PWM controlled single-stage converter operating in DCM/CCM for universal off-line applications

A single-stage converter (SSC) operating either in discontinuous conduction mode (DCM) or in continuous conduction mode (CCM) to achieve high power factor, high efficiency and low stress for universal line voltage range from 90 Vac to 264 Vac is presented. At light load, the proposed system is operated in the DCM; while at heavy load the system is operated in the CCM; thus, the DC-link voltage can be properly controlled to a certain voltage. The overall system is controlled with a pulse width modulation robust control and with a fixed frequency. In the design, the load variation and line voltage variation are treated as plant uncertainties. The H/sup /spl infin// robust control method is adopted to design a proper robust controller to achieve robust stability and robust performance. Finally, a prototype is implemented to verify the effectiveness and feasibility of the analysis and design.