Application of the Generator Mode to Obtain a Diagnostic Signal in the Diagnosis of Permanent Magnet Synchronous Motors

To perform effective diagnostics of the PMSM without its decommissioning, it is necessary to receive a signal that is a carrier for diagnostic information. The number of options for obtaining this signal is quite a lot, but they are specific for each type of drive and for each case. The use of current diagnostics implies the removal of a signal from the supply rail and the use of a direct current signal as a source of diagnostic information. This approach has high validity for asynchronous drives, due to their design features and the absence of permanent magnets in the system. From the point of view of PMSM, the use of direct removal of the current signal from the line in most cases is not justified. The supply voltage to the windings of the PMSM is carried out by switching the control power switches. At the same time, in addition to the control principle itself (touch, sensorless, scalar, vector), the switching principle is essential, namely simple valve switching, or the use of PWM in various frequency ranges, including the implementation of a PWM sinusoid. As a result, a large number of additional harmonic components are obtained in the spectrum of the consumed current, which has a very negative effect on the selectivity of current diagnostics when searching for spectral signatures. Receiving a current signal in generator mode allows you to obtain diagnostic information with minimal side harmonics.