Energy Consumption Optimization Strategy for Port Cranes Based on Pontryagin’s Minimum Principle and Filtering Strategies

This paper is concerned with developing an energy management strategy for port cranes, specifically Ship-to-Shore (STS) cranes. The objective is to optimize the crane’s energy consumption and reduce its energy consumption from the grid. The objective is achieved by applying a battery-supercapacitor hybrid energy storage system (H-ESS) and a combination of the filtering and the Pontryagin’s Minimum Principle (PMP) energy management strategies (EMSs) to the port crane. The port crane model is developed using the graphical energetic macroscopic formalism (EMR). The filtering-based EMS manages the power split between the grid and the H-ESS, while the PMP-based EMS manages the power split between the battery and supercapacitor inside the H-ESS. Overall, the proposed EMS for this study has a simple analytical cost function, is computationally fast, and is easier to implement while producing optimal and effective results. The EMR-based port crane model comprises the mathematical equations describing the crane systems, the cranes’ local control system, and the MATLAB Simulink simulation model. The experimental validation of the EMR-based port crane model is done by comparing the cranes’ EMR-based MATLAB Simulink software model with data recorded from a real-world crane. The results show that the port crane energy consumption from the utility decreased by 29%, and its peak power consumption decreased by 29.6%. During the crane load handling cycle, the supercapacitor and the battery get discharged and recharged by 26% and 8%, respectively. Furthermore, the EMS enhances the performance of the H-ESS by boosting efficiency, improving reliability, and extending its lifespan, making H-ESS more dependable and cost-efficient. Due to STS cranes being the largest port cranes with about 2MW power demand and the common drivetrain for many types of port and industry cranes, the EMS developed in this study can be adopted to other types of cranes.