单励磁区间电流数字化的SRM功率变换器故障诊断策略

Fault diagnosis strategy for power converter of switched reluctance motor based on single excitation current digitalization

以四相8/6结构的开关磁阻电机功率变换器为研究对象,研究不对称半桥(AHB)式功率变换器的故障问题。分析功率变换器不同开关状态的工作模态,计算单开关管开路和短路故障时的相电流和平均转矩,并对比故障特征;通过改变功率变换器电流传感器的安装位置,提出一种仅需检测单相励磁区间内励磁和续流总线电流的故障诊断策略。该策略可以诊断出功率变换器单相开关管的短路和开路故障,并且能够定位出桥臂上短路和开路故障器件的位置。该方法仅需利用一相桥臂的励磁区间就可以实现故障诊断和故障定位,易于实现,且具有诊断逻辑简单、运算量小、快速性好、准确度较高的优点。仿真和实验结果验证了本文提出的故障诊断方法的有效性。

Power converter of a four-phase 8/6 switched reluctance motor system was taken for study and the fault issues of the asymmetrical half-bridge(AHB) power converter was investigated. By analyzing the switching states and operation modes of AHB power converter, the phase current and average torque of phase switches were calculated and the fault characteristics were comparatively analyzed;By changing the installation position of the current sensors, a fault diagnosis strategy was proposed, which only required detecting the excitation and freewheeling bus current of each phase during excitation operation. The single-phase short circuit and open circuit fault of the power converter can be diagnosed by the proposed strategy, and the short circuit and open circuit fault device can be located. Only one phase excitation interval is needed by the proposed method, which possesses advantages of ease installation, simple diagnosis logic, low computation burden and fast speed and high accuracy. Finally, effectiveness of the proposed strategy were verified by simulation and experiment results.