Steady-state analysis of the constant-frequency clamped seriesresonant converter

A constant-frequency diode-clamped series resonant converter (CFCSRC) is proposed as a solution to problems associated with frequency-controlled resonant converters. This converter has two resonant frequencies, and control is achieved by varying the relative time spent at each switching frequency. Two zero-current-switching (ZCS) modes are examined and plotted in the output plane. An equation is given for the boundary between the two ZCS modes, as well as an expression for the boundary between ZCS and non-ZCS operation; both are plotted in the output plane. The output equation for the main mode is shown to be hyperbolic. Converter peak voltages limited to the input voltages, and peak currents are less than those of the frequency-controlled clamped series resonant converter over a large operating range. Data from a prototype converter are compared with theoretical data and are shown to be in good agreement with the theoretical model     

Comparison of resonant topologies in high-voltage DC applications

Because of their tolerance of transformer nonidealities, resonant converters are considered to be well-suited to high-voltage applications. The series and parallel resonant topologies, as well as a newly discovered hybrid resonant topology are compared for high-voltage applications. Design criteria which incorporate transformer nonidealities are developed and used in the construction of high voltage prototypes for each topology. It is found that the parallel topology leads to the lowest peak switch current and the most ideal behavior     

Analysis and prediction of regulation in a multiple-outputcurrent-mode controlled DC-to-DC converter

A technique is developed for predicting the closed-loop steady state output voltage regulation of a multiple-output current-mode controlled converter. The proposed model accounts for the current loop, the voltage loop, and the integrator in the compensation scheme. This method allows tradeoffs with respect to regulation between different components or feedback configurations to be evaluated during the design of a converter. Experimental verification on a three-output current-mode controlled push-pull converter with single output voltage feedback is provided     

LLC parallel resonant converter design by scaling the LC converter

An efficient and practical method for steady-state design of an LLC-type parallel resonant dc/dc converter (LLC-PRC) is presented. In general, the output characteristic curves of LLC-PRC can be obtained by multiplying the output curves of the LC-type parallel resonant converter (LC-PRC) by a ratio of the parallel and series inductances. The peak voltage and current stresses on the resonant elements also depend on the same ratio. The LLC-PRC with a filter inductor is examined for two conduction modes, continuous and discontinuous capacitor voltage conduction modes, to show the effect of the inductance ratio. A means to use the derived equations to obtain the zero current switching (ZCS) is given. Also, a design procedure, along with design examples, is given to illustrate the use of the equations and characteristic curves. An experimental LLC-PRC is built to ensure the validity of the equations and design examples     

Design of the Series Resonant Converter for Minimum Component Stress

For a given output voltage and power, the peak resonant capacitor voltage and peak inductor and switch currents of the series resonant converter depend strongly on the choice of transformer turns ratio and of tank inductance and capacitance. In this paper the particular component values which result in the smallest component stresses are determined, and a simple design strategy is developed. The procedure is illustrated for an off-line 200 W, 5 V application, and it is shown that an incorrect choice of component values can result in significantly higher component stresses than are necessary.