COP 20.00 (2000%) Times, Reactive Power Energy Source Generator,

[SeaMonkey]

FarmHand,

Your scope shots where you've added the "Take"
and "Give" regions are quite good.

Interestingly, the Take and Give timings are just
the opposite of what a Reactive component would
do.

I can see how this would confuse the Power Meter.

Extracting power from the input waveshape on the
downward slope is easy stuff for Power Factor Correction
Circuits such as those used in Compact Fluorescent Lamps.

[listener191]

This simulation uses two parallel charge series discharge circuits each handling a half cycle. Careful use of squarewave sources with duty cycle setting and phase shifts was required to get the pulse switching pattern, which you can see if you scope the signal sources. Falstad could do with a decent pulse generator!

The discharge is switched out to an identical transformer which has an arbitrary load on the secondary.

Unfortunately Falstad is a lacking an RMS or average function on the metering. The current peak on the discharge is missleading as in practice you dont see this, and also looking at a visual average of the discharge its no more than 25% whereas in the real circuit this is closer to 66%, as measured.

This setup does illustrate what happen to the input when the power is not being returned. You can see the power developed in the discharge load resistor and the power developed in a resistor across the substitute transformer secondary.

The discharge power developed in a generator would depend on winding impedance.

Anyway I will let you all pick over the bones of this.

Barry






$ 1 5.0E-6 382.76258214399064 43 5.0 50
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[Farmhand]

Ok so I took the liberty of modifying your wave form again with blue lines to show approximately what the current trace would be.
From that we can determine the normal "not switched" load power. If we assume the voltage trace to be 560 volts peak to peak
and the current trace to be 0.076 volts peak to peak and sensed through a 0.1 Ohm resistor, then we would need to convert to
RMS voltage on both so that would be 198 volts and current trace (0.027 volts across the 0.1 Ohms) or 0.27 Amps RMS.

Remember I'm just working this out based on what I think the traces mean.

Normal Not switched load power.
So 198 Volts RMS x 0.27 Amps "RMS" = 53.46 VA RMS then if we look at the phase it seems to be 30 degrees or
0.866 power factor. So 53.46 x 0.866 = 46.29 Watts "real load power" with 53.46 VA which would leave 7.17 VAR. 

Now if we move more current from in phase to "out of phase" we will change the power factor and therefore the real load power
will reduce even though the 53.46 VA won't change, there will be more VAR and less "real load power". That's just the load power.

Obviously the switched load power must be less than the not switched load power.

We also need to consider that some current is taken from one half cycle "in phase" and returned to the next half cycle
(opposite polarity and mostly out of phase). An energy meter would likely not deal well with that.

But we can calculate what the effect of the moving of the current actually does to the load power, and the reactive power due to
the switching will be returned. If the input wave forms mirror the output then we can determine the powers that way as well.

..

[listener191]

Hi Farmhand,

Cheap energy meters see the peak of the projected current sine over the gap between charge and discharge pulses, hence for this waveform on my setup, the meter displays 34W, 93VA, 0.37PF so 59VAR, 68 deg.

Barry

[listener191]

Attached is a circuit that I am prototyping for a new hi power Bi-directional power switch.

As SERPS is hard switching at various points on the incoming AC sine wave, both IGBTS and MOSFET's have a hard time with this, as their SOA's accommodate high current pulse switching with limited duty cycle.

When you look at their high duty cycle or continuous ratings, they paint a sad picture, with many 100A peak rated devices only handling 10A or less in the 100 to 230V region. Their square RBSOA's mean they can turn off at max current and max voltage rating. Most IGBTS operating on AC circuits are zero voltage switched to avoid the turn on limitations.

This switch uses an IGBT in series with an SCR.
The IGBT turns on before the SCR and can handle 40A under this condition and is used to turn the SCR off.
The SCR I am using can turn on within 900ns and can switch at full current and voltage rating. The IGBT can turn on in 43ns and turn off within 127ns. The IGBT only sees  its CE volt drop during switching.

The SCR has a delay applied to its gate of 100ns obtained via the propagation delay of 4 inverters. The delay always ensures the the SCR turns on after the IGBT. After testing  the SCR 900ns turn on time v 43ns IGBT turn on time may  confirm that no additional delay is necessary.

The TLP351F is used as a compact isolator driver for both devices. The output current rating allows it to also provide the trigger current for the SCR, whereas many opto couplers have boarderline  capability to trigger the 25TTS12PbF SCR  i.e. 40-60mA.

An SCR with a larger current rating could also be used with this IGBT  to extend the rating of the switch to 40A if required.

The ULN2804A transistor array is used to drive the photo coupler led's. 4049's could provide enough drive current for this but in the past, heating of this inverter was a problem and the rise time is better via the transistor array approach.

I have tested one SCR IGBT section of the switch and it looks to be good.

Barry