Rotating Magnetic Field's and Inductors.

[picowatt]

OK,after many attempts to get to the workshop to get this done,here are the result's.

MH
If this is not how you wanted it done,let me know.

The video is unlisted,and no adds,so you must use the link below to view.


Brad


https://www.youtube.com/watch?v=vL6uBgDoVaY

Tinman,

An efficiency of 40% is very low for a boost converter.  If you were to modify your circuit, layout, and drive parameters specifically intending to make a better boost converter without the rotor, 60% or better efficiency would seem much more reasonable (with 75-85% not an unrealistic expectation).   

My take on this thread is that you have constructed a very inefficient boost converter.  Most likely, a portion of the efficiency loss is due to non-idealized switching of the inductor.  With the rotor in play, some of the energy being wasted in the non-idealized switching of the inductor is used to accelerate the rotor.  During the off time, energy stored in the rotor's inertia is recovered by the inductor in generator like action.  In this fashion, energy being lost or wasted without the rotor is instead being stored and recovered with the rotor.

PW

[gotoluc]

Tinman,

An efficiency of 40% is very low for a boost converter.  If you were to modify your circuit, layout, and drive parameters specifically intending to make a better boost converter without the rotor, 60% or better efficiency would seem much more reasonable (with 80-90% not an unrealistic expectation).   

PW

PW, in your efficiency calculations of Brad's boost converter, have you included the power dissipated of each 1 Ohm CVR (in and out) and the DC resistance of his non ideal coil?

Luc

[picowatt]

PW, in your efficiency calculations of Brad's boost converter, have you included the power dissipated of each 1 Ohm CVR (in and out) and the DC resistance of his non ideal coil?

Luc

Luc,

No, I just grabbed a number from Tinman's video.  Even with 10-20% measurement errors and losses, as a boost converter the efficiency seems very low.

There's plenty of room for improving the circuit as a boost converter, including some of the areas you mentioned.

PW

[gotoluc]

Luc,

No, I just grabbed a number from Tinman's video.  Even with 10-20% measurement errors and losses, as a boost converter the efficiency seems very low.

There's plenty of room for improving the circuit as a boost converter, including some of the areas you mentioned.

PW

So does it really matter if this device is not an efficient boost converter?... I don't think so, as Brad's device stays the same non efficient way since all he changes is adding or removing one thing... the magnet rotor.

I think it's a valid comparison test and we have to stop trying to make it something it can never be, like a boost converter which the coil would need to be in a potted ferrite core to be efficient, which means the coil could not be used as a motor coil, right?... as there are no efficient boost converters with open end cores (like Brad's coil) and on top of that, operating at low frequency that will ever be efficient. So why try to even go there?

Just my opinion

Luc

[picowatt]

So does it really matter if this device is not an efficient boost converter?... I don't think so, as Brad's device stays the same non efficient way since all he changes is adding or removing one thing... the magnet rotor.

I think it's a valid comparison test and we have to stop trying to make it something it can never be, like a boost converter which the coil would need to be in a potted ferrite core to be efficient, which means the coil could not be used as a motor coil, right?... as there are no efficient boost converters with open end cores (like Brad's coil) and on top of that, operating at low frequency that will ever be efficient. So why try to even go there?

Just my opinion

Luc

Luc,

I'm not trying to burst bubbles here, but I suspect that if the transistor's drive current, layout inductance, rail impedance, switching time, etc, were modified the circuit could be made more ideal as a boost converter using that inductor.

What I take away from the videos is that given the test parameters used, the rotor makes the circuit less "inefficient" and that is most likely due to the capturing and recovering of a portion of the losses via the rotor's inertia.

Just because "something" makes something less inefficient does not necessarily mean that "that something" is actually providing energy to the system. 

PW