A New Variable Step Fuzzy Logic Control Technique for Minimum Emission Point Tracking of Ship Microgrid

The emission reduction and electrical active power control of ships in ports have a lot of challenges due to the lack of shore power and satisfied regulations. This article proposes a new bidirectional power sharing between shore power system and ship microgrid for minimum emission point tracking (MEPT). The proposed power sharing is performed by a new variable step fuzzy logic control (FLC) technique instead of fixed step and iterative methods to reach the optimal operating point of the ship’s auxiliary engines and achieve minimum fuel consumption and emissions. The evaluation of the emission reduction based on the proposed power-sharing method is carried out on the berthing ships in the port of Kaohsiung City as a practical case. Various loading conditions are created to demonstrate the effectiveness of the proposed power-sharing method. In addition, the robustness of the developed FLC is validated by considering the variations of specific fuel consumption (SFC) regions. The results emphasize that the proposed variable step FL technique can reach the optimal operating condition of the ship’s auxiliary engines fast and without oscillation. Furthermore, the proposed technique can achieve ship emission reduction by 5.25% compared with other traditional techniques.