I am trying to build a current sensor here. My original thoughts starts from this paper [real-time current-waveform sensor with plugless energy harvesting from AC power lines for home/building Energy-management systems][enter link description here] Anyway, if you do not scan that paper is OK. [link]: http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=5746292
Now just take the DC battery into consideration. I wanna detect the current as accurate as I could be when it charges. The charging current could be very small or very big(the up limit is several or decades amps, and the down limit is smaller, and better I hope)
I have two main thoughts how to realize it. One way is use the Hall effect current sensor, but I know it is costly, and I am still trying to find more things about it. (I am not sure if it is the best way, what is the state-of-art hall effect current sensor now? )
The other way is use the shunt resistor way. Depicts like this:
WRT the current detecting device, I can use a Differential Amplifier or more complex device to get the voltage, but here is the Question, the resistor is changing when it charges, the resistor's value is a function of the temperature parameter T. So as I wanna have a very accurate current sensing, how can I deal with the resistor's change by temperature?
BTW, the resistor with low coefficient, such as the open air sense resistor, their temperature resistance range is like 0.005 ohm~0.03 ohm @70°, which is big to me. So is there any possible, I dont even need to know the exact resistor value(just know the vague value, 'cause it is changing due to temperature.), and I can also detect the current flowing the resistor? Or is there any temperature compensation way to make the change smaller than the open sense resistor?