PERFORMANCE CHARACTERIZATION OF A HIGH-POWER DUAL ACTIVE BRIDGE DC-TO-DC-CONVERTER

This paper describes the performance of a high-power, high-power-density dc-to-dc converter based on the single-phase dual active bridge (DAB) topology [1]. The dual active bridge converter was shown to have very attractive features in terms of low device and component stresses, small filter components, low switching losses (by virtue of zero voltage switching), high-power density and high efficiency, bidirectional power flow, buck-boost operation, and low sensitivity to system parasitics. For high-output voltages, in the order of kilovolts, a cascaded output structure is considered. The impact of snubber capacitance and magnetizing inductance on the soft switching region of control are discussed. Various control schemes are outlined. Since the leakage inductance of the transformer is used as the main energy transfer element, coaxial transformer design techniques [2] have been utilized to carefully control this parameter. The actual layout and experimental performance of a prototype 50-kW, 50-kHz unit operating with an input voltage of 200 Vdc and an output voltage of 1600 Vdc is presented.