Novel Online Non-Invasive Measurement Approach for PMSM-Transmission Chain Radial Natural Frequency Based on Driving PMSM Radial Force Injection

In motor drive systems, the radial natural frequency of the system is a crucial parameter, which is very helpful for system working condition selection, condition monitoring, and fault diagnosis. Most traditional methods for testing the natural frequency of are offline or invasive. In order to achieve online non-invasive measurement of the radial natural frequency of the motor transmission system, this study proposes a radial force generation method for permanent magnet synchronous motors based on multi rotation PI current injection, which enables the motor to have both driving and excitation functions, to excite the radial resonance of the system. The effectiveness of the proposed method has been experimentally verified and is well consistent with the offline test result.