Dual Mode Control Scheme for DAB Based Solid-State Transformer

This article proposes a Dual mode control (DMC) scheme for a Dual active bridge (DAB) based solid-state transformer (SST). Under this control scheme, a control path is developed to achieve zero voltage switching (ZVS) and minimize peak transformer current for the entire load range. Two operating modes are used for implementing the control scheme. ZVS conditions and peak transformer current characteristics for respective operating modes are analyzed. Key performance parameters, including peak transformer current, ZVS range and backflow power are compared with existing control strategies, indicating overall efficiency improvement for the proposed DMC control scheme. Besides, an experimental prototype of 1.2 kW was developed to validate the effectiveness of the proposed control scheme.