Improved Control Strategy of Unified Power Quality Conditioner Using Fractional Order Controller and Particle Swarm Optimization

It is well known that the role of the Unified Power Quality Conditioner (UPQC) is to improve power quality on both the source side and on the load side. In this article, to improve the performance of the UPQC, the classic Proportional Integrator (PI) controller is replaced with a Fractional Order PI (FO-PI) controller, in which the order of the integrator is fractional, thus providing an additional degree of freedom. The most important elements of the UPQC are a series active power filter, respectively a parallel active power filter. The tuning of the parameters of the controllers of these active power filters is performed using a Particle Swarm Optimization (PSO) method. The main element of comparison consists in maintaining the steady voltage in the DC intermediate circuit. The superior performance of the FO-PI controller is validated by numerical simulations performed in the Matlab/Simulink development environment.