Matrix converter based voltage regulator for managing smart microgrid with high renewable energy penetrations

This thesis examines the use of matrix converter (MC) in voltage regulators intended for use in the low voltage (LV) distribution network. Voltage balance and voltage regulation can be controlled by adding a series compensation voltage with a transformer. The MC supplies the injection transformer with an appropriate voltage which may be significantly unbalanced. Prior-art MCs have been predominantly applied in motor drives which have relatively balanced voltages and currents. This thesis shows the existing methods are not ideal for very unbalanced situations. It is shown that a traditional MC supplying an unbalanced load develops current harmonics at its input terminal. This thesis provides an improved MC modulation method that can eliminate input harmonics. This result is confirmed by simulation and experimental work. The thesis extends the traditional 3× 3 matrix into four wire compatible MC topologies including 3×4, 4×3 and 4×4 converters. For these cases, and generalised cases, solutions are presented for switch commutation. These are implemented with a field programmable gate array (FPGA). An experimental study is made of switch commutation for silicon and silicon carbide metal oxide semiconductor field-effect transistors (MOSFETs).