Sharing ideas on how to make a more efficent motor using Flyback (MODERATED)

[itsu]

verpies,

I don't remember what coil's core and magnets Itsu is using but if it is a ceramic ferrite and ceramic magnets then this would make a difference because NdFeB magnets are internally conductive and allow Eddy current to develop inside them just like in steel.

I use neo's as magnets and some cut up welding rods in a soft iron sleeve as a core.

I foresee, that once we make sure that Itsu's energy recovery efficiency numbers are not a result of some measuring error, then we will try to loop the energy stored in C2 back into the power supply (...or L1).

I will redo these tests, presently i am working on a coil shortener using a reed relais triggered by a hall sensor (+ transistor), hopefully the 15 or so mJ in the cap will not fuse together the reed relais contacts.

Itsu

[itsu]

I put up a simple test using my SG to provide a 5Vpp 40Hz sine wave signal to a 50 Ohm resistor with a 1 Ohm csr.
I setup the math function Ch1 x Ch2 to show the wattage across the 50 Ohm resistor.

The signals can be seen in the below screenshots, but as can be seen, both screenshots (with or without the cursors) show the same Math mean value.

So either Partzman has an extra feature (advanced analysis) in his scope or our models are behaving differently.
Video here:  https://www.youtube.com/watch?v=tvnUN8u2ILk&feature=youtu.be

Regards Itsu

[tinman]

So for Itsu's setup, comparing power out vs. power in and rotor vs. no rotor does not look conclusive if you are looking at the power out vs. power in metric.

Let's just look at the power draw of the coil itself.  When you add the spinning rotor you get reduced power draw.  That is clear and has been replicated many times.  But how about this:  Instead of adding the rotor to reduce the power draw, why not forget about the rotor completely and just reduce the drive voltage for the coil?  So that also gives you reduced power draw without adding a rotor.  The back spike might still output the same amount or power.  Do you see what I mean?  This is highly academic because what can you do with a pulsing coil if you don't have a rotor?

No MH
When the rotor was stopped,the input power went up,and the output power from the spike went down.

It is hard to keep up now Luc's thread seems to have drifted over to what my thread was about-the alternating external magnetic fields from a spinning rotor decreasing P/in and increasing P/out.
But it is good to se that Itsu is showing the same sort of results as i did with the alternating magnetic fields.


Brad

[tinman]

My electric bike uses a 3 phase hub motor.  I had posted about it in the rotating thread.  I hooked up my scope to just 2 of the 3 wires going to the coils just to see if there is anything to grab when it comes to bemf.  Surprisingly there doesnt seem to be much. When the motor is WOT wide open throttle, there is no pwm pulses. Just acts similar to a pulse motor. And when I throttle down some to where there is pulsing, im not seeing any great spikes. Like the whole pwm 3phase process is clamping the spikes.  So the motor may have to be driven another way, possibly by even separating the windings and having individual drive circuits for each in order to avoid the clamping, or what ever is happening.

It is a 48v system. Scope seems to be showing more. Not sure what is up with that yet. Probably the little bit there is of spiking. I kinda expected some big spiking. Maybe the diodes on the fets putting out the flames.  Was thinking to put a bridge rectifier across the coils in pairs where there would be 3 bridges to collect from.  The bridge diodes would have to be lower conducting voltage than the fets diodes in order to get output, if the diodes in the fets are what is clamping the spikes.

The scope shots were of the hub motor wheel off the ground free wheeling.  The pyramid shape of the trace turns into a clean sine when the throttle is turned to off showing the motor generating near what the wave forms show and dies out as the wheel slows to a stop.

Not trying to distract. Just noticed your 3 phase motor and posted this. Be nice if we could figure this out. Will be playing with this more.

Mags

It is a sure bet the inductive spikes are being clamped by a diode feeding into a cap. But at 100% duty cycle,you will not get any inductive kickback,as it is an AC cycle, and so the spike is being bombed with a reverse current flow.


Brad

[verpies]

So either Partzman has an extra feature (advanced analysis) in his scope or our models are behaving differently.

...or Partzman has a different firmware