Study of a modified parallel resonance AC-DC convertor with unity power factor and high efficiency

This article proposes a new topology and control strategy to optimise the power factor of a parallel resonance AC/DC convertor of high power while retaining high efficiency. The static and dynamic characteristics determined by the phase-plane method and the results obtained from simulation with Matlab software are detailed and analysed with an example of design of a convertor operating at 33 kHz and 2.5 kW. With adjustment of the commutator control signal a line current of sinusoidal form can be created in phase with the network voltage while maintaining soft switching. The amplitude and phase of the current can be adjusted separately