阅读说明：本技术 一种同时抑制开关磁阻电机转矩脉动与振动的控制方法 (Control method for simultaneously inhibiting torque pulsation and vibration of switched reluctance motor ) 是由 孙建忠 贺锡之 白凤仙 于 2020-06-10 设计创作，主要内容包括：本发明提供一种同时抑制开关磁阻电机转矩脉动与振动的控制方法,属于开关磁阻电机技术领域。本发明能够实现对转速、转矩、径向力三个对象进行控制,在保证电机拥有良好转速特性的情况下,使电机输出转矩更加平滑,转矩脉动明显减小,保证其在电气传动系统中更加平稳、高效地运行。同时,有效降低了开关磁阻电机定子的径向振动,使其产生的振动噪声大大减小。(The invention provides a control method for simultaneously inhibiting torque pulsation and vibration of a switched reluctance motor, and belongs to the technical field of switched reluctance motors. The invention can realize the control of three objects of rotating speed, torque and radial force, and under the condition of ensuring that the motor has good rotating speed characteristic, the output torque of the motor is smoother, the torque pulsation is obviously reduced, and the motor can be ensured to run more stably and efficiently in an electric transmission system. Meanwhile, the radial vibration of the stator of the switched reluctance motor is effectively reduced, and the generated vibration noise is greatly reduced.)

1. A control method for simultaneously inhibiting torque pulsation and vibration of a switched reluctance motor is characterized in that a system for realizing the control method comprises a rotating speed controller, a torque-radial force estimator, a reference generator and a current controller; the rotating speed controller controls the switched reluctance motor to reach a set rotating speed and keep stable; the torque-radial force estimator estimates the current torque value and the radial force value according to the external signal; the reference generator processes the torque value and the radial force value to obtain a reference phase current; the current controller determines a switching signal of the power converter according to the reference phase current and the actual value to realize the control of the switched reluctance motor; the control method of the system comprises the following steps:

(1) rotating speed controller

Reference rotation speed omega set manually^*The actual speed omega of the motor is input into a speed controller, and the speed controller uses proportional-integral regulation, namely PI regulation, to the difference between the reference speed and the actual speed so as to obtain a referenceCurrent i^*As an output;

(2) torque-radial force estimator

The control method uses the torque-radial force estimator twice; the method comprises the following steps: reference current i output by a rotating speed controller^*And the actual angular position theta of the position sensor output as input, estimating the reference torque T^*Reference radial force F^*(ii) a The other time is as follows: actual phase current i of switched reluctance motor_nAnd the actual angular position theta measured by the position sensor is used as input, and the actual torque T and the actual radial force F are obtained through estimation;

(3) reference generator

The reference generator comprises a torque distribution function part and a parameter setting part;

A. part of torque distribution function

The torque distribution function is trigonometric function type, and the trigonometric function type torque distribution function is mainly divided into a phase advancing function f_upAnd phase function f_dnTwo parts, see formulas (1) and (2); the trigonometric function curve is similar to the curve profile of the actual phase torque of the switched reluctance motor, and the relation of the formula (3) is ensured to be satisfied, namely the sum of the phase-in reference torque and the phase-out reference torque is equal to the total reference torque;

∑T^*＝f_up+f_dn(3)

ξ and lambda are torque regulating coefficient and radial force regulating coefficient respectively used for regulating the magnitude of the setting reference torque and the phase-in and phase-out share, ξ and lambda have initial values when the control system starts to run, see formulas (4) and (5), ξ and lambda are given by a parameter setting part during the running process, theta represents the actual angular position output by the position sensor, and theta represents the actual angular position output by the position sensor_onIndicating the position of the opening angle, theta_offRepresents the off angular position;

ξ₀＝1 (4)

B. parameter setting section

T from torque-radial force estimator output^*、F^*Determining a current working point by T and F; with (T)^*，F^*) The original working area is divided into four areas I, II, III and IV as the center, so that the following relations exist in each area:

