| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for detecting the magnetic pole of a synchronous electric motor accurately even when a load is being applied by eliminating the need for providing an expensive absolute-value encoder for generating pulses that indicate a magnetic pole position. SOLUTION: In a method for detecting the rotor magnetic pole position of a synchronous electric motor 2 with an encoder 3 and a phase detector 4, the current position of a phase detector 4 is set as a zero point before starting the synchronous electric motor 2. By feeding a DC current Ir and a DC current that is K times larger than that to a zero-point position being set to the stator of the synchronous electric motor 2, positions after the rotor rotates are read into a phase calculation part 9 as phases θ1 and θ2 from the zero point of the phase detector 4, a magnetic pole position θ of the rotor when viewed from the zero-point position of a stator is obtained by θ=(θ1 -θ2 )/(K-1) by a phase calculation part 9 and the phase of the phase detector 4 is initialized at the magnetic pole position θ. |
