| 摘要 |
PURPOSE:To reduce the rise in the primary voltage of an induction motor, by using a prescribed function generator when performing the constant-output filed weakening control of the motor. CONSTITUTION:The output signal omegar of a rotational frequency detector 4 and a speed reference signal 7 are applied to a comparator 8 to produce a difference signal. The difference signal is supplied to an inverter 1 through a speed controller 9, a primary current instantaneous reference calculation circuit 18, a current refernce signal calculation circuit 19 and a phase conversion circuit 20. The speed of the induction motor 2 is regulated by a control signal supplied from the inverter. A comparator 16 which subtracts the output of an automatic field weakening control circuit and a calculated magnetic flux value phi2 from a field strengthening reference 15 and supplies a difference signal to a magnetic flux control circuit 17, a function genetator 22 which produces a prescribed function, multipliers 11, 21 and another comparator 13 are used to control the field system of the motor. When the speed of the induction motor rises to a ground level (angular velocity omegar=1), a field control signal is applied to the comparator 13 to reduce the rise in the speed of the motor. |
