Estimation of Angular Speed and Park Matrix from Resolver Position Sensor Signals without Using Trigonometric Functions

Abstract

Resolver is an angular position sensor widely used in electric/hybrid vehicles and robotics. However, estimating the angular position and speed from resolver outputs is as difficult task. Most algorithms in literature use trigonometric functions to estimate the angular position. However, these functions are difficult to implement, especially in FPGAs. On the other hand, in speed vector control of three-phase motors, the angular position is only used to estimate the mechanical speed and Park transformation matrix. This paper presents a simple technique to get the mechanical speed and Park matrix without calculating trigonometric functions and without estimating directly the angular position. Filtering and synchronous demodulation allows obtaining the sine and cosine of the angular position, while the compensation of the delay produced by filtering and the estimation of the Park matrix are done using simple trigonometric properties and taking advantage that the number of pole pairs is an integer number. Experimental results show the accuracy of the proposed approach.