The thesis aims at investigating an active power factor correction circuit. In boost power converter, we ser up average large signal model with Matlab and derive control¡Voutput function for pole assignment of control loop with ac small signal model. In controller, control circuit of conventional active power factor correction and modified PI control circuit are adopted, separately. Through simulation results and experimental responses of hardware circuit show that under variation of load or alternating input voltage, modified PI control circuit has better regulating capacity than that of conventional control circuit .

This thesis mainly focuses on active power factor correction (PFC) circuit research. Based on DSP, a circuit with a digital controller is developed. Boost converter is used as the power stage. For power factor correction, the control law is realized with DSP and the control strategy of controller adopts the multi-loop method, i.e. voltage-loop and modified PI current-loop. Finally, compared with the circuit using the conventional PI control law, performances of the modified PI current-loop circuit are obviously optimized.

In this paper, the development and control of a switched reluctance motor (SRM) applied to the intelligent electric vehicle are presented. In the SRM control policy, speed control and constant torque/constant power control are implemented with modified PI(RISC) control and a chopped current control(CCC). The control policy can restrain torque ripple effectively, and the vibration and acoustic noise are reduced involuntarily. Simultaneously, The speed response to sudden load change becomes less dramatic. Simulate results suggest that modified PI is more powerful than fuzzy control and PI. In the experiment, this paper compares the advantages and disadvantages of PI, fuzzy control and modified PI under no load, fixed load and unfixed load condition. Finally, a Digital Signal Processor(DSP)is adopted to verify the accuracy of simulation, which contributes to the planning of the program composition flow.