Multiple Input DC-to-AC Grid Tie Inverter

Hello gusmenocal

How much in terms of total kW or MW are you talking about?

How many DC inputs are you intending?

While such a multiple DC input Inverter may be made, it would be more practical to have separate units, as the simpler a unit, the less trouble it is going to give during its service life.

More complexity, and several isolated different DC inputs, are going to mean if one part gives trouble, the full unit is down.

Separate units also mean physical plus electrical isolation, so one faulty unit may be easily replaced, while the rest continue to give service during the downtime of the failed unit.

Kind Regards....

All at once or selected sequentially? How much power total output at AC end? You need to provide much more data if you expect useful answers.

For an on the fly answer, if the separate dc in puts are the same voltage level, they could be brought to a battery bank or a set of caps to take out the ripples and give a steady dc to the inverter. put in some blocking diodes to prevent voltages from fighting each other. As we get more info we can remove many of the variables and solve you issue.

Our friends above are right. This kind of application is very complex and without more details cannot be solved. If you are looking for hundreds to low thousands of watts, there are commercial units available (check solar energy systems providers). If you are talking about hundreds of KW to a few MW, you have to talk to specialised firms like my employer to adapt custom hardware and software to your application. We can merge various sources with different voltage and isolation levels. It is not a "for my house" type of technology though.

When you connect to the grid, you need an automatic disconnect switch to prevent feeding power into the utility power line as it is dangerous for maintenance crew and can confuse their protections. If you want to sell power, you will need a licence to do so.

Hi gusmenocal,

There's several questions posted that really need to be addressed if you want to get a realistic answer. Like what you are trying to do...etc.

If you are simply trying to power an inverter from multiple batteries or DC supplies ...seperately...and want the best source to power it... you can use a "best DC" diode affair. Get appropriately sized diodes and hook each DC source to the diode anodes ...seperately... and then common the cathodes and go out to your load. This will pass the highest voltage.

Hello gusmenocal

I just realised what you hope to probably use these for: The 34 microturbines here: http://cr4.globalspec.com/thread/17342/Converting-AC-to-DC-for-a-micro-hydro-turbine

Kind Regards....