Design Of Half-bridge LLC Resonant Converter Power Supply For Metro Platform Screen Door

As an important part of the rail transit system,the platform screen door system provides passengers with a safe and comfortable waiting environment.However,the control power performance in the metro platform screen door system has a greater impact on the entire system.In order to ensure its safe and reliable operation,the metro platform screen door system has high requirements for its control power supply.The half-bridge LLC resonant converter not only can achieve Zero Voltage Switching（ZVS）of the switch tube in the full load range,but also has the advantages of high conversion efficiency and good voltage regulation performance,so this thesis is based on the half-bridge LLC resonant topology to design the metro platform screen door control power supply.First,the structure of each part of the half-bridge LLC resonant converter is briefly introduced,and the modal analysis of its operating principle is performed.The Fundamental Harmonic Analysis（FHA）is used to model the half-bridge LLC resonant converter and the equivalent model of each part is obtained.After that,the AC equivalent model of the converter is obtained by unifying each model.Based on this,the formula of DC voltage gain is deduced,the gain curve is drawn,and the influence of the inductance ratio L_n,quality factor Q and operating frequency f_s on the converter is analyzed.Secondly,the constraint conditions of the half-bridge LLC resonant converter to realize the ZVS of the primary MOS transistor are discussed.According to the relationship among the parameters,a parameter design procedure of the half-bridge LLC resonant converter is given.After designing the resonance parameters according to the given design steps,after the PSIM simulation software is verified,the hardware part of the control power supply is started to be designed,and a 600W control power supply prototype is produced to test the performance of the prototype.The performance test result of the control power supply prototype shows that the prototype can realize ZVS of the MOS transistor in the full load range when the rated voltage is input,and can also realize the ZCS of the rectifier diode,and its maximum conversion efficiency reaches91.12%.The output voltage range from no load to full load is 23.93V²3.97V,its dynamic response time is 178μs,the overshoot△V₂ is 350mV,and the maximum output voltage ripple is 76mV,all meeting the requirements of control power supply performance indicators.