Design of an H∞ robust controlled single-stage converter with high power factor and fast regulation

This paper presents the design of an H^∞ robust controlled single-stage power converter (SSC) operating in the discontinuous conduction mode (DCM) to achieve high power factor and fast output regulation. With the grafted scheme, a buck-boost power converter and a flyback power converter can be integrated to form the proposed SSC. The buck-boost semi-stage operating in the DCM functions as a power factor corrector and the flyback semi-stage operating in the DCM acts as a voltage regulator. With a proper control, the DC-link voltage is independent of load variation. A small-signal model of the SSC operating in the DCM is developed based on the two-part networks theory. An H^∞ robust control is adopted to design a proper controller to achieve system stability and dynamic performance. Simulation results of the proposed robust controlled system and an optimal PI controlled scheme are presented for comparison purpose. Hardwave measurements have shown the feasibility of the proposed system