Direct Instantaneous Torque Control System Research Of Switched Reluctance Motor

Switched Reluctance Motor(SRM) has advantages of simple structure, high reliability and efficiency and excellent speed adjusting performance, thus gains widespread attention in recent years. But its unique double salient poles structure leads to serious torque ripple. The thesis researched the method of improving switched reluctance motor's torque performance from the control point of view.The most serious torque ripple happens in commutation areas. In this paper, the torque characteristic of SRM was analyzed firstly, then the theory of Direct Instantaneous Torque Control(DITC) method was introduced. According to its commutation strategy, the toque controller of DITC method was designed, adopting a kind of double hysteresis loops to adjust torque. Simulation results showed that the DITC method could limit torque wave in the hysteresis loop strictly under any conduction angles, and improve switched reluctance motor's dynamic and steady torque performance effectively. Considering that the nonlinear modeling of SRM is too complex, a function was designed to fit the flux curve by comparison. Simulation results showed that the DITC system using this function to estimate torque on-line, comparing with traditional current chop control method, could still reduce the torque ripple effectively. The whole control system was more practical.The hardware and software design work of SRM speed adjusting system were finished. The circuit used DSP TMS320F2812 as core controller, including power converter, current and position detection module and control circuit. The whole system's work procedure was divided into two parts, startup and speed adjusting under DITC. PI speed adjusting method with integral separation could reduce speed overshoot effectively. Each program section's thought and flow chart was explained. The experiment achieved switched reluctance motor's startup using two-phase current chop method.