A study of the DC link capacitor selection for 250kW battery energy storage system

Lithium-ion based battery energy storage systems have become promising energy storage system (ESS) due to a high efficiency and long life time. This paper studies the DC link capacitor selection for a 250kW ESS. The battery bank in an ESS needs a low ripple environment to extend the lifetime. For filtering the switching ripple on the DC bus, large electrolytic capacitors are needed to absorb the current ripple which leads to a bulky capacitor bank. If we can choose film capacitors instead, this problem can be solved. Moreover, film capacitors also have other advantages like longer life time and low equivalent series resistance (ESR). This paper shows some simulation results by PSIM to support the replacement.