阅读说明：本技术 一种磁通切换电机转矩脉动抑制控制系统及控制方法 (Torque ripple suppression control system and control method for flux switching motor ) 是由 程明 周嘉炜 于 2020-03-20 设计创作，主要内容包括：本发明公开一种磁通切换电机转矩脉动抑制控制系统及控制方法,实现对磁通切换电机的控制；所述控制方法步骤是：测量磁通切换电机的转子位置角θ<Sub>m</Sub>,计算得到转速ω<Sub>r</Sub>；根据转速ω<Sub>r</Sub>以及给定的目标转速ω<Sub>ref</Sub>,计算得到q轴电流的给定值<Image he="73" wi="44" file="DDA0002419425730000014.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>观测转速ω<Sub>r</Sub>中与齿槽转矩频率一致的分量,得到干扰值<Image he="62" wi="57" file="DDA0002419425730000011.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>根据q轴电流的给定值<Image he="76" wi="54" file="DDA0002419425730000013.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>干扰值<Image he="61" wi="59" file="DDA0002419425730000012.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>以及d轴、q轴电流实际值,计算得到电压矢量值u<Sub>cd</Sub>和u<Sub>cq</Sub>；将电压矢量值u<Sub>cd</Sub>和u<Sub>cq</Sub>由dq-αβ坐标变换到α-β坐标系下的电压矢量u<Sub>cα</Sub>和u<Sub>cβ</Sub>；基于电压矢量u<Sub>cα</Sub>和u<Sub>cβ</Sub>得到三相的PWM信号,并据此生成三相电压值,驱动磁通切换电机运转。此种技术方案仅需了解定位力矩的频率信息,无需了解其幅值相位,定位力矩幅值发生变化时,能够及时修正补偿值,保证控制效果。(The invention discloses a torque ripple suppression control system and a torque ripple suppression control method for a flux switching motor, which are used for controlling the flux switching motor; the control method comprises the following steps: measuring rotor position angle theta of flux switching motor m Calculating to obtain the rotation speed omega r (ii) a According to the speed of rotation omega r And a given target rotational speed ω ref Calculating to obtain the given value of the q-axis current Observing the rotation speed omega r The component consistent with the cogging torque frequency is neutralized to obtain a disturbance value According to the given value of q-axis current Interference value And d-axis and q-axis current actual values, and calculating to obtain a voltage vector value u cd And u cq (ii) a Vector value u of voltage cd And u cq Transformation from dq- αβ coordinates to voltage vector u in α - β coordinate system cα And u cβ (ii) a Based on voltage vector u cα And u cβ And obtaining three-phase PWM signals, generating three-phase voltage values according to the three-phase PWM signals, and driving the flux switching motor to operate. According to the technical scheme, only frequency information of the positioning torque is needed to be known, amplitude phase of the positioning torque is not needed to be known, and when the amplitude of the positioning torque changes, the compensation value can be corrected in time, so that the control effect is guaranteed.)

1. A torque ripple suppression control system of a magnetic flux switching motor realizes the control of the magnetic flux switching motor; the method is characterized in that: the control system includes:

a photoelectric encoder mounted on the rotor shaft of the flux switching motor for measuring the rotor position angle theta of the flux switching motor_mAnd respectively sent to an angle calculation module and an angular velocity calculation module;

an angular velocity calculation module for calculating a rotor position angle theta based on the rotor position angle measured by the photoelectric encoder_mCalculating to obtain the rotation speed omega_r；

An angle calculation module for calculating a rotor position angle theta based on the rotor position angle measured by the photoelectric encoder_mAnd the number of rotor poles p_rMultiplying to obtain an electrical angle theta_e；

A rotation speed PI controller for calculating rotation speed omega according to the angular speed_rAnd a given target rotational speed ω_refCalculating to obtain the given value of the q-axis current

Improved disturbance observer for observing rotational speed omega_rThe component consistent with the cogging torque frequency is neutralized to obtain a disturbance value

