Compensator for servo drive power variations - has limiting measuring amplifier and sawtooth generator with output signals compared to give pulse width modulated signal

摘要

The controller has a sawtooth generator (3) which is connected via a rectifier and smoothing circuit (2) to a supply source delivering the operating voltage (UB). The amplitude of the sawtooth generator is proportional to the operating voltage and its output is connected to the input of a control stage (4). The servo drive (6) can be a thermal servo drive. The sawtooth generator can have a capacitor whose charging is controlled via a first resistor and discharging via a second resistor by means of a threshold switch with a threshold voltage adjustable by a voltage divider. The control stage supplies a pulse width modulated output signal (UST) to control a switching unit.