An Ultra Sparse Matrix Converter with a Novel Active Clamp Circuit

The ultra sparse matrix converter (USMC) is a AC-DC-AC converter that requires only 9 power switches compared to the 18 switches required for a conventional matrix converter. The simplified input switch configuration restricts this converter to unidirectional power flow applications in which the maximum displacement angle between input and output voltages and currents is plusmnpi/6. A novel clamp circuit is therefore used to protect the converter from overvoltages incurred under regeneration conditions. This paper presents the design of a 5.5 kVA USMC which uses space vector modulation in combination with a zero current commutation scheme at the input rectifier stage. The design of the system is detailed and the hardware implementation of the converter is described. Experimental results demonstrate the operation of the clamp circuit and show that the converter draws sinusoidal currents from the input and supplies sinusoidal currents to the output with a conversion efficiency of up to 94%.