Power sensor-less MPPT control scheme utilizing power balance at DC link-system design to ensure stability and response

The authors previously proposed a new MPPT (maximum power point tracking) control scheme for PV (photovoltaic) power systems connected in parallel with the AC system line. It is characterised by utilizing power balance at the DC link under steady state conditions, hence eliminating the array output power detection and achieving power sensorless operation. However, the system response and stability greatly depend on its main circuit and control system parameters. This paper shows a system design to ensure stability and response based on system transfer functions. Response of the experimental system has been proved fast enough for practical use. Full-daytime testing data show the successful tracking results of the system.