Optimal Trajectory Control Of Series Resonant DC/DC Converter

With the development of power electronics, resonant DC / DC converter has been given more and more attention in large power and high power density applications, because of high efficiency, minimize switch losses, stresses and EMI as well. In order to get superior performance, resonant DC / DC converter not just to rely on its topology, control methods also play an important role.Now, common control methods of the series resonant DC/DC converter have variable frequency control,phase-shift control,self-sustained oscillation control,self-sustained phase-shift control,optimal trajectory control and so on. The main research content of this topic is based on the state plane analysis of the optimal trajectory control principle in the full-bridge series resonant DC / DC converter applications.Optimal trajectory control of series resonant DC / DC converters is divided into variable frequency and constant frequency optimal trajectory control. The above two cases separately contain two kinds of working condition are switching frequency above and below the resonant frequency. Firstly, this paper introduces eight kinds of operation mode equivalent circuit of the full-bridge series resonant DC / DC converter, and analyses their state-planes. Secondly, the steady state-plane diagrams of the four kinds of working conditions are constructed and the corresponding control laws are introduced in the paper. In order to improve the robustness of the converter, the control laws also are simplified to a"linear approximation"form. Similarly, in order to illustrate the excellent performance of the optimal trajectory control on transient response, the phase-shifted control is also introduced in the paper. Lastly, the simulation results verify the correctness of the principles analysis of optimal trajectory control.The experimental circuit structures of all subjects using the analog devices. In the article, except to introduce the main circuit parameters, but also introduced the optimal trajectory control and phase-shifted control of the control circuit design, and built a phase-shift control circuit, a variable frequency and a constant frequency optimal trajectory control circuit. The relevant experimental results are given to verify the correctness of the working principle and analysis of the circuit correctly.