A Novel Approach in Designing a Filter for a Solid Rotor Alternator to Minimise Harmonics

Solid rotor alternator is of great importance at high ratings for generation of electric power as they can with stand huge centrifugal forces developed in the alternator. When a non liner load is connected to such an alternator network it invariably injects harmonics into the system which becomes a power quality issue. In order to compensate for the harmonic content a shunt active filter is connected across the load. A single-phase inverter with four controller switches, a standard H-bridge inverter is chosen as active filter. The AC side of the inverter through a filter inductance is connected in parallel with the other nonlinear loads. The DC side of the inverter is connected to a filter capacitor. The shape of the current through the filter inductor is controlled by the neural network based controller such that the line current is of the same shape and in phase with the input voltage. The supply current spectral analysis shows the successful reduction of harmonics, which are produced by the load, by the neural network active filter using Matlab Simulink to model the system. The reduction in harmonics injected by multiple nonlinear loads is shown in simulation results. An attempt is made to perform an experiment to validate the results.