New inductor current feedback control with active harmonics injection for inverter stage of solid state transformer

Solid state transformer (SST) is considered the key unit for power processing and conversion in the future distributed renewable energy network. The role of SST is to enable the active management of distributed energy resources, energy storage devices and different type of loads in a distribution grid. Inverter stage of SST supplies sinusoidal voltage to the users. In this paper an improved inductor current control based on active harmonics injection is proposed to overcome the drawback of inferior performance of conventional inductor current feedback control for the nonlinear loads. The inductor current overshoot during the load transient is investigated by using both capacitor current feedback control and inductor current feedback control. The inductor current feedback control has the capability to limit current overshoot even with a smaller inductor, which shows the potential to further reduce the size and weight of the passive components.