An Automated Resolver Error Compensation Method Based on Sinusoidal Representation of the Error Term

Abstract

This paper presents a novel error compensation method for resolvers to improve motor drive performance. It is shown that the nature of the error terms of the position information provided by the resolver is deterministic to a large extent, as they mainly stem from the physical imperfections regarding the resolver and its mounting. This motivates a model-based approach of extracting the error terms and modelling them as the sum of sinusoidal waveforms. Therefore, the resolver output signal can be corrected by the recorded error model without any delay. In the proposed method, the memory requirement and computation burden to the CPU is negligible. Thus, the method is very convenient for practical applications. To determine the error model, hence the compensation parameters, an offline calibration procedure is run once and the extracted parameters can be used for the entire life cycle of the motor as long as the mounted resolver is not removed. Enhanced performance parameters of the motor driver system are verified on a 100kW Internal Permanent Magnet Synchronous Motor (IPMSM) test setup and the results are presented. It is experimentally shown that the proposed compensation algorithm is able to decrease the peak-to-peak position error magnitude from 3.834 to 0.322 degrees (91.6% reduction).