The Dynamic Optimization Algorithm Design Based The High Frequency LLC Resonant Converter

LLC resonant converter(lc resonance converter)is widely used in high power density in the field of power supply module because it can realize the zero voltage switching(ZVS)in the range of the full load.But because the resonant tank of LLC resonant converter is too complicated,it causes that average space of the traditional modeling method can not be used and the dynamic effect of the trajectory control is poor.According to the above problem,a dynamic optimization control algorithm is proposed for a 150 W half-bridge LLC resonant converter.At first,begin with the precise modeling of the high frequency?state trajectory control algorithm and its optimization ? the control of the overshoot problem,the basic principle of the dynamic optimization algorithm from above three aspects.And then this the concrete solutions are put forward in this thesis:(1)At first,to get the linear equations,making the Fourier transform in the midpoint voltage and the current of the former vice edge of the transformer.Then get the large signal model based on the harmonic balance method,and then do the small signal disturbance and linearization.(2)Based on the relationship between the resonance capacitance variation and the switching frequency,the relationship of the load and the frequency is deduced.(3)When the load is switching,the PID control is joined between the current frequency and the target frequency to realize the step by step adjustment.(4)On the output voltage sampling and the current sampling strategy,this thesis takes the parallel processing scheme to reduce the time of the adjustment.On this basis,the dynamic optimization algorithm is realized by the Saber and MATLAB joint simulation,finally the algorithm of this thesis is verified in a 150 W,24V/6A power system.The measured results show that: in this thesis,under the same condition,the dynamic optimization algorithm that this thesis proposed can be used to realize the overshoot problem,the results show that the overshoot of the output voltage is 4.2%.Of course,the time of the dynamic is reduce to about 90?s.At the same time,the peak efficiency is up to 94%,conform to the design index in this thesis.