Steuereinrichtung für einen in beiden Richtungen laufenden Motor

摘要

A control system for a reciprocating drive motor includes a phase comparator which determines a difference in phase between pulses synchronous with the rotation of a motor and reference pulses whose period corresponds to a specified velocity, to produce a pulse while any phase difference exists and in accordance with the advancement/retardation of the phase. A charge pump circuit is connected between the phase comparator and a loop filter of the control system to produce a voltage which is zero level when the phase difference is zero, and positive (negative) or negative (positive) with respect to the zero level in accordance with the advancement/retardation of the phase. Until the motor enters a constant velocity control mode, the output of the loop filter is maintained zero level by switching means. In a constant velocity control mode, while the phase difference is zero (meaning that the motor is in rotation at a specified velocity), the output voltages of the charge pump and loop filter are kept zero level regardless of the specified velocity. When the operation mode shifts from a start mode to a constant velocity control mode, the output voltage of the loop filter is held zero level regardless of the specified velocity. The control system further includes compensation voltage supply means for energizing the motor with a current large enough to overcome frictional forces of a system which is driven by the motor.