A current PI controller for controlling the given value of the q-axis currentInterference valueAnd d-axis and q-axis current actual values, and calculating to obtain a voltage vector value u_cdAnd u_cq；

2r/2s converter for converting an electrical angle theta_eDividing the voltage vector value u_cdAnd u_cqTransformation from dq- αβ coordinates to voltage vector u in α - β coordinate system_cαAnd u_cβ；

SVPWM module for voltage vector u based_cαAnd u_cβObtaining three-phase PWM signals and sending the three-phase PWM signals to an intelligent power module; and the number of the first and second groups,

and the intelligent power module is connected between the direct-current voltage source and the flux switching motor and used for generating a three-phase voltage value according to the three-phase PWM signal and driving the flux switching motor to operate.

2. The flux switching motor torque ripple suppression control system of claim 1, wherein: the improved disturbance observer comprises an inverse model, two identical low-pass filters, a motor torque coefficient module, a reciprocal module and a difference making module, wherein the input end of the inverse model is connected with the output end of the angular velocity calculation module, and the output end of the inverse model is connected with one input end of the difference making module through the first low-pass filter; the input end of the motor torque coefficient module is used for inputting a q-axis current given value, and the output end of the motor torque coefficient module is connected with the other input end of the difference module through a second low-pass filter; the output end of the difference making module is connected with the input end of the reciprocal module, and the output end of the reciprocal module outputs an interference value

3. A torque ripple suppression control method for a flux switching motor realizes the control of the flux switching motor; the method is characterized in that: the control method comprises the following steps:

step 1, measuring rotor position angle theta of flux switching motor_mCalculating to obtain the rotation speed omega_r；

Step 2, according to the rotating speed omega_rAnd a given target rotational speed ω_refCalculating to obtain the given value of the q-axis current

Step 3, observing the rotating speed omega_rThe component consistent with the cogging torque frequency is neutralized to obtain a disturbance value

Step 4, according to the given value of the q-axis currentInterference valueAnd d-axis and q-axis current actual values i_d，i_qAnd calculating to obtain a voltage vector value u_cdAnd u_cq；

Step 5, the voltage vector value u_cdAnd u_cqTransformation from dq- αβ coordinates to voltage vector u in α - β coordinate system_cαAnd u_cβ；

Step 6, based on the voltage vector u_cαAnd u_cβAnd obtaining three-phase PWM signals, generating three-phase voltage values according to the three-phase PWM signals, and driving the flux switching motor to operate.

4. The torque ripple suppression control method of a magnetic flux switching motor according to claim 3, characterized in that: in the step 2, the rotation speed omega is used_rAnd a given target rotational speed ω_refCalculating to obtain the given value of the q-axis currentThe expression is as follows:

wherein G is_vpiIs the transfer function of the rotational speed PI controller.

5. The torque ripple suppression control method of a magnetic flux switching motor according to claim 3, characterized in that: the specific content of the step 3 is as follows: firstly, to omega_rPerforming inverse operation, and low-pass filtering to obtain T_e1(ii) a Multiplying the given value of the q-axis current by the torque coefficient of the motor, and then performing low-pass filtering to obtain a result and T_e1Making difference, then calculating reciprocal to obtain interference value

6. The torque ripple suppression control method of a flux switching motor according to claim 5, wherein: the method for calculating the given value of the q-axis current comprises the following steps: setting the q-axis current obtained in the step 2And interference valueMaking a difference to obtain a q-axis current given value i_qref。

7. The torque ripple suppression control method of a flux switching motor according to claim 5, wherein: the expression for the low pass filtering is:

wherein i_m、j_nThe coefficient is the coefficient of a low-pass filter, and the denominator order M is more than or equal to the numerator order N;

the resonators r(s) are designed in the form:

R(s)＝R₁(s)×R₂(s)

wherein, ω is₁，ω₂Fundamental and second harmonic frequencies of cogging torque; a is₁，a₂，b₁，b₂Are low pass filter coefficients.

