串联谐振逆变器均匀PDM功率控制方法

Series Resonant Inverter With Symmetrical PDM Power Control Method

串联谐振逆变器脉冲密度调制(PDM)功率控制可以在全功率范围实现功率器件的零电压开关(ZVS),但会导致输出电流波动变大,尤其在低品质因数时会造成电流断续。为了解决逆变器输出电流波动大的问题,提出了一种改进的PDM功率控制方法,脉冲分布采用ΔΣ调制,无需存储器查找表即可实现在任意调功周期下的逆变脉冲均匀分布,减小了输出电流波动,提高了功率控制精度。使用现场可编程门阵列(FPGA)芯片作为主控制器,搭建了一台50 kW串联谐振逆变电源样机,仿真和实验验证了上述控制方法的有效性。

The pulse density modulation(PDM)power control of series resonant inverter can realize the zero voltage switching(ZVS)of power devices in a full power range,but it will cause the output current ripple to increase,especially when the quality factor is low.In order to solve the problems of the inverter output current ripple,an improved PDM power control method is proposed,usingΔΣmodulation on the pulse distribution,without memory look-up table can be realized under arbitrary cycles of inverter pulse symmetrical distribution,reducing the output current ripple,and the power control precision is improved.A 50 kW series resonant inverter prototype is built by using field programmable gate array(FPGA)chip as the main controller.Simulation and experiment verify the effectiveness of the above control method.