Single-switch bipolar output DC-DC converter for photovoltaic application

Bipolar DC grids have become an adequate solution for high-power microgrids. This is mainly due to the fact that this configuration has a greater power transmission capacity. In bipolar DC grids, any distributed generation system can be connected through DC-DC converters, which must have a monopolar input and a bipolar output. In this paper, a DC-DC converter based on the combination of single-ended primary-inductor converter (SEPIC) and C´ uk converters is proposed, to connect a photovoltaic (PV) system to a bipolar DC grid. This topology has, as main advantages, a reduced number of components and a high e ciency. Furthermore, it can contribute to regulate/balance voltage in bipolar DC grids. To control the proposed converter, any of the techniques described in the literature and applied to converters of a single input and single output can be used. An experimental prototype of a DC-DC converter with bipolar output based on the combination of SEPIC and C´ uk converters was developed. On the other hand, a perturb and observe method (P and O) has been applied to control the converter and has allowed maximum power point tracking (MPPT). The combined converter was connected in island mode and in parallel with a bipolar DC microgrid. The obtained results have allowed to verify the behavior of the combined converter with the applied strategy.info:eu-repo/semantics/publishedVersio

Apparent power and power factor in unbalanced and distorted systems. Applications in three phase load compensations

Abstract. The apparent power and the derived power factor are two of the quantities of the biggest use and application inside the Electric Engineering. However, nowadays it continues staying the controversy on their definitions and more appropriate meaning in the most general situations in unbalance and distortion, and unequal resistances in the distribution lines. In the last years they have been distinguished two focuses concerning the functional definitions of apparent power: the European approach, more theoretical and better developed, and the American approach, more practical focus but with smaller rigor. Although from the point of view of their practical application, the use of a definition or another doesn't suppose important numeric differences, if present differ from the conceptual point of view. This is made notice in applications that suppose the use of modern equipments of static compensation. The apparent power of the European approach in its conception only permits parallel compensation, while the apparent power of the American approach admits the seriesparallel compensation. This paper introduces the definitions of apparent power of both approaches and it establishes a discussion on its application in the three-phases loads compensation