Variable frequency control and filter design for optimum energy extraction from a SiC wind inverter

This paper proposes the optimised control and filter design of a 12 kW 3-phase 2-level wind inverter specifically taking into account the intermittent nature of the input power. In particular, the applied control scheme aims at optimising the low-load efficiency, which corresponds to the most frequent operational condition in time, by varying the switching frequency. Specifically, a silicon carbide (SiC) converter is addressed, which operates at relatively high frequency, thus enabling a significant reduction of the filter elements. So, the output filter design also needs to be optimised to ensure that the inverter electro-magnetic performance and the size reduction enabled by SiC are kept. That is achieved by designing a variable inductor based on soft saturation core material.