Design and analysis of voltage clamped bidirectional DC-DC converter for energy storage applications

The coupled inductor (CI) bidirectional DC-DC (BDC) converters are becoming popular in energy storage applications owing to high range factor, reduced device stress and high efficient. However, the applications of CI-BDC are limited due to the leakage energy of CI. Hence, this work proposes a voltage-clamp (VC) CI-BDC converter that effectively recovers the leakage energy while clamping switch turn-off voltage spikes, thus, guard the device from high-voltage stress. The working principle of proposed BDC converter with its characteristic waveforms and the steady-state analysis is presented. The equivalent circuits are obtained for the each interval operation of CI-BDC converter with voltage clamp in both boost (discharging) and buck (charging) mode. A Simulink/MATLAB-based design is presented for the CI-BDC converter with voltage clamp. A 60 W, prototype of proposed converter has been developed and validated experimentally with the simulation counterparts. To confirm the elimination of leakage energy of CI, the analyses of VC-CI-BDC converter are compared with CI-BDC converter counterparts.