Grid Tied Inverters

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Grid Tied Inverters

Postby TonyB » Tue Jun 17, 2008 2:52 am

A Grid Tied Inverter or a (GTI), allows a direct connection between the DC solar array and your homes AC power grid. This means that PV system can operate without batteries. From there the DC power generated by the solar modules is inverted to higher voltage AC and its either used directly by your AC appliances or its sold back to your utility company which lowers your monthly electric bill. Having a grid tied solar setup also lowers the cost of going 'green', and is more efficient than using a conventional system which uses a battery power bank.

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Grid tied inverter work just like a conventional DC-AC inverter. They will take the input DC power, step it up, filter it into a pure sine wave, and feed it back in to the AC grid. The step up is done via high frequency DC-DC converter (PWM controlled inverter), and the filtration is done via inductors and capacitors. The electricity flows back the other way because the output voltage is slightly higher than the AC grid voltage.

Effects on the grid power quality

In order for grid tie inverters to comply with utility electrical standards, the output power needs to be clean, undistorted and in phase with the AC grid. Typical modern GTI's have a fixed unity power factor, which means its output voltage and current are perfectly lined up, and its phase angle is within 1 degree of the AC power grid. The inverter has an on board computer which will sense the current AC grid waveform, and output a voltage to correspond with the grid.

There are currently around 22 company around the globe that manufacture grid tied inverters. However the US and European markets are dominated by two brands SMA (Sunny Boy) and Xantrex.

Attached is the data sheet of a 6KW Sunny boy 6000U inverter.
Attachments
sma_6000U.pdf
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-TonyB
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Re: Grid Tied Inverters

Postby Benny » Thu Aug 28, 2008 8:08 pm

Hi Tony - not many contacts yet but a good idea for distributing info on solar power.

Does anybody have any info on accessing the serial port output from a sunprofi inverter ? We know it has an output that can be connected to a PC but they won't release any info on how to do this. First issue is that its an RS485 connection rather than RS232 but I have a converter. We tried just listening to the port and evenmeasuring with a multimeter but couldn't detect anything.
Benny
 

Re: Grid Tied Inverters

Postby TonyB » Thu Sep 04, 2008 10:06 am

Hi Benny,
Ive never used that particular inverter, however if you have an oscilloscope, you should be able to locate the TX and RX pins on the output, and also measure the Baud rate.

With these you should be able to connect through a terminal program like hyper terminal.

cheers.
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Re: Grid Tied Inverters

Postby arpithas bhat » Sun Feb 14, 2010 12:39 am

hi
i hav chosen my final year project on grid tie inverter..so can u please give me some links where i can get more information bout this???
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Rea/connect output of CMS-200 inverter on computer

Postby susambas » Mon Jun 14, 2010 11:37 am

We have six Enertech Solar E-170 watt panels installed on an 18 degree north facing no shaded tiled roof.
The Grid Feed inverter is a CMS-2000.
The meter is an EM 1200 Co Generating Metering system Origin label on the meter reads: CO-GEN. The grid feed diverter is under the house some 16 meters away, I need to get under the house to read it. Any suggestions of a cheap way of getting the reading in to the house office computer and how to connect the CMS-2000 or the meter to the computer so that I can follow the output daily without having crawl under the house?
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Re: Grid Tied Inverters

Postby TonyB » Mon Jun 14, 2010 1:56 pm

You could try a using a rs232-Bluetooth converter. These have up to 50 Meters range and easily work with the 9600 Baud rate of the CMS.
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Re: Grid Tied Inverters

Postby WROSCOE » Fri Sep 10, 2010 7:48 pm

Hi , I ahve got my CMS2000 inverter cable connected and working with Procontrol software , I have tried an RS232 to Bluetooth converter with no luck , the notebook recognises the bluetooth device plugged into the inverter but it but Procontrol doesn't recognise the inverter at all, I have tried com port settings and baud rates etc , no luck
TonyB , if you are using Bluetooth what sort /brand of adaptor are you using ?
thanks
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Re: Grid Tied Inverters

Postby chinaeu » Sun Feb 20, 2011 11:01 pm

very nice grid inverter :D
http://www.chinaeu.de/
http://solar-lamp.chinaeu.de/
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