Abstract
Due to the advantages of high power factor, low input current harmonic distortion and low output voltage ripple, three phase boost PWM ac/dc converters are very suitable for high performance high power sources or as a dc-link of an ac/ac converter. Therefore, the goal of this thesis is to further explore a more effective design method of this high performance converter. Major contributions of this thesis may be summarized as follows. First, the characteristic of this system is comprehensively analyzed. Then the relation between parameter values and dynamic response characteristic of this system is analyzed and an analytic formula of inductor parameter is derived by considering the crossover frequency of the system open-loop transfer function. In addition, an energy factor is proposed, for the first time, in this thesis and another analytic formula of capacitor parameter is derived based on this new factor. It follows that design of the parameters of inductor and capacitor becomes a simple calculation according to the formulas. Second, although a proportional -integral (PI) controller in the synchronous frame can be adopted for the converter to achieve zero steady-state error, the time consuming process of repeated coordinate transform and inverse transform is rather inefficient for the controller. On the other hand, the recently developed proportional-resonant (PR) controller has the advantage of achieving zero steady-state error without coordinate transformations. Hence, the PR control together with another feedforward control is adopted as the controller of the converter system to achieve high performance. At last, a prototype is constructed to verify the effectiveness of the proposed parameter design and the control strategy. The system controller is implemented digitally with a DSP, namely TMS320 F2812, to simplify the hardware circuit and for convenient maintenance.