Dynamic Level Shift Control Scheme for Power Loss Reduction in T-type Traction

A Dynamic Level Shift Control Scheme (DLSC) is proposed to improve the efficiency by reducing the losses in the switching devices. In this scheme, a hysteresis comparator is used to compare the instantaneous loading with the loading threshold set by the user. This threshold is decided based on the power loss such that, when the operating conditions cause more losses, a three level-inverter Space Vector Control (SVPWM) is implemented while when the losses are less than desired threshold, the control switches to two-level control, hence reducing the losses in the neutral legs. The proposed control has been implemented in a GaN based T-type traction inverter. The simulation results verify the proposed control. Further, the block diagram used to design the control scheme has also been presented.