A weighted efficiency enhancement control for modular grid-tied photovoltaic generation system

A novel control to improve the European efficiency for modular grid-connected PV generation system is proposed. The modular inverters in parallel operation share both the dc and ac bus. Two DC bus voltage regulators with different output limits are employed in each inverter module, based on the inherent relationship of dc bus voltage and generation power. And the suitable one of the regulators is enabled naturally by the PV power to run the inverter at the highest efficiency point as the first choice, and at the full load point only if the PV power is high enough. As a result the European efficiency of the system is improved with no additional hardware cost. The operational principle of the system is analyzed in detail with the implementation for the control and design guideline for key parameters given. The analysis is verified with both the state-steady and dynamic experimental results. And the tested European efficiency of the system is improved by 0.43%.