Testing the TK Tar Baby

[Rosemary Ainslie]

Golly TK.  And I thought you were in love...? ? ?   Whatever next?

Ainslie, you have just spammed this thread AGAIN with contentless posts and long quotations that add only your gratuitous INSULTS and nothing of value.

You are not a very nice person at all and I don't think I like you very much.

If it's any consolation at all - I like myself enormously.

Rosie Pose

[TinselKoala]

Golly TK.  And I thought you were in love...? ? ?   Whatever next?
If it's any consolation at all - I like myself enormously.

Rosie Pose

That much is abundantly clear.

[MileHigh]

TK:

integration of the product of the instantaneous measured voltage and current waveforms over a time interval, divided by the duration of the interval, will give you the average power during that interval.
Yes?

Same page here!

And the Math trace in the Ainslie scopeshots _of the oscillations only_  is the instantaneous multiplication of those measurements on the circuit during that time, right?

Yes.

So the proper calculation of power for the period of the oscillations only, would be to INTEGRATE this trace and then divide that value (which is in Joules) by the time interval.  (Remembering to correct the CVR voltage values by whatever you decide to use for the impedance of the shunt resistor at 1.5 MHz.) Right?

Yes but with one caveat.  My proposition is that the returned or negative power is just energy that was stored energy in the MOSFET capacitance.  So it's almost like you are double-counting the same energy.  Think of it like this:  Per cycle you pump 100 units of energy into the circuit and 95 units bounce back at you.  So what is the energy per cycle, 5 units?  100 units?  My answer is that the energy per cycle is nearly 100 units.  I am making the assumption that the 95 units that bounce back at me are mostly lost as heat.  Therefore, I don't really want to measure the same energy twice.

I am also not comfortable with the whole impedance of the shunt resistor at 1.5 MHz thing.  That assumes that you are putting a sine wave through the shunt resistor but the switching doesn't resemble a sine wave at all.  Poynt said you are safe keeping this simple and just stick with the pure resistive value for the shunt.  That's good enough for me, I am not 'hard core analog.'

So, if we go through this process, or even just use the VxV value corrected for the shunt impedance right off the numbers in boxes ... how do we then get a power level in the oscillations sufficient to bring the overall average power down to 50 Watts, if the DC power is 365 Watts for 45 percent of the time?

I am not sure if the 50 watts is what the box is saying or if it's what Poynt said or both.  Plus, aren't we normally working with DSO captures that show a negative VV average?  Sorry I am not able to really comment right now.

However, what's interesting is if you are seeing an anomaly in the average power reading, it's somewhat analogous to the apparent anomaly in the per-cycle returned energy being larger than the supplied energy.  There may be no connection, but you never know.

And I don't think a current can go "through" a battery in the way that you describe. You seem to be saying that a fast, higher voltage pulse can go through the battery as if it were a resistor, without affecting the battery chemistry. I'm no expert on batteries, but this doesn't seem right to me at all. The battery has, like all components, an equivalent series resistance ( or internal resistance) , an inductance, and a capacitance. In addition it is an active component with chemistry happening. All of these allow current flows of one kind or another to pass "through" the battery. But there are lots of battery chargers on this forum that work by sending a fast HV pulse into the battery to charge it. SO... I dunno.

We can agree to disagree, nor am I an expert on batteries.  I have always viewed batteries as sluggish sloths.  In my example I imagine that the actual chemistry in the electrolyte takes some time to "get organized" such that the charging chemical reactions start to actually "flow" and the different molecules start to "dance together."  It takes time for the ducks to all get lined up in a row, perhaps milliseconds.  So what happens when you have a microsecond pulse of current?  My assumption is that the battery looks like a conductive fluid to the microsecond pulse - i.e.; a resistor.

Don't forget that the inductive-pulse battery chargers are putting out very long pulses compared to what we are talking about here so I don't think the comparison is a good one.

MileHigh

[MileHigh]

Rosemary:

You are acting like a low-life piece of gutter trash and you are doing exactly what I was complaining about just the other night.

Gutter Efforts at Misdirection

MileHigh

[Rosemary Ainslie]

My dear MileHigh

Rosemary:

You are acting like a low-life piece of gutter trash and you are doing exactly what I was complaining about just the other night.

Gutter Efforts at Misdirection

MileHigh

Why are you repaying my eloquent tribute to your true 'genius' with this parade of insults?  it is NOT appropriate.

Rosie Posie