A DCT/PET Submodule with Symmetrical Bipolar DC Outputs

A novel dc-dc converter with symmetrical bipolar low-voltage dc (LVDC) outputs is proposed, which is based on dual-active-bridge converter with one active-neutral-point-clamped (ANPC) arm. With the ANPC arm, bipolar dc bus voltages can be balanced. The proposed dc-dc converter can be employed as the submodule of DCT and constitute the bipolar LVDC distribution grid. Comparing to the schemes which adopts two DCTs or voltage balancer, the scheme based on proposed converter can obtain lower volume and higher power density. Additionally, all switches in proposed converter can achieve ZVS turn-on, which help improves the conversion efficiency. In this paper, the operation principle of proposed converter is analyzed in detail, on the basis of which steady-state control strategy are derived. Also, considering the possible faults of dc bus, control strategy for fault situation is discussed. Finally, simulation with PLECS verifies the feasibility of proposed converter.