Resolver signal requirements for high accuracy resolver-to-digital conversion

Tracking resolver-to-digital (R/D) conversion has emerged as the most robust method for obtaining high-resolution position information from resolvers. When driven by ideal resolver signals, tracking R/D converters currently offer position resolutions up to 2¹⁶ quantization intervals/period (16-b resolution), and accuracies to 2¹⁴ intervals/period (14-b accuracy). The effects of nonideal resolver signal characteristics commonly encountered in practice are investigated. Expressions for the position error reported by an R/D converter due to amplitude imbalance, quadrature error, inductive harmonics, reference phase shift, excitation signal distortion, and disturbance signals are found. From these expressions, bounds on the position accuracy achievable in practical resolver-based position-sensing systems are determined