#65🚀 Where is the Problem with the Magnetics?
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👋 Hello, friends! Dr. Molina here 👨🔧
Welcome to Dr.Molina Newsletter, where I break down Magnetic design for you every week, in
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Today, I will give some thoughts about why engineers say that Magnetics is the bottleneck of Power Converters. If we look other components, we find a different approach.
For instance, Mosfets. The new semiconductor technologies are showing great potential in terms of power density and are also doing excellent marketing. They publish a lot of application notes showing examples of converters with their Mosfets and control chips.
On the other side, we have magnetics—the bulky and heavy parts of the converter.
I have referred to the Magnetics as the bottleneck of the power converters (like a lot of engineers), but I’m trying to think why I said that, and I remembered a RAP session at the APEC conference. The title was something like the
Where is the Problem with the Magnetics?
And the panelists were a mix of consultants and manufacturers of magnetics. There were discussions where consultants criticized manufacturers for the lack of information for the designers, and the manufacturers were polite.
The conclusion was;
Magnetics is the bottleneck; someone needs to invest a lot of money. (But it wasn´t clear who…)
To understand the origin, I have to go back to my early days designing power converters.
When you are prototyping a power converter, the number of semiconductors that dies could be considerable. Magnetics used to need iteration, but they don´t use to exploit as Mosfets do. During the design phase, it’s very common to have 10-20 Mosfets as a backup in stock, while it’s not common to have more than one transformed backup.
Nobody will say; there is a problem in the Mosfets because there isn´t another option than dealing with the layout, driver circuit, oscillations, dV/dt, and finding a stable point. You will never call a semiconductor company to ask for a new Mosfet design because the one you are using it’s not working as you expect.
The same happens for capacitors, PCBs, and other custom components.
After thinking about this for weeks, I would say.
Magnetics is the bulkiest component of a power supply, representing 30% of the volume. Then, instead of bottleneck, I would say:
Magnetics are the most important component, and we aren´t choosing the best approach to design them.
After talking with more than 3.000 people and after seeing thousands of power supplies from those engineers, I would say the problem is the approach engineers are taking, specifically:
1) The Design of the Magnetics
2) The Manufacturing of the magnetics
The Design of the Magnetics
The power converter design should consider the magnetics. A classic approach of designing the converter and specifying the magnetics later forces the magnetics to have antinatural parameters.
For example, in an FBPS, where the Leakage Inductance (Llk) helps to get ZVS, the value of the Llk should be considered from the beginning. If not, you will need to add an additional inductor in series.
Magnetics need to be integrated with the converter in operation and mechanically. You need to understand the role in each topology.
The Manufacturing of the Magnetics
We, Electrical engineers, consider Magnetics as electronic parts.
Manufacturers consider magnetics as a piece to be manufactured with mechanical procedures.
As an Electrical engineer, understanding manufacturing procedures is mandatory for designing good magnetics
Conclusion
Magnetics is the most critical and bulkiest component in the power converter. There is a myth about being the bottleneck, but the reality is that people doing great integrations are getting excellent results. With a good understanding of the role of the magnetics and manufacturing process, you will succeed.
I’m sure you have other ideas. I would love to listen them and create a conversation about it. This week, I invite you to join my discussions in Linkedin about it.
Do you want to know how to improve your Magnetics?
In the last months, I have received hundreds of messages through Linkedin and emails from electrical engineers asking me for support in their magnetics.
I have decided to experiment with a Consultancy Service for one month, having a maximum of 2 consultancy sessions per week.
Therefore, in total, I’m offering eight consultancy sessions.
Before the meeting, I will ask you to email me the questions or topics you want to discuss. If I can´t help you, I will be honest and refund you the money.
The Consultancy topics I will cover are:
- Magnetic design
- Integration of Magnetics in your Power Converter
- Frenetic Online Demo Design
Follow the link to book a consultancy with me.