| 摘要 |
PURPOSE:To control the speed of an AC motor without using a speed detector such as a tachometer generator by controlling the speed with the amount proportional to the ratio of the average value of a motor counterelectromotive force to the average value of a magnetic flux as the actual speed value. CONSTITUTION:The phase component of a counterelectromotive force obtained by subtracting motor voltage by the voltage drop of the armature resistance and the armature leakage reactance is inputted to an absolute value circuit 211, and the phase components of a magnetic flux obtained by integrating the phase components of the counterelectromotive force are inputted. The sum of the absolute values of the phase counterelectromotive forces and hence the sum of the average counterelectromotive force and the absolute values of the phase magnetic fluxes, i.e., the average magnetic flux value is outputted from the absolute value circuits 211, 212. These outputs are divided by a divider 22, multiplied by a coefficient by a coefficient unit 23, and used as a speed feedback signal for controlling the speed. |
