This study presents the control and modelling of modular multilevel converter (MMC) with grid‐connected photovoltaic system. Synchronisation is an important issue in grid‐connected system. Even though conventional proportional–integral (PI) controller used for synchronisation provides adequate performance, it yields poor transient response of the system because of poor tuning of controller gain values. In this study, the fuzzy tuned PI controller is designed and implemented to overcome this problem. The fuzzy logic controller refrains the controller gains based on the operating point of the system. The improved performance parameters such as faster transient response, tracking of the reference current with low overshoot and short settling time with system parameter changes under partial shading of the proposed controller are validated. The results are compared with conventional PI controlled grid‐connected MMC with various PI gains. The developed controller algorithm is implemented through TMS320F28335 digital signal processor.