Ⅰ：T>T^*，F>F^*；

Ⅱ：T<T^*，F>F^*；

Ⅲ：T<T^*，F<F^*；

Ⅳ：T>T^*，F<F^*；

when the working point is located in the area I, the current needs to be reduced to enable the current working point to be close to the reference working point, and the corresponding scheme is to reduce a torque adjusting coefficient xi of a torque distribution function;

when the working point is located in the region III, the current needs to be increased to enable the current working point to be close to the reference working point, and the corresponding scheme is to increase a torque adjusting coefficient xi of a torque distribution function;

when the working point is in phase change in the region II, the working point correspondingly occupies a larger share, and the corresponding scheme is to increase the radial force adjustment coefficient lambda of the torque distribution function;

when the working point is in the region IV for phase change, a corresponding larger share is obtained, and the corresponding scheme is to reduce the radial force adjustment coefficient lambda of the torque distribution function;

with (T)^*，F^*) A rectangular area with the length and the width of a and b as the center is regarded as an allowable error range; proper values of a and b are selected according to the system, the system responds frequently when the value is too small, and the control precision of the system is influenced when the value is too large; when the error is within the allowable range, the torque regulation coefficient and the radial force regulation coefficient are not adjusted, even if the torque and the radial force are ensuredKeeping unchanged;

finally, the torque curve f can be adjusted according to the angular position θ_upAnd f_dnConverted into a current curve to determine the reference phase current i at different positions_n ^*；

(4) Current controller

Phase reference current value i_n ^*With actual phase current i_nAnd performing difference making, namely performing PI regulation on the difference value to obtain an output PWM duty ratio, so as to determine a switching signal of the power converter and realize control on the switched reluctance motor.

2. The control method for simultaneously suppressing the torque ripple and the vibration of the switched reluctance motor according to claim 1, wherein the estimation method of the torque-radial force estimator is divided into two types:

A. a table look-up method, wherein two tables of torque-current-angle TI theta and radial force-current-angle FI theta are obtained in an off-line mode and are stored in the main controller;

B. the data fitting method also needs to obtain two tables of TI theta and FI theta off line, then fits the data into an evaluation function, and calculates the values of T and F on line when in use.

Technical Field

The invention belongs to the technical field of switched reluctance motors, and relates to a control method for simultaneously inhibiting torque pulsation and vibration of a switched reluctance motor.

Background

The Switched Reluctance Motor (SRM) is a novel special motor, has the characteristics of simple and firm structure, good speed regulation performance, more controllable parameters, high starting torque, low starting current, suitability for severe environment and the like, and therefore, has a wide application prospect.

However, switched reluctance motors have their inherent disadvantages of large torque ripple and vibration noise. During the low-speed operation stage of the switched reluctance motor, large torque ripple is often generated, which is mainly influenced by the switching form and nonlinear factors. The vibration noise of the switched reluctance motor is mainly caused by the radial vibration of the stator, and the radial vibration of the stator is caused by the generation of the driving torque of the switched reluctance motor. The two defects affect the efficiency and reliability of the switched reluctance motor, and further development of the switched reluctance motor in the fields of electric automobiles, household appliances and the like is hindered.

In order to solve the two problems of the switched reluctance motor, experts and scholars at home and abroad carry out a great deal of research on the control strategy of the switched reluctance motor. They mostly consider only one aspect of torque ripple or vibration noise and do not combine the two to provide a solution. Therefore, it is necessary to invent a control strategy for simultaneously suppressing the torque ripple and the vibration of the switched reluctance motor.

Disclosure of Invention

The invention aims to provide a control strategy for simultaneously inhibiting torque pulsation and vibration of a switched reluctance motor so as to improve the output quality of the torque of the switched reluctance motor and reduce the influence generated by the vibration of the switched reluctance motor, thereby realizing stable and efficient operation of the motor and expanding the application field of the motor.

