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Pulsewidth-modulation inverters and rectifiers are required in widespread applications such as energy-storage power plants, telecommunication systems, and electric-vehicle propulsion systems. Some of the stringent requirements of these applications can be achieved by high switching frequency. On the other hand, the use of high switching frequency may degrade the overall system efficiency, which can be alleviated by the utilization of soft-switching techniques. In this paper, a generic soft-switching diagram that can generate topologies for turn-on snubber, zero- voltage transition, zero-current-zero-voltage transition inverters with coupled filter inductor is proposed. This approach facilitates the understanding of these techniques by both newcomers and senior engineers, making the advantages and disadvantages of each soft-switching technique much clearer. [ABSTRACT FROM AUTHOR]

This paper presents the analysis, design, and implementation of a parallel connected maximum power point tracking (MPPT) system for stand-alone photovoltaic power generation. The parallel connection of the MPPT system reduces the negative influence of power converter losses in the overall efficiency because only a part of the generated power is processed by the MPPT system. Furthermore, all control algorithms used in the classical series-connected MPPT can be applied to the parallel system. A simple bidirectional dc-dc power converter is proposed for the MPPT implementation and presents the functions of battery charger and step-up converter. The operation characteristics of the proposed circuit are analyzed with the implementation of a prototype in a practical application. [ABSTRACT FROM AUTHOR]

This paper proposes a design criterion for calculating the resonant auxiliary elements of zero-voltage transition dc-dc pulsewidth-modulated (PWM) converters that use a dc auxiliary voltage source. The proposed criterion is based on stored energy in resonant auxiliary elements and takes into account the influence of the auxiliary voltage source value. Using this criterion, the reactive energy can be kept at a minimum level and a reduction of the auxiliary elements current ratings is achieved, which leads to lower conduction losses and improved converter efficiency. In addition, a reduction in size of auxiliary magnetic elements can be accomplished. To illustrate the usefulness of the proposed design criterion, the paper compares results obtained from the True-PWM Zero-Voltage Switching pole boost converter designed according to the proposed criterion, and from the original design guidelines. Experimental results show an efficiency gain of about 1 % for a wide load range and 1.5% at full load. In addition, a reduction of about 52% in the auxiliary transformer volume for the implemented prototype was achieved, ensuring a reduction in overall converter size. Experimental results were obtained using a 1-kW 100-kHz laboratory prototype. [ABSTRACT FROM AUTHOR]