Energy Storage Science and Technology ›› 2022, Vol. 11 ›› Issue (5): 1583-1591.doi: 10.19799/j.cnki.2095-4239.2021.0482

• Energy Storage System and Engineering • Previous Articles     Next Articles

Fault-tolerant control strategy for modular multi-level hybrid converter battery energy storage system

Feng TIAN(), Zhijiang CHENG(), Handi YANG, Tianxiang YANG   

  1. School of Electric and Engineering, Xinjiang University, Urumqi 830046, Xinjiang, China
  • Received:2021-09-15 Revised:2021-09-24 Online:2022-05-05 Published:2022-05-07
  • Contact: Zhijiang CHENG E-mail:tianfeng066@163.com;67078267@qq.com

Abstract:

Battery energy storage system based on modular multilevel converter (MMHC-BESS) is suitable for medium and low voltage power grid, which is conducive to solve the problem of renewable energy grid connection. But as the number of sub-modules increases, the reliability of the system is facing great challenges. To enhance the fault-tolerant operation capability of energy storage systems, aiming at the unbalanced operation state of sub module fault, a fault-tolerant control strategy without hardware redundancy is proposed. Based on carrier phase-shift modulation algorithm, the line voltage balance and grid connected power are maintained by modulation signal reconstruction algorithm. In addition, in order to improve the utilization rate of energy storage battery capacity, a SOC equalization strategy based on fault-tolerant control is proposed. Through zero-sequence voltage injection and dynamic adjustment of in-phase SOC equalization factors, an inter-phase and in-phase two-stage SOC equalization strategy is constructed. Finally, a simulation model based on PLECS is built to verify the feasibility and effectiveness of the proposed strategy.

Key words: MMHC, fault-tolerant control, battery energy storage system, state of charge (SOC)

CLC Number: