Reducing PV I2R losses electronically?

fepps

Hi All,

I wonder if anyone here has ever taken a look at US patent 4024410, “Alternating Current Energy Converter” invented by Dr. Reinhard Dahlberg? It describes a straightforward way to make many direct energy converters like solar cells, thermoelectric generators, and fuel cells more efficient. I believe this technology could be extremely useful in reducing thermal losses in all sorts of energy systems.

Example 6 using a PV panel is on pg. 14, referencing fig. 6 on pg. 5. In his example, the output power approaches Iss * Voc, which is of course a considerable improvement on normal performance.

The initial discussion of the operating principle is on pg. 11, col. 2, line 45, referring to the simplified thermoelectric generator shown in fig. 1 on pg. 2-- but the method seems broadly general. In a nutshell, by adding the DC output of a direct energy converter of whatever type to each pole of an already existing AC current, and then controlling this current with capacitive reactance, the current in the converter is reduced, reducing I2R losses.

His fig. 6 example using a PV panel is a bit more complex. A 5 Hz AC current is fed through transformer 8. Thyristor sets 3 and 4 switch the PV panel output so it is continuously in line with the AC current. This summed current is put through load 9 and capacitor 7 in parallel. Current is determined by the well known relation Irms = Vrms/Xc at the given frequency. It will be noted that the current, and thus I2R losses, can be controlled almost arbitrarily by choice of operating frequency.

Dahlberg was a well-known engineer working for Siemens and AG Telefunken in the 70s and 80s, and was one of the first advocates of large scale solar power. At one point he spoke before Congress on the subject. He has more than 80 semiconductor patents. This, and the simple and lawful nature of the principle described, inclines me to think that this is worthy of consideration by today's solar and thermoelectric engineers. I am not a builder but a patent researcher so I can only post this information and hope that someone will test it.

Fred

BB.

Welcome to the forum Fred,

And feel free to link to the patent:

https://patents.google.com/patent/US4024410A/en

More reading required....

-Bill

fepps

Thanks, Bill, I should have done that!

fepps

The patent is cumbersome because he gives examples of 16 different energy conversion systems that can be used with his invention. Many like MHD have never been put into practical use. He was head of Telefunken's satellite PV division so he probably did actually test the solar version. The satellite PV division was sold to another firm soon after, and this project was discontinued, AFAIK.

Fred

fepps

I see that a few people have looked at this post. I'm concerned that the complication of the patent has obscured the simplicity of the concept. In the broadest, most general form, the Xc of the circuit is made >> than the resistance, so that I2R losses are no longer dependent on the bulk R of the cells. In my opinion, the basic effect should be visible in a very simple circuit consisting of a series string of cells whose output is switched to alternate across a capacitor and load resistor. At switch frequencies where Xc >>R, the voltage rises across the cells, and power absorbed by the load resistor will increase. Given that a potential 20-30% increase in output is shown by this method, it seems like a no brainer to at least try it out. Any takers?

Fred

Dave Angelini

If it works correctly and has measurable (hard to do) results, why not? When it is critically tested and for sale in products here in the store or at my suppliers I will look. Systems off the shelf now are pretty darn good. Any loss is often made up with more panels, quite easily.
 I will pass on the chance to test it unless the check is in the mail. Interesting but, thanks for posting it though.

fepps

Hi Dave, thanks for your comment. Yes, I understand your viewpoint-- from the perspective of someone who currently sells panels/systems, there is no real incentive to pursue something that may or may not work. You are right to wait until it is proven and in durable systems. On the other hand, although it's hard to come up with exact numbers, it appears that more than a half a billion dollars is spent a year to increase the efficiency of cells by a few percent, using sophisticated and expensive technologies like meta materials. A few years ago I was in a company that developed a method for using parametric amplification to increase PV efficiency by a few percent (using C change near Vos) and backers balked because they found it incredible that electronic gains were even possible. Backers didn't have any problem with the complexities of the approach, since almost all the research is even more complex. This method appears to be much simpler, and with larger gains. Well, as I see it, my duty to the planet is to put the info out there.

Fred

Dave Angelini

Probably the area for you to look at that is producing measurable results is Bifacial solar. It still is hard to measure but engineering has done a decent job in the last 5 years of making the decision for commercial apps.

fepps

Hi Dave, Thanks, I wasn't aware that this tech was something that was being adopted. It's not new, it's something I saw in the patent literature going back 30 years or so, often with the inclusion of mirrors under the back face. My tight focus on methods for electronically enhancing performance, rather than build or material methods is due to the perceived timeline of climate crisis. My focus is, what can be installed in place in currently existing systems, to increase output? This leads to the idea of using electronics to modify the cell performance in some way. I was able to identify 8 different possible methods for doing this, and, since the company I did the work for is no longer in existence, I am disbursing this information where it might be useful. I happened to start on this forum because there is an emphasis on advanced electronics.