Yes, you will need to do a complex series-parallel connection of up to 30 or so 5W lamps. You will have a hard time keeping the illumination on the panel constant while you reconfigure the lamps.

The electronic load I proposed will let you "tune" to the MPPT much more quickly.

 

do you mean the sensitivity is 5 Ω ?

No, I expect that the resistance required to get MPPT is closer to 5Ω rather than 10Ω

You dont need high resolution. The first derivative of the MPPT function is zero near MPPT, so a couple of points either side is all you need... Say 0.5Ω steps.

 

No, I expect that the resistance required to get MPPT is closer to 5Ω rather than 10Ω

You dont need high resolution. The first derivative of the MPPT function is zero near MPPT, so a couple of points either side is all you need... Say 0.5Ω steps.

I already did simulation and mppt is at 8 Ω at 25 ° C

 

Ok, then you need 6 to 10Ω, in steps of 0.5Ω. Fit a quadratic though those points, take a derivative, set it equal to zero...

 

Yes, you will need to do a complex series-parallel connection of up to 30 or so 5W lamps. You will have a hard time keeping the illumination on the panel constant while you reconfigure the lamps.

The electronic load I proposed will let you "tune" to the MPPT much more quickly.

i think that hard time will be just at first configuration . after that it will depend on the pot, did i hit ?

 

You are talking to a person that thought a 1 watt pot could be used to load a 150 watt solar panel and you're telling him to fit a quadratic and set a derivative equal to zero?

 

You are talking to a person that thought a 1 watt pot could be used to load a 150 watt solar panel and you're telling him to fit a quadratic and set a derivative equal to zero?

for sorrow ,it's your opinion and you are wrong

 

Good to know. I was afraid Mike was talking over your head.

 

Good to know. I was afraid Mike was talking over your head.

it was an oversight in design , any one can make mistakes .

 

It has been my experience that folks who can Maximize a function are the ones that would think a 1W pot could load a 150W panel

 

It has been my experience that folks who can find minima/maxima of a function are the ones that would think a 1W pot could load a 150W panel

 

I missed that one as badly as I ever have!

 

Let's face it, what percentage of people even know what finding a max or min even is? Glad to hear the OP understands. It's rare to find.

Just to clarify what I was suggesting with bulbs was something like 3 automotive headlights in parallel (to handle up to 150W), assuming the max voltage at that load is not more than 15V or so, to act as the primary power dump. Or maybe even a 150W incandescent. Current would NOT be controlled by swapping bulbs around but by a current controller like the one Mike already suggested.

I'm just pointing out that cheap bulbs can replace costly power resistors. And it's so much more fun to make them glow.

 

Just to clarify what I was suggesting with bulbs was something like 3 automotive headlights in parallel (to handle up to 150W), assuming the max voltage at that load is not more than 15V or so, to act as the primary power dump. Or maybe even a 150W incandescent. Current would NOT be controlled by swapping bulbs around but by a current controller like the one Mike already suggested.

.

it's gently of you pointing to that . max voltage of panel which is also VDS of FET will be 34 maximum , from datasheet VDS of this FET up to 100 . so if the lamp is working on 12 or 15 volts , the FET will work on 19 or 20 volt.

 

I found this bulb 12V 75/75CP P45t , its in candle power not watt , so can it be loaded to this pv panel ?
i have read on google that cp can't be converted to watt , do you think 75 cp is close to 55 watt in withstanding ?

 

Note that the power in the source resistors R1-4 peaks at 5W each, so you should use 10W resistors. The power in the NFETs peak at 34W each, so you should use TO220 style NFETs bolted to a very large metal plate heat sink. Note that the drains of the four NFETs are electrically common, so no insulating kit need be used under the NFETs, but the heatsink plate will be tied to the Panel+.

The sum of the power dissipated in the four resistors R1-4 and the four NFETs M1-4 is the same as the peak power delivered by the panel...

I did this configuration except that i used two lamps , i think that it is 12 v/62 watt cause it's unit is in CP . when i connected one of them to the op amp as a feedback , the op amp (MCP617) burnt up , and i think that i lost it . I think that a large current passed through the feedback , so what is the solution?

 

A lamp has almost a zero resistance when the filament is cold. It cannot be used in the electronic load circuit in place of the 1.5Ω resistor. That circuit requires a constant resistance to be used to derive the feedback to the opamp. Use a resistor like in the attached pdf.

 

A lamp has almost a zero resistance when the filament is cold. It cannot be used in the electronic load circuit in place of the 1.5Ω resistor. That circuit requires a constant resistance to be used to derive the feedback to the opamp. Use a resistor like in the attached pdf.

any wattage and resistance or will that affect the op amp ?
by the way I measured the lamp cold resistance and it was 1Ω almost close to the one you used.

 

A lamp has almost a zero resistance when the filament is cold. It cannot be used in the electronic load circuit in place of the 1.5Ω resistor. That circuit requires a constant resistance to be used to derive the feedback to the opamp. Use a resistor like in the attached pdf.

why should I use this resistor ?, i could use 8Ω 5 watt without housing i think it will do the job

 

MikeML I made your circuit which is four resistor 7 watt and four Mosfets , but the whole circuit heat raised up . the four Mosfets and the op amp.
I don't know what is the reason . I connected the ground of the op amp supply with ground of the pv panel . the readings of the current is hesitating up and down .when I split the ground of the opamp and the pv panel and turning the potentiometer there was no response .