METHOD OF OPERATING AC DRIVING APPARATUS WITH PARALLEL DC LINK POWER CONVERTER

摘要

PURPOSE: To suppress specific harmonics by operating an AC driver comprising a plurality of power converters connected in parallel in a load commutation mode for suppressing pulsation of torque. CONSTITUTION: An AC driver 1 comprises two three-phase DC link converters 2a, 2b connected in parallel between a three-phase AC power supply 3 and a three-phase load 4, e.g. a synchronous motor. Each converter 2 comprises a pair of line side converters 5, 6 having interlinked leads 7, 8. Each converter 5, 6 has a control commutation switch 9 for each phase of AC current. In this regard, switches of the load side converter 6 are not operated in parallel but one switch 9 is fired earlier than the other switch 9 (with phase lead of 30 deg., for example). According to the arrangement, fifth and seventh harmonics in a composite load current can be reduced significantly.