直流母线与辅助电路并联的谐振直流环节软开关逆变器

Resonant DC-link Soft-switching Inverter With Auxiliary Circuits in Parallel With DC Bus

谐振直流环节逆变器的直流母线上通常设置了一个辅助开关器件,制约了其效率提高,这也是其在高功率领域应用推广不多的原因之一。为解决这一问题,文中设计的谐振直流环节软开关逆变器的辅助电路与直流母线并联,辅助开关器件和谐振元件均没有串联在直流母线上,有助于提高效率及降低辅助谐振电路的功率损耗。文中对所设计的电路拓扑结构采用相平面分析法来分析其动力学行为、软开关实现条件以及设计规则,并建立起辅助谐振电路损耗和效率提高值的数学模型。搭建一台10 k W的实验样机,将实验结果和硬开关逆变器比较,结果表明,设计的逆变器满载时的效率提高值高于轻载时的效率提高值。因此,文中所设计的软开关逆变器有利于减小辅助谐振电路的能耗,保障电能的高效利用。

One auxiliary switch is usually set on the DC bus of resonant DC link inverter, which restricted efficiency improvement. That is also one reason why resonant DC link inverter is not applied in the high-power field. To solve the problem, this project proposed a resonant DC-link soft-switching inverter with auxiliary circuits in parallel with DC bus. Auxiliary switches and resonant elements were not on the DC bus of the novel topology, which was helpful to reduce loss of auxiliary resonant circuit and improve efficiency. In the paper, the phase-plane analysis technique was established for the novel resonant DC link inverter in order to study transient dynamics, soft-switching condition and design rule. The mathematical models for auxiliary resonant circuit loss and the value of improvements in efficiency were established. A 10 k W laboratory prototype was built. Experimental results demonstrated value of efficiency improvements in full load was no less than that in light load. Therefore, the proposed soft-switching inverter is beneficial to reduce loss of auxiliary resonant circuit and ensure high power utilization ratio.