8. The torque ripple suppression control method of the magnetic flux switching motor according to claim 4, characterized in that: in the step 5, the voltage vector value u is calculated_cdAnd u_cqTransformation from dq- αβ coordinates to voltage vector u in α - β coordinate system_cαAnd u_cβThe expression is as follows:

wherein, theta_eIs the electrical angle, theta, of the rotor of the machine_e＝p_r×θ_m，p_rIs the number of rotor poles.

Technical Field

The invention belongs to the technical field of motor driving, and particularly relates to a torque ripple suppression control system and a torque ripple suppression control method for a magnetic flux switching motor.

Background

The permanent magnet motor has the characteristics of high power density, small volume, good electromagnetic performance and the like, and is widely applied to industrial production, the permanent magnet is generally arranged on a rotor of the conventional permanent magnet motor, so that the permanent magnet is difficult to dissipate heat, the loss of magnetism is high, in addition, the surface-mounted permanent magnet motor also needs an additional fastening device to prevent the permanent magnet from falling off in high-speed operation, and the motor cost is improved.

In order to solve the above problems, researchers have proposed a stator Permanent Magnet motor, and a Flux Switching motor (FSPM) is used as a kind of stator Permanent Magnet brushless motor, and has the advantages of simple rotor structure, suitability for high-speed operation, convenience in cooling and the like, and has a good application prospect in the fields of new energy electric vehicles, industrial servo and the like. But the torque ripple is relatively large, so that the further popularization and application of the FSPM motor are limited. The common strategies for inhibiting the torque ripple comprise structural optimization and compensation, the structural optimization starts from the design of a motor body, reasonable size parameters are selected, pole groove matching, common methods such as an oblique pole, a chamfer angle and an auxiliary groove are adopted, the problem of overlarge torque ripple can be solved from the source, but part of motor performance can be generally sacrificed, in addition, the non-standard motor is long in processing period, high in production cost and limited by processing precision, and the actual effect is possibly greatly deviated from theoretical calculation. The compensation control method does not require redesign of the motor structure, and has been receiving attention in recent years. The current harmonic injection method and the model predictive control strategy based on the positioning moment model are two typical compensation control strategies, and good control effects are achieved, but the positioning moment of the motor needs finite element analysis, in an actual motor operation system, the positioning moment can change due to changes of an assembly process and a load condition, harmonic injection cannot be accurately compensated, and the effect of the scheme in an experiment is not obvious. The compensation torque model is obtained through offline finite element analysis, and the model prediction control structure is different from the traditional double closed-loop vector control structure, so that a corresponding controller structure needs to be designed, the model prediction control algorithm has more parameters, and the parameter adjustment is more complex.

Disclosure of Invention

The invention aims to provide a torque ripple suppression control system and a torque ripple suppression control method for a flux switching motor, which only need to know frequency information of positioning torque and do not need to know amplitude phase of the positioning torque, and can correct a compensation value in time when the amplitude of the positioning torque changes, so that the control effect is ensured.

In order to achieve the above purpose, the solution of the invention is:

a torque ripple suppression control system of a magnetic flux switching motor realizes the control of the magnetic flux switching motor; the control system includes:

a photoelectric encoder mounted on the rotor shaft of the flux switching motor for measuring the rotor position angle theta of the flux switching motor_mAnd respectively sent to an angle calculation module and an angular velocity calculation module;

an angular velocity calculation module for calculating a rotor position angle theta based on the rotor position angle measured by the photoelectric encoder_mCalculating to obtain the rotation speed omega_r；

An angle calculation module for calculating a rotor position angle theta based on the rotor position angle measured by the photoelectric encoder_mAnd the number of rotor poles p_rMultiplying to obtain an electrical angle theta_e；

A rotation speed PI controller for calculating rotation speed omega according to the angular speed_rAnd a given target rotational speed ω_refCalculating to obtain the given value of the q-axis current

Improved disturbance observer for observing rotational speed omega_rThe component consistent with the cogging torque frequency is neutralized to obtain a disturbance value

