Armazenamento e conversão de energia utilizando inversores fonte de impedância modificados em sistemas fotovoltaicos de iluminação.

Abstract

Events such as the blackouts in Brazil between 2001 and 2009 have raised concerns about future energy availability, which is intensified by a forecast of 55% increase in demand by the year 2022. Renewable energy sources , such as wind and solar, play an important role in supplying this demand, and can operate with low environmental impact. In this work we study the use of solar photovoltaic energy to power night lighting systems, allowing the energy that would be consumed by them to be redirected to other applications. Photovoltaic night lighting systems are generally composed of a set of generator modules, accumulators, charge controller, inverter and lamps, the first four being studied in this work. In order to obtain instrumental knowledge for the rest of the work, the accumulators were studied and a test platform was designed for them. From the results obtained in tests, a model for simulating accumulators was obtained, which presented voltage error of the order of 50mV for accumulators with more than 20% load. It was also obtained a model based on neural networks for load state estimation, obtaining typical error of 2% and reaching 6% in the worst case. In order to optimize the use of the photovoltaic generator a new Maximum Power Point Tracking (MPPT) technique. This technique is based on the combination of a heuristic technique with a model-based technique, presenting both the 0.1% steady-state error characteristic of the heuristic techniques and the 70: 1 gain in the characteristic tracking speed for techniques. model-based. The use of load converter and inverter as two distinct elements is not optimal, since single load controllers do not implement MPPT, and more complex models add reactive components in addition to those already present in the inverter. In this work, impedance source inverter (ZSI) based converter topologies are proposed, which are capable of replacing the inverter and load controller with a single converter. Each topology has different day and night modes of operation, the first topology being relay reset and the second only by change in control laws. Both topologies enable component sharing between modes of operation, reducing volume, cost and complexity of system installation.