Analysis Of Series Resonant Converter Research Articles

Time-Domain Analysis of a Phase-Shift-Modulated Series Resonant Converter with an Adaptive Passive Auxiliary Circuit

This paper presents a comprehensive time-domain analysis of series resonant converters operating with phase-shift-modulated full-bridge above resonance. Closed-form formulas for all quantities are derived using two methods: the commonly used fundamental harmonic approximation as well as a precise time-domain analysis considering the effect of all the harmonics. Detailed analytical method describes steady-state behavior of the converter in three mutually exclusive and collectively exhaustive modes of operation based on continuity of the resonant inductor current: a discontinuous mode and two continuous modes. The difference between two continuous modes is in the existence of natural zero-voltage switching in the leading leg of the full bridge. Quantitative predictions of the key quantities from two methods are compared and the accuracy of the first harmonic approximation is examined. The time-domain approach provides useful insights for design considerations with no need to know the load value. It precisely determines closed-form equations for the boundary conditions of the three operation modes. An adaptive passive auxiliary circuit is suggested to guarantee zero-voltage switching for the entire operating conditions. Experimental results from a 100 W prototype confirm the predicted time-domain behavior and achievement of soft switching using the proposed auxiliary circuit.

Analysis of series resonant converter with series–parallel connection

In this study, a parallel inductor-inductor-capacitor (LLC) resonant converter series-connected on the primary side and parallel-connected on the secondary side is presented for server power supply systems. Based on series resonant behaviour, the power metal-oxide-semiconductor field-effect transistors are turned on at zero voltage switching and the rectifier diodes are turned off at zero current switching. Thus, the switching losses on the power semiconductors are reduced. In the proposed converter, the primary windings of the two LLC converters are connected in series. Thus, the two converters have the same primary currents to ensure that they can supply the balance load current. On the output side, two LLC converters are connected in parallel to share the load current and to reduce the current stress on the secondary windings and the rectifier diodes. In this article, the principle of operation, steady-state analysis and design considerations of the proposed converter are provided and discussed. Experiments with a laboratory prototype with a 24 V/21 A output for server power supply were performed to verify the effectiveness of the proposed converter.

Frequency-domain analysis of series resonant converter for continuous conduction mode

Most previous analyses of a series resonant DC-DC power converter (SRC) have been performed in the time domain. A comprehensive frequency-domain analysis of the SRC for steady-state operation, along with experimental results is presented. Simple analytical design equations are derived for the basic performance parameters of the converter operating in the continuous conduction mode (CCM) using Fourier series techniques and a high-Q/sub L/ assumption. Three types of class-D current-driven rectifiers are considered. The diode threshold voltage and forward resistance as well as the ESR of the output filter capacitor are taken into account. Experimental results were in good agreement with theoretical predictions. >