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Will China Take Over the Inverter Market?

7:00 am in Solar, BOS/Inverters, Research & Analysis by info@greentechmedia.com

Sungrow. It’s not a name you hear all the time at solar conferences at the moment, but give it a few years.

The Hefei, China-based company is the first of what could become a wave of inverter makers from China using that time-tested formula of low costs, increasing technical sophistication and domestic support to soak up global market share.

Sungrow shipped 500 megawatts of inverters last year, according to GTM Research analyst MJ Shiao, and will expand this year.

That constitutes a drop in the bucket in the overall inverter market. Globally, 21.2 gigawatts' worth of inverters shipped in 2010 and 24 gigawatts will ship this year, Shiao added.

The company, though, can often undercut European and North American manufacturers by 10 percent, he added. Lesser-known Chinese names have tried to undercut established manufacturers by 20 percent.

Founded in 1997 to supply solar and wind inverters to government projects, Sungrow controls 40 percent of the small, but rapidly growing, Chinese market, according to various estimates, but ships most of its products overseas. Overall, Sungrow claims it has planted 1 gigawatt of inverters in the field.

In March, UniCredit Leasing Group confirmed that Sungrow is on the “bankability” list, which potentially will ease the way for participating in European projects. A few weeks later, it formally opened a joint manufacturing facility in Ontario with HiFi Solar Energy that is capable of generating 200 megawatts' worth of inverters a year.

 In 2010, it had 1 gigawatt worth of capacity and hopes to triple that in 2013 to 3GW.

A rumored IPO in the U.S. earlier this summer did not materialize. Nonetheless, U.S. investors are interested. VC firm Kleiner, Perkins Caufield and Byers is an investor.

Historically speaking, Sungrow and the other Chinese inverter makers would seem like a lock. Ten years ago, Chinese solar module makers constituted an asterisk. Suntech didn’t even exist: Zhengrong Shi founded the company in September 2001. Now, Suntech is the largest manufacturer in the world and companies like Trina and Yingli fill out many of the top spots in cells and modules.

Polysilicon? It is a sophisticated, highly technical market where Europeans and North Americans could maintain advantage, some have argued. No one told GCL-Poly Energy holdings. GCL President Yumin Liu said in April that the company’s wafer capacity will balloon to 5.5 gigawatts and hit 6.5 gigawatts by the middle of 2012, while polysilicon production will rise from 31,000 tons to 65,000 tons in the same period.

GCL’s costs come to an “obscenely low” $22.90 a kilogram, according to Shyam Mehta of GTM Research. (Disclosure: the analysts quoted here are co-workers.)

Inverters are pieces of electrical equipment, similar to the billions of pieces of equipment manufactured in China every year. Cost also remains a paramount concern: under the SunShot program, the Department of Energy hopes to drop the cost of inverters in solar installations to ten cents a watt, or one-tenth of the overall capital budget, by around 2017.

Satcon, PowerOne and a few other international manufacturers already have inverter manufacturing facilities in China. A migration of talent, skills and know-how to lower-cost domestic firms seems almost inevitable.

Taiwanese contract manufacturers with large mainland operations could become more prominent in the market too. (Eaton, the U.S. conglomerate, bought Taiwanese inverter maker Phoenixtec in 2007.)

The inverter market, though, does come with a few wrinkles. Inverters might account for the smallest part of the budget of solar installations, but they often cause the lion’s share of headaches, giving incumbents an advantage.

“There are a lot more components in inverters [than in panels] — and a lot more components that can go wrong,” Shiao said. “Quality and reliability are a big deal.”

Microinverters have also begun to gobble up market share at the expense of the centralized inverters. In North America, microinverters have become commonplace in residential installations and are gaining ground in commercial arrays because of touted advantages in uptime, power production, and installation.

Europeans have begun to take an interest in microinverters, too, said Ron Van Dell, CEO of microinverter maker SolarBridge Technologies. AUO and Kyocera, among others, will soon release so-called AC modules with integrated SolarBridge inverters. The return of AC modules — an experiment that didn’t work the first time around — comes as a result of recent technological improvements that will effectively give microinverters a 25-year lifetime.

Sungrow and many of the other Chinese inverter makers specialize in centralized inverters.

Inverters, despite price wars, will also likely become more sophisticated. Executives at Solectria and General Electric recently outlined how inverters will absorb many smart grid functions, acting almost like the computerized brain of solar fields. Could Chinese companies figure this out? Sure. Local IT outfits like networking giant Huawei could participate. But it could take time to fine tune the technology.

While China won’t colonize inverters this year, the trend definitely bears watching, particularly in periods of high demand. Ramping up factory capacity in inverters is relatively straightforward. Manufacturers don’t need to fine-tune deposition chambers or automated factory lines. Inverters are largely assembled. Expanding capacity means getting some more warehouse space, workers and equipment.

Suddenly, a name that vaguely sounds familiar says it can help, and it can cut your costs ten percent…

No Inverter Required: Analyzing Array’s Current Converter Patents

7:10 am in Solar, BOS/Inverters, Research & Analysis by info@greentechmedia.com

Array Converter (Array) is a Sunnyvale, California company that designs inverter-less solar power systems to 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, the “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 powered 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 website 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," according to the firm's website.

More details on the company here. Recent news on distributed electronics for solar here.

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Eric Lane is a patent attorney at Luce, Forward, Hamilton & Scripps in San Diego, where he works in the Intellectual Property and Climate Change & Clean Technologies practice groups. Mr. Lane can be reached at or at elane@luce.com. He authors the Green Patent Blog. He wll discuss his new book — Clean Tech Intellectual Property: Eco-Marks, Green Patents and Green Innovation — in San Francisco later this month.