Informatics Publishing Limited

R. Sivaraman ¹, V. Sandeep ², K. V. Shriram ³

Affiliations
1 Department of Sensor System Technology, VIT University, Vellore, IN
2 Aricent Technologies, IN
3 VLSI Design, VIT University, Vellore, IN

Abstract

This paper mainly aims at developing a FPGA-based speed controller for a synchronous machine with an internal current control loop based on a predictive current controller. Due to the complex computation schemes, predictive current controllers implemented in a full digital system are characterized by an inevitable delay in calculating and applying the switching states to the inverter. Consequently, their performances are affected and the achieved sampling frequency is limited. These digital control limitations are mainly due to the processing speed versus computational complexity trade-off. To cope up with this problem, specific digital hardware technology such as FPGA can be used as an alternative digital solution to ensure fast processing operation and to preserve performances of predictive current controllers in spite of their complex computation schemes. In order to illustrate this, an FPGA implementation of a synchronous machine speed controller based on a predictive current controller is presented and fully analyzed in this work.

Keywords

FPGA, Predictive Current Controller, Synchronous Motor.

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K. Sathyanarayana ¹, V. Sandeep ¹, K. R. Pradeep ¹, D. Sujib ¹, K. Ravindra ¹, G. V. V. Ravi Kumar ¹

Affiliations
1 Engineering Services, Infosys Limited, Electronic City, Bangalore, IN

Abstract

Composites structures are widely used both in military and commercial aircraft industries. Design of tapered composite skins is quite laborious and time consuming. Optimization of these composite skins is essential for realizing the full benefits offered by composites. Composite skins are optimized in two stages. In the first stage, thicknesses of various zones of composite skin along with the percentage of fiber orientations is computed using gradient based algorithms. In the second stage, the stacking sequence generation is performed mostly using knowledge based engineering approaches using rules and heuristics. The stacking sequence generation is a combinatorial problem and is quite complex. Such combinatorial problems can be solved elegantly by genetic algorithms. The available genetic algorithm based stacking sequence approaches are mostly theoretical and are demonstrated mainly as research and academic problem for laminates of constant thickness with few constraints. In this paper a genetic algorithm based approach for stacking sequence generation of tapered composite skins with multiple zones is presented. This approach is scalable and can solve large size composite skin generation problems with reasonably good number of constraints. The paper also demonstrates the usefulness of the current approach by solving few large scale stacking sequence generation problems in real life aircraft industry.

Keywords

Composite Wing, Stacking Sequence Optimization, Aircraft Structures, Genetic Algorithms.

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