Research on Single-Stage High-Frequency-Link SST Topology and Its Optimization Control
Xiaofeng Sun, Huafeng Wang, Lei Qi, Feilong Liu
Abstract
This article proposes a new single-stage high-frequency-link based single-phase solid-state transformer (SST) topology. Switching tube multiplexing is carried out to reduce the number of switching devices and the corresponding modulation strategy is given. An optimized hybrid control analysis for reducing the average conduction current of insulated gate bipolar transistor (IGBT) and inductor was performed. By switching different control modes, the average current value of the SST inductor is kept being the minimum so as to reduce the conduction losses of IGBTs in the SST. As the core unit of the SST is the dual active bridge converter, the proposed optimal control is based on the extended phase-shift control, instead of triple-phase-shift control, that makes the implementation method very simple. And the feasibility of topology and optimized hybrid control scheme is verified through experiments.