop to obtain V_d(ii) a Then to V_q,V_dCarrying out inverse Park conversion to obtain V_α,V_β(ii) a Then obtaining V through SVPWM algorithm_a,V_b,V_cAnd finally, the current is input to three phases of the motor, so that the control of a primary current loop is completed.

In the current closed loop and speed open loop stage, only a small current can be supplied to the motor, so that the rotor can rotate without positioning.

And step 504, when the duration of the first control reaches a set time threshold, switching to a current closed loop and a speed closed loop for control.

Wherein, after switching to the speed closed loop, the control mode please refer to fig. 4, ω_refIs the speed value to which the speed command corresponds,

the feedback of the rotating speed is obtained by calculating a motor encoder. Will omega_refAnd

error calculation is performed, the calculated error value is used as the input end of the speed PI ring, at this time, the d-axis current in the current PI ring is set to be zero, because the d-axis current does not generate output force for the rotation of the driving motor, the d-axis current is normally set to be zero,

the current loop and the speed loop are combined with the output of the speed loop, so that the double closed loop control of the current loop and the speed loop is realized.

Because impeller washing machine's mode of operation is different, and the acceleration that the host computer sent is also different, at the second control stage, by the speed open-loop switch to speed closed loop, if speed amplitude variation fluctuation is great, can reduce the start success rate, consequently, for letting start more level and smooth, according to the acceleration of difference, the mode that the rotational speed order increases is different, and concrete control mode is as follows:

(1) acceleration carried by the start command being greater than a first speed of rotation omega₁。

(1.1) the working mode of the pulsator washing machine is a washing mode.

Speed command omega_refGradually accumulating from 0, if the rotation speed command omega is at the initial stage of switching_refThe corresponding current rotation speed is less than or equal to the second rotation speed omega₂Then the initial speed value of the speed command is ω₂Speed command from ω₂Starting to increase the rotating speed once every set time interval until the permanent magnet synchronous motor reaches the target rotating speed; if the rotational speed command omega_refThe corresponding current rotation speed is greater than the second rotation speed omega₂Then the initial speed value of the speed command is the current valueAnd the rotating speed command is increased once every set time interval from the current rotating speed until the permanent magnet synchronous motor reaches the target rotating speed.

(1.2) the working mode of the pulsator washing machine is a dehydration mode.

Speed command omega_refGradually accumulating from 0, if the rotation speed command omega is at the initial stage of switching_refThe corresponding current rotation speed is less than or equal to the third rotation speed omega₃Then the initial speed value of the speed command is ω₃Speed command from ω₃Starting to increase the rotating speed once every set time interval until the permanent magnet synchronous motor reaches the target rotating speed; if the rotational speed command omega_refThe corresponding current rotation speed is greater than the third rotation speed omega₃And then, the initial speed value of the rotating speed command is the current rotating speed, and the rotating speed command is increased once every set time interval from the current rotating speed until the permanent magnet synchronous motor reaches the target rotating speed.

(2) Acceleration carried by the start command being greater than a first speed of rotation omega₁。

And (2.1) the working mode of the pulsator washing machine is a washing mode.

Speed command omega_refGradually accumulating from 0, if the rotation speed command omega is at the initial stage of switching_refThe corresponding current rotation speed is less than or equal to the second rotation speed omega₂Then the initial speed value of the speed command is ω₂Speed command from ω₂At the beginning, when the rotation speed of the permanent magnet synchronous motor reaches omega₂Then increase a speed, e.g. 1 revolution, with a speed command of ω₂+1, when the rotation speed of the permanent magnet synchronous motor reaches omega₂+1, once more, e.g. 1 revolution, with a speed command ω₂+2, when the rotation speed of the permanent magnet synchronous motor reaches omega₂+2, once more, e.g. 1 revolution, with a speed command ω₂+3 … … is repeated until the PMSM reaches the target speed.

And (2.2) the working mode of the pulsator washing machine is a dehydration mode.

Speed command omega_refGradually accumulating from 0, if the rotation speed command omega is at the initial stage of switching_refCorresponding current rotation speed less thanIs equal to the third rotational speed omega₃Then the initial speed value of the speed command is ω₃Speed command from ω₃At the beginning, when the rotation speed of the permanent magnet synchronous motor reaches omega₃Then increase a speed, e.g. 1 revolution, with a speed command of ω₃+1, when the rotation speed of the permanent magnet synchronous motor reaches omega₃+1, once more, e.g. 1 revolution, with a speed command ω₃+2, when the rotation speed of the permanent magnet synchronous motor reaches omega₃+2, once more, e.g. 1 revolution, with a speed command ω₃+3 … … is repeated until the PMSM reaches the target speed.

Wherein, ω is₂Greater than omega₃。

The above realizes the one-time motor starting process from 0 starting to the maximum speed, if the washing mode is adopted, the motor is stopped after reaching the maximum speed after being started, and then the motor is rotated reversely, the reverse rotation process and the forward rotation process are the same and are realized by the steps, and the motor is stopped after the reverse rotation reaches the maximum speed and then is rotated forwardly, so that the work of the washing mode is completed; if the dewatering mode is adopted, the motor reaches the maximum speed after being started, the motor can be kept for a certain time, and then the motor is stopped.

In summary, the embodiments of the present invention can at least achieve the following advantages:

1. in the embodiment of the invention, when a starting instruction is received, a current is supplied to the motor by adopting a current closed loop, so that the rotor starts to rotate, when a set time threshold is reached, the rotor has a rotating inertia, and at the moment, the speed closed loop is directly switched to control the electrode, so that the positioning time is saved, and the starting of the permanent magnet synchronous motor can be quickly realized.

2. In the embodiment of the invention, because the working modes of the washing machine are different and the accelerated speeds sent by the upper computer are also different, in the second control stage, the speed open loop is switched to the speed closed loop, if the fluctuation of the speed amplitude is large, the starting success rate can be reduced, and the rotating speed command is controlled in a different increasing mode according to different accelerated speeds, so that the starting of the motor can be ensured to be smoother, and the starting success rate can be improved.

3. In the embodiment of the invention, because the position estimation algorithm is inaccurate in estimation at low speed, an initial speed value needs to be set in order to ensure the successful start of the permanent magnet synchronous motor, and in the initial switching stage, if the current rotating speed corresponding to the rotating speed command is less than or equal to the initial speed value, the initial speed value is taken as the rotating speed command, so that a proper speed can be ensured, the position estimation algorithm is more accurate, and the success rate of the motor start is improved.

Because the information interaction, execution process, and other contents between the units in the device are based on the same concept as the method embodiment of the present invention, specific contents may refer to the description in the method embodiment of the present invention, and are not described herein again.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising a" does not exclude the presence of other similar elements in a process, method, article, or apparatus that comprises the element.

Those of ordinary skill in the art will understand that: all or part of the steps for realizing the method embodiments can be completed by hardware related to program instructions, the program can be stored in a computer readable storage medium, and the program executes the steps comprising the method embodiments when executed; and the aforementioned storage medium includes: various media that can store program codes, such as ROM, RAM, magnetic or optical disks.

Finally, it is to be noted that: the above description is only a preferred embodiment of the present invention, and is only used to illustrate the technical solutions of the present invention, and not to limit the protection scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention shall fall within the protection scope of the present invention.