A current PI controller for controlling the given value of the q-axis currentInterference valueAnd d-axis and q-axis current actual values, and calculating to obtain a voltage vector value u_cdAnd u_cq；

2r/2s converter for converting an electrical angle theta_eDividing the voltage vector value u_cdAnd u_cqTransformation from dq- αβ coordinates to voltage vector u in α - β coordinate system_cαAnd u_cβ；

SVPWM module for voltage vector u based_cαAnd u_cβObtaining three-phase PWM signals and sending the three-phase PWM signals to an intelligent power module; and the number of the first and second groups,

and the intelligent power module is connected between the direct-current voltage source and the flux switching motor and used for generating a three-phase voltage value according to the three-phase PWM signal and driving the flux switching motor to operate.

The improved disturbance observer comprises an inverse model, two identical low-pass filters, a motor torque coefficient module, a reciprocal module and a difference making module, wherein the input end of the inverse model is connected with the output end of the angular velocity calculation module, and the output end of the inverse model is connected with one input end of the difference making module through the first low-pass filter; the input end of the motor torque coefficient module is used for inputting a q-axis current given value, and the output end of the motor torque coefficient module is connected with the other input end of the difference module through a second low-pass filter; the output end of the difference making module is connected with the input end of the reciprocal moduleOutput of the block

A torque ripple suppression control method for a flux switching motor realizes the control of the flux switching motor; the control method comprises the following steps:

step 1, measuring rotor position angle theta of flux switching motor_mCalculating to obtain the rotation speed omega_rThe expression is as follows:

step 2, according to the rotating speed omega_rAnd a given target rotational speed ω_refCalculating to obtain the given value of the q-axis currentThe expression is as follows:

wherein G is_vpiIs the transfer function of the rotating speed PI controller;

step 3, observing the rotating speed omega_rThe component consistent with the cogging torque frequency is neutralized to obtain a disturbance valueThe expression is

Wherein, K_tIs the motor torque coefficient, R₁，R₂Is a transfer function of a resonator inside an improved disturbance observer, i_qrefThe torque current set value containing the suppressed harmonic component, and g is the bandwidth of the filter;

step 4, according to the given value of the q-axis currentInterference valueAnd d-axis and q-axis current actual values i_d，i_qAnd calculating to obtain a voltage vector value u_cdAnd u_cqThe expression is as follows:

u_cd＝(i_dref-i_d)×G_dpi

wherein G is_dpi，G_qpiRespectively are transfer functions of a d-axis current PI controller and a q-axis current PI controller;

step 5, the voltage vector value u_cdAnd u_cqTransformation from dq- αβ coordinates to voltage vector u in α - β coordinate system_cαAnd u_cβThe expression is as follows:

wherein, theta_eIs the electrical angle, theta, of the rotor of the machine_e＝p_r×θ_m，p_rThe number of rotor poles;

step 6, based on the voltage vector u_cαAnd u_cβAnd obtaining three-phase PWM signals, generating three-phase voltage values according to the three-phase PWM signals, and driving the flux switching motor to operate.

The specific content of the step 3 is as follows: firstly, to omega_rPerforming inverse operation, and low-pass filtering to obtain T_e1(ii) a Multiplying the given value of the q-axis current by the torque coefficient of the motor, and then performing low-pass filtering to obtain a result and T_e1Making difference, then calculating reciprocal to obtain interference value

The method for calculating the given value of the q-axis current comprises the following steps: obtained in step 2Given value of q-axis current ofAnd interference valueMaking a difference to obtain a q-axis current given value i_qref。

After the scheme is adopted, the invention provides the control system based on the disturbance observer to solve the problem of overlarge torque ripple of the flux switching motor and aim at the characteristic that the main component of the torque ripple of the flux switching motor is the first harmonic and the second harmonic of the cogging torque. The interference observer in the control system is simple in structure and strong in expansibility, can be combined with the torque pulsation characteristic of the magnetic flux switching motor under the condition that the structure of the magnetic flux switching motor is not required to be changed, can realize smoother torque output and lower rotation speed fluctuation, has good system expansion performance, and can effectively expand the application range of the magnetic flux switching motor.

