Soft-Switching Bidirectional DC-DC Converters

Bidirectional DC-DC converters allow the transfer of power between two DC sources in either direction. They are increasingly used in applications such as DC uninterruptible power supplies, aerospace power systems, DC motor drive systems, and hybrid-energy electric vehicles.Employing soft-switching techniques in bidirectional DC-DC converters reduces switching loss and improves efficiency of the converters. The soft-switching converters can operate in higher frequency. As a result, the converters will have high power density and fast dynamic response.In this dissertation, two new families of soft-switching bidirectional DC-DC converters are proposed according to different topology configurations and control methods, i.e. a family of compound active-clamped PWM bidirectional DC-DC converters and a family of zero-voltage-switching phase-shift bidirectional DC-DC converters. The converters are composed of various fundamental bidirectional switch cells.The proposed soft-switching bidirectional DC-DC converters' topologies are very simple. All of active switches in the converters can achieve soft switching in both forward and backward operation modes, so switching losses of the converters are reduced. Most of the converters can maintain soft switching in wide load range. Moreover, synchronous rectifier operation and less circulating energy make conduction losses of the converters reduced. The converters have high efficiency and fast response. In addition, the soft-switching techniques in the dissertation also can be used for reference in some unidirectional DC-DC converters.The generations of the two new families are explained. Taken as examples of the new families, the operation principles and analyses of six particular converters are illustrated, respectively. Simulation results and experimental results are also presented.