Gain-scheduling adaptive control of the STATCOM for electrified railway systems using PSO

This paper presents a gain-scheduling adaptive control scheme of a static synchronous compensator (STATCOM) in the electrified railway systems by means of Particle Swarm Optimization (PSO). A STATCOM with PSO-implemented controller is considered to suppress harmonic distortion, voltage fluctuations and to compensate reactive power in the for traction load. The PSO is distributed intelligent paradigm for solving optimization problems that originally took its inspiration from the biological patterns by swarming, flocking and herding phenomena in vertebrates. As the PSO is a population-based optimization tool, it has been utilized to evaluate parameters of the controller. Firstly, the dc bus capacitor voltage is measured for achieving to the objective function to obtain an optimized control of dc bus voltage under dynamic and unbalanced load conditions. Then, the best controller parameters Kp and Ki has been evaluated by using PSO. Finally, the performance of the STATCOM to various loads perturbations and unbalancing has been adaptively controlled with gain-scheduling procedure in terms of reduction in stress on the dc bus capacitor voltage. A detailed simulation in MATLAB Simulink has shown that this strategy has been achieved a meaningful effect to meet IEEE-519 standard recommendations on harmonic distortion compensation in electrified railway systems.