Booster converter Circuit

[parsiva]

Hello
I am working on booster converter project
and i chose my switching device MOSFET IRFZ44N
My input is 2-3V and i want the desired output as 10-15V
Will my MOSFET turn on for this input
will my circuit work??
please help me out
Thank you.

 

[betwixt]

Not impossible but getting enough gate voltage might be a problem.
What is the load current requirement and how are you driving the MOSFET?

Brian.

 

[parsiva]

thank you sir for responding
i am driving the MOSFET through Arduino uno
with the help of MATLAB
and when i checked the gate voltage it was around 5v

- - - Updated - - -

and sir
i am not able to figure out the switching frequency of the MOSFET and load current is 0.26 A sir
and i am using IN4007 diode

 

[betwixt]

We really need more information, particularly how you have it wired and a schematic.

I presume the Arduino is producing the gate signal. If the frequency is more than a few hundred Hz the Arduino alone probably can't manage the gate current needed to switch the MOSFET quickly enough, you would need to add a driver circuit. Also note that above about 1KHz, the 1N4007 stops being a good choice because it's recovery time is fairly slow, they are really intended for 50Hz/60Hz rectifiers and they become less efficient (=hotter!) as the frequency increases. A better choice would be a Schottky power diode because their recovery time is much shorter.

Brian.

 

[parsiva]

Done sir
i will change the diode definitely.
thank you sir
i will upload the schematic diagram sir

Actually sir when i simulated in MATLAB the output was 3OV for and input of 1V
i was happy
But when i wired it was complete failure

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This is the circuit simulated in Matlab.



i brought the same components and worked where i gave input from a battery which was 6V and the output slowy degraded.

 

[parsiva]

Sir can u tell about the driver circuit?
I used MCT2E as the Ic for driver ckt
Pin1= it goes to a 100ohm resistor to the Arduino 9th pin(PWM)
Pin 2= goes to the arduino ground
Pin3=NC
Pin4=goes to the gate of MOSFET
Pin5=goes the input
Pin 6= NC
These are the connections sir

I am really sorry if i am disturbing u

 

[betwixt]

You need a resistor from the gate of the MOSFET to ground so it returns quickly to 0V when the MCT2E turns off. However, the MOSFET needs a minimum of 4V on its gate to guarantee it starts conducting and ideally several volts more than that. With a supply voltage of only 1V it will never work. You could try substituting an NPN BJT instead of the MOSFET, it will then turn on with a much lower voltage but has the disadvantage of not being such a lossless switch. If you try a BJT, add a resistor in the base pin of about 47 Ohms to limit the current through the MCT2E to a safe level.

Brian.

 

[parsiva]

Okay sir
Thank you.
Can a suggest a BJT for this purpose
And sir should i follow the same technique for BJT like i followed for the MOSFET( through arduino and pwm)?


Actually sir its my project
From a tree when we insert electrodes which a cathode and an anode we get a voltage of 1V (one tree)
So boost converter is what is the crucial thing and i really want it to be working and utilize efficiently.

 

[BradtheRad]

It's too much for you to expect 100mA from your setup. It's not that different from the store-bought LCD clock powered by a battery made from copper and zinc strips poked into a lemon... or two potato batteries connected in series.

A 'joule thief' type of boost converter is adequate to do the job. Or, here is a 2-transistor boost converter.



The 20 ohm resistor is unnecessary. It represents some amount of resistance in the coil and power supply.

 

[parsiva]

Hello sir
is there any chance that i would use a MOSFET which works for this 2-3V
which has Vgs=2V
Then would it work?

 

[betwixt]

Your real problem is the 'power' you can harvest from a tree is incredibly tiny. The voltage you measure, presumably with a voltmeter is actually created by the metal of the meter probes reacting chemically with the sap in the tree, rather like the acid in a car battery reacting with the Lead plates. If you want to see how much power you might be able to extract, set the meter to measure current (in mA) and multiply the reading by the voltage you measured. It will not be accurate because the current is being measured under short-circuit conditions, the actual amount will be something like half the power you calculate.

Example: 1V measured, 1mA measured, power = V * I so it equals 1mW, a likely usable power would be around 500uW.

The tree isn't generating electricity, all you are seeing is the effect of your probing it. Trying to increase the voltage and make it useful for other purposes is futile.

Brian.

 

[parsiva]

sir
thank you for letting us know the real truth

But we already submitted the abstract sir
and we must present something

So we got to do something and submit the prototype.

There is a website Plant-e which inspired us to do something

and now we stand no where.

Thank you sir for your response

And kudos to this website i am grateful to utilize this website.

 

[betwixt]

To be honest with you, it will be hard.