The technical scheme of the invention is as follows:

a control method for simultaneously inhibiting torque pulsation and vibration of a switched reluctance motor comprises a rotating speed controller, a torque-radial force estimator, a reference generator and a current controller; the rotating speed controller controls the switched reluctance motor to reach a set rotating speed and keep stable; the torque-radial force estimator estimates the current torque value and the radial force value according to the external signal; the reference generator processes the torque value and the radial force value to obtain a reference phase current; the current controller determines a switching signal of the power converter according to the reference phase current and the actual value to realize the control of the switched reluctance motor; the control method of the system comprises the following steps:

(1) rotating speed controller

Will be artificially constructedSet reference rotational speed omega^*The reference current i is obtained by inputting the reference current and the actual rotating speed omega of the motor into a rotating speed controller, and the rotating speed controller uses proportional-integral regulation, namely PI regulation, on the difference between the reference rotating speed and the actual rotating speed^*As an output;

(2) torque-radial force estimator

The control method uses the torque-radial force estimator twice; the method comprises the following steps: reference current i output by a rotating speed controller^*And the actual angular position theta of the position sensor output as input, estimating the reference torque T^*Reference radial force F^*(ii) a The other time is as follows: actual phase current i of switched reluctance motor_nAnd the actual angular position theta measured by the position sensor is used as input, and the actual torque T and the actual radial force F are obtained through estimation;

(3) reference generator

The reference generator comprises a torque distribution function part and a parameter setting part;

A. part of torque distribution function

The torque distribution function is trigonometric function type, and the trigonometric function type torque distribution function is mainly divided into a phase advancing function f_upAnd phase function f_dnTwo parts, see formulas (1) and (2); the trigonometric function curve is similar to the curve profile of the actual phase torque of the switched reluctance motor, and the relation of the formula (3) is ensured to be satisfied, namely the sum of the phase-in reference torque and the phase-out reference torque is equal to the total reference torque;

∑T^*＝f_up+f_dn(3)

ξ and lambda are torque regulating coefficient and radial force regulating coefficient respectively for regulating the setting reference torque and the phase-in and phase-out portion, and ξ and lambda have initial values when the control system starts running(4) And (5) during operation, ξ and lambda are given by a parameter setting part, theta represents the actual angular position of the position sensor output, and theta represents the actual angular position of the position sensor output_onIndicating the position of the opening angle, theta_offRepresents the off angular position;

ξ₀＝1 (4)

B. parameter setting section

T from torque-radial force estimator output^*、F^*Determining a current working point by T and F; with (T)^*，F^*) The original working area is divided into four areas I, II, III and IV as the center, so that the following relations exist in each area:

Ⅰ：T>T^*，F>F^*；

Ⅱ：T<T^*，F>F^*；

Ⅲ：T<T^*，F<F^*；

Ⅳ：T>T^*，F<F^*；

when the working point is located in the area I, the current needs to be reduced to enable the current working point to be close to the reference working point, and the corresponding scheme is to reduce a torque adjusting coefficient xi of a torque distribution function;

when the working point is located in the region III, the current needs to be increased to enable the current working point to be close to the reference working point, and the corresponding scheme is to increase a torque adjusting coefficient xi of a torque distribution function;

when the working point is in phase change in the region II, the working point correspondingly occupies a larger share, and the corresponding scheme is to increase the radial force adjustment coefficient lambda of the torque distribution function;

when the working point is in the region IV for phase change, a corresponding larger share is obtained, and the corresponding scheme is to reduce the radial force adjustment coefficient lambda of the torque distribution function;

with (T)^*，F^*) A rectangular area with the length and the width of a and b as the center is regarded as an allowable error range;proper values of a and b are selected according to the system, the system responds frequently when the value is too small, and the control precision of the system is influenced when the value is too large; when the error is within the allowable range, the torque regulation coefficient and the radial force regulation coefficient are not adjusted, even if the torque and the radial force are kept unchanged;

finally, the torque curve f can be adjusted according to the angular position θ_upAnd f_dnConverted into a current curve to determine the reference phase current i at different positions_n ^*；

(4) Current controller

Phase reference current value i_n ^*With actual phase current i_nAnd performing difference making, namely performing PI regulation on the difference value to obtain an output PWM duty ratio, so as to determine a switching signal of the power converter and realize control on the switched reluctance motor.

