Resumen de Efficient application of multiple-reference-frame controllers for power quality improvement with power electronics devices in electric distribution systems
The concern for power quality in electrical systems has always been present but has increased dramatically in the last few years. Power-quality problems include voltage/current harmonics, voltage/current unbalance, voltage sags/swells and low load-power factor Those problems affect not only electric utilities, but also consumers: system efficiency, protection equipment, automated equipment (such as adjustable speed drives), programmable logic controllers, switching power supplies and arc furnaces, for example, are very vulnerable to power-quality issues.
This thesis is focused on the control of power electronics devices to tackle voltage and current quality problems in electric distribution systems, using a comprehensive and unifying approach. The existing control algorithms for power flow control and harmonic compensation are reviewed and an efficient implementation of a controller using Multiple Reference Frames (MRF) rotating with harmonic space vectors is proposed. A fully detailed analysis of the control proposal is carried out, with a special interest in its design procedure, stability and an efficient implementation for real-time applications.
Different power electronics devices (a shunt compensator, a series compensator and a UPQC) have been specially built to tackle power-quality problems in order to test the performance of the proposed control method and the results have been very satisfactory. In addition, the control method proposed has also been implemented in front-end converters for renewable energy sources, which were not initially designed with this controller. In this case, the implementation process was smooth and excellent performance was also achieved. The proposed algorithm has a simple design procedure, shows a very reasonable computational effort and it is easily implemented in real time. Finally, the conclusions and guidelines for further research are presented.
