| 摘要 |
PURPOSE:To control the speed of a motor in wide range with stable characteristic by providing a compensating circuit for varying the gain of a speed control loop by a detected speed signal. CONSTITUTION:The output e4 of a speed detector 2 is converted by an absolute value circuit 7a to an output e5, and a variable gain amplifier 7b alters the output e5 as a parameter at a ratio of e3/e2. A speed deviation signal e1 is applied through an amplifier 3 and the variable gain amplifier 7b to the firing circuit 4 of a thyristor amplifier 5 to thereby control the speed of a DC motor 1. Thus, the firing frequency omega of a speed control loop is altered by the different firing period of the phase control to allow the speed control loop gain K to respond to the motor control characteristic variation so that the product of K.omega may become constant to thereby restrict the control characteristic variations in the entire control region. Thus, the motor 1 is controlled at its speed in wide range with stable characteristic. |
