High Frequency Full-Bridge LLC Resonant Converter with Interleaved Buck-Boost Stage for Low THD and High-Efficiency

A novel technique has been adapted for achieving high PFC in AC-DC conversion by introducing dual buck–boost power- factor correction (PFC) converters and a full Bridge series resonant DC/DC converter for higher power quality improvement. We aim to comply with the more regulation on current harmonics and to improve the power factor. Our Ac-dc converters will incorporate an active power factor correction (PFC) and harmonic current reduction technique at the point of common coupling (PCC) which improves voltage regulation and efficiency. We develop a circuit for PFC using active filtering approach by implementing two boost converters arranged in parallel. It shall be based on an optimized power sharing strategy to improve the current quality and at the same time reduce the switching losses. The conventional rectifiers inject unwanted ac line current harmonics and low power factor into ac sources. The adverse effects of power system harmonics are well recognized and include heating and reduction of transformers and induction motors life, degradation of system voltage waveforms, insecure currents in power-factor-correction capacitors and malfunctioning of certain power system protection elements. Conventional rectifiers are harmonic polluters of the ac power distribution system. With the extensive use of electronic equipment, rectifier harmonics have become a major problem. Therefore, there is a need for high-quality rectifiers that can operate with high power factor, high efficiency and reduce generation of harmonics. A number of international standards now exist that in particular limit the magnitude of harmonics currents, for both high-power equipment such as industrial motor drives, and low-power equipment such as electronic ballasts. Power Factor gives a measure of how effective the real power utilization of the system is. It is a figure of merit that measures how effectively power is transmitted between a source and load network.