3次谐波谐振电路在桥式射频电源中的应用研究

Application of Third-order Resonant Circuit in Full-bridge RF Power Supply

在桥式射频电源中接入3次谐波谐振电路,用于改善MOSFET的快速开关状态。通过在桥式逆变器的交流端连接3次谐波谐振电路,将3次类正弦波电流叠加于正弦负载电流上,从而实现对MOSFET输出电容的快速充电或放电,使MOSFET适用于更高的工作频率。对2 MHz/2 k W射频电源进行仿真分析,其结果表明:接入3次谐波谐振电路不仅减少了MOSFET的换向时间,而且降低了MOSFET的开关损耗;同时,死区和3次谐波谐振电路品质因数对电路的影响分析,验证了3次谐波谐振电路的可行性和有效性。

A third-order resonant circuit is connected to a full-bridge RF power supply to improve the fast switching states of MOSFET. By connecting the third-order resonant circuit at the AC terminals of a full-bridge inverter, the third-order sine-like resonant current is superimposed on a sinusoidal load current, which helps to quickly charge or discharge the output capacitance of each MOSFET and makes it suitable for higher operation frequencies. Simulation results obtained from a 2 MHz/2 kW RF power supply show that the connection of a third-order resonant circuit not only reduces the commutation time of MOSFET, but also reduces its switching loss; at the same time, the influences of deadtime and the Q-factor of the third-order resonant circuit on the circuit are analyzed, which verifies the feasibility and effectiveness of the third-order resonant circuit introduced in this paper.