Effective battery usage strategies for hybrid power management

In developing countries there are a large number of isolated areas not connected to the main grid. The energy demands of these remote, isolated communities are met by diesel operated power systems. These systems are often highly polluting and with time, an effort is made to make a transition to systems wherein single or multiple renewable energy sources are used to augment the diesel generators and thereby reduce the environmental footprint. Majority of such off-grid hybrid systems include a massive battery bank to store excess energy to supply the user when the renewable is inefficient. Inclusion of such large batteries results in additional investment costs and recycling issues. Therefore it is necessary to minimise the battery size as far as possible, and operate the system under a strategy to ensure maximum utilisation of renewable supplies and minimal DG usage. In this paper the power management strategy for a PV-battery and VSDG system was developed. A battery was modelled in MATLAB and four different battery operation algorithms were simulated for a set of data comprising of load and solar power output for every ten minute period for a day and the effective usage of DG was compared and analysed.