闭环状态下并网逆变器故障诊断

Grid-connected inverter fault diagnosis in closed loop

目前针对并网逆变器的故障诊断方法主要应用于开环系统中,而实际的并网逆变器多数为闭环控制系统。因此针对闭环状态下的并网逆变器,提出一种基于相电流的故障诊断方法。通过分析闭环状态下并网逆变器在正常和各开路故障类型下的相电流,得出发生多管开路故障下的相电流平均值和平均绝对值残差的故障特征。首先利用闭环控制回路中Park变换所产生的相电流与实测相电流进行平均值运算,然后根据归一化的相电流平均值和平均绝对值残差相结合来进行故障诊断。最后通过实验验证该诊断方法能够在闭环控制下快速检测和识别单管和多管开路故障。

At present,the fault diagnosis method for the grid-connected inverter is mainly applied to the open-loop system,and the actual grid-connected inverter is mostly a closed-loop control system.Therefore,for the grid-connected inverter in the closed-loop state,this paper proposes a fault diagnosis method based on phase current.By analyzing the phase current of the grid-connected inverter in the closed loop state under normal and open fault types,the fault characteristics of the average value of the phase current and the average absolute residual value under the open circuit fault are obtained.Firstly,the average value of the phase current generated by the Park transform in the closed loop control loop is compared with the measured phase current,and then averaged according to the normalized phase current.The value is combined with the average absolute residual to diagnose the fault.Finally,it is verified by experiments that the diagnostic method can quickly detect and identify single-tube and multi-tube open-circuit faults under closed-loop control.