Resolver-To-Digital Conversion and Sensor Fault Identification of PMSM

The permanent magnet synchronous motor (PMSM) is the core equipment for next-generation trains in the rail transportation field, and the resolver is a commonly used position sensor for PMSM. The position of the motor is conversed from the output orthogonal waveform of the resolver. This paper presents a method for resolver-to-digital conversion (RDC) and a sensor fault identification method of PMSM. In the first part, the structure of the resolver is introduced, as the resolver modulates the angle value with the high-frequency excitation signal and outputs it to the system. So, the system first needs to demodulate the signal and then make resolver-to-digital conversion. This conversion uses a phase-locked loop to get the rotor angle. In the second part, a sensor fault identification method is presented. When the sensor gets a fault, there will be a pulsation in the stator’s current, and the angle error is calculated from the motor current pulsation. According to the simulation results, the method has small identification errors and fast response speed.