A Direct Power Electronic Conversion Topology for Multi-Drive Applications

The matrix converter (MC) is known as a single stage ac/ac converter, which is able to provide sinusoidal PWM output voltages and input currents, inherent bi-directional power flow and no reactive elements (bulky dc-capacitors and large line inductors). However, the increased number of active switches (18), as well as the need of a protection circuit involving twelve diodes with rated voltage/current ratings used only during faulty situation, makes this topology not so attractive. In this paper, a two-stage converter topology consisting of a three-phase to two-phase matrix converter directly linked to a Voltage Source Inverter (VSI) that provides direct power electronic conversion (DPEC) is analyzed. While the functionality is similar to a matrix converter, the analysis of the conduction losses shows a different shape of the efficiency curve, which in HVAC-applications may be an advantage. In addition, a new topology is proposed where several VSIs are connected to the same dc-link and their switching patterns are synchronized, which is especially useful for multi-drive applications. The functionality of the proposed two-stage multi-drive DPEC topology is analyzed by simulations and proven by experiments.