Resonant converter in high power factor, high voltage DC applications

The performance of a high-frequency high-order series resonant power converter operating in a high power factor mode is presented. The pulsating DC voltage obtained from a single-phase uncontrolled diode bridge rectifier is applied to the high-frequency full-bridge configuration of the resonant power converter. Such an AC-DC power converter operates at a high power factor without any active control of the input line current. High frequency (HF) transformer nonidealities (i.e. leakage inductance and magnetising inductance) are incorporated for analysis of the basic operation of circuit. This configuration is well-suited for higher output voltage applications such as high voltage DC power supplies. The lower order harmonics present in input line current are minimised by removing the gating pulses to the HF switches for a predetermined duration known as modulating window. A useful analytical technique, based on classical complex AC circuit analysis is suggested for designing the high-order series resonant tank circuit. The output voltage is regulated by independently using variable frequency control and duty ratio control. This AC-DC power converter is simulated using the TUTSIM and PSPICE packages, and an experimental prototype unit is developed using high frequency switches (MOSFETs)