Simple PDM pattern generation for an AC/AC resonant converter

PDM control applied to a series resonant inverter reduces switching losses and eliminates the requirement for the rectifier DC voltage smoothing filter. Synthesis of a PDM control signal is quite complex and the aim of the paper is to simplify the PDM control law based equations. In the control law derived from the simplified model, PDM signal is generated by comparing a triangular carrier and a power reference signal. It is shown that the proposed simplified model is very accurate if the carrier frequency is below a certain limit. Validation of the simplified model is based on the comparison of harmonics content of the input current. Simulation results validate the proposed PDM pattern generator.