Performance Investigation of Multilevel Neutral Point Clamped Dual Active Bridge Converter and Identification of Optimum Operating Zone

In this paper a multilevel Dual Active Bridge (DAB) converter synthesizing a five level voltage waveform at high frequency is presented. The performance investigation of neutral point clamped multilevel DAB is carried out with respect to switch stress on various switches. A closed loop controller is proposed for balancing of capacitor voltage and providing the necessary phase shift for the DAB. The operating zone is obtained by comparing the switch stress at various phase shifts. Also the stable and unstable operating phase shifts are obtained for the DAB. The simulation studies for validating the topology and the closed loop controller are carried out in MATLAB/Simulink environment.