Voltage regulation in an electronic engine control system having digital

Abstract

The unregulated AC electrical power provided by an engine driven alternator to an airborne electronic engine control system which controls the performance of a gas turbine engine, is rectified to provide unregulated DC voltage signals for system electrical power. The system provides position control of a plurality of controlled surfaces within the engine through a plurality of digital effector servo actuators, each of which includes a mechanical assembly for providing displacement of the surface in each of two directions in response to a magnetic field provided by a respective one of two oppositely polarized solenoids disposed within the actuator. The unregulated DC voltage signal is presented to one or the other of the solenoids, in dependence on a desired displacement direction, through a corresponding one of a pair of gated switches in response to the ON portion of a position gate signal presented to a gate input thereof, the energized solenoid providing a magnetic field with a polarity in dependence on the selected displacement direction. Voltage regulation circuitry provides voltage regulation gate signals having an ON portion with a time duration proportional to the excess amplitude of the unregulated DC voltage signal amplitude above that of a reference voltage level, and presents the regulation gate signals, simultaneously, to both solenoid gated switches in each of the plurality of actuators in the absence of a position gate signal to the respective actuator to provide cancelling magnetic fields which inhibits actuator displacement while increasing the current load to cause attenuation of the unregulated voltage signal amplitude.