基于区间滑模观测器的逆变器开路故障诊断方法

A Diagnosis Method for Open-circuit Faults in Inverters Based on Interval Sliding Mode Observer

为了提高逆变器系统故障诊断的鲁棒性和准确性,该文提出一种基于区间滑模观测器的逆变器开路故障诊断方法。首先利用开关管在正常工作和故障状态下的电流流向路径建立逆变器的混合逻辑动态模型,并设计一种电流区间滑模观测器,其通过上界滑模观测器的电流估计值和下界滑模观测器的电流估计值的凸加权和来估计逆变器在正常工作状态下的三相电流值。通过比较实际系统和观测器的输出得到电流残差进行故障检测,根据残差中包含的故障信息建立残差信息表进行故障定位。设计的电流区间滑模观测器不仅可提高区间观测器的收敛速度,并且可有效减小抖振,提高故障诊断系统的鲁棒性。最后,通过仿真和一台200W的电机实验平台验证该方法的有效性和可行性。

To improve the robustness and accuracy of inverter system fault diagnosis, a diagnosis method for open-circuit faults in inverters based on interval sliding mode observer was proposed. Firstly, the Mixed Logic Dynamic model of the inverter was established by using the current flow direction of the switch under normal working and fault conditions, and a current interval sliding mode observer was designed, which is constructed via a convex weighted sum of the current estimators of the upper bound sliding mode observer and the lower bound sliding mode observer and is used to estimate the normal three-phase current value of the inverter. The current residual which was obtained by comparing the current from the actual system and the observer was used to detect fault. And the residual information table was established according to the fault information contained in the residual to perform fault location. The designed current interval sliding mode observer can not only improve the convergence speed of the interval observer, but also effectively reduce the chattering and improve the robustness of the fault diagnosis system. Finally, the effectiveness and feasibility of the proposed method were verified by simulation and a 200 W motor experimental platform.