Optimal Feedback Control of Power Systems Using Eigenstructure Assignment and Particle Swarm Optimization & Frank Ferrese, Qing Dong, Nat Nataraj, and Saroj Biswas Abstract The US Navy has a continuing interest and investment in basic and applied research in the area of automation and control. The potential naval applications for this research are numerous and wide ranging. The need for advances in control and automation systems exists from missile defense, to shipboard auxiliary systems, to naval aircraft, and virtually everywhere in between. This research is performed in industry, academia, and in naval laboratories across the nation. This paper will detail particular research in control theory being performed in the area of automation and controls in the naval laboratories. A particle swarm optimization algorithm is used to manipulate the state and control weighting matrices of a linear quadratic regulator to achieve an optimal control for a desired eigenstructure. The algorithm is demonstrated on a nonlinear power system model, and is found to be highly effective in the stabilization of the system output performance, showing both rapid convergence and a closed loop eigenstructure very close to the specified eigenstructure. Introduction The control of linear systems is largely a func- tion of the placement of the eigenvalues of the closed loop system. Methods of specifying the eigenstructure of the closed loop system began with techniques from classical control theory such as root locus design, and proportional integral derivative control. Modern control theory introduces techniques such as pole place- ment methods, where all the pole locations can be specified by the selection of an appropriate controller. For example, in Sobel and Shapiro (1985), the authors use eigenvalue assignment to design a multimode aircraft controller. Methods from optimal control theory deal with the selection of a controller that minimizes a cost function, which is often based on a weighted sum of the system state and the energy required to enact control. In Ferrese and Nataraj (2009), optimal control methods were used in conjunc- tion with a particle swarm optimization (PSO) algorithm that modified the weighting in the cost function to find the optimal controller that would result in a specified eigenstructure. This method gave good results when implemented to discover a controller for the lateral dynamics of a high performance aircraft. In this work, the method developed in Ferrese and Nataraj (2009) is utilized to find an optimal control for a power system with specified closed loop eigenvalues. In addition, an enhancement is made in this work. In Ferrese and Nataraj (2009), the fitness function for the PSO was based only on the geometric distance of the eigenstructure for the closed loop system and the desired eigenstructure. Here, the condition number of the eigenvector matrix is also TECHNICAL PAPER & 2011, American Society of Naval Engineers DOI: 10.1111/j.1559-3584.2010.00300.x 2011 #1 &67