zinc-air battery emulator.

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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!!

 

[colin]

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!!

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 =^.^=

 

[aleximas]

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 =^.^=- 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

 

[colin]

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 =^.^=

|- 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 =^.^=