windy boys

[eduardolino]

Hi, We are building a Hugh Piggott type of turbine for a college campus in Chile.

We want to show to the authorities that we can save electricity using the wind and sun.

Our question will be if we can connect the turbine (1 Kw Max) with a solar panel ( 10 watts)to a windy boy to turn the meter backwards. The amount saved does not count. Only the proof that it works matter. Also, the turbine produces AC, do we have to convert the Ac to DC for the windy boy and then hook it to the 220V 50 Hz meter?

Thanks for your help

Eduardo

[drdongle]

If the turbines output is AC, then yes it will have to be rectified to power the grid tie inverter. You will also need an inverter designed for that purpose.

[Phil Timmons]

Chile?  Sounds great to me.  I would love to be doing wind equipment in your far Southern reaches.  But I guess the low population centers in the far South would mean you have to send power back a LONG ways?

Anyway, your question was regarding "Windy Boys," which I understand are the close cousin of "Sunny Boys," an inverter system that takes DC from PV arrays and directly puts out grid tied AC?

Details here >>>

http://www.windandsun.demon.co.uk/windy_boy.htm

and here >>>

http://www.dependablesolarproducts.com/inverters/windpowerinverters.htm

The second of which says (among other things):

"Windy Boy 1800U & 2500U

This new inverter is the same hardware as the world renowned SMA Sunny Boy Inverters with a modified software package that allows it to be connected to a wind turbine. The new UL listing on the SMA inverters allows direct grid interconnection without having to use a cumbersome system involving batteries. The result is a typical net increase in energy production of 50% at the same efficiency as you have come to expect from the Sunny Boy Inverters. SMA's stringing technology also makes system expansion simple. SMA inverters have several communication options available including remote capabilities and computer . . . "

Speaking from personal knowledge and experience the Sunny Boys work well, and handle a wide range of DC inputs from the PV arrays.  

I understand that your question is whether an AC wind generator needs to rectified (converted to DC) for the input of the Windy Boy?  I agree that seems likely.  Offhand, I would guess that a simple bridge rectifier with some large smoothing capacitors and a current limit resistor should do the trick, but let's see if anyone here shoots that down before you actually give it a try.

But for the best answer -- SMA (the manufactuer of Sunny Boy and Windy Boy) would be the correct folks to direct this question towards.

The second link above also says:

"To see what other wind generators will function with a Windy Boy power inverter, check SMA's website here."

Here being:  http://www.sma-america.com/index.aspx

They also have on-line documents on the SMA website.  But in all truth, I detest reading SMA manuals because they never seem to leave "Public Relations" and Sales mode and concisely give me the information I want.  So as far as RTFM (Reading The Fine Manual) you are on your own.

But let us know how this is all going, too.  It is very interesting and encouraging to see everyone working towards common goals around the world.  

[Phil Timmons]

OK, I actually got curious and looked at the SMA manual for Windy Boy:

http://www.sma-america.com/ftp/Windy%20Boy%20Operation%20Manual%20Addendum%20V12.pdf

Did not read as bad as I feared.

Page 3 says:

"Background

Historically, grid tied wind turbines have charged batteries through a charge controller and used another converter to process power from the battery to the utility grid. The dual conversion and inherent losses associated with moving power through a battery resulted in very inefficient delivery of wind power to the utility. Overall transfer/conversion losses were easily in the 40-50% range. This means that 50% of the energy available from the wind turbine was being delivered to the utility.

The Windy Boy inverter is a single conversion, DC to AC inverter, which is similar in operation to the Sunny Boy grid tied PV inverter. Mechanical power from the turbine is delivered to the inverter as DC voltage (speed) and current (torque). Most small turbines use an AC alternator and a diode rectifier bridge to convert variable frequency AC from the alternator to DC power.

The inverter uses a programmed power versus voltage curve to command current from the turbine dependent upon the DC voltage generated by the turbine. Each alternator design has an optimum operating point or power curve of speed (voltage) versus torque (current). The Windy Boy incorporates a linear power curve that may be programmed by the user to match the characteristics of the specific wind turbine alternator."

So yeah, it looks like you do use a bridge rectifier and feed the Windy Boy from your AC wind generator.  The input requirements on page 3 and 4 also say:

"Maximum DC Ripple 5% peak-to-peak"

So I would think that means some smoothing capacitor(s) are required, as well.

Also to consider -- I have no idea what DC voltage your windmill can/will produce.  But the Windy Boy specs a max DC input:

"Maximum Input Voltage 400Vdc" for the WB1800U model

"Maximum Input Voltage 600Vdc" for the WB2500U model

My experience is that if you go above that, the Sunny Boy (for PV) inverters will shut off --  that may leave your windmill with no load (free spinning?).  I know that I do not know about that, but I would think that may be a reasonable condition to caution against.

They also say:

"DC Over-voltage Protection

The largest danger to the inverter is from DC over-voltage. This is the common result of a wind turbine over-speed condition. The most radical over-voltage condition occurs when the inverter is processing power from the turbine and an event (most commonly a utility line fault) occurs causing the inverter to immediately stop processing power. When this happens, the power that was going to the utility is transferred back into the turbine as speed. The wind turbine will quickly increase speed, which causes the DC voltage to also increase rapidly. This can produce voltage in excess of 2000Vdc, if the turbine was fully loaded at the time of an event. Exceeding the maximum input voltage will void the inverter warranty.

Most turbine manufacturers have designed a protection circuit to protect power

processing equipment from this condition."

So you may want to have some system monitoring on the windmill portion that drops out a relay for over-voltage?  And shifts it over to a dump-load?  Dunno.

But they clearly do not want your problems to be their problem -- I guess they are not joking with the Warnings:

"Product Limitations and Warnings

The Windy Boy inverter is a standard inverter designed to be installed only with qualified wind turbines. Input protection is the responsibility of the turbine manufacturer or system integrator/installer. Misapplication of the Windy Boy may cause irreparable damage to the inverter and turbine system, and will void all product warranties. Please contact your turbine manufacturer for detailed system information.  

The Windy Boy inverter is designed to operate with wind turbines employing a 3-phase generator and rectifier that produce current and voltage within the allowable operating ranges of the inverter. All protective wind turbine input functions (over-current, overvoltage, over-power, fault tolerance and recovery, turbine mechanical protection, etc.) are the responsibility of the turbine manufacturer or system integrator/installer."

[Nando]

EDUARDO:

Send a me message to me, directly, my address is in the heading, I can assist you!!

Enviame un mensaje directamente a mi correo electronico que esta en el encabezamiento de mi mensaje, te puedo ayudar.

Nando

[eduardolino]

Nando:

Thanks I sent the reply. In case it does not get to you, here is what I wrote to you.

Is it possible to connect together a 1KW turnibe (Piggott type)with a solar panel. And have these two connected to a single sunny or windy boy?

Thanks

[eduardolino]

Nando:

The messages that I send to you, return undeliverable. We might need an email in Ingles por favor

Gracias

Eduardo