Title: Direct Nyquist array design of PID controllers for boiler-turbine units based on gain and phase margins

Authors: Hui Pan; Minrui Fei; Ling Wang; Kang Li; Lin Qian

Addresses: Shanghai Key Laboratory of Power Station Automation Technology, Shanghai University, No. 149 Yanchang Road, Shanghai, 200072, China. ' Shanghai Key Laboratory of Power Station Automation Technology, Shanghai University, No. 149 Yanchang Road, Shanghai, 200072, China. ' Shanghai Key Laboratory of Power Station Automation Technology, Shanghai University, No. 149 Yanchang Road, Shanghai, 200072, China. ' School of Electronics, Electrical Engineering and Computer Science, Queen's University Belfast, Belfast BT9 5AH, UK. ' Shanghai Power Construction Testing Institute, No. 68 Gaoyou Road, Shanghai, 200031, China

Abstract: In this paper, a direct Nyquist array (DNA) method for the design of PID controllers for multivariable boiler-turbine units with specifications of gain and phase margins is proposed. The essential objective is to propose a method for the design and auto-tuning of both straightforward and robust PID controllers that can be more easily implemented for the boiler-turbine units in coal-fired power generation plants in the same framework. For this purpose, the model of the original multi-input multi-output (MIMO) system is first converted into a diagonal/diagonal dominance matrix after the system is appropriately compensated. Then, various PID controller design methods for single-input single-output (SISO) systems can be easily extended to decoupled or quasi-decoupled MIMO systems. In particular, the proposed method allows the user to specify the robustness and other key performances of the system through the gain and phase margins specifications. Illustrative example is given to show the design procedure and to compare our method with other existing tuning rules.

Keywords: PID control; controller design; gain margins; phase margins; boiler-turbine units; robustness; direct Nyquist array; coal-fired power plants.

DOI: 10.1504/IJCAT.2012.045835

International Journal of Computer Applications in Technology, 2012 Vol.43 No.1, pp.4 - 12

Published online: 13 Mar 2012 *

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