LC Parallel Resonant Step-Up DC/DC Converter

Chapter 1 points out that most of the resonant step-up grid-connected MV dc/dc converters have the following shortcomings: (1) the switching frequency widely varies throughout the full load range, which is unfavorable for the input and output filters design; (2) the resonant inductors are unidirectionally magnetized or asymmetrically bi-directionally magnetized, hence core utilization is insufficient, resulting in large size and heavy weight of the resonant inductors. To address the above problems, this chapter proposes a novel resonant step-up dc/dc converter, which can realize high voltage gain, zero-voltage switching (ZVS) turn-on and quasi-ZVS turn-off for switching devices, and zero-current switching (ZCS) turn-off for rectifier diodes. Besides, a relatively lower variation range of switching frequency and symmetric bi-directional magnetization of the resonant inductor can also be achieved. In this chapter, the operation principle of the converter and the optimized design of resonant parameters are presented. Besides, the control method is investigated. Finally, a 100 V/1000 V/1 kW prototype is developed for experimental verification.