Single‐phase cascaded multilevel inverter topology addressed with the problem of unequal photovoltaic power distribution in isolated dc links

This study presents a control scheme for a grid‐connected cascaded H‐bridge multilevel inverter (CHBMLI) based solar energy conversion system (SECS) addressing the problem of distinct temperature and irradiations which raise to partial shading and panel mismatch conditions in large‐scale photovoltaic (PV) generation. Along with feasibility in high‐voltage system, the major advantage of isolated dc links in CHBMLI suffers the distinct dc‐link voltage conditions when employed as a pulse‐width modulated (PWM) converter governing either unequal dc loads or dc sources due to variable power consumption or generation, respectively. The proposed control scheme has the ability of balancing the dc‐link capacitors in each H‐bridge cell of CHBMLI adopted for this system and during the above‐said power generation mismatch conditions in SECS. The proposed system along with maximum and efficient energy conversion, the power quality in the grid‐side voltage and injected currents is also monitored and maintained as per standards. In addition, the modelling analysis of the converter has also been derived to define the mathematical model of CHBMLI as PWM converter adopted for this application. The performance of system has been analysed using MATLAB simulation and validated experimentally on prototype model by using dSPACE‐1104.