摘要 |
Disclosed is a method for detecting an angular difference between a motor magnetic pole position and an encoder reference position in a permanent magnet synchronous motor equipped with an incremental encoder, wherein a DC current command for supplying a monotonically decreasing DC current is applied to the permanent magnet motor for DC excitation, and the angular difference is detected by detecting an amount of rotor movement due to the DC excitation by using the incremental encoder. By applying a DC excitation current command for supplying a monotonically decreasing DC current rather than supplying a DC current of constant magnitude as in the prior art, it becomes possible, without estimating the initial magnetic pole position, to shorten the time required for the motor rotor to stop, while preventing the phenomenon in which the rotor does not stop at the magnetic pole position but oscillates around that position. <IMAGE> |