Design And Realization On SRM Speed Control System

As a new speeding motor, Switched Reluctance Motor(SRM) has been widely applied in many fields, such as Household appliances, general industrial, aviation industry and the field of electric vehicles and the property of Switched Reluctance Motor Drive(SRD) is being promoted. SRM has advantages of simple structure, high reliability, large starting torque, small starting current and the ability to maintain high efficiency over a wide speed range, which has brought the SRD a terrific development opportunity. Due to the late start of the study, slow development, faultiness technology and the large market inertia in traditional speed control system, the SRD application is backward. Therefore, carrying out applied research for SRD has practical significance.As one of the main performance index, speed is the critical part of SRD application. This paper takes speed performance as the starting point to carry out the hardware circuit and software design studies. However, the flexible control parameters and characteristics that different speed control strategies should be taken in different speed make SRM hard to control and diffcult to play its advantages.In this paper, a three-phase 12/8 pole with rated power of 7.5kW SRM was used as the research object. The SRM basic working principle and Complete mathematical model is introduced. The characteristics of the motor was analysised in Linear models and quasi-linear model in different accuracy requirement.Based on the two mode, Chopping control and angle position control(ACP) were analysised and speed control algorithm analysis and design were also implemented.Based on the theoretical analysis, hardware circuit of speed control system which consists of power converter, master chip TMS320F28335, position detection circuit and drive circuit and can achieve basic functions and arithmetic functions was designed. According to speed control requirements, system software was designed and programming ideas and implementation methods about location identification, speed calculation, closed loop speed control and system protection were introduced based hardware platform. Faced with the diffcult such as that power electronic transistor off peak absorption circuit can’t absorb the off peak votage when Overcurrent and short circuit, it is prone to disorder and can not properly run when switched reluctance motor starts and nonlinear and variable structure should be overcame when the speed control was implemented, active clamp was introduced to the design to ensure the power electronic transistor safe shutdown at system error, implementation scheme is proposed in order to achieve an arbitrary initial position start without inversion and variable arguments PI algorithm and integral separation PI control algorithm were adopted to realize Speed control.At last, relying on the designed hardware platform, experimental verification was implemented based on the problems that this paper intended to resolve and speed control requirements. Experimental data and waveform showed the system design reasonable and the theoretical analysis is correct, and laid the foundation of further research and practical application.