Implementation of single stage line interactive multilevel inverter for renewable energy sources with mppt capability

Thesis Type: Doctorate

Institution Of The Thesis: Gazi Üniversitesi, Fen Bilimleri Enstitüsü, Turkey

Approval Date: 2013


Supervisor: İBRAHİM SEFA


One of the widespread renewable energy source is photovoltaic. In this study, three-phase, neutral point clamped, single stage grid interactive inverter importing DC energy generated by photovoltaic modules to the public grid is designed and implemented. Designed inverter can also be used for wind systems with small modification. The inverter is designed voltage source and current controlled. Reference current of the inverter is determined by a sub-program of maximum power point tracking in order to obtain maximum power from photovoltaic modules for all instant. While a modified incremental conductance method is applied for maximum power point tracking algorithm, a PI controller is used for the current control. Simulations and experimental results show that the designed inverter imports energy to the grid with unity power factor and total harmonic distortion level is 3,8%. This value is in the limits of the international standards. In addition, the total efficiency of the system is measured as 93,08%. Proposed system provides maximum power point tracking of photovoltaic modules and exporting the generated energy to the grid without using additional DC/DC converter.