Flux linkage measurement method for switched reluctance motors and inductor/transformers using a real-time DSP system

Abstract

The switched reluctance motor (SRM) has received considerable attention from researchers for its many inherent advantages, and thus has become a popular research topic in the field of variable-speed drives as well as servo drives. The research on SRMs mainly includes its design, modelling and performance analysis, control, as well as applications. However, for verification of design, performance prediction and development of a high-performance sensorless control algorithm, accurate measurement of the magnetic characteristics of the SRM is most critical. Hence, one of the most important problems in the field of SRMs is a practical and accurate instrumentation system for the measurement of the SRM magnetic characteristics.This paper first describes an accurate, fully automated digital method for the measurement of the magnetic characteristics of SRMs, including on-line offset error removal and winding resistance estimation. In this method, a digital signal processor-based virtual instrumentation for measurement of flux linkage is developed. Then the results of measurement conducted on a four-phase SRM are presented. The accuracy of the measurement system is verified by comparing it with that found via a magnetics analyzer. Finally, the various sources of errors are discussed and their contributions to the errors are quantified. The scheme can also be used in general for transformers or inductors.