变频微波炉电源用LLC谐振变换器

研制了一款专为变频微波炉中磁控管供电的高频软开关电源。采用倍压输出式LLC谐振变换器作为该电源的主电路,并用基波分析法建立了其稳态基波等效电路模型;对其直流增益、谐振电流及零电压导通条件等进行了分析,并对高频变压器的电压比、品质因数、励磁电感、谐振电感及谐振电容等核心参数进行了优化设计。仿真和实验表明所建立的稳态电路模型及其理论分析是正确的,给出的谐振网络参数及其优化设计是正确的,这对于分析、研究和改进变频微波炉电源的设计及指导生产具有现实意义。

Study of LLC Resonant Converter for Variable-Frequence Microwave Oven Power Supply

A high-frequency soft switch power supply prototype was developed,which was technically designed to provide power source for magnetron in variable-frequence microwave oven.A LLC resonant converter whose output end combined with a voltage doubling rectifying circuit was used as its main circuit topology.The main circuit’ steady-state equivalent circuit model was established based on first harmonic analysis method.By means of the model the circuit’ DC gain,resonant current and zero-voltage-switching(ZVS) condition were theoretically analyzed,and the converter’ key parameters such as turns ratio of high frequency transformer,quality factor,excitation inductance,resonant inductance,resonant capacitance were optimized.The simulation result and the experimental verification indicate that the established steady-state equivalent circuit model and its theoretical analysis are correct,and the resonant network parameters’ theoretical analysis and its optimal design are correct.The results have practical significance for analyzing,studying,improving magnetron power supply and guiding its production.