# zinc-air battery emulator.

• posted

hello everybody,

i would like to start for thanking for taking the time to read this little discussion of mine! my aim is to produce a battery emulator, and not just any battery emulator but a zinc-air battery emulator. what i basically have to do is get a mathematical model of a battery and implement it in hardware: a power source, a microcontroler, some D/A and A/D converters some temeperature sensors (which i might actually drop) and voila my battery emulator ;).

in order to acheive this i have undertaken some EIS analysis of the batteries and am pretty close to getting an equivalent circuit that fits very nicely with the measured data. i plan from this equivalent circuit to obtain a transfer function for my system in the s domain. now here comes the question! what i need your guys input for is to figure out how i can make a feedback for my system. it is not enough to just have a transfer function because without a feedback the output will stay constant...diferent from input naturally but constant over time. this feed back however has to be sensitive about the load of the system and in this way reduce the input voltage so that the output voltage gets modeled in the way a battery would modulate its output voltage dependant on the load. i have no idea where i should start to think about how my feedback system should look like. this seems very difficult to me and i need some suggestions about how i can tackel the problem!! any idea will be greatly appreciated!

THANK YOU SOOO MUCH FOR YOUR TIME!!

• posted

If your feedback needs to monitor the current in the load, this can be a simple low value resistor in series with the laod so it doesnt reduce the voltage to much and an op amp to amplify the small voltage.

its fairly simple, theres many ways to do it, if you look in many op amp datasheets there are numerous examples, or search for 'current sense amplifier' etc.

Colin =^.^=

• posted

snt

thank you for your answer collin, it opened my eyes to be quite frank :)! thank you again and 5 stars from me

• posted

|- Skjul tekst i anførselstegn - | | - Vis tekst i anførselstegn -

|thank you for your answer collin, it opened my eyes to be quite |frank :)! thank you again and 5 stars from me

your most welcome :) if you still have trouble im sure we can help more, incidently you dont need such a low voltage as I was thinking. becuase you can easily compensate for the voltage drop by increasing the output voltage by the same amount.

if you have plenty of supply volts and your load is isolated you could have a resistor dropping say 1 volt at max current and drive the mcu a/d directly.

Colin =^.^=

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