Modeling and Control of an Energy Storage System for Peak Shaving in Industrial Pulsed Power Applications

Industrial manufacturing processes are characterized by dynamic and pulsed power applications. These applications cause a high load factor combining a high peak with low average load characteristics and lead to a waste of recuperative energy. However, at the shared DC link, higher energy efficiency can be achieved by energy recuperation using energy storage systems (ESS). This paper analyzes the dynamic power profile in the production process, using measurement-based curve fitting to acquire the front-end rectifier characteristics. Then, it introduces a flywheel energy storage system (FESS) in the DC link for peak shaving purposes. The focus of the study is to verify the feasibility and control stability if a high-speed flywheel is installed at the DC link to realize fast response for recuperation and peak shaving. From the introduction of fundamental motor modeling to the droop control simulation, this paper explicitly provides the characteristic identification for the rectifier and control design for an ESS. Frequency analysis shows which factors influence the control performance. The simulation illustrates a significant peak shaving effect with proper control configuration. The simulated control scheme is implemented by the motor inverter, a programmable logic controller and measurement devices. The FESS is integrated in a DC lab and will be tested based on the framework of the research project "DC-INDUSTRIE 2".