Interview with Bogdan T. Bucheru

Featured Engineer

Bogdan T. Bucheru

Bogdan T. Bucheru - Senior R&D Engineer, Delta Energy Systems

How did you get into electronics/ engineering and when did you start?

My first contact with electronics was in middle school, when I started building simple audio toys. Later on I was attracted to audio amplifiers and radio. During high school I specialized in automation electronics. In my years of physics engineering college I had the chance to study semiconductors and electronic devices and I specialized in measurements.

My first job was in a semiconductor factory, giving me the opportunity to directly apply my newly acquired knowledge. Later on I was attracted to switching power supplies; I find them to be very complex and rewarding.

What are your favorite hardware tools that you use?

Everything related to power and measurements. I am designing switching power supplies, so I appreciate all power sources, electronic loads, signal generators and automated acquisition data systems. I found infrared cameras to be very useful in rapidly pinpointing hidden issues.

What are your favorite software tools that you use?

I do a lot of modeling using Mathcad, its models are limited only by the user’s capability. There are many SPICE modeling software products, Powersim being one of my favorites.

What is the hardest/trickiest bug you have ever fixed?

There so many bugs to talk about… Probably the hardest one was finding the failure root cause of a DC-DC converter that employed an integrated magnetic transformer. It was particularly difficult because the lab tests were always good. Just a small fraction of production units were defective. In the end it was clear that some unwanted gaps appeared inside the transformer core legs during the gluing process at the factory. Replacing that gluing process with a mechanical clamp proved to be an easy solution.

What is on your bookshelf?

Recently my bookshelf became electronic – I am a big supporter of eBooks. I still have my old paper books, I can mention R.W. Erickson & D. Maksimovic, “Fundamentals of Power Electronics”; P. Horowitz and W. Hill, “The art of electronics”; R. Fitzpatrick, “Classical Electromagnetism”; and Fang Lin Luo, Hong Ye, M. Rashid, “Digital Power Electronics and Applications”.

I do read a lot of non-technical books and I write when time permits.

Do you have any tricks up your sleeve?

Magnetic Core Loss is always difficult to measure in a real application. Data-sheets are very theoretical, very few power supplies are using sinusoidal magnetic field, and so modeling losses are also very difficult. A hands-on approach is more direct, and the loss measurement results can be plugged back into the original model, improving the future predictions.

What has been your favorite project?

The present project is always my favorite. It brings new challenges that make me forget the previous works.

If I have to choose, I may say that I will always remember my first design, a four output, wide input range and low cost power bias supply.

Do you have any note-worthy engineering, as well as out of engineering experiences?

I have a couple of patents and a few more pending. I have over ten papers published and I hope to reach one hundred before I retire.

Blowing up things is something I got used to, what is still worrying me is that it tends to happen late Friday evenings.

I recently published my second book of fiction in my native language, Romanian.

What are you currently working on?

I have a couple of projects at the present, a very compact and very low stand-by power AC-DC adapter and a Step-Up DC-DC isolated stage.

First it is challenging because it is very small and the efficiency has to be very high to keep the power dissipation low. And a stand-by power under 10mW requirement makes it very difficult from control point of view.

The second one needs to be extremely efficient or else will compromise the entire sytem.

What direction do you see your field heading in the next few years?

High frequency switching has been a long time dream, but now new semiconductor devices are making it practical. SiC and GaN switching devices are coming out of infancy and the next decade may completely transform the switching power supply industry.

Wired power versus wireless power – which path is the future?

Wireless power has made a first major step, going out from the labs and entering the commercial products area. Small wireless cell phone charges are now everywhere, and some kilowatts level chargers were publicly presented in the past year.

I still believe that copper wire cannot be beaten in price and efficiency by a complex wireless transfer system; but there are real life applications were safety, flexibility and fashion can make wireless power a future winner.