PMSM parameter determination using pulsating torque decoupling for feed-forward control

Many methods have been published for minimizing pulsating torque using programmed reference current waveforms (PRCW), however there are still several problems with their implementation. One major problem is the need to determine motor and controller parameters very accurately. The task of parameter determination is a considerable challenge as any measurement usually involves a number of conversions or scaling factors. Previous implementations of PRCW methods have either used data-sheet values for this scaling or separate calibrations of each individual scaling factor. The limited success of these implementations suggests that a more accurate method is required for parameter estimation. This paper presents an approach to parameter determination using pulsating torque decoupling (PTD), where the motor parameters are determined from the pulsating torque itself from an initial test. To validate this method, it has been implemented on a test motor. Using traditional methods of motor parameter determination, the pulsating torque was approximately 4%. Using the proposed PTD method, the pulsating torque was reduced to approximately 1%.