Photovoltaic system maximum power extraction: an application of simulated annealing

Photovoltaic (PV) Systems are becoming increasingly common, particularly at residential scale, as society becomes more conscious of the environmental impact of conventional electricity generation. PV systems are made up of a number of PV cells joined together in series and parallel arrangements, which are then connected to a local load or utility grid through power electronics interfaces such as DC-DC converters and DCAC inverters. These power electronics interfaces are necessary to enable the PV system to be controlled and to mitigate the impact of non-linear power-voltage (P-V) characteristics that arise in PV systems. In particular, in a residential environment, a PV system may be partially shaded by a tree or other structure which leads to a multi-peak P-V characteristic.Maximum Power Point Tracking (MPPT) is usually implemented in the DC-DC converter to ensure that the maximum power can be extracted from a PV system under these conditions. The area of MPPT is quite broad and many techniques have been adopted ranging from conventional techniques which can track a MPP under uniform conditions, to those that are designed specifically for the multi-peak scenario. The global searching capability of the Simulated Annealing (SA) technique makes it a good candidate method for solving the PV system MPPT problem in residential environments even with quite arbitrarily selected parameters. This chapter will detail the development of the SA based MPPT method and highlight simulations evaluating the performance of the technique. Special treatment will be given to the parameters of the SA method and which of these have most influence based on the PV system configuration.