JPS5759487A - Controlling device for imverter - Google Patents

Abstract

PURPOSE:To control the acceleration or deceleration of a motor by applying sufficiently high frequency command to a speed command at the start accelerating time, applying the maximum oblique speed command defined by a limiter thereto at the stopping time, and applying a DC brake command at the sufficiently low speed time. CONSTITUTION:An effective frequency command of P1 is obtained from a frequency setting unit 7 at zero speed at the start accelerating time to apply sufficient frequency speed command from the initial acceleration time, thereby generating the sufficient torque in a slight wasteful time. At the deceleration stopping time it reaches the creep speed at the point P5 when the deceleration starts from the point P4 at the decelerating stopping time. When a motor stop commnand (DB command) is applied at the point P6, the oblique limiter produces an ablique speed command of full limiter, thereby decelerating the motor. A DC brake signal (DBON) is applied to an inverter by the detection signal of the comparator 4 at the point P7 of the low frequency of the degree not excessive when the phase rotation of the inverter output becomes slow, thereby stopping the motor.