Synthesis of cycloconverter and current-source-inverter presentation of a new control strategy

Several proposals have been published to combine the principles of operation of the cycloconverter (CC) and of the current source inverter (CSI) in large power adjustable speed drives with synchronous motors. Converters allowing such a combination can be referred to as `CC/CSI converters´. The objective of this research has been to overcome the well-known difficulties of the loca-commutated current-source-inverter at standstill and at low speeds (torque ripple and unsufficient commutating voltage). In this paper, a novel control strategy is described for a CC/CSI converter feeding a synchronous motor with six stator windings. This novel control strategy is compared to a control strategy previously published, where the same CC/CSI converter feeds a usual synchronous motor with three stator windings. An industrial application of a CC/CSI converter drive is described