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Forum Index : Windmills : 1000 W Wind Grid Tie Inverter repair

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DaveP68

Senior Member

Joined: 25/11/2014
Location: New Zealand
Posts: 292
Posted: 06:25pm 04 Oct 2017
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Flc1 had 1 of his 2 45-90 VDC 1000 W Grid Tie Inverters fail recently and sent it too me to try and repair.

As it turned out was a very simple fault traced to the Dump Load circuit. Require 2x power MOSFET's had gone short circuit. Order 2 of them at a cost of only $5 each soldered them in and it worked perfectly once powered up.

Photos of where they are (removed) on the board.



New MOSFET's installed.




The following photos are of the test rig to check it at full power output under controlled conditions.






Used a 48 VDC battery in series with a 4x 3p Delta 36 pole stator to boost power into inverter to >1200 W to test over voltage protection at full power output. Over voltage protection started to cut in at 91 VDC.

Ended up generating a maximum of 1270 W on DC side, 91.8 VDC at 13.84 Amps. Peak output power of 1080 W AC generated into Grid. By my calculations with inverter 92% efficient about 90 W of power was diverted to the load dump resistor.

Also the cut in voltage for this inverter was increased from 45 VDC to 49.5 VDC. This was required due to dual stator set up cut in RPM ended up a to close to single stator system. The wind turbine can only start up on single inverter, so this should solve that issue which was a minor problem anyway.Edited by DaveP68 2018-05-21
There are realities if you do not accept, will lead to frustration because you will be spending time on wrong assumptions and the results cannot follow! The Dunning Kruger Effect :)
 
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