| 摘要 |
PURPOSE:To compensate secondary resistance variation over the whole operating range by providing a secondary resistance compensating block for compensating a secondary resistance variation. CONSTITUTION:A primary voltage signal generator circuit 21 of a secondary resistance compensating block 20 takes out a primary voltage signal from a PWM current control circuit 19. A phase difference detector 22 detects a phase difference theta between a current signal of a current detector 4 and a voltage signal of the primary voltage generator circuit 21. A phase difference estimator 23 obtains an estimated phase difference theta0 between primary current and primary voltage from the current signal and a slip frequency command Ws from a command value setting circuit 14 by using an induction machine model employed in vector control. A subtracter 24 obtains a deviation value between the phase difference theta and the estimated phase difference theta0. A compensating circuit 25 corrects a slip by using a phase deviation value signal theta from the subtracter 24. Thus, a secondary resistance variation is compensated equivalently. |
