PIDA CONTROLLER DESIGN AND ITS APPLICATIONS

Abstract

The current trend of this era is to design and analyze complex systems, which have multiple nonlinearities and uncertainties. The main aim of control system researchers is to design a simple, robust, and efficient controller or control algorithm for engineering applications. In spite of modern control techniques, the proportional integral derivative (PID) controller is still the most important controller in the industry and academia due to its simplicity, low maintenance cost, easy understanding of its operating principle, and availability of various tuning algorithms. However, the limitations of PID controller restrict its performance and efficacy in the control system applications. Proportional integral derivative acceleration (or double derivative) PIDA (or PIDD2) controller is an extension of PID. This controller provides more degrees of freedom in design and also satisfies more constraints or specifications of the control system in comparison to the PID because of more unknown coefficients. Thus, the tuning of PIDA controller is an interesting and challenging task for the control system researchers. Coefficient diagram method (CDM) is a polynomial control design technique, and it guarantees stability of the control system. But, in CDM, the values of stability indices (or characteristic ratios) are computed using the trial and error method. The characteristic ratios are the design parameters of the characteristic ratio assignment (CRA) approach. The CRA is an extension of coefficient diagram method (CDM). This thesis presents a novel polynomial controller for all types of linear second order systems. The proposed controller is designed using CRA. The important features of this controller are that it has simple design steps, set-point tracking, and disturbance rejection capabilities. Moreover, it is also proven that the proposed controller is an equivalent of the 2DOF-PIDF controller. In addition, the proposed controller is designed for an unstable non-minimum phase second order system to demonstrate the performance and robustness. Subsequently, the presented controller is validated on the non-ideal dc-dc buck and boost converters. The proposed controller is implemented using dSPACE 1104 real-time controller. Applicability of the presented controller is corroborated experimentally on the non-ideal dc-dc buck and boost converters.