Detection and classification of turn fault and high resistance connection fault in permanent magnet machines based on zero sequence voltage

Health monitoring and fault detection are becoming more and more important in electrical machine systems due to the increasing demand for reliability. Winding turn fault is a common fault in permanent magnet machines which can cause severe damages and requires prompt detection and mitigation. High resistance connection (HRC) fault which result in phase asymmetry may also occur but does not require immediate shutdown. Thus, apart from the fault detection, the classification between the two faults is also required. In this paper, a new technique for detecting and classifying turn fault and HRC fault by utilizing both the high and low frequency components of the zero sequence voltage is proposed. The dependence on the operating conditions is minimized with the proposed fault indicators. The effectiveness of fault detection and classification has been verified by extensive experimental tests on a triple redundant fault tolerant permanent magnet assisted synchronous reluctance machine (PMA SynRM). The robustness of the turn fault detection in transient states and under no load conditions has also been demonstrated

Current residual based stator inter-turn fault detection in permanent magnet machines

Inter-turn short circuit fault, also known as turn fault is a common fault in electric machines which can cause severe damages if no prompt detection and mitigation are conducted. This paper proposes a turn fault detection method for permanent magnet machines based on current residual. After the impact of the turn fault is firstly analyzed on a simplified mathematical machine model to assess the fault signature, a finite element (FE) model is developed to obtain healthy machine behavior. The residual between the measured and estimated currents by the model with the same applied voltages contains mainly the fault features. The quality of the fault detection can be improved because the fault signatures are enhanced, and the impact of the current controller bandwidth on fault signature is minimized. The dc components in the negative sequence current residuals are extracted through angular integration and their magnitude is defined as the fault indicator. The robustness of the fault detection against transient states is achieved. The effectiveness of the proposed method is validated on a triple redundant fault tolerant permanent magnet assisted synchronous reluctance machine (PMA SynRM)

High frequency voltage injection based stator inter-turn fault detection in permanent magnet machines

An inter-turn short-circuit fault in the stator winding of an electric machine, denoted as turn fault, has been recognized as one of the most severe faults in permanent magnet machines which requires swift and reliable detection, in order to implement appropriate mitigations. The asymmetry brought by a turn fault is widely used for the fault detection. However, similar features also emerges in a less severe high resistance connection (HRC) fault, which may led to incorrect fault identification. In this paper, a more exclusive turn fault detection method with the ability to differentiate from the HRC fault is proposed. It injects high frequency square wave voltage signals and makes use of the difference in high frequency impedance under the two fault conditions. The sensitivity to HRC fault is largely reduced. The proposed turn fault indicator is independent of operating conditions and robust with respect to state transients. This method is validated in a fault tolerant permanent magnet assisted synchronous reluctance machine drive

An Early Stage Interturn Fault Diagnosis of PMSMs by Using Negative-Sequence Components

This paper proposes an early stage interturn short-circuit fault (ISCF) diagnosis method for permanent magnet synchronous machines. A fault indicator is suggested based on a new theoretical analysis of the relationship between the fault current and the rotor speed. The fault indicator is shown to be robust to the rotor speed changes in slight ISCFs. It is calculated by introducing negative-sequence components (NSCs). It is shown that the fault indicator using NSCs can diagnose slighter ISCFs than that using zero-sequence components. Experimental results demonstrate the effectiveness of the proposed method for diagnosing early stage ISCFs with a small number of short-circuited turns and low fault current. ? 1982-2012 IEEE.117Nsciescopu