Quasi Z-source inverter with improved incremental conductance MPPT for rapidly varying solar irradiation

The photovoltaic (PV) energy and its conversion into electrical energy has a raising importance in the renewable energy marketplace. It is essential to harvest the maximum power from the PV arrays since they have very low conversion efficiency. This process requires the power electronic converter as the power conditioning device. The quasi Z-source inverter is chosen as power conditioning device because of its capability of boosting and DC to AC conversion in single stage. An improved incremental conductance maximum power point tracking algorithm is developed with the aim to prevent the bewilderedness during rapidly changing solar irradiation. This algorithm controls the shoot-through duty cycle of the inverter to attain the maximum power point of the PV array. A novel modified space vector pulse width modulation technique with four shoot-through states is proposed for the inverter to control the inverter. Simulation and experimental results are provided to establish the performance of the proposed system. The comparison with the conventional algorithm is also presented.