Demagnetization Fault Indexes in Permanent Magnet Synchronous Motors—An Overview

Demagnetization fault is the most widespread fault in permanent magnet synchronous motors (PMSMs). Diagnosing this fault and extracting appropriate indexes for the PMSM are proposed and discussed in this paper. The index-extracting techniques and their advantages, disadvantages, and significant ambiguities are proposed, and it is emphasized how these ambiguities can be eliminated. This can help the newcomers to this field as well as designers and manufacturers of protection and fault diagnosis industry. In light of this information, the readers will have a full view on different aspects of each index. An optimum index can be chosen based on the sensitivity of application and the cost of index implementation.