A capacity monitoring system with HV current sensor and calibrated current estimation approach

Abstract

This paper presents a battery module capacity monitoring system with a high voltage (HV) current sensor and a calibrated current estimation approach (CCEA) method. Battery modules usually are utilized to generate HV and large currents to drive motors of electric vehicle (EV). The battery modules are controlled and monitored by a system to protect the modules from possible hazards, e.g., battery management systems (BMS). However, since the BMS needs to deal with HV signals, it is very difficult to be implemented using logic integrated circuits (ICs). The proposed design, by contrast, is implemented using a typical 0.25 μm 1P3M 60V BCD process and field programmable gate array (FPGA) to resolve this issue. The sensing current range of the proposed system is 0.44 A ~ 2.2 A, while the voltage is from 36 V to 55 V. The worst-case deviation of the capacity estimation is 8.6 %.