First Wind Project - Help Needed

[Markc9126]

Dear All,

I'm very new to this but have been reading this forum with interest for some time.

I am currently working on a project to Construct a 2.4m diameter axial flux type wind turbine based on a design by Hugh Piggott.

I wish to use the turbine to provide supplementary power for my home which is currently grid connected.  I live in a rural area along the coast of Northern Ireland with plenty of wind.

The turbine average power is rated at 100Watts - 2.5kWh per day.

The permanent magnet alternator can also be wired for 12, 24 or 48v battry charging.

My preference is to connect the turbine to the grid to avoid the need for storage. The electricity generated could then be used in the home with any surplus overspilling onto the grid. The plans I have suggest this is done using a "grid-connect inverter" such as the Windy boy type from SMA and that the wind generator would deliver 200-300volts DC to the invertor depending on windspeed.

The plans state the software in the invertor would run the wind turbine at its optimum speed and voltage to get best output. However the software needs to be adapted to suit the particular machine characterisitics and the author was not aware of anyone that has done this yet for home made machines.

I have spoken to a UK supplier of SMA invertors who recommended using a 700W Windy Boy Invertor linked up to my turbine, and stated this would provide a simple and effective solution.

Has anyone else here done anything like this and do you think this solution would work. Will this invertor suit the design of my turbine - also what voltage should i select for my turbine and do i need to introduce any form of protection circuits for the invertor for instance in the event of a mains power failure.

I would be most grateful for any advice on this topic and any wiring diagrams or information relating to connecting the components up.  Also luv to hear from anyone who has been using this type of set up successfully.

Thanks in Anticipation.

Markc

P.s Have been quote £900 UK Sterling for this inverotr does this sound reasonable.

[Flux]

You would need to wind the alternator for a higher voltage to suit the "windy boy".

I think you need to work from about 350v to 600v. I suspect that you will have to produce a voltage clamp to limit the maximum voltage.

If your supplier is prepared to help then I am sure it can be done, but you will need a fair bit of support from your supplier or SMA.

The voltages you quote may be for the 120v version of the "windy boy" I am sure it is a lot higher for 240v

Flux

[Nando]

Adding to FlUX message;

An inverter, needs about 30 % higher voltage than the GRID maximum peak voltage, though at very low output power the input voltage may be close to the peak voltage.

For 230 volts and to reduce the working peak voltages the, output circuitry is formed by a full bridge feeding a transformer-choke configuration that with an output capacitor integrates and filters the generated sine wave current.

When the generator starts reaches its peak voltage ( ~ 600 Volts); the inverter loads the GRID with maximum power -- AT THIS POWER level the wind mill needs to be limited via mechanical means ( FURLING, PITCH ) and the GRID tied inverter needs to have the power capacity to dump a bit higher power for stable Wind Mill System, so if the Inverter is not capable of putting out the necessary power, a resistive PWM load needs to be implemented to the mill.

For a wind mill tied to the GRID, a BETTER marriage between the Wind Mill and the Generator and this system to the GRID tied inverter.

Good GRID wind mills produce high voltage 600 Volts Peak Voltage at maximum power, wind mills producing low voltages will require voltage conversion to the upper voltage needed by the inverter.

Some companies are trying to develop a GRID Inverter

Nando

[Nando]

ADDING DUE TO THIS MESSAGE THAT BY MISTAKE I SENT prior finishing my final sentence.

Some companies are trying to develop a GRID Inverter "with low voltage input" to take advantage of many wind mills with low generated voltages, maybe there are some available now.

Nando