Inverter Power Supplies in Parallel

Hi tcrooks

I recently raised this mater in a recent post (inverter), and was advised that paralleling of inverters is not advisable. But out of that discussion a few thing where raised, a modular unit would be a lot cheaper to put together, and a control circuit is theoretically possible. this link is a paper proposing how it may be possible to achieve that, and this link to manufacturers. Best of luck.

Regards JD.

Thanks, parallelling "inverter" generator sets is being done effectively in the Honda Model 2000 and 3000 EUI (2 and 3 kW) gen-sets. Inverters, taking DC power output can produce 60 cycle AC power, regardless of engine RPM. This allows the small engines to operate at optimum RPM in their power band and not be constrianed by isochronous RPM requirements traditionally tied to alternator pole configuration (i.e., isochronous engine RPM -1200 RPM, 1800 RPM or 3600 RPM). This has proven very succussful for them. They also provide paralleling kits to facilitate operating two inverter/gensets. The paralleling interconnects are made by Reliance. Given these facts, I know inverters can be operated in parallel providing cheap, reliable and clean AC output. I'm just looking for a manfuacturer that makes inverter pralleling IC products.

There are units available that will convert DC to AC, and the added ability to "Gang" the inverters together, for either more power handling (load sharing) or redundancy.

M+H Power Systems sell these products http://www.mhpower.com.au/pages/home/home.html

they sell the units as complete "Turn-Key" equipment, not as modular equipment.

On the controlling side, I feel you would need to have the units processor controlled, with some kind of "interlinking" so each controller can (upon finding the link) do the necessary control drive to operate in the mode(s) that you require.

As for the circuits themselves, I doubt you'll find many available, or the ones you do, could be simplified.

I am sure you have considered charging a single storage battery with your multiple DC sources and then converting from the battery.

I wish I knew something of our application.

Gavilan

It is a good idea and it is being done currently. The ability to parallel multiple modules to provide whatever capacity is required and to accomodate future load growth would be a tremendous advantage. Electrical efficiency and installation costs can be optimized by allowing the designer to install the right number of inverter modules for the load conditions and add more capacity as load increases, or to power down excess modules during periods of light loading to both save energy and reduce wear and tear on the UPS. The ability to hot-swap out individual inverter modules to perform maintenance or upgrades would also be a plus.

There is an industry working group promoting this technology called "Blade Technology." www.blade.org

Here is an example of a UPS system using this technology and available from Emerson Powerware: http://www.powerware.com/bladeups/Default.asp?CC=1

Here is a 20 page PDF whitepaper from APC with some really good details as to the advantages of modular UPS inverter technology: http://www.blade.org/docs/wp/WP108_VAVR-6LJV7V_R1_EN.pdf

Good luck!

ask these guys http://cgi.ebay.com/Envirotechs-200W-Grid-Tie-Inverter-for-Solar-Wind-Power_W0QQitemZ130257800945QQcmdZViewItem?hash=item130257800945 this unit seems to be what you are contemplating.

This technology exists and is mature. I have been repairing inverter systems made of 6kVA modules, up to 300kVA, for the past 18years. Newer equipment is now processor controlled. To see examples of the market leaders go see:- www.mastervolt.com, www.victronenergy.com, www.xantrex.com. All of these produce parralleable inverters also with auto-synchronization allowing them to assist a generator in periods of overload. All of these also double as battery chargers (combi units) switching automatically from one mode to the other dependant on whether 230V (or 115V) is available at the input. Sorry sir, you're reinventing the wheel.

Thanks for your comments! I knew it could be done and that others were doing it. (See Honda 2000 and 3000 EUI paralleling inverter gensets). My objective is to locate and acquire the "off-the-shelf" technology and marry it to a new prime mover generation power source. Your comments have been very helpful.

Yes, we can parallel both converters and inverters when done properly.

We have been doing it for seven years from 50KW to 2MW using IGBT technology.

We have both water and air cooled. We can also combine Dc sources.