The estimation method of the torque-radial force estimator is divided into two types:

A. a table look-up method, wherein two tables of torque-current-angle TI theta and radial force-current-angle FI theta are obtained in an off-line mode and are stored in the main controller;

B. the data fitting method also needs to obtain two tables of TI theta and FI theta off line, then fits the data into an evaluation function, and calculates the values of T and F on line when in use.

The invention has the beneficial effects that: the three objects of rotating speed, torque and radial force are controlled, the output torque of the motor is smoother under the condition that the motor has good rotating speed characteristics, the torque pulsation is obviously reduced, and the motor is ensured to run more stably and efficiently in an electric transmission system. Meanwhile, the radial vibration of the stator of the switched reluctance motor is effectively reduced, and the generated vibration noise is greatly reduced.

Drawings

FIG. 1 is a block diagram of a control system of the present invention.

FIG. 2 is a schematic diagram of a torque distribution function.

FIG. 3 is a schematic diagram of a torque-radial force operating zone.

FIG. 4 is a hardware structure diagram of a switch reluctance motor control system

In the figure: 1, a microcontroller; 2 three-phase switched reluctance motor; 3 a power converter; 4, a PWM driving unit; 5 a current detection unit; 6 a position detection unit; A. b, C are three-phase stator windings of the motor respectively; c1, C2, and C3 are current sensors installed in three phases.

Detailed Description

The invention is further illustrated below with reference to specific experiments and with reference to fig. 4.

An 12/8-pole three-phase switch reluctance motor is adopted in an experimental prototype, the rated power is 4kW, and the rated rotating speed is 2200 rpm.

Microcontroller 1 chooses singlechip STM32F103RBT6, and C1, C2, C3 use voltage type hall current sensor, can introduce the three-phase current signal into the singlechip. The single chip microcomputer converts the analog signals into digital signals through the A/D conversion module for processing and use by an internal program. The position detection unit consists of a rotor position measuring fluted disc, three groove type Hall switch devices and a corresponding circuit. The single chip microcomputer acquires the states of the 3 Hall switches by inputting capturing interruption, so that the current position of the rotor is determined.

The control program adopts the control strategy of the invention, and the parameters of each part are set as follows: rotating speed controller PI parameter: coefficient of proportionality K_p12, integral coefficient K_i110; current controller PI parameters: coefficient of proportionality K_p21, integral coefficient K_i20.5; the reference generator parameter setting partial torque radial force error range a is 2, and b is 10. The torque radial force estimator adopts a rotor position slice function fitting method which is a compromise scheme between a table look-up method and a data fitting method.

In order to embody the objective and effective of the experimental conclusion, the experimental result of the control strategy provided by the invention is compared with the current mainstream control strategy DITC (direct instantaneous torque control) and the rotating speed current double closed loop.

The torque ripple and radial force ripple for the three control strategies are given in table 1 and table 2, respectively, for different situations. Therefore, when the control strategy is adopted, the control effect on the radial force is superior to that of DITC and double closed-loop control. While the torque ripple of the control strategy of the present invention is less than that of the double closed loop, it is in some cases greater than the DITC because the DITC considers only torque and not radial force, and the double target control is difficult to achieve for both. However, the control strategy of the invention is very effective in inhibiting torque pulsation and radial force pulsation in view of the combination of two indexes of torque and radial force.

TABLE 1 Torque ripple comparison of three control strategies

TABLE 2 radial force pulsation contrast for three control strategies

The control strategy of the switched reluctance motor can effectively inhibit the torque pulsation and vibration of the motor, greatly improve the output torque quality and the operation stability of the motor, and has important significance for the application of the switched reluctance motor to wider fields.