Study Of12/8Poles SRM Speed Control System

Switched reluctance motor (SRM) has a lot of features, such as simple structure, high reliability and control flexible, and so on, so it attracted widespread attention since it come out. But its double salient structure and stepping operating principle lead to the motor has strong nonlinear characteristics. With the traditional control strategy, Switched Reluctance Drive System (SRD) has a strong torque ripple and noise, and it has become the major factor to limit SRM’s development. Mathematical model of motor body is the premise of studying switched reluctance motor control, strategies, but strong nonlinear characteristics of SRM courses that establishing accurate mathematical model of switched reluctance motor is too difficult. So the accurate modeling and high performance control strategy about switched reluctance motor be the key to promote the development of switched reluctance motor.In this paper, the traditional function analytical method and two-dimensional look-up table were improved, and two simulation models of the motor body were built in MATLAB environment. Where the function analytical method is mainly based on the Fourier decomposition, with segmented high-order polynomial, Binary function expression of the flux linkage was obtained by using numerical fitting method, further the current and torque expression were got. Look-up module of Matlab was used in two-dimensional look-up table, and the simulation model was built through directly look-up table of current and torque discrete data. Current discrete data is obtained by reverse interpolating for flux linkage data, and discrete data of the simulation models are obtained by the finite element analysis. With angular position control mode, simulation analysis of the motor models was done. The correctness of the motor body simulation model was verified through comparing simulation waveform with experimental waveform of current. Through comparing and analyzing the advantages and disadvantages of the two modeling methods, this paper select the simulation model based on dimensional look-up table method to study on control strategy.In order to explore the control strategy to reduce the torque ripple and noise, and to improve the control system stability, in this paper, on the basis of the traditional speed current double closed loop control and torque distribution function (TSF) control, PI parameters adaptive control and improved torque distribution control strategies have been proposed. With the simulation model of the motor body, simulation analysis of direct torque control (DTC)、improved torque distribution control and PI parameters adaptive control for switched reluctance motors have been done. The simulation results show that direct torque control and improved torque distribution control strategies can effectively reduce the torque ripple. But direct torque control is prone to torque runaway, its operational stability is poor, and table lookup method was used in both direct torque control and torque distribution control, it make that regulator parameters can’t be directly got by setting calculation. So the two control strategies are not conducive to engineering applications. Reference to speed current double closed loop control theory of DC motor, with voltage pulse voltage control, speed current double closed loop control system of switched reluctance motor was built. PI regulator parameters change with the rotor position angle, parameter tuning is very easy. Regulator parameters relational expression was built by using numerical fitting method, the look-up table operation is not needed. To some extent, the torque ripple was reduced, and the operation stability of the control system was improved. Finally, PI parameters adaptive control was used in experimental study in this paper.Finally, experimental platform for switched reluctance motor speed control system was built by using DSP as the control chip, with PI parameter adaptive control, the corresponding experimental study has been done. The effectiveness of the control strategy for inhibiting torque ripple is proven by comparing the simulation results and experimental results, and the system has good speed performance.