Introduction
Remaining battery capacity was a concern for most users, it is the reliability of power system are closely linked together. Over the remaining capacity of the battery, more reliable system. Therefore, how not to consume the battery without affecting the electrical equipment in normal working conditions, the line detection in real time the remaining battery capacity, is of great importance. VGP-BPS10A/B VGP-BPS10B
The battery is a complex electrochemical system that, in different temperature Fuzaitiaojian or different tracks, the remaining capacity Shi Shi Ji Fang varying, and Zhao Xu Sui Dianchi Shijianzengjia use, its ability Yejiang down. Usually based on the density of battery electrolyte to estimate the remaining capacity, the method has important limitations: the battery using the latter, with positive and negative plate corrosion, broken ribs, hard accurately calculate the remaining capacity, the same time, this approach also difficult to adapt to the current widely used VRLA batteries online. Several popular among the last remaining stack method detection capabilities, online using the battery, the resistance method produces the least impact on the system, and can be accurately measured throughout the life of the battery, thus the resistance method is as an ideal approach. However, if noise level was found, the accuracy of current measure of remaining battery capacity satisfactory, therefore, where high battery residual noise detection method of online capabilities is imperative. VGP-BPS11 VGP-BPL11
An internal resistance of the remaining capacity of predicting the implementation of the program
Many studies show that the resistance of the internal battery and the degree of support a good correlation between [1] [2]. GNB company had a capacity of 200 ~ 1000A @ h, battery voltage 18 ~ 360V nearly 500 VRLA batteries tested, the experimental results show that the strength and capacity of the internal battery is very good correlation, the correlation coefficient can to 88%. Made with the process of charging the battery, the internal resistance to a gradual reduction of the discharge pipe, the internal resistance increases gradually. Furthermore, as the batteries age, the remaining capacity has decreased and the resistance also increases. Battery internal resistance and the remaining capacity of the typical curve in Figure 1.
The battery is fully charged (filled) and total rejection (full version), its internal resistance varies from 2 to 4 times the rate of change is much higher than the rate of change of battery voltage (approximately 30% -40 %), therefore, by measuring the internal battery resistance can accurately predict the remaining capacity. In addition, for online use of batteries, the resistance of France and an important advantage is the least impact on the system can be accurately measured throughout the life of the battery. Therefore, it is easy to see which method is best suited to the strength of the VRLA battery residual capacity of the online measurement. VGP-BPS12 VGP-BPS14/S
Predicting the remaining capacity of the internal resistance of the concrete implementation of the program are: first, the battery is fully charged (at 2V battery, for example, charging to 2.23V, the float current to 10mA) then at 0.1 C rate discharge battery, records in the process of liberation and the remaining capacity of the size of the internal resistance. When the discharge of the battery is completed (2V battery discharge to 1.80V) will receive a complete discharge curve, the resistance of the remaining capacity and the corresponding relationship between the internal battery. This curve in the control system battery FlashROM, in the same model after the test, the battery of the same size, the processor has received under the test line in the resistance, by table look-up has calculated the residual capacity. Therefore, the key is how this approach on the resistance of the battery measured.
Battery internal principle of resistance measurement is as follows: both ends of the Battery Exchange to impose a constant current audio source, then, to detect the terminal voltage Vo is Vo and the angle between θ. Obviously, the impedance of the battery is Z = Vo / East, and R = Z × cosθ should we get the battery inside the resistance. The specific application program in Figure 2. IBM thinkpad t42 series battery IBM thinkpad t43 battery
2 cases of the method of measuring noise levels in line
Measured by the battery capacity remaining high precision measurement error offline less than 7%. However, as online in real time, but found that the accuracy of current measure less than satisfactory battery capacity remaining, and sometimes more than 10% error. What are the causes of this error then? To this end, we are working on several states of the battery, which under normal circumstances, the state offers to float state and municipal electric shock in case of default and the failure of the state controller has been tested and criticized UPS circumstances, can be obtained with off-line testing the precision of approximation. Thus, it can be concluded because of the low accuracy of the information of the UPS caused by noise, and we try to use the low-pass filter (cutoff frequency of 1 kHz) method to improve accuracy, the results are not satisfactory, showing inverter device noise information in the range of less than 1 kHz, therefore, difficult to realize in hardware.
3 results
For the parameters of the battery and AC and DC voltage results of the test system are given as an example. Test standard form ESCORT3155A; battery of tests for GFM200 Southern Company, and rated load conditions for flow rate of 0.1 C discharge capacity at constant current obtained as a standard capacity; test temperature of 18 ℃. IBM thinkpad t40 battery IBM thinkpad t41 battery
The results can be seen through the least squares fitting from measurements was almost measures offline. Its accuracy can reach the power of communication and control system based air conditioning requirements technical “requirements.
4 Conclusion
Remaining battery capacity on the line to the power grid’s reliability of supply has a profound impact. It has also been a research focus at home and abroad and difficult problems. In this paper, the remaining capacity of the battery internal resistance measurement of plan implementation in practice, a case of high noise on the remaining battery capacity to improve the detection program online. The experimental results show that the method can be improved satisfactorily in the precision measurement of noise levels. IBM thinkpad r51 battery IBM thinkpad r52 battery