Phase detection method, phase detecting apparatus, synchronous-motor control method, and synchronous motor controller

摘要

It is determined (S101, S102) which of six continuous sections having different magnitude correlation of signal amplitude of each phase of an input three-phase signal a section is. Predetermined subtraction is performed between respective phases in the section, to obtain (S103) a normalized amplitude value normalized in the section, using the subtraction result. The normalized amplitude value is converted to a vector phase for one cycle based on a predetermined phase and output (S104) corresponding to the determined section.