The invention has the beneficial effects that:

(1) the control system provided by the invention can obviously reduce the torque pulsation of the magnetic flux switching motor under the condition of not changing the structure of the magnetic flux switching motor, and realize smoother torque output and lower rotating speed fluctuation;

(2) the improved interference observer can observe the fundamental wave and the second harmonic characteristic of the cogging torque according to the mechanical rotating speed of the motor without cogging torque data, and can be popularized to magnetic flux switching motors with any stator and rotor structures;

(3) the method can be combined with the existing vector control strategy, does not change the vector control structure, has good adaptability, and can be used as a patch of the existing structure;

(4) the improved disturbance observer can be popularized to any stator permanent magnet type motor driving system.

Drawings

FIG. 1 is a schematic diagram of a magnetic flux switching motor control system based on a disturbance observer according to the present invention;

FIG. 2 is a block diagram of a disturbance observer according to the present invention;

FIG. 3 is a graph of the amplitude-frequency characteristics of the closed-loop transfer function of the disturbance observer according to the present invention;

in fig. 4, (a) is a simulation graph of an output torque waveform (load torque 3N · m) without using the control method according to the present invention, and (b) is a simulation graph of an output torque waveform (load torque 3N · m) using the control method according to the present invention;

in FIG. 5, (a) is a simulation diagram of a rotational speed waveform (target rotational speed 1000 rpm) without using the method of the present invention, and (b) is a simulation diagram of a rotational speed waveform (target rotational speed 1000 rpm) using the method of the present invention.

Detailed Description

Because the FSPM motor has higher air gap flux density, the stator and the rotor are in a double salient pole structure, and the cogging torque of the stator and the rotor is relatively larger. Excessive cogging torque can cause torque pulsation, mechanical vibration and noise during the operation of the motor, reduce the performance and efficiency of the FSPM motor and limit the application of the FSPM motor. At present, most torque ripple optimization methods select to redesign the structure of the magnetic flux switching motor, and the methods have a good effect of inhibiting the torque ripple of the magnetic flux switching motor, but the non-standard motor has high production cost and long production period, and the average torque can be reduced while inhibiting the torque ripple, so the methods have certain limitations. From the control angle, utilize compensation control to compensate positioning torque, can optimize the output characteristic of motor after the motor processing is accomplished, need not redesign motor structure, greatly reduced manufacturing cost shortens production cycle, consequently has good prospect.

The research on torque ripple suppression control of the flux switching motor based on the interference observer can estimate the cogging torque disturbance by an observation method and compensate under the condition that accurate data of the cogging torque of the flux switching motor are not needed, so that the method can be widely popularized to flux switching motors with various sizes and structures, has very good expansibility and universality, and has great theoretical significance and application value for promoting the application of the flux switching motor in the fields of electric vehicles, industrial servo and the like.

The technical solution and the advantages of the present invention will be described in detail with reference to the accompanying drawings.

The invention provides a torque ripple suppression control system of a magnetic flux switching motor, which is structurally shown in fig. 1, and the system structure comprises a direct-current voltage source 1, an intelligent power module 2, a magnetic flux switching motor 3, a photoelectric encoder 4, an angle calculation module 5, an angular velocity calculation module 6, an SVPWM module 7, a 2r/2s converter 8, a 3s/2r converter 9, a d-axis current PI controller 10, a q-axis current PI controller 11, an improved interference observer 12 and a rotating speed PI controller 13. A photoelectric encoder 4 is arranged on the rotor shaft of the flux switching motor 3 and used for measuring the rotor position angle theta of the flux switching motor_mAnd calculating the rotational speed omega_rFurthermore, unlike the conventional permanent magnet synchronous motor, the angle calculation module calculates the rotor position angle θ output from the photoelectric encoder 4_mAnd number of rotor poles p_rMultiplying to obtain an electrical angle theta_e。

Further, a given fundamental torque current component is obtained by the rotational speed PI controller 13Improved disturbance observer by observing rotation speed omega_rThe component consistent with the cogging torque frequency is neutralized to obtain a disturbance valueSubtracting the two to obtain a given value i of the torque current with suppressed harmonic component_qrefThe given voltage value u can be calculated by using a current loop PI controller_cd，u_cqAnd the switching signals required by the intelligent power module are calculated by the SVPWM module after the coordinate transformation and projected to an α - β coordinate system, and the corresponding alternating voltage is generated by the inversion of the intelligent power module, so that the motor is driven to operate.

