基于误差分析的电池组高精度测量系统的设计

Design of a battery group high-precision measurement system based on error analysis

动力电池成组技术是电动汽车技术的核心之一，电池组的容量、能量、功率等特性的测试，对于成组电池性能的评价显得尤为重要。提出了一种基于误差分析的电池组测量系统的设计方法，实现了宽电压（0—1000V）、电流（0—400A）范围内，电压、电流、瞬时功率、安时和瓦时的高精度测量。系统测量的电压、电流为自变量，通过DSP计算出来的瞬时功率、安时和瓦时为因变量。基于误差分析，推导出因变量的精度表达式，提出了同步高精度隔离采样方案。通过简化隔离环节，减少了采样电路的线性误差；通过差分输入、LCL滤波调理电路，提高了电压、电流采样的抗干扰能力。

Power battery group technology is one of the cores of electric vehicle technology, it is particularly important to test the battery available capacity, energy, power and etc. for the evaluation of battery pack performance. This paper presents a design method of the battery group measurement system based on error analysis, which achieves the high- precision measurement of voltage, current, instantaneous power, Ah and Wh in a wide voltage range of 0-1 000 V and current range of 0-400 A. The voltage and current measured by the system are independent variables, and the instantaneous power, Ah and Wh calculated by the DSP are dependent variables. Based on the error analysis, the pre- cision formulas of the dependent variables are deduced and a synchronous high-precision isolation sampling scheme is proposed. The linearity error of the sampling circuit is reduced through simplifying the isolation circuit. The anti-inter- ference ability of the voltage and current sampling circuits is improved with differential input and LCL filter condi- tioning circuit.