INITIAL PHASE DETECTOR FOR SYNCHRONOUS MOTOR

PROBLEM TO BE SOLVED: To solve the following problem associated with initial phase detectors having a function of detecting the magnetic pole position of a synchronous motor, by a position detector and setting an initial phase including time of power application: encoder waveform definitions differ and phase sequence is changed, logic is inverted, or any other like event occurs, and thus wrong connections or the like results. SOLUTION: An encoder detection circuit 30 includes a mode change function 31a for converting the absolute value signal of many bits into a binary signal and encoding it; a table unit 31b constituted of 6 phase storage registers; a mode number setting part 31d, wherein a mode number is set to the phase of the table part 31b; and a table selection function 31c, which selects the set mode number by the mode number changed by the mode change function and outputs the initial phase. COPYRIGHT: (C)2009,JPO&INPIT