Comparison of SPMSM Rotor Speed Estimation Techniques Based on the Flux Linkage Evaluation

Abstract

This paper presents results of rotor speed and position estimation accuracy research for the surface permanent magnet synchronous motor (SPMSM) by sensorless FOC vector control. Various options for estimation these quantities are considered using the calculation of flux linkages in the stator reference frame based on measured phase voltages and stator currents. It is shown that variants based on the initial calculation of the angular position using the arctangent function require the conversion of a discontinuous periodic signal into a continuous one. However, even the converted signal has sharp increases of estimation error at the connection points of the discontinuous sections. This leads to even greater errors in estimating the speed when differentiating the position estimation obtained in this way. Among the options based on the initial speed calculation with its further integration for estimating the rotor angular position, methods with and without using explicit differentiation are analyzed. It is shown that minimal errors in coordinate estimation are provided by the method with differentiation of the permanent magnets flux vector components in the stationary stator frame.