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An accurate modeling of the series-parallel resonant converter operating in self-sustained oscillation mode including the overlap effects of the output rectifying stage due to the leakage inductance of the transformer is presented. This paper presents a systematic procedure to study the aforementioned effects on the converter dynamic and steady-state performance. Such information is critical in designing isolated high-frequency resonance-based voltage-regulator modules for powering future subvoltage very large scale integration circuits such as microprocessors. The extended describing function technique is used to extract the steady-state characteristics in order to get an optimum converter design. Averaging state-space techniques are employed to derive a small-signal model that can describe the converter dynamics accurately. Analytical and simulation results are given. Finally, a 1-kW experimental prototype is built to verify the validity of the proposed work. Index Terms--Modeling, resonant converters, self-sustained oscillation (SSOC).

This paper presents an improved self-sustained oscillating controller suitable for the single stage single phase power factor correction circuits. It has a modified active controller, which improves the performance from no-load up to full-load. The steady state characteristics are developed and a design example is given in detail. The proposed controller allows zero voltage switching at any loading condition with a reasonable power factor that satisfies the IEC 61000-3-2 standards together with a promising efficiency. Analytical, simulation, and experimental results verify the achievement the design specifications. Index Terms--Power factor correction (PFC), resonant converters, self-sustained oscillating controller (SSOC), zero voltage switching (ZVS).

This paper presents an improved control technique for the full bridge series, parallel, and series-parallel resonant converters. This control technique combines a self-sustained oscillation mode witha phase shift modulation technique that can significantly reduce the range of frequency variation necessary for obtaining zero voltage switching in the resonant converters. This frequency reduction provides optimized component ratings and operating frequency. A simple and accurate low order mathematical model based on the sampled data technique that fully describes the steady-state, and dynamic performance of the resonant converters, has been developed. A refinement algorithm is developed to enhance the accuracy of the modeling technique and the converter design. The improved converter performance and the feasibility of the developed dynamic model have been investigated using the series-parallel resonant converter topology with a capacitive output filter. Finally, MATLAB numerical solutions, PSIM simulation results, and experimental results are given to highlight the merits of the proposed work. Index Terms--Phase shift modulation (PSM), resonant power conversion, sampled-data modeling, variable frequency control, zero-voltage switching (ZVS).