Pulsed Electric Bus Charging Management Considering Charge Redistribution Effect

摘要

This paper aims at incorporating the supercapacitor charge redistribution effect into the cooperative control of networked hybrid AC/DC microgrids that consisting of electric buses charging infrastructures and PV generations. Hybrid energy storage systems, which consist of supercapacitors and Li-ion battery units, are controlled to integrate the highly pulsed charging demands caused by electrified bus fleets. Each major transit hub is modeled with a hybrid AC/DC microgrid and needs to handle charging needs of electric bus fleets as well as maximizing penetration of PV energy. Energy storage resources are shared among the neighboring microgrids in a coordinated manner based on the bus schedules. This paper includes a more accurate and advanced model of supercapacitors to integrate the supercapacitor redistribution effect to the control strategy. The supercapacitor redistribution is the automatic recovery of supercapacitor terminal voltage to a certain percentage depending its discharge pattern. For this application, the supercapacitor will be discharged quickly due to the high current of the electric bus load, thus the redistribution effect could recover 10-15% of supercapacitor voltage by delaying recharging the supercapacitor. This provides an opportunity for energy savings and improvement on the previous control strategy.