Behind the scene: Small micro-inverters, such as the one shown above, can be attached behind each solar panel to convert DC power into AC and improve the system’s overall efficiency.
Enphase Energy
Startup Enphase Energy is shrinking DC-to-AC inverters to extract more juice from solar panels.
There's more to solar power than blue glassy panels shimmering on rooftops. Just as important are the inverters that convert DC power created by the solar panels into grid-ready AC power. Typically, all the panels in a rooftop PV system are connected to one large inverter mounted on the side of a house.
Startup Enphase Energy of Petaluma, CA, is now making the first micro-inverters. These smaller inverters can be bolted to the racking under each solar panel, to convert DC power into AC for each panel individually. The company claims that the devices will increase a PV system's efficiency by 5 to 25 percent and decrease the cost of solar power.
Enphase has raised more than $20 million in its latest round of funding. The company has teamed up with various distributors and partners, including solar-module manufacturer Suntech Power Holdings and installer Akeena Solar, to bring its device to customers. The micro-inverters could be used on residential, commercial, or even utility-scale PV systems, says Todd Wilson, a general partner at RockPort Capital Partners, one of the leading investors in Enphase's technology.
In addition to DC-to-AC conversion, inverters are in charge of getting the most power from solar modules. They have a logic circuit that constantly searches for the best voltage and current levels at which the panels can operate. (Power is the product of voltage and current.)
In a conventional PV system, solar panels are wired together in series, and their combined high-voltage DC power is fed to an inverter. Therefore, the inverter's logic circuit optimizes the total current and voltage levels. But if one panel's current drops, it limits the overall output of the system. "Something as simple as a leaf blowing over a module, or dust or debris or shade on one module, will affect the entire array of all those modules that are connected in series," says Leesa Lee, director of marketing at Enphase.
Micro-inverters optimize the voltage-current levels at each panel individually. This squeezes the most power from each panel and then adds it together, increasing the system's efficiency. "Any impact on a module is limited to that module alone," Lee says. In addition, the equipment cost for micro-inverters is about 15 percent less than the cost for a traditional system, she says, because expensive DC components, such as signal combiners and disconnects, can be replaced with off-the-shelf AC parts.
Skyline Solar, a new startup, is combining conventional technologies to lower solar-power costs.
Dear Friends
I have lived alone on small islands dependent on solar powered battery charging usually for communications but also for entertainment, radio, boom box, also DC lights. A car tail light 3 watts has a very pure restful feeling it does not fluctuate like AC and is more comfortable once your eyes adapt to lower lights which saves money if the entire house is DC tail lights. You can use aluminum foil as a reflector to concentrate light. This also works with candles and kerosene lanterns. But the points are; use aluminum foil reflectors supported around solar electric panels to increase power on overcast days to charge DC batteries. To be more efficient bypass the wasteful AC transformers in most devices. Just use a multimeter to check output of rectifier bridge then bypass by switching the necessary batteries into circuit. The best thing is to make all devices 12 volt but I have found most devices are very tolerant of voltage levels, for example a boom box at 9VDC can accept 12 to 13VDC input. On a side note the transformers of boom boxes when AC is available can be used as battery chargers as long as they are not subjected to a large power drain. A light bulb in parallel can indicate charge level. I hope this helps the people of the world.
Cheers
Odin
during my 10 years in los angeles,ca i lived "homeless"-almost,when i bought a old motorhome for $2000. witch-concidering the rents out there,was maybe two month's rent..
-this tuned me into how D.C. power for general lighting,water pump,etc,was a great alternative..
-my bigggest problem was no solar panels to recharge the batt. used propane to power the fridge and what cooking i did-a5 gallon -bargeque sized bottle ran me for 2 months,i thought thaty was good for me..
-i turned many of my fellow rv-homeless on to marker light bulbs for low power consumption,even hooked up a dual battery system -in his car,witch he drove more than the motorhome,pull in,plug in a lead to aux battery,and worked well..
-l.e.d's are really interesting,as they use even less power,and last many times longer..
-am fixing to build a house on land mom inherited in kentucky..and am planning a d.c. system..
**there needs to be a "push"to get electronic manufactures to include a "12v" port to their device3s,as most use a power robbing ac/dc converter-and the actual component runs on d.c power anyway.. **
--we all keep working away on it,and we just might get things to work more effienciently.
good luck!
Then what's the point of being off the grid?
Seems to me, a simple need needs a simple fix.
And what about EMI?
Patel does not seem to understand the problem of keeping all those micro inverters in the same phase so they can use a common bus. Maybe (he, she) should brush up a bit on AC electrical engineering. If those micro inverters get out of step they will burn up in seconds.
These are grid tie inverters. They sync with the local grid, not with each other.
I agree basically sync inverters with the grid line voltage. OTH, whenever if completed isolation from line voltage condition is reached, say, if electric grid has problem, each inverter should sync to one inverter which the system selected. Using DSP to perform fast phase lock is not difficult, but it is difficult to keep voltage equalization if output of one or two of those inverters derivate much from the nominal output level. U can imagine, whenever one is sick, the stronger ones will attach the sick one. This is based on superposition theory or harmonic theory. If the target AC output is a non-sinosiual one, the system would be simpler (a cheaper version microinverter will come!). Anyway, DSP can handle the 3D datum, time, voltage and phase easily.
Robustness is a key point for such a new system. "We know the microinverter system is a plug and play system. It is ideally u can add or deduce a plane any time u want to do it!"
Of course, one inverter ties to one panel will generate good sales. In case we increase the power handling capacity of each inverter. Then, apply these enhanced inverters to panel groups located in different zones. The average conversion efficiency may more or less the same as the system using many many microinverters. It is because the microinverters may have insertion loss due to non-prefect switching and synchronization.
Words from Hong Kong DIY guy :-) Edmond Kum
More AC Power from Solar Panels
The idea is as old as the hills. Silacon sold systems similar to this back in 93'. No one was interested in energy savings so it died a painful death revived as of late in advanced form. Recently, new SMPS conversion semiconductors permitted Silacon to create conversion at the cell, multi-cell and panel levels that exceed 94% efficiency while blending with the cell to panel production process. AI applied to these systems permits adaptation to changing cell and panel properties. Multi-physics (Use COMSOL.com) synthesis optimization of power systems such as these is important thus PhD level participation is a good idea. Most BS degree programs do not include the applied mathematics to optimize systems. (Go to Wolfram.com) Silacon plans production of rigorously synthesized PV micro-power based build-outs. There must be fifty groups that worked on inventor Patel's kind of idea over the last 15 years. Patel's system can work but is not the most efficient approach. Optimization mathematics is the key. Good luck, Tiger.
BUILT, Yes Built, My Own Solar Panel!!
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Manufacturing in the United States is in trouble. That's bad news not just for the country's economy but for the future of innovation.
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jwgorman
15 Comments
when you need AC
a DC refrigerator, without the need for a transformer, is more efficient than an AC one. An electric car will store electricity from a DC input. An open-source EV project worth looking into:
http://www.tumanako.net/
Reply
killian
74 Comments
Re: when you need AC
The same idea would work for DC to DC conversion, with the resulting outputs paralleled. Introducing a conversion (whether to DC or AC) can increase the efficiency of the system.
For those who want to stay DC, consider this technology:
http://www.nextekpower.com/
Reply
visagejack
1 Comment
Re: when you need AC
The Enphase Microinverter System integrates state-of-the-art solar microinverters with advanced communications technology and web-based monitoring and analytics--according to their power inverter site..but I do hope to understand more about the solar panel.
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