Array Converter (Array) is a Sunnvale, California, company that designs inverter-less solar power systems to directly convert the direct current (DC) electricity produced by solar modules into alternating current (AC) for the grid.

Array owns several patents relating to its converter technology, including U.S. Patent No. 7,884,500 and a patent family consisting of U.S. Patents Nos. 7,719,864, 7,929,324, and 7,929,326 (collectively “Converter Patents”).

The Converter Patents are directed to a DC to pulse amplitude modulated (PAM) current converter, which is referred to by its acronym, PAMCC, and to electrical power conversion systems comprising arrays of PAMCCs.

A PAMCC (400) receives direct current from a photovoltaic panel (401) through positive and negative input terminals (402, 403), each connected in series with coils L1 (406) and L2 (405), respectively. These coils comprise a single transformer T1 (407).

A controller (412) controls several independent lines (419-422) of circuits (423-426). Capacitors (438, 440) are across the input side of coils (430, 432), respectively and a neutral output terminal (432).

Control signals on lines 411 and 419-422 connect and disconnect the current provided by the PV panel (401) in sequence within the PAMCC (400) in such a way as to provide an output whose amplitude is a PAM signal approximating a sine wave.

Several claims of the Converter Patents are directed to a plurality of PAMCCs and recite the following key feature:

the current pulses of at least two converters are out of phase with respect to each other, thereby summing the current pulses of all of the converters such that a signal modulated onto the pulse output of the converters is demodulated

According to the Converter Patents, when an array of PAMCCs are connected in parallel such that the PAMCCs’ output pulses are out of phase with respect to each other, the result is an AC current waveform suitable for both local load use and connection to the utility grid:

An array of PAMCCs constructed in accordance with the present invention form a distributed multiphase inverter whose combined output is the demodulated sum of the current pulse amplitude modulated by each PAMCC. If the signal modulated onto the series of discontinuous or near discontinuous pulses produced by each PAMCC was an AC current sine wave, then a demodulated, continuous AC current waveform is produced by the array of PAMCCs. This AC current waveform is suitable for use by both the “load”, meaning the premises that is powered or partially power by the system, and suitable for connection to a grid. For example, in some embodiments an array of a plurality of PV-plus-PAMCC modules are connected together to nominally provide split-phase, Edison system 60 cps 240 volt AC to a home.

Other advantages discussed by the Converter Patents include that the high voltage portion of the PAMCC is physically very small (a few square inches) and can be located on the back of a solar panel assembly, making insulation simple and lightweight.

Array’s web site touts the simplicity of the inverter-less technology and notes that it is “less than a quarter of the complexity of the simplest power inverter without the need of short-lived filled or plastic film components.”

The bottom line, though, is cost:

Simplicity means every cost is reduced while Array Converter improves LCOE by both reducing each cost and increasing energy harvest.

Eric Lane is a patent attorney at Luce, Forward, Hamilton & Scripps in San Diego and the author of Green Patent Blog. Mr. Lane can be reached at elane@luce.com.

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Fighting a war on the ground in Afghanistan has to be one of the hardest things a young person can do.

Fortunately, the U.S. Department of Defense, or DOD, is on the ground with our troops offering help and support – albeit in some very unexpected ways.

According to Tony Bui, an engineer with the U.S. Army Communications-Electronics Research, Development and Engineering Center, or CERDEC (located at Fort Monmouth, NJ), newly developed renewable energy devices will give U.S. troops more mobility, allow them to stay in the field longer, and protect the average soldier from exposure by ensuring that battery changes happen once in a blue moon. Literally.

The first is called REPPS (the Rucksack Enhanced Portable Power System). Made up of flexible solar photovoltaic (PV) panels rated at 62 watts, it represents a continuous, portable power generation system that can be used to keep laptops and similarly sized electronics running in the field.

Charging can be done in five or six hours. For larger items – that is, larger than a laptop and smaller than a Jeep – REPPS units can be chain-ganged to deliver even more electricity, thanks to integrated power conversion technologies.

Another system, called RENEWS (Reusing Existing Natural Wind and Solar system), marries solar and wind energy and integrates inverter technology to allow soldiers to connect to the device through AC/DC (alternating or direct current) outlets.

Because the device also incorporates battery storage of electricity, RENEWS needs the combined muscle of two soldiers to transport. Even so, it provides all the electricity needed to power communications and surveillance equipment, even in the boonies, where vehicle and grid power often aren’t available.

Both are still in development, but thanks to the American Recovery and Reinvestment Act (Recovery Act; 2009), 700 REPPS and 125 RENEWS will soon be headed to the troops in Afghanistan.

As Fort Bliss Commanding General, Howard B. Bromberg noted, “We are looking for game-changing technologies…”

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If micro-inverters are the current craze in the solar industry, then I predict that solar energy monitoring systems will be the next big thing.

