Research On High-Efficiency Load Tracking Control Of LLC Resonant Converter

At present,the continuous consumption of non-renewable energy and the increasing output of automobiles worldwide,the situation of energy shortage is becoming more and more severe.As the world's largest energy input,the output of petroleum is also rapidly consumed.Oil and fossil energy The resource shortage is becoming more and more prominent,and as these nonrenewable energy consumption and environmental problems also follow,so more and more countries begin to expand other new energy products in the field of new energy,in order to deal with various new energy power conversion Many power conversion systems have been derived.The power conversion system is generally composed of various converters,of which the resonant converter is one of them.The resonant converter is a special converter.Its important feature is the structure of the resonant cavity.According to the different combinations of capacitance and inductance,a variety of resonant cavities can be formed.The current research focus is on the LC resonator,LLC resonator,LCL resonator and so on.The resonant converter has good characteristics such as suppressing the return power and making it easier to achieve soft switching.In this thesis,based on the basic research materials,on the basis of theoretical analysis,the fundamental wave analysis method is used to model and analyze the LC resonant converter and LLC resonant converter models,operation analysis comparison,calculation analysis comparison and simulation analysis comparison.Later,it was found that the LLC resonant converter has more excellent features that the LC resonant converter does not have.Then,the focus is on modeling and analyzing the energy transmission efficiency and structural complexity of the LLC resonant converter,and calculating and adjusting the control method and algorithm complexity.,Derived energy transfer model and proposed load tracking control method,including impedance matching tracking method and voltage tracking method,and finally verified the results through simulation and experiment.For a resonant converter,there are generally three parts: the study of physical model structure,the study of modulation strategy,and the study of control strategy.This article will focus on detailing these three parts.Through these three parts,the energy transmission efficiency curve and control will be studied.Means,the rest will focus on soft switching and controller algorithms.By analyzing the input impedance characteristics and output impedance characteristics of the LLC resonant converter,the control characteristics in the load tracking control mode are derived,the impedance matching mode is realized by the phase tracking method,and the voltage tracking method is realized by switching off the frequency conversion-phase shift modulation..