Supplying shipping vessels with electricity at the ports can improve the air quality of the ports, reduce the greenhouse gas emissions from the shipping industry, contribute to the economic growth, and increase the political dependency of the countries by reducing the dependence on conventional fossil fuels. Several countries promote supplying the vessels when they are docking at ports from renewable energy systems by establishing dedicated funding mechanisms to remove the obstacles facing the shore power systems. In this context, this paper presents a new modular power electronic converter for shore power systems at shipping ports, which can perform three functions. Firstly, it will harvest the energy from a renewable energy source, such as hydroelectric and solar photovoltaic (PV) sources and ensure maximum energy extraction. Secondly, it will control the power flow from these sources to the battery storage. Finally, it will control the power flow from the battery to the vessels and/or the utility grid when necessary. A current-source converter based on isolated Cuk converter is used as the submodule (SM) of the proposed modular converter due to several features. The Cuk SM can provide high efficiency, minimised dc capacitance, and flexible output voltage higher or lower than the input voltage from the PV modules. To verify the mathematical analyses and computer simulations, experimental results are obtained from a small-scale modular prototype controlled by a TMSF28335 DSP.