Inductor minimum calculation based on analysis of AC current ripple for PWM converter with dead-time effect

摘要

A calculation method of inductor minimum based on analysis of ac-side current ripples for three phase PWM converter with SVPWM control strategy is presented. Most inductors in used are far above the ideal minimum, while large inductors lead to difficulty in controller designing and bigger converter size and weight. The method in this paper abandons unnecessary approximation to get precise minimum and analyzes influencing factors such as DC-link voltage, grid voltage and switching time. Dead-time is taken into account as it affects the accuracy of quantities in inductor calculation. Analysis shows that the inductor minimum has three changing regulations in one main frequency cycle. With harmonic analysis, the inductor closed to the actual minimum rather than an excessively large one is suggested. Simulation shows the method is effective, so the conclusion can be used as theoretical basis of device selection and can be extended to other applications.