Intelligent Optimized Design of PI Current Controller of LCL Filter Using PSO in Grid Connected Converters

Abstract

The use of Dispersed or Distributed Resources (DR) is rapidly increasing in modern distribution networks because of their potential advantages. As many types of these resources generate electrical energy in the form of dc voltage source, they need a dc/ac converter for energy transfer to the grid through a simple L filter to reduce the injected current harmonics. However, LCL filters can provide better harmonic attenuation and reduce the filter size at the same time. This paper is concerned with the subject of grid connected converters using LCL filter topology. Basic expressions related to LCL filters are derived and compared to that of L filter. The control strategy is briefly described and it is shown that how the system can be stabilized by proper state plus output. Now LCL filters have become more and more popular and the design of LCL filter has become a hot research topic in industry field. The requirement when design a LCL filter is to achieve the required filter effort with inductor and capacitor value as small as possible. In 2005, Marco Liserre presented a step by step design method to design the filter which is an effective method in article for the first time. Recently, artificial intelligence has become a popular search technique used in computing to find exact or approximate solutions to optimization and search problems. There are many kinds of artificial intelligence and Genetic Algorithm (GA) is used mostly. Genetic algorithms are a particular class of evolutionary algorithms that use techniques inspired by evolutionary biology such as inheritance, mutation, selection, and crossover. It become successful because of it’s concise arithmetic describing. But recently, the Particle Swam Optimization (PSO) is proved to an effective optimal arithmetic which is a novel kind of global Optimization. Compared to GA, PSO don’t have to operate crossover and mutation so it is easier and faster to optimize.