Hello, Sotiris here! 👋

 🚀 Today’s newsletter is about manufacturability tips and how I applied them to the winding of the 2^nd PSFB transformer.

👉 Manufacturability should be an important aspect of the design process. Designing a magnetic component can’t be considered a success if it can’t be manufactured easily, in my opinion.

👉 Manufacturability means affordable samples and scalability when you move into production.

✅   Frenetic offers this type of services to its clients.

A couple of questions to contemplate:

• Have you considered primary-secondary creepage distance, to address the high voltage differences❓
• Have you considered pinout❓
• How are the windings going to be directed to the pins❓

On the left picture, I drew exactly how the sample was wound. I followed the same winding topology as before, the PSPS (primary-secondary-primary-secondary) topology.

• The blue wires are the primary winding, split into 2 layers. 12T on the 1^st layer and 12T on the 3^rd layer makes the 24T in total.
• The brown wires are the secondary windings, that are connected in parallel. The first winding sits on the 2^nd layer and second on the 4^th layer, then their leads are connected in parallel and directed to the pins.

   At right picture, you can see the first layer is wound. The insulating tape as well as the margin tapes are visible too. The primary Litz wire located the left side isn’t cut, just left hanging until the 2^nd layer is finished and I could continue winding the 3^rd layer with it.

   Also, notice that the pins are located on the right side of the bobbin as depicted in the photo. The primary winding end leads are the easy to direct to the pins, because it starts in the 1^st layer and ends on the 3^rd layer on the same side with the pins.

But the secondaries which are connected in parallel, on the one side are far from the pins. How will the wires go back to the right (pin side) side to be connected to the pins? Is there enough space?

Think how you would do it…

❌  Either go in between layers to return to the pins side?

✅   Or you leave everything hanging until the end of winding process and then return the wires on the pins on top of the 4^th layer in this case, like below?

⭐️   Simple things like directing the wires to the pins can be the difference between a good easy to manufacture design and a bad, very restricted, hard to assemble, design.

⭐️   That’s why when using our tool, you can verify your design with the help of a professional that has real hands-on experience winding inductors/transformers who can suggest changes to make the design manufacturable, if need be.

💥   PSFB transformer 2^nd attempt – Winding specs 💥

 👉   Project details here!

About windings, so I’ll be quick today. Just look at the circled specs on the winding images above, or explore the design on your own.

Summarizing the main things that changed:

🔑   Current density is limited to <5-6A/mm² which is a recommended guideline

🔑   Temperature prediction dropped from 91°C to 42°C from the previous design compared to this one, at the same power level (1kW). I’m doing something right 🍺

🔑   Power losses dropped

🔑   This sample was much easier to wind. Look at the filling factor 😉.

DO YOU WANT TO TRY SOMETHING NEW?

Our brand-new  Circuit Simulator is off to a great start! A lot of visitors have already been using and giving us great feedback. You don´t want to be the only one that hasn´t tried it 😉

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And if you want to learn more and get a personalized demo, just click here to book a meeting. 👈

WHAT’S COMING NEXT WEEK?

👉 Next week it’s a test week. I’m making measurements, to see how the sample turned out in reality, measuring its specs and putting it under load in a 1kW PSFB circuit.

👉As always, if you have a question or an idea, let me know at sotiris.zorbas@frenetic.ai

Previous Newsletters: here!

 👋  Until next week 👋 

Sotiris Zorbas, MSc 

Power Εlectronics Εngineer