Open-Loop and Real-Time Control Method of Series-Resonant HF-Linked Converter with DC Input and AC output.

Abstract

This paper proposes a open-loop and real-time control method of a series-resonant high-frequency linked converter with a DC input and a single-phase sinusoidal AC voltage output.Resonant converters have lately attracted considerable attention because they can perform zero-current or zero-voltage switching, which produces little switching loss, and high frequency operation which realize compact converters. The conventional resonant converters are mainly DC-to-DC converters and DC-to-AC ones, and their control algorithms are based on the transient operations from microscopic viewpoint. Therefore, the macroscopic transient characteristics of the converters including their load has not been studied sufficiently from macroscopic viewpoint. Moreover, the conventional control algorithms of DC-to-AC converters require detection of the voltage or current in the resonant circuit or the switching devices to realize stable resonant operation and zero-current or zero-voltage switching.In this peper, an approximate analysis of the basic series-resonant converter is performed, and then simple equations and an equivalent circuit of the converter are obtained by introducing some rules to the switching sequences of the converter. Based on the equations and the equivalent circuit, a realtime and openloop control algorithm of the series-resonant converter is derived in the same way as the conventional PWM inverters/converters to obtain a single-phase sinusoidal and rectangular voltage waveform.Experimental results to confirm the feasibility and the usefulness of the proposed control algorithm are presented.