Photovoltaic System For Supplying Public Lighting As Peak Demand Shaving

Abstract

This paper describes the design and implementation of a grid connected photovoltaic system aimed to supply energy to the public lighting during the time of high peak demand of the grid. The system is made of two main parts: the solar energy storage unit and the lighting unit. The energy storage unit is composed by a PV panel operating at its maximum power point (MPP) and a battery charger. The lighting unit is composed by an electronic reactor (ballast) for high pressure sodium (HPS) lamp, that operates with zero-voltage switching (ZVS), and a flyback converter to boost the battery voltage to the level required by the electronic reactor. The interconnection between the electric grid and the proposed system is made by a rectifier with a power factor correction (PFC) stage connected in dc link of the electronic reactor. A microcontroller determines if the battery bank or the grid supplies the lighting unit. Simulation and experimental results for the proposed system supplying a 70W HPS lamp are presented. A prototype, which is in continuous operation for more than two years in the field, is also presented.

Keywords

• ballast
• charge controller
• microcontroller
• PV systems