Design of Battery Internal Resistance Measurement System Based on Software PLL

MENG Yan-jing，CHONG Ma-gang，WANG Su-e
（College of Electrical and Information Engineering，Shaanxi University of Science & Technology，Xi’an 710021，China）
Abstract：Aiming at the existing problems in the measurement of battery internal resistance，on the basis of AC injection method，using software PLL and model?鄄based methods designed a set of battery internal resistance measurement system.The system included a control core with DSP，AC constant current source，differential amplifier，etc，and used the software PLL to replace lock?鄄in amplifier and RMS detection circuit，simplifing system design.The measuring principles and implementation of hardware and software is described.The experimental results show that the measurement results of the system are stable and reliable so that it possesses good application value.
Key words：battery internal resistance；AC injection method；software phase locked loop（PLL）；model?鄄based design；DSP