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Usually, the high-gain high-efficiency dc–dc converters consist of many passive components, which increases the order of the system. As the order increases, system modeling and control become more complex. Thus, there is a need for the simplification of the small signal modeling process of such converters. This paper presents a generalized small signal model and equivalent circuit for an $n$ th-order coupled-inductor-based high-voltage gain converters (CIHVGC) that can be conveniently used for the control design. The state variable representation of a generalized coupled inductor with p windings is included. A simplified step by step procedure to obtain small signal model using visual inspection is presented. Analysis is included and verified using simulations and experiments for the output voltage regulation of high-voltage gain converters. The usefulness and versatility of the proposed model is verified with three examples of high gain converters belonging to the CIHVGC family. All the analytical, simulation, and experimental details of this paper are presented. [ABSTRACT FROM AUTHOR]

The conventional current-source inverter has two major problems: unidirectional power flow and voltage boost operation, which make it impossible to be used in many applications, such as hybrid electric vehicles and general-purpose variable-speed motor drives. Z-source inverters (ZSIs) can solve both problems. Quasi-ZSIs (qZSIs) were recently proposed as an important improvement to traditional ZSIs. Besides the advantages inherited from ZSIs, qZSIs also have several of their own merits. This paper presents a comprehensive study on the new features of current-fed qZSI, including the advantageous buck–boost function, improved reliability, reduced passive component ratings, and unique regeneration capability. The current-fed qZSIs are bidirectional with an additional diode, unlike the voltage-fed ZSI that needs a switch to achieve bidirectional power flow. A modified space vector pulse-width-modulation method is proposed, and the available operating regions for motoring and regeneration operation are analyzed in this paper. Since the current-fed qZSI has the same operation as the current-fed ZSI, many results of this paper are also applicable to the current-fed ZSI. A reverse-blocking insulated-gate bipolar-transistor-based current-fed qZSI prototype was developed in the laboratory. Simulation and experimental results are shown to verify the theoretical analysis. [ABSTRACT FROM PUBLISHER]

Digital average current controllers for boost power factor correctors (PFCs) are usually designed for continuous conduction mode (CCM). However, discontinuous conduction mode (DCM) appears in the inductor current near the zero crossings of the input current at light loads, resulting in input current distortion. It is caused by inaccurate average current values obtained in DCM and by the linear CCM PFC controller that is unable to ensure input current shaping in DCM whereby the converter exhibits nonlinear characteristic. This paper proposes a simple digital DCM control scheme that is achieved with minimal changes to the CCM average current control structure. It is mathematically and computationally simple. The result of all arithmetic operations in the proposed current control loop to obtain the desired control output can be achieved in a single clock cycle, whereas other DCM control schemes require multiple clock cycles. Good input current shaping is achieved in both CCM and DCM with the proposed CCM–DCM digital controller. [ABSTRACT FROM AUTHOR]

This paper proposes a zero-voltage-transition (ZVT) pulsewidth-modulated (PWM) synchronous buck converter, which is designed to operate at low voltage and high efficiency typically required for portable systems. A new passive auxiliary circuit that allows the main switch to operate with zero-voltage switching has been incorporated in the conventional PWM synchronous buck converter. The operation principles and detailed steady-state analysis of the ZVT PWM synchronous converter with a passive auxiliary circuit are presented. All of the semiconductor devices aside from the main switch operate under soft-switching conditions. Thus, the auxiliary circuit provides a larger overall efficiency. The feasibility of the auxiliary circuit is confirmed by the simulation and experimental results. [ABSTRACT FROM PUBLISHER]