Modern dynamo electric machinery

Abstract

This paper presents techniques for design and control of a brushless direct-current (DC) limited-angle torque motor (LATM) with its application to fuel control of gas turbine engines. Given the desired specifications, a two-pole brushless DC LATM with a toroidally wound armature is designed using selected ferromagnetic material and rare-earth permanent magnets; its electromagnetic characteristics is then computationally found and well tuned using the finite element method (FEM) in order to ensure whether the design meets the performance specifications. To achieve the simple and inexpensive semi-closed-loop fuel control, a robust position controller (including a proportional-integral-derivative (PID) controller with a prefilter) is synthesized for providing the required positioning performance for the developed motor, thereby achieving an inexpensive semi-closed-loop fuel control. A closed-loop fuel controller associated with the proposed position controller and a flow meter is then proposed based on multi-loop control structure in order to achieve required linear input–output relationship. All the proposed fuel control laws were implemented using a stand-alone single-chip digital signal processor (DSP). Experimental results are conducted to show the efficacy and usefulness of the developed limited-angle torque motor with its application to an experimental gas turbine fuel control test platform.