基于吸收功率管变频控制的软开关逆变器研究

Soft-Switching Inverter Based on Variable-Frequency Control of Absorber Power Device

针对正激直流环节软开关逆变器提出一种新的吸收功率管变频控制策略 ,给出了变频控制逻辑 ,详细分析了逆变器的工作模态 ,给出了实验波形。通过仿真进行了吸收功率管定频和变频运行特性对比分析。该控制方案有助于降低逆变桥功率管的电压应力、提高逆变器的效率 。

A resonant DC link soft-switching inverter is composed of resonant DC converter and full-bridge inverter. The resonant DC link outputs a DC pulse voltage, thus providing zero-voltage-switching condition for power devices in inverter bridge. Compared with the hard-switching inverter, the cur rent pulsation of output filter inductor and the voltage stress of power devices in the inverter bridge are raised because of the DC pulse voltage. For this rea son, this paper proposes a novel variable-frequency control strategy of absorbe r power device for forward DC link soft-switching inverter. The control logic i s given. The operational modes of inverter are analyzed and experimental results are presented. Performance contrasts under constant-frequency and variable-fr equency control of absorber power device are analyzed by simulation. This contro l strategy is benefitable for reducing the voltage stress of power devices in in verter bridge and improving the efficiency of inverter. The power devices realiz e zero-voltage-switching as before.