Projeto de controladores robusto e por cancelamento de pólos, aplicado a um retificador para recuperação da corrente de carga na ocorrência de curto-circuito

Abstract

This work discusses and describes about the implementation of classic pole cancelation and robust controllers to recover the current 𝐼𝑑 of the rectifier which is localized by the DC side of a furnace of aluminium ingot casting circuit, after the application of faults as short-circuit type. Beside this, other analysis are realized like, how the impact of the short-circuit can affects the 𝑉𝑎𝑏𝑐 voltages, 𝐼𝑎𝑏𝑐 currents and how the developed passive filter to mitigates the harmonics which have more energy (that are 5th and 7th order) acts in this voltages and currents, respectively. The system that was chosen is based on the Cigrée Benchmark (Sood, 2004) and represents an industry system of high importance, which is constituted by a furnace of aluminium ingot casting. The developed controllers firstly used the PI’s classic methodology by pole cancellation and another that would like to achieve a more reliable margin in its use, it is designed to be a robust controller and has a great performance with uncertainties that are caused by the set of electronic equipment, as resistors and inductors. So, the plant was linearized and from the transfer function of the interval plant, it was developed a robust controller using the numerical methodologies of Kharitonov and Bhattacharyya, these methods relate the set of interval polynomials and the respectively transfer functions to generate a polyhedron, where can be choose the controller using the gain and phase margin designed by the engineer, it gives an increase in the reliable of the designed controller. The obtained results in the simulation tests showed a good performance by the designed controller, with a faster recover in the currents, after the application of a fault. This allowed to obtain an important result, giving a safety operation for the industrial plant, which without the use of the controller could happens problems, as accident, the production’s stop and the loss of the stability.