When the control system works, firstly, the angle and angular speed signals of the motor are collected through the photoelectric encoder 4 and used for angle calculation and angular speed calculation, and the angular speed signal omega is used for calculating the angular speed_rWith a given target speedAnd (3) forming a negative feedback channel, calculating a difference signal by the rotating speed PI controller 13 to obtain a given value of the q-axis current, and then making a difference value with the interference value calculated by the improved interference observer 12 to be used as a new given value of the q-axis current. Because the method is based on control, the d-axis current given value is set as 0, the d-axis and q-axis current given values are differed with the d-axis and q-axis current actual values obtained after the dq-abc coordinate transformation, and a voltage vector value u is obtained through calculation by the two current PI controllers 10 and 11_cdAnd u_cqAnd obtaining a voltage vector u under a α - β coordinate system through dq- αβ coordinate transformation_cαAnd u_cβAfter passing through the SVPWM module 7, three-phase PWM signals can be obtained and input to the intelligent power module 2, and three-phase voltage values required for driving the motor can be generated.

In the above process, the angular velocity signal ω_rAlso one of the input signals of the disturbance observer 12, the angular velocity signal ω, which is an improved disturbance observer according to the invention_rThrough the inverse model 14 of the nominal model, the improved low-pass filters 15 and 16 can obtain the nominal (i.e. under the condition that the modeling has no error with the actual system) current rotating speed omega by reverse estimation_rCorresponding torque in the target frequency band, and q-axis current set value i_qrefAfter multiplying with a motor torque coefficient 18, a torque value generated by a given current value in a target frequency band can be obtained through improved low-pass filters 15 and 16, an electromagnetic torque difference value of a nominal model and an actual model can be obtained by subtracting the two values, the difference value is interference generated by system modeling errors, external working conditions and other factors, the interference is multiplied by a reciprocal 17 of the torque coefficient, and the interference is compensated to a forward channel of a system through a feedforward channel, so that the effect of torque ripple suppression can be realized.

The control object, namely the magnetic flux switching motor, is a brushless alternating current motor, the sine degree of the back electromotive force is high, but the stator and the rotor of the brushless alternating current motor are of a double-salient-pole structure, so that the cogging torque component is high, the torque pulsation of the motor is high, and the application occasions of the motor are limited. The cogging torque of a flux switching motor was analyzed to be composed mainly of fundamental and second harmonics, where the fundamental componentThe period is related to the mechanical angle relationship, if the number of stator teeth is p, for a flux switching motor_sThe number of rotor teeth being p_rLet p denote_sAnd p_rHas a least common multiple of N_cogThen the fundamental component period of the cogging torque can be expressed in mechanical degrees as:

C_cog＝360°/N_cog

while the electrical cycle of a flux switching machine can be expressed in mechanical terms as:

C_e＝360°/p_r

the multiples of the fundamental component frequency of cogging torque and the electrical frequency can be expressed as:

K_cog＝p_r/N_cog

because of the mechanical rotation speed omega of the motor_rThe ratio of the frequency to the electrical frequency is a fixed value, so that the mechanical rotating speed omega of the motor is obtained_rThe fundamental frequency of the cogging torque can be obtained.

The traditional interference observation technology generally uses a low-pass filter for filtering, signals lower than a cut-off frequency are reserved, when the cut-off frequency is higher than a second harmonic frequency of cogging torque, cogging torque harmonics in a rotating speed signal are identified, and on the premise of reserving the advantages of the traditional structure, a targeted filter is designed by combining the torque ripple characteristic of a magnetic flux switching motor, so that the compensation capability of a system can be further improved.

