Active Filter Current Direct Control System

Abstract

The main direction of research is the optimization of the active filter, simplification of the control system and the identification of new algorithms for calculating the compensating currents. There has been improved the direct current control system of active filter with the formation of sinusoidal signals equal to the fundamental harmonic of phase load currents, as well as non-sinusoidal asymmetric signals, as the difference between input phase currents of load and fundamental harmonics, to filter higher harmonics and balancing currents filtering of higher harmonics and balancing of nonlinear asymmetric loads. The control system, which consists of two units: the unit for generating the current compensation of higher harmonics and the unit for converting currents from the phase coordinate system to the coordinate system of instantaneous symmetrical components, provides almost complete compensation for linear and nonlinear distortion. In the case of using one unit for converting currents from the phase coordinate system to the coordinate system of instantaneous symmetrical components, which significantly simplifies the implementation of the control system, provides sufficient for mass consumers quality compensation of higher harmonics (provides compensation of the third, fifth, seventh and ninth current harmonics , and the level of uncompensated higher harmonics is determined by the eleventh and thirteenth harmonics, the content of which is significantly lower) and full load balancing. It is shown that the system of direct current control of the active filter in the case of using the vector of phase currents and the vector of phase voltages can be used for full compensation of reactive power. In this case, there is a slight initial overregulation of the reactive power, which is automatically compensated. The reactive power is regulated indirectly by the voltage support circuit on the capacitor of the active filter voltage inverter.