Auxiliary power supply for medium-voltage power electronics systems

Abstract

This paper presents an auxiliary power supply for medium-voltage (MV) power electronics systems, based on modular multilevel series-parallel converter (MMSPC). The converter connects to 2.4 kV RMS at the input, and produces 24 V dc at the output, providing 100 W of power with 10 kV isolation. Unlike the traditional solutions which use a grid-frequency bulky and heavy potential transformers, the proposed converter can operate at higher switching frequencies, thus reducing the weight and providing higher power density, compared to the traditional approach. Additionally, the proposed converter features an internal capacitor voltage balancing and achieves power factor correction (PFC) by using predictive control. The proposed converter is simulated and its operation is experimentally validated on the developed prototype at low input voltage.