Title: Fractional order PD controller design for non-monotonic phase systems

Authors: Kalal Muralidhar Goud; Shyam Krishna Nagar

Addresses: Department of Electrical Engineering, Indian Institute of Technology (BHU), Varanasi, 221005, UP, India ' Department of Electrical Engineering, Indian Institute of Technology (BHU), Varanasi, 221005, UP, India

Abstract: This paper presents a novel technique for the analytical design of the fractional order controller for non-monotonic phase systems. The PD controller is designed for non-monotonic system based on gain crossover frequency and phase margin specifications. The method provides a minimum phase margin in the desired bandwidth. The proposed method redefines the concept of phase margin for non-monotonic system with decreasing phase. Introduction of the fractional power parameters offers some advantage in terms of robust performance. For comparison, the proposed non-monotonic method and the conventional method are chosen for the same set of tuning constraints.

Keywords: fractional order control; PD control; non-monotonic phase systems; robust control; phase margin; gain crossover frequency; controller design.

DOI: 10.1504/IJAAC.2015.070004

International Journal of Automation and Control, 2015 Vol.9 No.2, pp.130 - 142

Available online: 22 Jun 2015 *

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