It's always hard to tell people what we do. The range is so vast, from mW to MW.

What is the best definition you have heard?

OK how about this:

A power electronics circuit is one in which there is vastly more power readily available than the semiconductor devices can handle.

Unless the electronics maintain complete and rugged control of things, failure is inevitable, rapid, and dramatic.

Take a little 12 V POL converter. If there are two 1 mOhm switches, and they overlap for any reason, the instantaneous power available is 72 kW. Not much chance of those little SMT packages handling that for very long.

Ray:

Your definition of

"A power electronics circuit is one in which there is vastly more power readily available than the semiconductor devices can handle."

is true in some branches of power electronics but not always true in its battery management branch.

Here, both power and energy are usually in scarcity.

In this case, timing overlap of 2 switches connecting the voltage supply rail to Ground might not do any hard damage, but might waste some precious energy. So is too much dead time between those 2 same switches.

You can be nickeled and dimed to death as well as killed by sticks and stones.

Maybe power electronics is any design that changes the form of the power from one type to another. i.e. Changing DC to AC, DC at one voltage to DC at another, AC or DC electrical power to mechanical or other form (acoustic, magnetic, heat, etc.).

I think that we have to add the caveat that the form-changing process has to involve potential extreme stress on the semiconductors that they cannot handle if it is not done right. That is what keeps us all in the game.

Power electronics: Keeping the magic smoke in while delivering controlled power to the end user in the space a postage stamp and a cost of $0.0001......