| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a control unit 1 capable of stabilizing the calculation value of a phase difference ξ early, and maintaining high-efficiency operation in a synchronous motor 2. <P>SOLUTION: Since the control unit 1 calculates an unadjusted phase difference ξp even in cases other than zero-crossing, the calculation frequency of the phose difference ξ is high. And, in a phase difference adjusting device 13, a first threshold is set so that a distortion variation component is contained in a first frequency component, thus eliminating the distortion variation component from the calculation value of the unadjusted phase difference ξp. As a result, variation width by the distortion of a phase current or an application voltage is reduced and hence an error becomes smaller in the calculation value of an adjusted phase difference ξn as compared with that of the unadjusted phase difference ξp, so that a voltage characteristic computing unit 11 can calculate voltage characteristics by using the calculation value of the adjusted phase difference ξn having a small error and a high acquisition frequency. Therefore, the phase difference ξ can be stabilized early and the high-efficiency operation of the synchronous motor 2 can be maintained. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
