2) Your control loop is a basic Proportional type. Try adding about 2% of 3rd harmonic voltage to the ‘grid’ (I.e. make that sine wave a bit flat topped) and see what happens.
Thanks, this is interesting, because virtually all the PFC control chips (eg LT1248 etc etc) use the rectified mains voltage itself to act as the sinusoidal reference for the PFC control…and it might be flat-topped mains, but they still use it as the sinusoidal reference.
So it makes you wonder why using the mains itself to provide a sinusoidal reference for a grid tied inverter controller is so drastically unacceptable? Surely, the prime responsibility of drawing power with ~unity power factor should logically lie mostly with the loads, not the inverters?
It does sound as if these regulations are being made way too strict…obviously, very strict , lengthy regulations suit the big, rich electronics corporations, because they can afford to pander to such strictness without the bottom line taking a big hit…smaller companies often just can’t afford this.
Seriously I think the electrics regulations are getting way over the top…they are even talking about 98% efficiency needed for PFC stages now (the titanium regs).
All this unity power factor stuff, and low THD, pertains to efficiency, because yes I agree, if power is drawn with non unity power factor, then overall, there is more dissipation in the supply distribution system.
But hang on, if we are really interested in saving the worlds energy, and using less of it, then why aren’t more relevant targets being chosen?…for example, why are people not paying more penalty to drive around in big gas-guzzling range rovers when there are far more efficient cars available……why aren’t people who fly places for non essential reasons being taxed big bucks to prevent this high use of energy…..why aren’t carpets being banned…because after all, you then need to expend energy with vacuum cleaners to clean them……..many of the (mostly hot) countries in the world manage fine without carpets, and just have a few rugs…..because such kinds of things (gas guzzling cars, planes, vacuum cleaners, etc etc) use far more energy than a few more percentage of THD in the mains. And if it’s the distribution capacity that’s the reason why THD must be reduced to microscopic levels, then why is for example the UK admitting 300,000 migrants into the country every year?, because all these extra people will mean more electricity being drawn through the electricity grid. Ditto Germany, where recently Germany admitted 500,000 migrants in during one year.
Seriously, these regulations are going way over the top...and its all coming down from the big electronics corporations who want to get rid of their smaller competitors.
Oh, and while we are at it…lets ban people using electric showers for more than 10 minutes at a time…(put a time switch on them) electric showers use around 15kW, so they use loads of energy in our countries…many people shower for an hour at a time…….ditto baths……some people are in the tub for hours, constantly topping up the hot water…lets limit this by having a time switch on people’s hot taps ……..such measures would save far more energy and electrical capacity than making the THD regs extremely tight.
Seriously, when I was in the Army overseas. ....We had to shower with less than one minute of water flow……..we had to wet ourselves fror 30 seconds maxiumum, then turn off the shower and get soaped up….then we were allowed another 30 seconds to rinse off the soap…seriously, its perfectly possible to get very clean like that….and save loads of energy.
There's no need to make THD regulations extremely tight to save energy, as discussed, there are much better ways of doing this.
LT1248 datasheet
http://www.analog.com/media/en/technical-documentation/data-sheets/1248fd.pdf