| 摘要 |
<P>PROBLEM TO BE SOLVED: To detect the step-out of a synchronous motor accurately and without constraint with a simple structure. <P>SOLUTION: A voltage command value calculating portion 16 obtains output voltage command values Vd*, Vq* at d-q coordinates, based on an output current command Id*, a target operating frequency command f* that changes by modulated frequency F0, and d-q coordinates current components Id, Iq, and gives the values to an output voltage vector calculating portion 17. At a step-out detecting portion 8, a modulated frequency F0 component Iqω0 of a torque current component Iq is extracted from the d-q coordinates current components Id, Iq and the modulated frequency F0 of the target operating frequency command f*. A comparison result signal Si is generated from the relation of magnitude of a reference current Ith and a modulated frequency F0 component Iqω0 of the detected torque current component Iq. The magnitude is compared of the number of crossing times obtained from the comparison result signal Si and a number-of-times reference value G_Level. When the number of crossing times does not exceed the reference value G_Level, the motor is judged to be in a step-out state so that a state signal Sy_err that is given to a PWM signal generating portion 19 is changed over to "1" level. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
