| 摘要 |
PURPOSE:To eliminate a danger of commutation failure even at a load abrupt speed time by rapidly detecting the fact that the phase between an induced voltage and a rotor shaft do not coincide, and inverter-controlling on the detection. CONSTITUTION:In the case that thyristors U, X are fired when the phase does not coincide, the counter output theta2 of 120 deg. delay is used without using the counter output theta1. Thus, a bias generator 6 generates a bias amount corresponding to 2/3, the bias amount is added by adders 71, 72, 73 to the counter outputs theta2, theta1, theta3 to form new firing angle actual angles theta1', theta2', theta3'. A microprocessor 3 controls the firing on the basis of the actual firing angle value obtained thus and the command value alpha*. This is when the motor is in a drive mode, and a switch 8 is shifted to the opposite side by a switching signal generator 9 when in a regenerative mode. |
