7200 watt solar panels on the roof

[gary350]

I checked out several companies and some are way over priced, 3 times more expensive than another company. I hate to be an advertisement for ANYONE but SolarCity has the best deal. For $14K they put 33 panels on the roof for a total of 7200KW. SolarCity gets the federal income tax rebate this reduces my total price. SolarCity guarantees everything even my roof and house and if the roof needs to be repaired they take care of it at their cost. All maintenance and repairs are covered too. If I move the whole systems can be signed over to the new home owner. There is enough solar during the day to power the house and sell power back to the local power company durning peak rates. At night I buy power from the power company at the lowest rates.

Question. How is the power from the solar cells put back into the 60Hz power lines so it is in phase?

 

[BeerBelly]

That sounds like quite a deal.
With solar panels, inverter, installation, and maintaining the system,the Federal gov must be picking up a lot of the bill.
My house runs on solar power but I am off the grid so I get no tax break.
As for your question
I expect the inverter uses a microcontroller IC to keep track of zero crossing and phase of the AC at the beginning of each cycle.

 

[dr pepper]

Your system will use a grid tied inverter.
These are not too different from an ordinary 12v to 240v inverter, the differences are that the o/p of the inverter frequency and phase wise is synchronized to your mains supply, also theres a safety shut off or zero volt relay function where if the mains to your house is cut off the inverter stops generating, sposing the electric board cutoff your house for an emergency repair if your inverter didnt switch off the mains wiring would still be live presenting a danger to the engineers working on the system.