Four quadrant unipolar pulse width modulated inverter

摘要

A four quadrant unipolar pulse width modulated (PWM) power conversion circuit for supplying a desired current to an inductive load uses an H-bridge circuit topology with an upper and lower pair of switching elements including a diode in parallel with each of the switching elements to provide a current path from the load to the power source when its respective switching element is non-conductive. A control algorithm generates switching element control signals to cause the instantaneous voltage across the load to alternate between a single polarity voltage and zero for a portion of the output load waveform to cause the average value of the load current to correspond generally with the desired average load current.