Fuzzy logic control for active power factor correction
Abstract
The harmonic distortion introduced to the power grid by the massive use of low-power electronic equipment, is currently a major global problem of quality and efficiency of the network. The nonlinear characteristic of these devices produces large harmonic currents, which generate heat, faults and over current in a system designed for 60 Hz. Traditional solutions based on passive filters not only fail to solve the problem completely, but are to be bulky and expensive. Active solutions, on the other hand, require the use of high performance control schemes, given the need to rebuild the current wave while output regulation is made, all at a much higher rate than that of network. In this sense, we present here a proposal for a scheme based on fuzzy logic control for active correction of power factor on a DC/DC boost converter. The structure and design are raised according to the operational and performance requirements for a typical medium power application. The final performance is verified by tests on a laboratory prototype, assessing and analyzing the behavior to changes in input voltage. The results show a significant reduction in harmonic content (PF = 0.924, THD = 21.2%), and high dynamic response around the operating point (response times below 100 ms).
