Research On Torque Ripple Reduction For Switched Reluctance Motor Based On Fuzzy Logic Control

In the 1980s, the overseas lead developed a new kind of AC motor, which is Switched Reluctance Motor (SR motor). The SR motor is simple, firm, reliable and efficient, Switched Reluctance Drive (SRD), which is made from SR motor, has a large start torque, a wide scope of velocity modulation and a high efficiency. Moreover, SRD has the merits of direct-current transmission and the ordinary alternating-current transmission. It is being applied gradually in household electric appliances, general industry, servo and drive, traction motor, high-speed motor, astronautics instrument and auxiliary device of automobile, etc. SRD has the formidable market competitive power and is concerning by the domestic and foreign scholar increasingly. However, SRD also has some shortcomings, for example, the torque ripple and noise is large, the more phases, the more main wiring, and it can't be turned on the electric network directly to move steadily. On the torque ripple reduction, the domestic and foreign scholars has proposed many control strategies, such as micro-step control, direct torque control, instantaneous torque control and so on. This paper uses a new control method - - a fuzzy-logic-based turn-off angle compensation control, to improve the drive performance of SRD, reduce the torque ripple of the SR motor. The major work completed mainly including:(1) The linear, semi-linear and the non-linear mathematical model of the SR motor is analyzed. Based on the environment of MATLAB/Simulink, the linear and the non-linear simulation model of the four-phase (8/6 poles) SR motor is established. The inductance, the inter phase current, the one torque, the synthesis torque and the angular speed of the SR motor is simulated by using the Current Chopping Control pattern. The simulation results indicate the non-linear model is more precisely reflected the movement characteristic of the SR motor compare to the linear model. And the simulation model of the voltage Pulse Width Modulation pattern for SRD is established.(2) A fuzzy-logic-based turn-off angle compensation control strategy is proposed. Based on SR motor linear and non-linear simulation model, dynamic simulation model is built by integrate power transformer and controller and fuzzy logic controller. Based on the fuzzy logic turn-off angle compensation, the simulation model of Switched Reluctance Drive is established. The real-time compensation to the SR motor turn-off angle is carried out by using fuzzy logic controller, and the SR motor turn-off angle is changed timely to reduce torque ripple. The simulation results indicate that this method can reduce torque ripple, particularly, the torque ripple of the SR motor at low speed. Because this system has not the torque feedback signal, the work is simple, reliable, and easy to realize.(3) The experiment of the voltage chopping control pattern for the SR motor is carried out. The design and manufacture of the hardware and the programming of the software for SRD was carried out based on the DSP. A no-load test on a 750W SR motor is performed. The experimental result indicates this control strategy is feasible.