Fully decentralized control strategy for heterogeneous energy storage systems distributed in islanded DC datacentre microgrid

Abstract

Currently, communication-based distributed cooperative control strategies are employed to control energy storage systems in an islanded DC datacentre microgrid. This paper proposes a fully decentralized, communication-less control strategy for heterogeneous energy storage devices distributed in the DC datacentre. In the proposed strategy, decentralized virtual resistance based control allocates the low frequency component of loads to batteries while the high frequency component is allocated to ultracapacitors with the virtual capacitive droop control. Furthermore, the proposed control system balances the batteries’ state of charges to a common value. During operation, the microgrid local bus voltages are regulated within 360–400 V range in accordance with the ETSI EN 300 132-3-1 standard. The proposed control approach offers advantages in terms of reliability and flexibility, as it does not require any communication infrastructure. Performance of the proposed decentralized control strategy is demonstrated on an islanded 380 VDC datacentre microgrid with variable loads, using Real-Time Digital Simulator (RTDS) with detailed switching converter models and nonlinear battery models.