Self-Oscillating Polyphase Inverter with Current Feedback

A three-phase self-oscillating inverter of reduced volume and minimal phase-distortion is proposed. To reduce core size, a diode-bridge and a common resistance are inserted in the control source for the saturable cores. The windings of the saturable cores are ring-connected to effectively improve the phase distortion and the stability. The oscillation frequency is derived analytically and methods to control the frequency are discussed. The effect of the current feedback is investigated for the case in which the induction motor is driven by this three-phase inverter.