Fuzzy logic controller for Steinmetz symmetrizing circuitry with variable reactor

The presence of high power single-phase loads produces certain disturbances in low voltage distribution networks: supplementary negative and zero sequence currents will cause excessive heating of electrical machines, saturation of transformers, ripple in rectifiers, protection and interference problems etc. Load compensation at the load bus is an effective method to eliminate those undesired sequence currents. The Steinmetz circuitry, consisting of a reactor, a capacitor and the receiver, suitable connected with each other, is widely used for this purpose. Unfortunately, as usually the load characteristics fluctuate, the parameters of the supplementary reactive elements should also vary. The paper deals with the implementation of fuzzy controlled reactive elements in the Steinmetz scheme in order to compensate the load variation.