Power factor improvement of an AC/AC converter by association of PDM control and passive filtering

PDM control and passive filtering are combined to improve, to a significant degree and at lower costs, the power factor of an AC/AC power converter consisting of a single-phase diode bridge rectifier and a series inverter without the smoothing filter of the DC voltage. A low-pass filter absorbs the harmonics of the rectifier input current, whereas PDM control, applied to the inverter, reduces the size of it filters. An optimization routine is used to solve for the position of the pulses or equivalently the holes in the PDM pattern to cancel low order harmonics. The size of the filter decreases with an Increasing number of holes created by PDM control in the current drawn by the converter. Simulation results validate the theoretical results.