Control Strategies for Parallel Capacitive-Link Universal Converters with Low Voltage Stress and Current Stress

Capacitive-link universal converters, including series and parallel types, are relatively new classes of single-stage power converters that provide multiple benefits including high-reliability, high-power density and long lifespan. In the parallel capacitive link universal converters switches and diodes have lower current stress compared to the series type. However, both types of capacitive link universal converter suffer from high voltage stress across switches and diodes. In this paper, innovative control strategies are proposed for parallel capacitive link universal converters to lower voltage stress and current stress across the switches and diodes. In the proposed control method, the power is only partially transferred via the link capacitor, and the remaining power is directly transferred from input towards output. The proposed control strategies are expected to provide enhanced efficiency and reduced current stress as well as voltage stress in parallel capacitive link universal converters. In this paper, the principles of the operation of the capacitive link universal converter with proposed control strategies are explained, and the performance and benefits will be validated by simulation.