一种三相光伏并网逆变器故障诊断方法

A Fault Diagnosis Method for Three-Phase Photovoltaic Grid-Connected Inverter

并网逆变器的可靠性关系到电网和自身的安全运行,并网逆变器主电路由若干开关器件组合而成,开关器件存在短路和开路故障。根据光伏并网逆变器特点,提出一种三相光伏并网逆变器开关器件开路故障诊断方法。逆变器开关器件发生开路故障时电网中性点与直流侧负极之间的电压与正常工作时的电压不同,将该电压作为特征量。结合光伏并网逆变器单位功率因数并网特点,以电网电压矢量角度为参考,对开路器件进行诊断。仿真和实验结果表明,该方法可以在一个电流周期内准确定位开路故障器件。

The reliability of grid-connected inverter is related to the safety of grid and itself. The main circuit of grid-connected inverter is made up by a number of switch devices, and switch device has short or open-circuit fault. An open circuit fault diagnosis method of switch devices for three-phase photovoltaic grid-connected inverter is proposed accord to the characteristics of photovoltaic grid-connected inverter. The voltage between the grid neutral point and the negative terminal of DC side is different from that of normal working, when the switch devices open-circuit fault of grid-connected inverter occurs. As a character, the voltage is taken, and the grid voltage vector angle based on the unit power factor photovoltaic grid-connected inverter is combined for reference to diagnosis the open-circuit fault devices. Simulation and experimental results show that this method can locate open-circuit fault devices accurately in a current cycle.