A Start-Up Scheme for a Three-Stage Solid-State Transformer With Minimized Transformer Current Response

This letter is focused on developing a start-up scheme for a three-stage solid-state transformer that includes a high-frequency transformer. The proposed scheme is aiming at minimizing the high-frequency transformer current during the start-up transient. As a result, the input-inrush current is also eliminated. The scheme is implemented with no extra cost by synchronizing the start-up of rectifier stage and dc-dc converter stage. The scheme is compared with other start-up methods. The theoretical analysis and experimental results are provided to verify the proposed start-up scheme.