Research And Implementation Of A Method For Measuring The Impedance Angle Of Energy Storage Battery

lithium ion batteries are widely used in power system energy storage power stations,and the early and accurate perception of the temperature inside each single cell is of great significance for the safe and stable operation of energy storage power stations.the study shows that the impedance angle of the battery shows a certain relationship with the internal temperature,and the internal temperature of the battery can be estimated by measuring the impedance angle of the battery.In this paper,an impedance angle measurement scheme is designed and implemented.The main work is as follows:(1)The theoretical analysis of impedance angle measurement is completed and the overall design scheme is given.First,the basic concept of impedance angle is analyzed by voltage phasor diagram,and the impedance and impedance angle of the battery are analyzed to determine the measurement range;then the impedance angle information is extracted by AC impedance method;then the advantages and disadvantages of correlation detection method and zero-crossing detection method are compared,and then the impedance angle measurement is realized on the basis of zerocrossing detection method.Finally,the design index is determined and the overall design scheme is given.(2)In order to extract the weak response voltage signal from the battery terminal voltage,the AC/DC separation circuit is designed.Firstly,using the negative feedback control principle,the block diagram of AC-DC separation circuit is designed,and the feasibility of AC-DC separation scheme is verified from two aspects: the basic operation of the signal and the waveform change;then,the appropriate chip is selected to design the AC-DC separation circuit based on the range of the battery response voltage.Finally,a simulation circuit of AC-DC separation is set up in the Multisim.The feasibility of AC-DC separation circuit is demonstrated by simulation experiment.The hardware and software of the whole measuring circuit are designed,tested and optimized.Firstly,the whole measuring circuit is designed from the aspects of hardware and software,and the whole measuring circuit is made,and then the whole circuit is tested.The results show that the measuring circuit basically meets the design index.Finally,aiming at the problem that the zero-crossing jitter of comparator output affects the measurement accuracy,this paper proposes a measurement method with strong anti-interference ability,edge capture statistics method,and carries on the simulation verification in the MATLAB,determines that this method can improve the measurement accuracy.