Research On Characters And Parameters Optimization Method Of Llc Resonant Converter

Miniaturization and precision of electronic products require increasingly stringent accuracy on efficency and size of the power supply. Switching Resonant Converters technology is an effective way to reduce size of the power supply and improve efficiency.The thesis is focused on a primary resonant converter of high-voltage switching power supply—Half-bridge LLC resonant Dual Voltage Converter, which meets the requirements of certain national project. The prominent merits of LLC resonant converter can be specified as follows, realization of full load rang of ZVS for primary switches and ZCS for secondary diodes, easy integration of resoant inductor and transformer.Consequently it has become a top circuit due to the above advantages.Firstly, we improve LLC resonat converter according to project requirements, which called Half-bridge LLC resonant Dual Votage Converter.Then the paper analyses the whole working principle of the converter which gains some important conclusions, such as the soft-commutation condition of the switch tubes. Secondly, the DC gain characteristic curve is deduced based on the FHA. On this basis, the DC gain characteristics are discussed for establishing foundation of control strategy and parameters optimization. Then we draw the precise DC gain characteristic curve by Pspice simulations. Comparing the precise DC gain characteristic curve obtained from Pspice simulation with the curve based on the FHA, we obtain some valuable conclusions.Thirdly, based on analysis above, a new approach using the optimization theories is proposed. Optimization models are established with objective functions taking aid at four different circuit parameters, the first is minimal peak value of the resonant current, the second is minimal RMS value of the resonant current, the third is minimal cut-out current value of the switching tube, the fourth is minimal loss of the converter. The simulation results testify the validity of the parameters design method. Finally, we draw a conclusion by a hardware experiment that the main circuit taking the fourth design method can get the highest efficiency. All work of the thesis provide theory and technique support for certain national project.