The core of the improved disturbance observer is therefore a filter G, whose expression is as follows:

in the filter, i_mAnd j_nFor the coefficients of the conventional low-pass filter and the denominator order M is equal to or greater than the numerator order N, generally, N is 0 and M is g^-1And g is the filter bandwidth. Considering that the cogging torque is mainly composed of the second harmonic, the resonator r(s) is designed in the form of:

R(s)＝R₁(s)×R₂(s)

wherein, ω is₁，ω₂As a result of analyzing the torque ripple structure of the flux switching motor for the target frequency, it is easy to know that the torque ripple of the flux switching motor is mainly caused by the cogging torque and mainly includes the first and second harmonics, generally ω₁，ω₂Setting the fundamental frequency and the second harmonic frequency of the cogging torque; a is₁，a₂，b₁，b₂For the filter coefficients, the gain amplitude and phase for the harmonic frequencies can be adjusted by adjusting the coefficients.

Further, the structure of the resonator r(s) can be generalized to any combination of target frequencies, and the expression of the multi-harmonic resonator r(s) is as follows:

wherein, a_k，b_kIs the filter coefficient, ω_kIs the target frequency.

It is readily appreciated that the amplitude-frequency characteristics of a multiple harmonic resonator are as follows:

the core of the invention is an improved disturbance observer structure, as shown in fig. 2. By parametric design, its closed-loop transfer function can be expressed in the form:

comparison of the system closed-loop transfer function using the modified disturbance observer with the conventional disturbance observer system closed-loop transfer function as shown in fig. 3, it can be seen from fig. 3 that the modified disturbance observer has better correction than the conventional disturbance observer output at two target frequencies, and the modified disturbance observer has better response at high frequencies.

FIG. 4(b) shows the effect of the output torque after applying the improved disturbance observer of the present invention, and compared with the output torque shown in FIG. 4(a) without the method of the present invention, the torque ripple is reduced from 3 N.m to 1 N.m, and the reduction ratio is up to 66.7%. Fig. 5(b) is a rotating speed waveform simulation diagram of the flux switching motor under the control method of the invention, and it can be seen from the diagram that the rotating speed fluctuation is reduced from ± 2rpm to ± 0.1rpm due to the greatly reduced torque ripple, and it can be seen that the control strategy of the invention can well improve the rotating speed fluctuation of the flux switching motor, obtain smoother torque output, and greatly expand the application field of the flux switching motor.

In summary, the invention is based on the torque ripple characteristics of the flux switching motor, utilizes the interference observation principle, designs the improved interference observer for inhibiting the torque ripple of the flux switching motor in a targeted manner, extracts the signal consistent with the cogging torque frequency of the flux switching motor through the observation and compensation of the torque ripple interference, and carries out negative compensation through the feedforward channel, thereby reducing the pulsation rate, improving the running stability of the system, and meeting the requirements of high-precision industrial application fields such as electric vehicles, industrial servo and the like on the performance of the motor; the control method is tightly combined with the traditional vector control method, is easy to realize, and has strong expansibility of the interference observer structure and higher degree of freedom.

Compared with the two methods in the prior art, the method only needs to know the frequency information of the positioning torque, does not need to know the amplitude phase of the positioning torque, and can correct the compensation value in time when the amplitude of the positioning torque changes, thereby ensuring the control effect. In addition, the method can be effectively combined with the traditional vector control structure and used as a patch of a system without redesigning an algorithm structure. Compared with the traditional interference observation method, the method provided by the invention has the advantages that the observer expansibility and pertinence are greatly improved, and the research and development period is shortened.

The above embodiments are only for illustrating the technical idea of the present invention, and the protection scope of the present invention is not limited thereby, and any modifications made on the basis of the technical scheme according to the technical idea of the present invention fall within the protection scope of the present invention.