150V 45A MPPT - roll your own


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poida

Guru

Joined: 02/02/2017
Location: Australia
Posts: 747
Posted: 08:56am 26 May 2020      

Today was a bit up and down.

I hooked up a board running the latest code to the East facing array
and then drove the resistive load. I wanted to see how the MPPT would work
with a real solar panel array.
It found the peak easily and every minute had another look to find the peak.
This is as it should be.

here is a video of the mppt scan with a solar panel array.
Max. power at that time was about 800W.
You can see it scan all the way from pwm = very small to max pwm
and the inductor current (or power if you like) goes from low to high and back to low. I left the DSO display persistance on so we can see the range of values
obtained during the scan.
the video

I have broken the two nice LEM current sensors with careless change over of boards
while one board was still supplied with large input voltage.
(we won't go into exactly how "large". That will lead to some embarrassment)

Anyway, now I am using the VAC T60404-N4646-X662 15A (but actually +/- 51A)
current sensors I pulled out of an Aerosharp a while ago.

They of course work perfectly.
I was changing things over so that I could feed a board with 100+ Volts.
One board uses HY5110 MOSFETS and they are only good for 100V.
I wanted to use the one that has 150V.

Why? I have a current sensor on the inductor now that can go up to 122A before
it clips the output. Before in an earlier post I showed the 49uH 1mm gapped inductor clearly saturated at high outputs with 100V input voltage.

Here is exactly how high the current gets.

Vin = 108V
Pout = 2000W



This is not as bad as I thought.
Peak current is about 83 Amps and this current is switched by the 2 MOSFETS.
I think we are in safe operating area for the MOSFETS, at least as far as peak current.