并网逆变器的等效模型及其在孤岛检测中的应用研究

Study on Equivalent Model Based Grid-connected Inverter and Its Application in Islanding Detection

并网逆变器在新能源发电等系统中发挥着重要的作用.并网逆变器在研制、调试、开发过程中,若因控制算法、保护电路设计或调试方法不当等,很容易损坏主电路中的开关器件,导致经济损失、影响逆变器的研制开发进度.本文推导并建立了单相并网逆变器的模拟开关和运放模拟电路等效模型,以此等效模型为基础设计半实物硬件仿真系统来模拟实际的单相并网逆变器,并以主动电流扰动孤岛检测算法为例对此等效模型进行了可行性验证.该法可有效简化硬件设计、降低调试成本,仿真和实验结果验证了逆变器等效模型的有效性和实用性.

Grid-connected inverter plays an important role in new energy power generation system.In the development,debugging and building of a grid-connected inverter,the switching devices in the main circuit tend to be damaged due to the improper control algorithm,improper protection circuit design or improper debugging method,thus leading to economic losses and affecting the development progress of inverter.An analog switch and op-amp analog circuit based equivalent model for grid-connected inverter was derived and established,and a semi-object hardware simulation system based on this equivalent model was then designed to emulate the real single-phase grid-connected inverter.The feasibility of the equivalent model was verified through active current disturbing method of islanding detection.The proposal presented can effectively simplify hardware design and reduce debugging cost.The feasibility and effectiveness of the inverter equivalent model were verified with simulation and experiment results.