Design and performance evaluation of a bidirectional isolated dc-dc converter with extended dual-phaseshift scheme

This study describes the design and performance evaluation of a bidirectional isolated dc-dc converter with an extended dual-phase-shift (EDPS) scheme. The operation principle and equivalent circuits with consideration of the deadband are presented. The deadband effect with EDPS is different from the conventional phase-shift (CPS) scheme, and the corresponding compensation coefficient is determined. Different operation modes are identified with respect to phase-shift angles of EDPS and load conditions. The safe operational area is also analysed with the comparison of different operation modes. The output voltage and output power characteristics with open-loop or closed-loop operation are discussed. The average theoretical 48.5% reduction in the output voltage ripple using EDPS has been achieved. The average reduction in inductor peak and rms with EDPS are statistically calculated as 37.8 and 26.8%. The measured efficiency has improved from 68.1% using CPS to 81.9% using EDPS for low-power application.