Circuit-based flux linkage measurement method with the automated resistance correction for SRM sensorless position control

摘要

The accuracy of flux linkage measurement is significantly important for a number of sensorless control methods for switched reluctance motor (SRM). This study proposes a novel flux linkage measurement circuit with the automated resistance correction, which comprises only circuit components. During the SRM sensorless operation, the dependence of resistance on temperature leads to the errors in flux linkage measurement and position estimation. The developed scheme is based on the zero-crossing property which asserts that the flux linkage and current pass through zero simultaneously. Hence, the flux linkage error captured at the time when the current falls to zero represents the resistance error and is used for resistance correction. The proposed circuit has been successfully implemented and tested on a sensorless SRM system. Experiment results indicate that the proposed system in sensorless control can be operated stably at different load torques and at the condition of given speed mutation and load mutation, and the speed range in steady state with rated load torque is 0-160 r/min. The overall estimated position error remains within an acceptable margin of 2%. Hence, it significantly improves the sensorless position estimation and thus SRM performance.