I. Introduction
Recently, in medium-voltage (MV) motor drives, pulse-width-modulated (PWM) current-source converters (CSCs) appear to be a good alternative to voltage-source converters (VSCs) due to their advantages including four-quadrant operation, reliable short-circuit protection, machine-friendly waveforms, and reduced cost [1]. As Fig. 1 shows that the CSC is composed of six symmetrical gate-commutated thyristors with reverse voltage-blocking capability. On the dc side is an ideal current source, which is usually obtained by a current-source rectifier (CSR) and a series inductor in practice. A three-phase capacitor must be connected at the output of the CSC to assist the commutations of switching devices and also used as a filter.
Topology of a single-bridge CSC.