ABSTRACT
This PhD thesis deals with shunt active compensation systems used to improve power quality and efficiency in low voltage electric power networks. In this work, a new active power filter with selective capabilities has been developed. Furthermore, new improvements are added to some parts of the active power filter.
The most popular global compensation strategies used in shunt active power compensators are presented, and a global compensation method based on IEEE Std 1459-2000 is proposed. A comparative study of these compensation strategies has also been performed.
The active power filter compensating currents are obtained from the decomposition of load currents. Two different methods of separating the load current components are proposed in order to obtain the selective compensation currents. The first method is based on the calculation of the per-phase load conductances and the three-phase load equivalent conductance. The second one is based on the load power decomposition proposed in IEEE Std 1459-2000. Both methods have been studied.
The complete shunt active filter has been analysed. Its control system includes: a moving window technique applied to the extraction of reference currents, a current regulator with a low computational cost, a DC voltage control loop, and a new 3D space vector modulation technique.
Both simulated and experimental results of the proposed selective shunt active power filter, including different loads and supply conditions, are presented. The results demonstrate not only that the proposed system improves the electrical power quality but also the excellent behaviour of the selective compensation method.