Micro-inverters (and other parallel technology) are given lots of attention because they can increase the efficiency of a system by up to as much as 10%-20%. Similarly, solar electricity systems that are hooked up to monitoring systems have a 10% energy production increase over systems that are not hooked up to monitoring systems, according to Will Shortt, CEO of Deck Monitoring.

PV solar panels last at least 25 years, where as inverters only come with an 8-10 year warranty. That means that sometime in the 8-10 year range the inverter will die and the system will stop producing energy. With a monitoring system in place the installer or homeowner will know immediately that the system has been compromised. Otherwise it could be weeks or months before the homeowner looks at their energy usage statement from their utility company and realizes that their solar electricity system is not longer producing energy.

Monitoring systems currently cost around $1,000, which seems like a small price to pay for installers to be able to ensure that a homeowner’s system is working properly. With a monitoring system in place an installer could offer a “performance assurance”, and that may be just the differentiator needed to close the deal.

All California installers are required to give a 10-year warranty, but this might compel them to give even longer warranties. Similarly, it may motivate installers to offer warranties in other states.

Combine a warranty with monitoring systems and I can see how a solar installer could proactively call a homeowner to say that they’re going to drop by to clean the panels when they see the productivity drop rather than the other extreme of having a system fail for some reason, then have a furious customer calling because their $20,000 solar energy system has not been producing electricity for the past month. I’d much prefer to read stories on yelp about how great an installer is because they called a customer to say there was a problem that they were going to come out to fix before the customer even knew there was an issue.

Thomas Dinkel, CEO of SunReports said that SunPower, SunRun, Solar City, and Sungevity all offer monitoring with any systems they install, and therefore to be competitive with them other installers will likely start offering monitoring as well.

The most compelling feature of monitoring systems is the ability to measure performance against what was promised and what is expected of the system. Not only is it fun to see, but it also serves as a great indicator if something goes wrong with the system.

Lastly, when homeowners are able to view their solar energy production or energy usage in a clear, easy to view fashion, they inevitably will adjust their behavior and start using less energy, which is a great positive side-effect.

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The biggest deterrent for retail consumers to install solar panels on their rooftops is the upfront cost, which may vary depending on the country and state incentives. The cost of repair is on the owner of the panels (most panels are insured for 20 years or more and since they have no moving parts are pretty stable). The inverter that coverts the current to a usable form needs to be replaced every twelve to fifteen years and this portion of the system costs thousands of dollars.

The benefits to a buyer of the solar panel are all of the tax credits, RECs, the guaranteed payment for the solar energy from the utility company, and peak load offset that significantly reduces the consumer’s utility bill.

The solar lease model put into effect by companies such as Sungevity in the US and the Green Home Company in the UK are making solar installations affordable by eliminating the upfront costs and reducing people’s energy bills. This is making solar adoption on a mass scale faster. In the words of Sungevity, “The Sungevity Solar Lease is a game changer: In one day this month we sold more solar power than our previous biggest month – people are voting with their mouses to get a lower electricity bill and do something for the planet.”

By eliminating the upfront cost in the contract and including repair and insurance, this eliminates the hassle of choosing the right system. Solar leases are revolutionizing the solar market and converting many more people to solar adopters. Is this model risk free and right for every consumer?

It is not cheaper to lease solar panels then to buy them. There is plenty of housing transfer and rating risk to worry about. Moreover, the consumer forfeits the tax incentives. Are the the leasing companies that are springing up creating the right model or are we heading for a mortgage like bubble that hit the financial markets last year but now in the green space?

Let us consider an example. The lease payments increase on a yearly basis from 2-5%. A 4kW system may cost $7,500 (after tax credits). If leased, this eliminates the tax credit and can cost more than $13,000 (20 year loan, $45 per month, 2% annual increase, numbers referenced from The Green Home Company rate). To lease then is almost double the cost of buying the panel upfront and at the end of the term the panels are not owned by you.

If a resident wants to vacate the home and transfer it to another person, she can run into credit risk in terms of transferring the lease of the solar panels. Many of the lease companies also mention that should the lessee want to break the lease, the removal of the solar panels will be at the lessee’s expense. Since one of the biggest cost components of solar is the installation, this will further increase the lessee’s cost.

It is great to see new financial products that make green choices accessible to every consumer. However, more clear warnings and risk outlines need to be documented and standards put in place to protect the consumer and give the consumer the tools to make the right choice.

Article by Elena Potylitsine, a strategy, risk and finance consultant. Elena closely follows the Renewable Energy Sector and helps promising start-ups reach the growth stage.

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With an eye on Ontario, Conergy and Sustainable Energy Technologies have partnered up to supply Sunergy inverters to one of North America’s most active solar markets.  Over the next year, the two companies hope to produce 3MW of clean energy, spread across a number of different projects.  First on the list is a 75kW rooftop installation on Brampton’s Metex Heat Treating facility.

