Digital control strategy for solar photovoltaic fed inverter to improve power quality

This paper presents the design of control circuit based on digital logic functions for a solar Photovoltaic (PV) fed Cascaded Multilevel Inverter in order to reduce the number of semiconductor switches and also to improve power quality. The proposed control circuit is used to achieve the maximum number of output voltage levels without the requirement of transformers, boost choppers, and complicated look up tables. The multilevel inverter is implemented with asymmetrical DC sources from solar PV to get 2ns+1-1 levels, where ns is the number of inverter stages. In conventional multilevel inverter, it requires n DC sources or n number of transformers for 2ns + 1 level. Hence to obtain a 15 level inverter, the proposed method requires 12 switches whereas in conventional method it requires 28 switches. The advantage of this method is the reduction of Total Harmonic Distortion in a renewable energy system. Simulations are carried out in MATLAB/Simulink for various levels of multilevel inverter. The mathematical...

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