Navigating the future: Generalized power flow for ships with inverter-based resources

“We develop a generalized three-phase Newton power flow algorithm for modern shipboard microgrids incorporating inverter-based resources. The proposed method enables to solve shipboard power flow when inverter-based resources are regulated under advanced grid forming controls.” says Dr. Fei Feng, the lead researcher at the Department of Electrical Engineering at State University of New York Maritime College.

They published their study in August, 2025, in iEnergy.

A new way to manage energy at sea

Unlike traditional approaches that rely on a single “slack bus” to balance power, the devised power flow algorithm incorporates the grid forming control characteristics of inverter-based resources. This allows power flow methods to calculate steady state of shipboard microgrids when multiple inverter-based energy sources share power proportionally and regulate voltage in real time. “The innovation lies in embedding grid forming controls directly into the power flow equations,” explains Dr. Peng Zhang, the lead researcher from Stony Brook University. “This makes the model highly adaptable to both balanced and unbalanced shipboard conditions.”

Stable scalability under different scales of power systems

In the study, the team validated the devised shipboard microgrid power flow on different systems ranging from 18 to 141 buses. Results showed the method can achieve stable power flow even under heavy-load conditions. For example, in a 141-bus test system, the devised power flow method successfully restored bus voltages to nominal levels under secondary control, even when system load was increased by 50%. “The devised power flow algorithm shows great scalability performance. This scalability makes it suitable for both naval vessels and large commercial ships.” Says Dr. Lizhi Wang, the research scientist at Siemens Foundational Technology, Specializing in shipboard microgrid modeling.

Toward sustainable maritime transportation
The study demonstrates that the devised power flow not only provides foundations for energy management of future ship power systems but also enables effective use of inverter-based resources. By enabling flexible integration of inverter-based energy resources, the method supports the International Maritime Organization’s efforts to strengthen reliability and security across the shipping sector. “Our results bridge the gap between traditional power flow algorithms and the next generation of shipboard microgrids,” Dr. Feng notes.

This research offers deeper insight into the complex dynamics of modern maritime energy systems by accurately modeling interactions between inverter-based energy resources and layered control schemes. “This advancement enables the design of smarter, more adaptive vessels, paving the way for a more reliable maritime industry” says Dr. Zarrabian, the researcher from United States Naval Academy.