Research And Design Of High Frequency Resonant Soft Switching Converter

Modern power electronics technology develop in the high-frequency, modular, digital direction. High-frequency can reduce the filter parameters and the volume of the transformers,but also increase the switching loss and decrease circuit efficiency. High frequency resonant soft switching converter solves the switching loss and noise problems, but the resonant converter is usually a strong nonlinear system, the circuit analysis and design process is very complicated, so it is more and more urgent to study the accurate mathematical model of high frequency resonant soft switching converter.Based on the research project, The time domain modeling method and control technique of series resonant converter are studied. The main contents include the following aspects:In this paper, based on the analysis of the common topology and control method of high frequency resonant soft switching converter at home and abroad, the series resonant converter is chosen as the main circuit topology. Turning on and turn off the IGBT when resonant current through the diode current or intermittent to achieve zero voltage switching (ZVS) and zero current switching (ZCS).High frequency and high voltage transformer is an important component of series resonant converter. This paper analyzes its equivalent models, the leakage inductance,distributed capacitance, the influence of them on the circuit topology and the suppression method. A method for measuring leakage inductance and distributed capacitance is presented.Due to many working modes,this paper analyzes the working mode and resonance process of switching frequency greater than resonant frequency, derives mathematical description equation of different period of harmonic oscillator and simulation verification, studies influence of switching frequency on the output voltage, draws the steady-state trajectory of resonant current and resonant capacitor voltage, and also analyzes the mode of the switching frequency less than the resonant frequency, compares influence of different Q on the resonance current.Finally, based on time domain model, This paper analysises the resonant parameter design method and frequency conversion control technology,writes the control algorithm, and builts the experimental verification platform. The hardware is debugged and verified by experiments.The experimental results are in agreement with the theory.