Performance Improvement of the Battery Module Used a Single Switched Capacitor Battery Equalizer

J. B. Wang

《電機工程學刊》 21卷2期 (2014/04) Pp. 57-66

https://doi.org/10.6329/CIEE.2014.2.03

並列摘要

A battery module (BM) using a single switched capacitor equalizer to obtain lower balancing power loss for a parallel DC/DC converter system is presented in this paper. The BM integrates battery string with peak current charging, constant voltage charging and balancing control together. In order to obtain smooth switchover during each charging phase, the small signal model of the peak current charging control was investigated and designed. Furthermore, a low cost 8-bits microcontroller PIC16F877A controls and monitors each operating phase correctly. The battery string consists of 6 lithium ion battery cells in series connected, however, the switched capacitor balancing control scheme adapts only one balancing capacitor with closed loop control. After analyzing the connection diagram of the balancing circuit breakers, the discharging and charging states with respect to different battery cells or modules are defined. The microcontroller monitors the battery cell voltages and sorts the maximum voltage difference among the battery cells to initiate the discharging and charging states for performing charge transfer. As a result, it reduces the power loss of the balancing circuits significantly; furthermore, the proposed pre-charge control scheme can also reduce the DC bus voltage dip and inrush current of the switched capacitor at the beginning startup stage. A systematic method to design the proposed BM and to integrate within DC/DC converter will be demonstrated. Finally, some simulations and experimental results will be provided to validate the performance of the proposed BM.

並列關鍵字

balancing control ； battery