Abstract-This paper presents a simple and systematic approach to the design of a practical sliding mode voltage controller for buck converters operating in continuous conduction mode. Various aspects of the design, including the associated practical problems and the proposed solutions, are detailed. A simple and easy-to-follow design procedure is also described. Experimental results are presented to illustrate the design procedure.

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Abstract-This paper discusses a systematic method for deriving basic converter configurations that achieve power factor correction (PFC) and voltage regulation. The discussion begins with a general three-port representation of power supplies that provide PFC and voltage regulation. Based on this representation and a power flow consideration, a systematic procedure is derived to generate all possible minimal configurations. Among these configurations, only a few have been known previously and used in practice. It is found that the efficiency of PFC voltage regulators can be improved by reducing the amount of redundant power to be processed by the constituent converters. A systematic circuit synthesis procedure is proposed for creating PFC voltage regulators with reduced redundant power processing. Experimental measurements verify the improved efficiency.

Abstract-Using the reduced redundant power processing (R 2 P 2 ) principle, a single-phase power-factor correction (PFC) power supply can achieve a higher overall efficiency as a result of the use of a noncascading structure that involves less repeated processing of the input power. This paper investigates a single-phase noncascading PFC power supply based on the R 2 P 2 principle. The circuit employs a current-fed full-bridge converter as the PFC preregulator, and a buck-boost converter as the voltage regulator. This paper addresses the design of this noncascading PFC power supply and in particular the relationships between the gained efficiency, the transient response and the size of the energy storage. Experimental results obtained from a 1 kW laboratory prototype are presented.Index Terms-Buck-boost converter, continuous conduction mode (CCM), current-fed full-bridge converter, noncascading structure, power factor correction (PFC).

Abstract-A major disadvantage of applying sliding mode control to dc/dc converters is that the steady-state switching frequency is affected by line and load variations. This is undesirable as it complicates the design of the input and output filters. To reduce switching frequency deviation in the events of line and load variations, an adaptive feedforward control scheme that varies the hysteresis band according to the change of line input voltage and an adaptive feedback control scheme that varies the control parameter (i.e., sliding coefficient) according to the change of the output load are proposed. This paper presents a thorough investigation into the problem and the effectiveness of the proposed solutions. In addition, methods of implementing the proposed adaptive control strategies are discussed. Experimental results confirm that the adaptive control schemes are capable of reducing the switching frequency variations caused by both line and load variations.