一种新型无源软开关三电平逆变器

软开关技术可以最大限度提高效率和功率密度,是满足工业应用高功率和高频化要求的最佳选择。但目前三电平逆变领域软开关技术鲜有应用且缺点尚多,如辅助开关器件繁多、控制复杂化、振荡以及开关管电压应力大等。提出一种新型无源软开关三电平逆变器,辅助电路简单且无需改变调制方式,能够平稳实现所有开关管的零电压关断和零电流开通。依据各模态的等效电路,详述了所提软开关逆变器的工作原理,总结了软开关实现的基本条件。最后,原理样机试验表明该软开关逆变器能够实现所有功率管的软开关动作,功率管电压应力限制在安全裕度以内,中点电压波动较小,换流过程不会出现高频振荡。

Novel Passive Soft-switching Three-level Inverter

Soft switching technology maximizes efficiency and power density and is the best choice for high power and high frequency require-ments in industrial applications. However, the current soft-switching technology in the three-level inverter field has few and shortcom-ings, such as a large number of auxiliary switching devices, complicated control, oscillation, and large voltage stress of the switching tube. Therefore, this paper proposes a novel passive soft-switching three-level inverter. The auxiliary circuit is simple and does not need to change the modulation mode, and can realize zero voltage turn-off and zero current turn-on of all the switch tubes smoothly. According to the equivalent circuit diagram of each mode, the working principle of the proposed soft-switching inverter is detailed, and the basic conditions of soft-switch implementation are summarized. Finally, the prototype test shows that the soft-switching inverter can realize the soft switching action of all power tubes, the power tube voltage stress is limited to the safety margin, and the high-frequency oscillation does not occur in the commutation process.