Thank you for the kind introduction and I want to start right off with a PRS slide and
the work that I've done in basically the last year.
And there's one published or some published publications and there's one publication
under preparation and this is the one that I will be talking about today.
So this is kind of work in progress and you will notice at some point that it's like that.
And I hope to get your feedback on that and incorporate it into the further work.
So let's start with the motivation.
Why do we talk about PV power estimation?
And the main question that we want to solve basically is we want to judge whether a solar
module is still okay, whether we still would want to use it in the field because it's performing
well or if it's not like that.
And let's take a step back and I want to briefly outline what you can see here because probably
not all of you are familiar with this kind of modality.
We're using an electro-luminescence image here which means that we apply a current to
the module and then you get this kind of emitted light in the near infrared spectrum only for
the regions of the module that are active.
So the regions that are basically connected to the connections of the module.
And all regions that are disconnected appear black here.
So we roughly assume that these regions cannot contribute to the power production of the
module.
So what we want to do, we want to work toward an automated analysis of PV power plants and
we want to work towards contactless assessment of module power which is not, we're not yet
that year because that is not contactless.
So we still have to contact the module to apply the current but we're working on photoluminescence
imaging as well where we only excite the module by applying light to it and then we can have
a total contactless assessment of modules.
So let's briefly talk about the physics that is behind all that we see here and the main
thing that we discuss about today is the voltage current curve and what we want to estimate
is this point which is the maximum product of voltage and current which gives us the
maximum power, so called maximum power point the module can produce and in an ideal case
we roughly can assume that this is proportional to the active area, to the area that is not
dark in the module image.
But reality is different and this is what comes in here because there might be parts
of the module that are shaded, parts of the module that are defect and in these cases
it's not only these cells that do not contribute to the power production because the cells
are connected in series and if one of these cells doesn't work anymore the complete series
of cells doesn't work anymore and this is because there is a bypass diode here which
if one cell doesn't work anymore bypasses the current through that subdivision of the
module because otherwise this subdivision would, especially the cell that doesn't work
anymore would heat up and maybe damage the module.
So this assumption that it's proportional to the active area doesn't hold in practice
and therefore we cannot just use a very simple approach and we try to apply deep learning
to the topic.
So roughly introduce the approach that we have.
We have a data set of 719 electron luminescence images with corresponding IV curves.
So this is a very very small data set and we will see in the results that we are not
into the limit of data so it's working but I assume that it will work better if we get
more data.
We predict the power relative to the nominal power of the module because we have different
modules there with different nominal powers so we don't predict the absolute power but
Presenters
M. Sc. Mathis Hoffmann
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00:13:54 Min
Aufnahmedatum
2020-02-19
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2020-02-19 12:25:14
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