TL783 PSU current upgrade circuit

[GoGreenElectricsLTD]

I have an existing TL783 based PSU which I intend to set at 90vdc output. The input source being a wind turbine rages from Zero vdc to 130vdc. There is a dump load controller with a large capacitor and this diverts much of the unwanted power to a large resistor bank. However the output when the dump load is in operation includes significant ripple produced by the dump load pulsing on-off-on-off at 4Hz. The purpose of the regulator is to stabilise the final output to a steady DC at maximum power.

I believe the TL783 PSU circuit could do this. But I would also need to connect a couple of 300w MOSFETS to handle the high level of power I think these will work

http://www.ebay.co.uk/itm/FQA11N90C-11N90C-TO-3P-N-Channel-300W-11A-900V-Power-Mosfet-FSC-/111007704892?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item19d893273c

Please could someone help me to design a small ADD-ON circuit to work as I have described.

Thanks
Rob

 

[zebra50]

Hi and welcome to GroupDIY,

The lab (and is mostly everything else) is for audio and related projects. Perhaps this is one for the Brewery where we go a lot more off-topic, or even in the Jobs Available section, if you are looking for hired help.

Cheers!

Stewart

 

[GoGreenElectricsLTD]

Im just your average Joe currently unemployed, so not likely to be hiring anyone any time soon. However I thought the Brewery was for people interested in brewing home beer and wine ?. Also isnt there another room for stuff like Audio amps and Music ?

Rob

 

[zebra50]

I'm sure someone will here will dive in and help. The LTD on the end of your name makes you look like a ltd company!

If you look around, you will see almost everything is related to audio engineering in some form or another, but I wouldn't worry - I'm sure the mods will move it to a different forum if it is appropriate.

 

[GoGreenElectricsLTD]

Ahhh !... Thats because I do have a Ltd Company, but its presently dormant. I hope that some day when I have the money, I will be able to resurect the company and do somthing usefull with it. But for now I am unemployed and broke like 50% of all other UK citizens.

 

[PRR]

> There is a dump load controller with a large capacitor and this diverts much of the unwanted power to a large resistor bank. However the output when the dump load is in operation includes significant ripple produced by the dump load pulsing on-off-on-off at 4Hz.

Describe that thing.

A 4Hz on/off sounds like it wants a battery load. Can't you give it batteries?

> a couple of 300w MOSFETS to handle the high level of power

AND hefty heatsinks, probably with fans (ironic).

No, you want to dump the bulk of your excess power to resistors. Resistors are much cheaper per watt, and much more reliable.

The "per Watt" is critical. You say 130V. But 10% more wind is 10% more voltage and 21% more watts. Wind speeds are random, you are looking at the upper end of a bell-curve which goes far beyond the 1-year or 10-year observed winds.

But back up. When a windmill is over-blown you have several problems. It can blow away. It can over-speed and throw a blade (and the unbalance will wreck the rest of it). It can over-voltage and zap itself.

So most long-lived mills have some way to feather the blades or throw the disk at right-angle to the wind. This can double the survivable wind-speed (4X wind force) though with loss of power when power is most available (ironic).

The electric generator can usually be modulated. Car alternators have a field coil. Energize (about 1A 12V) for max output (voltage proportional to RPM), or de-energize for minimum output. (Residual magnetic flux will usually give 10% output even with zero field current.)

If you have excess power, do something useful. The load will hold-down both voltage and RPM. Charge batteries. Pump water. Heat water. Yes, if the wind keeps up your batteries will boil, your water-tower overflows, your water-heater steams. If a windmill is sized to be even slightly useful several days a month, there WILL be very-windy days you just can not absorb all it puts out.

I see several voltage-sense switches and a bank of big resistors. Assuming "100 Watt" nominal output at 90V, then at 90V switch-in a 100 ohm 100W resistor right across the dynamo. At 92V add another 100r 100W. At 94V clamp it with a 50r 200W, at 96V 25r 400W.

For short-term use, steel fence-wire is good low-cost resistance. Use ceramic supports (drawer-pulls) and keep it very dry so it don't rust-away.