High performance buck-boost converter based PV characterisation set-up

Photovoltaic panel characterisation finds extensive use in output prediction, efficiency estimation and defect detection in photovoltaic (PV) industry. Out of the various characterisation methods available, the use of switched mode power converters is one of the most attractive solutions, owing to high speed, low power loss and additional maximum power point tracking ability. Duty ratio variation for the controlled switch, from zero to one, leads to complete current-voltage curve tracing from open circuit to short circuit condition in case of a buck-boost converter. Therefore an IGBT based buck-boost converter is shown to work as a PWM controlled electronic load for the PV array characterisation. An input filter is further added to prevent the injection of high frequency current into the PV source. This filter is designed with a high resonance frequency which ensures small filter size as well as high speed characterisation of the PV array.