A novel active neutral point clamped multilevel converter with an advanced switching technique for grid integration of solar photovoltaic systems
The grid integration of solar photovoltaic (PV) systems has become a vital issue for power industry in the recent decades due to global warming and shortage of fossil fuel. The multilevel converter is one of the most promising converter topologies for grid integration of solar PV systems, because of its good features such as higher voltage handling capability and the capacity to generate high quality output power. Active neutral point clamp (ANPC) multilevel inverters are getting popularity for overcoming unequal loss distribution. However, ANPC inverters requires flying capacitors, which increases the system complexity and cost, and reduces the power conversion efficiency. In this paper, a reduced flying capacitor 7-level three-phase converter is proposed for a direct grid integration of the solar PV systems. Moreover, the proposed topology utilizes more dc-bus voltage than the conventional ANPC inverter. In addition, an advanced pulse width modulation technique is applied to the proposed topology to reduce the total harmonic distortion in the output voltage waveform as well as the converter losses. The practicality of the proposed converter topology is also verified with the simulation results from MATLAB/Simulink and the experimental results from a reduced-scale laboratory test platform.