Energy efficiency comparison of shunt active filter's control strategies for three phase four-wire power system

In the presented article, the values of the components of the total power of the three-phase four-wire power supply system for non-sinusoidal asymmetric modes, the condition for achieving a unit value of the power factor and the minimum value of the power losses were clarified. The obtained results were applied to compare the energy efficiency of shuntl active filters (SAF) using different control strategies. Based on the proposed apparent power formula, a new calculation formula for the experimental determination of the power factor has been obtained. It is proved that only the proportional-vector control strategy of the, which uses a reference vector of phase voltages with the optimally weakened zero sequence component, provides a unit power factor and the minimum possible power losses, exceeding other possible strategies in these indicators. It was shown that other known proportional-vector algorithms for forming the source currents of a three-phase four-wire power system with an integral value of the proportionality factor do not provide a unit value of the power factor. To confirm the energy efficiency of the proposed control algorithm for SAF in the MathWorks ® Simulink ® 2012a computer simulation was carried out. The model of a three-phase four-wire power system with a shunt active filter and a nonlinear load in the form of a three-phase rectifier with zero output, assembled according to the Mitkevich scheme and operating on the active resistance was investigated. The results of computer simulation confirmed the advantage of the proposed SAF control algorithm in value of power factor up to 7% in comparison with the algorithm of S. Fryze with full preservation of the zero-sequence component and up to 0.5% in comparison with the algorithm of P. Salmeron, J. Monton with complete suppression of the zero-sequence component. Ref. 9, fig. 3, tabl. 1.