In high-tech industries, it is not uncommon for such partnerships to emerge, with each side enjoying greater access to knowledge and skills outside of its core expertise.  According to Conergy’s Managing Director, Jared Donald, “Partnering with Sustainable Energy was an easy choice as the Sunergy inverters deliver exceptional performance for commercial rooftop solutions with safe, extra-low voltage technology.”  He adds, “With the Sunergy inverter and its parallel wiring architecture, our customers will now have access to a highly flexible rooftop inverter that delivers high performance even in non-ideal conditions.”

What sets the Conergy-Sustainable Energy Technologies arrangement apart, however, is the focus with which these two firms are approaching the Ontario market.  When multinationals collaborate, they usually do so to service global or national audiences – not provincial ones.  Hamburg-based Conergy’s interest in Ontario is especially telling given that Germany has long been the unquestioned leader in solar PV installation.

Part of this shift stems from Ontario’s domestic content requirements mandating that a portion of all parts and labour be sourced locally.  Consequently, those looking to tap into the province’s rapidly growing solar market have little choice but to establish a presence in the region.

Chairman of Ontario Solar Network, Jacob Travis, explains, “Ontario’s recent renewable energy legislation is generating great interest around the globe.  An industry infrastructure is being developed almost from scratch and the province is poised to become a global leader.”

Ontario-based Oya Solar has been commissioned to develop the upcoming solar plant, outfitted with Sunergy inverters, Sustainable Energy’s Paralex structure, and crystalline PV modules. 

photo: Abi Skipp

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GE just invested in them. Now, Guy Sella, founder and CEO of Israeli company SolarEdge, is planning a revolution. Don’t be alarmed though, this one isn’t dangerous. His goal is to transform the way photovoltaic systems are now operated, in terms of efficiency, safety and cost.

“People haven’t been looking at photovoltaic systems from a holistic point of view,” Sella tells ISRAEL21c. “Panel manufacturers care only about the panels and panel conversion efficiency. The people that develop classical inverters only care about the efficiency of the inverter. I asked: can we create a system that is better than we currently have?”

The answer, according to SolarEdge, is yes. The Herzliya-based has created “intelligent panels” that work together with a central Power Box, which would replace the passive panels that are the current norm. These new panels provide 25 percent more energy as well as solutions to some of the serious problems that plague current systems.

No feedback, no function

Today’s photovoltaic systems have a number of major disadvantages, according to Sella. For instance, there is no feedback from individual panels. If a panel is broken or not functioning properly, there is no monitoring system to detect the problem.

“In fields today you have hundreds of thousands of panels,” says Sella. “Even if some of them are not working, they don’t have any monitoring level, so you as the field owner can’t know if they are working. After a big hailstorm, people habitually walk through the field with a notebook, visually checking each panel and writing down its condition.”

Another problem with having no monitoring system is that people can easily steal the panels, which are worth between $600 to $800 each. These antediluvian conditions would be abolished by SolarEdge’s technology.

Turning passive panels into intelligent devices

In current systems, all the panels in a photovoltaic system are connected to an inverter box, which in turn connects the system to the power grid. SolarEdge, however, has taken all the technology in the inverter box and put it into an electronic chip, or ASIC.

Each photovoltaic panel contains its own ASIC chip, turning each panel into an electronic device that can alert the owner both to its functionality and possible theft. The system will also be connected to the internet, so the owner can go online to check the status of each panel.

These intelligent panels also provide more energy than current photovoltaic panels. “The panel can now optimize its energy output, and can verify that it is converting the maximum energy that it has,” explains Sella.

An additional advantage is that the very different voltage system created by this technology is much safer, says Sella. Current systems use thousands of volts in their DC lines, and are impossible to turn off, a serious hazard in cases of fire. The inability to shut off powerful voltages also makes these systems potentially dangerous to install.

With the SolarEdge system, the panel-embedded electronics can be shut down individually, either through the central power box or via the panel itself.

An excellent rate of growth

Confidence in SolarEdge is high. Founded in 2006, by Sella and co-founders Yoav Galin, Lior Handelsman, Meir Adest and Amir Fishelov, who met in an elite technology unit of the Israel Defense Forces, the 70-member company has raised $23 million in the past year, despite the poor economic climate.

It plans to start shipping products from mass production lines in Israel late this month.

“SolarEdge has partners all over the globe – in the US, Germany, Spain, France, and Japan,” explains Sella. “Through our partners we have access to 40-50 percent of the world market, which is basically wherever there is solar energy.”

This market is in the range of $30-40 billion; and Sella estimates that the worth of his own product is somewhere in the region of $3 billion.

Not surprisingly then, Sella is optimistic about the solar energy market even in the current recession. “The growth rate of the solar energy market makes it interesting. I’m not aware of any market since bubble days that has had this level of growth rate,” he says.

Eventually, Sella predicts, “Solar energy will be cheaper than fuel cells, and energy harvested from photovoltaics will either be cheaper or the same as fossil fuels.”

Article by Ilana Teitelbaum appearing courtesy of Green Prophet; first published on ISRAEL21c

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