Motor drive system and heat source device

Abstract

A motor drive system according to an embodiment of the present invention comprises: a rectifier circuit that rectifies an AC voltage supplied from an AC power supply; a noise filter that is positioned between the AC power supply and the rectifier circuit; a first DC / AC conversion circuit that is connected to the rectifier circuit output side and is composed of a plurality of semiconductor switches; a first motor in which windings in which each phase is independent each have one end connected to an AC output terminal of the first DC / AC conversion circuit; a second DC / AC conversion circuit that is composed of a plurality of semiconductor switches, the other ends of said windings being connected to an AC output terminal of said second DC / AC conversion circuit; a capacitor that is connected in parallel with the second DC / AC conversion circuit; a third DC / AC conversion circuit that is connected in parallel with the capacitor and is composed of a plurality of semiconductor switches; and a second motor that is connected to an AC output terminal of the third DC / AC conversion circuit.