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A master's thesis from Aalborg University
Book cover


Distributed Power Electronics for Second-Life Batteries

Term

4. term

Publication year

2022

Submitted on

Pages

110

Abstract

The use of battery storage systems (BESS) is widely considered for supporting the power grid. As the market for electric vehicles is growing rapidly, second-life batteries (SLBs) are becoming an attractive alternative for BESS. However, the use of SLBs has drawbacks due to the different state of health (SOH) and state of charge (SOC) of the batteries. In this work, different control methods for a cascaded H-bridge (CHB) topology for grid connection of second-life batteries are analyzed. By using a CHB topology, the possibilities of controlling the BESS are extended. Alternative switching techniques based on pulse width modulation (PWM) are shown and compared for multilevel inverters (MLI). Various battery energy management (BEMS) system strategies are proposed. Further, an active balancing technique is proposed to balance the state of energy (SOE) among the cells. The results show that the proposed strategies can be applied, extending and widening the battery control capabilities.