Try the "Joule Thief" idea, it will be most efficient at low supply voltages. You will not get a MOSFET to switch efficiently with less than about 3V and a tree probe will not supply enough current to drive it anyway.

I am not sure what exactly what you have to produce but my suggestion would be to build a Joule Thief circuit to light a single small LED, it will not be suitable for any heavier load but the LED lighting up will be a good demonstration of electricity being generated. For the tree as a power source, it would probably be more productive to experiment with extracted tree sap and different metal electrodes. Placing large metal electrodes in the tree itself will work but also kill it. :sad: I guess that isn't what you want to do!

Try different types of metal for each electrode, you will probably find the difference in voltage is greater if you choose one cathodic and one anodic metal. Basically you would be constructing a wet battery cell (similar to a car battery) but using tree sap instead of sulfuric acid and maybe Cu and Al electrodes instead of lead. Unlike a car battery it will not be re-chargeable so you would rely on the different types of metal to produce the potential difference.

If your project is to produce "eco electricity" you might consider trying other readily available natural liquids to produce a battery. It is well known that the acid in citrus fruit juices makes a good electrolyte but it is rather expensive to use on a commercial scale, you might find alternatives that make it economical.

Brian.

 

[BradtheRad]

From a tree when we insert electrodes which a cathode and an anode we get a voltage of 1V (one tree)

By trying various tests you may find an arrangement which creates greater voltage differential, and/or greater current.
Examples:

* One probe in the root, other probe several feet high.
* Between two trees.
* Between two trees in strong wind
* Tall plant with succulent stem (example, sunflower, milkweed, pokeberry, queen Ann's lace) --one probe near ground, other probe several feet high.
* Plant with fruit, one probe in stem, other probe in fruit.
* Between plants, one in sun, other in shade.
* Between two plants in marshy ground
* Between two plants near high voltage towers.
Etc.

 

[parsiva]

thank you sirs for sharing the knowledge

Our main objective was to glow an led like u said sir

And we tried with several metals
and finalized with anode as copper and cathode as zinc
which gave us a better output

and also sir the length of the electrodes was not more than 20cm


So sir
about the booster converter
what we thought of is we would take a 9V battery and use this to drive the MOSFET
and give the 9V battery connection to the MCT2E Ic
thereby the MOSFET turns on and it boosts the input voltage (1V)
We know very well that our input to run the MOSFET is 9V and output from it is less than 9V
but we have no choice sir cause we are almost near to deadline

 

[betwixt]

It seems a pointless exercise but if you have to do it:

Use the connections in post #6 with the extra resistor between gate and ground I mentioned in post #7. I suggest you use a 1K resistor.
The MCT2E pin 5 will have to go to +9V but the 100mH inductor will have to be fed with the 1V from your probes. That should give you about 8.5V pulses on the gate which will make the MOSFET turn on and off so it can step your 1V up to a higher voltage. I'm not sure what that voltage will be but it should be higher than the 1V you started with.

Brian.

 

[parsiva]

okay sir i will follow ur instructions for sure


you are right sir its pointless
But we never thought it would end up like this

And we more nervous about the professors
of our college who rise questions on our project.

Now we feel sad that we could have know about this earlier
:-(


And sir
we have like 4-5 days to reach the deadline
do u think we change to another plan and work on it sir?

 

[parsiva]

sir like you mentioned in the post #7 about the BJT
shall we go for that?

and give the same pulse from the arduino to it?

But you told that it has a disadvantage


Not able to decide anything
:-(

 

[parsiva]

also sir
we thought of taking 3 trees
so that the input would be aprox 3V

 

[betwixt]

sir like you mentioned in the post #7 about the BJT

If you have a 9V supply you can use the MOSFET will work fine. The reason I suggested a BJT is they need a much lower voltage between base and emitter pins to make them conduct but that was before you explained where the power source came from. A BJT is current operated, although it only needs about 0.7V to make it conduct, it needs current injected into the base pin and I don't think you will have enough current available.

we thought of taking 3 trees

You will have to experiment to see if you can get more voltage but I doubt you will get enough. As I explained before, the voltage isn't generated by the trees, it is the chemical reaction between the meter probe and the liquids in the tree. Wiring one tree to another will not necessarily produce more voltage and given that the trees are all planted in the same ground, there are other conduction paths in play.

Also bear in mind that you do not get something for nothing. Even if the converter was 100% efficient, it you double the output voltage it would halve the available current. If you wanted to convert 1V to 30V, it would only be at 1/30 of the current. Looking at it the other way, if you wanted 0.26A at 30V (post #3) you would need to draw 7.8W or 7.8Amps at 1V. As a simple boost converter would only be say 70% efficient, the current would more likely be around 11 Amps. That is probably more than 10,000 times the power a tree could provide! You need a very large forest, not a tree

Brian.