Research On The Methods Of Measuring And Compensating Battery Inner Resistance

At present there are many domestic and foreign production of battery internal resistance detection equipment used, but most of the equipment also can do offline or online measurement of open circuit measurement of single battery internal resistance, the inconvenience to the needs of health monitoring of battery internal resistance group users. This paper put forward a reliability, accuracy, detection equipment and measurements of batteries internal resistance the price is higher. Through the study on the influence factors of internal resistance measurement accuracy, proposed measurement impedance compensation, improve the accuracy of the research methods, on the measured resistance value is reduced due to internal resistance measurement error, error rate of the health status of the battery the value of compensation, is of great significance to optimize measuring equipment. More accurate estimates of the cell when working; the timely processing of the battery problem, improve power system reliability, avoid equipment paralysis after blackout; also can avoid blind battery replacement, and additional costs.Therefore, firstly, the analysis of battery internal resistance characteristics, resistance measurement model is established. According to the AC injection method to measure the internal resistance principle to design the internal resistance measurement method. And then put forward the overall design scheme of the system by using this model:sinusoidal signal generator produce 1kHz sine signal, through the drive circuit is coupled, in batteries have a same frequency and phase of the AC signal, after the battery impedance generated with the frequency of the AC voltage as the basic principle of measuring the internal resistance of accurate measurement of internal resistance of the battery. Then through the feedback resistance of AC voltage signal including small signal processing, interference filter, zoom and other a series of conditioning, optimize signal measurement, achieve the effect of compensation survey hardware. Through the hardware design scheme to solve the multi cell cascaded state measurement error voltage signal, the inaccurate problem, through the analysis of internal resistance measurement of the sampling error, analog circuit error and conversion errors and other several measurement error, put forward the corresponding hardware solutions. Formed a set of complete battery internal resistance measurement system hardware design.Finally, through the analysis of a great deal of field data acquisition and test to sort out internal resistance detection catastrophe quasi factors. According to these factors combined with statistical prediction software SPSS statistical analysis and forecasting, the prediction algorithm based on statistical prediction of multivariate regression, due to equipment by disturbance or reference resistance aging equipment impedance measurement error software compensation. The system after the compensation application can achieve the measurement of internal resistance minimum resolution for an 0.003m and complicated site conditions measuring accuracy can be raised to 1% ohm equipment to meet the technical requirements of the project, to further broaden the purpose of detecting batterv internal resistance of the market.