Development of a new microcontroller based MPPT method for photovoltaic generators using Akbaba model with implementation and simulation

A novel microcontroller based maximum power point tracker (MPPT) circuit for small scale, stand-alone photovoltaic generators, PVGs, has been built, simulated and tested. The I-V characteristic of PVG is characterized using five solar radiation dependent parameters, two of which are short circuit current and open circuit voltage of PVGs. A DC/DC converter is used as a matching circuit between the load and PVG. Selecting a suitable fixed frequency, the duty cycle (δ) of DC/DC converter has been determined adaptively by microcontroller, by getting feedback from the instantaneous value of the output voltage. As such the system is suitable for dynamic and static loads. Therefore the system needs two measurements, which are solar radiation intensity and feedback from the output voltage across the load, which are fed to microcontroller. The measured solar radiation intensity is converted by microcontroller into percent solar radiation, G, where the highest ever value of the solar radiation intensity in the location is fed to the microcontroller as the base value. The system parameters are PVG dependent and need to be obtained separately for every PVG. A prototype has been built and reasonable correlation is obtained between the measured and simulated results.