Discontinuous conduction mode Buck converter with high efficiency

Electronic devices require AC to DC converter (rectifier) to convert AC voltage from the grid to DC voltage for the electronics and its result is low power factor (PF) and harmonic current injection into the system. Nowadays, power factor correction (PFC) converters are being widely used which can achieve high power factor (PF) and reduce the harmonics caused during AC to DC conversion and buck PFC converter is one of mostly used converter. On the other hand, if this converter works with constant duty-cycle (CDC) control scheme, the overall losses are more and efficiency is less. In order to increase the efficiency of buck converter operating in discontinuous conduction mode (DCM), a variable duty-cycle (VDC) control scheme is proposed. The method of fitting VDC control scheme is given for making implementation of circuit simpler. The performance of buck converter is compared with CDC and VDC control scheme in terms of efficiency. For verifying the validity of proposed technique, the simulation results are carried out. The object of the research paper is to propose the control scheme to achieve high PF for DCM buck converter by only modulating the duty-cycle of buck switch.