Canadian Solar orders one of the largest single-project deployments of DC optimizers

canadian-solar-logoCanadian Solar is going to deploy Ampt LLC DC optimizers in a 33-MW PV system, which would make it one of the largest deployments of DC power optimizers in the world. The 33 MW installation capped off a six-month evaluation period by Canadian Solar, which began with a smaller demonstration project. Following the successful demonstration, Canadian Solar selected Ampt’s String Optimizer as it consistently outperformed other designs while costing less.

“Our initial work with Ampt surpassed expectations and laid the groundwork for the 33 MW utility-scale installation,” said Ken Rowbotham at Canadian Solar. “We chose Ampt for its clear technology advantages which support our broader commitment to being the industry-leading provider of clean solar energy across the globe.”

RELATED: How optimizers bridge the gap to 1,500-volt PV systems 

Ampt’s patented technology puts voltage and current limits on the output of each optimizer to allow twice the number of PV modules per string and eliminate half of the combiner boxes and associated cable and labor. Ampt also performs maximum power point tracking (MPPT) on every 20 modules to mitigate losses due to mismatch, and allows the inverter to operate at a high and narrow input voltage range to improve inverter performance. Ampt’s optional string-level data reporting via wireless communication helped validate comparison data.

“At Canadian Solar, we are always evaluating new technologies to lower the cost of solar energy for our customers,” said Ken Rowbotham at Canadian Solar. “The Ampt solution stood out, as it allowed us to reduce the cost of electrical balance-of-system (BOS) components, produce more energy and get the most out of the inverters.”

According to research from Global Market Insights, DC power optimizers will continue to see rapid growth in the solar market. While the use of DC optimization started with the residential market at the module level, Ampt’s String Optimizers bring unique power conversion technology to large commercial and utility-scale power plants by lowering the total upfront cost of systems while increasing energy generation.


— Solar Builder magazine

GreatWall Energy adds ‘Ampt Mode’ to line of inverters for string optimization

China Electronics GreatWall Energy, one of the world’s largest solar inverter manufacturers, has incorporated an Ampt Mode with its Satcon Equinox 750kW inverters. Using these inverters with Ampt String Optimizers can lower the total system cost while improving lifetime system performance to deliver more value than can be achieved by traditional systems without Ampt.

AmptV1000StringOptimizer - CUT 1

String optimizers, like this one from Ampt, put voltage and current limits on each string to achieve 100 percent longer strings without exceeding 1,000 volts.

The Equinox inverter platform offers industrial-grade engineering and a rugged design with advanced utility-ready features. With Ampt Mode, Equinox inverters operate in a narrow input voltage range that is closer to the maximum system voltage to increase the inverter’s rated output power. For example, the Equinox 750-kW inverter with Ampt Mode has a rated output power that is 50 percent higher than the same inverter operating in standard mode, which is equivalent to a 33 percent cost per watt savings. Since inverters with Ampt Mode are used with Ampt String Optimizers, more system-level value is unlocked.

Ampt String Optimizers are DC-to-DC converters that use Ampt’s patented String Stretch technology to double the number of modules per string, which removes 50 percent of the electrical balance-of-system (eBOS) components. Ampt String Optimizers also put dual maximum power point trackers (MPPTs) on each string to improve the system’s lifetime performance. Combining these benefits with the lower cost Equinox inverters with Ampt Mode delivers a lower cost and higher performing system.

RELATED: How optimizers bridge the gap to 1,500-volt PV systems 

“Our customers can achieve unprecedented value by using Ampt String Optimizers to take advantage of the built-in capabilities of the Equinox inverter platform,” said YC Yu, vice president of operations and international sales at GreatWall Energy. “In addition to our compatible technologies being a natural fit, the immediate and significant customer demand from multiple continents made offering this solution with Ampt a logical step in serving the global PV market.”

GreatWall also has joined the HDPV Alliance, an industry-wide initiative focused on lowering the cost and increasing the performance of PV solar systems. The addition of GreatWall forwards this mission and is representative of the Alliance’s growing member base overseas – and among varied industry verticals within PV, including inverters, storage, mounting and tracking systems, electrical components, O&M providers, EPCs and others.

For more on the Satcon Equinox 750kW inverter with Ampt Mode, hit this website.


— Solar Builder magazine

Ampt string optimizers added to PVsyst software update

Site planning is key to matching the perfect PV system architecture to the right jobsite, and software plays a big role in this. PVsyst is updating its latest software, PVsyst 6.43, to include Ampt’s DC String Optimizers, allowing users to model the performance benefits of said optimizers in large-scale PV systems.

AmptV1000StringOptimizer---CUT-1PVsyst’s software is made for PV system designers to predict the performance of different system configurations, evaluate the results and identify the best approach for energy production. The production reports are also used by project owners and financiers to estimate project revenues from energy generation. The inclusion of Ampt String Optimizers in PVsyst’s software update makes it easier for users to simulate the performance advantage of using Ampt in their solar power plants.

Ampt String Optimizers are DC/DC converters that manage power at the string level. Ampt optimizers perform MPP tracking on every 3-6 kilowatts (kW) of PV, which is 50 to 300 times more granular than typical central inverter designs. This helps recover system losses from electrical mismatch over the life of a power plant. In addition, systems with Ampt double the number of modules per string, which reduces the number of combiners, cabling and associated labor by up to 50 percent to save on electrical balance-of-system (BOS) costs.

RELATED: How optimizers bridge the gap to 1,500-volt PV systems 

The new release of PVsyst is also able to model systems that take advantage of inverters with Ampt Mode. Inverters with Ampt Mode operate in a narrow input voltage range that is closer to the maximum system voltage, which allows for a 40 to 70 percent increase in the inverter’s rated output power. This increase in rated output power lowers the inverter’s cost per watt. PVsyst users can import the “OND” files for inverters with Ampt Mode directly into the software.

“The ability to model PV system production is an essential part of developing a successful project,” said Levent Gun, CEO of Ampt. “With Ampt’s String Optimizer in PVsyst, our solution can be easily modeled through a globally recognized leader in PV system software. While our customers typically choose Ampt to lower cost, it’s also important to understand Ampt’s performance advantage and demonstrate that value to project owners and financiers.”

PVsyst 6.43 is available for download here. Customers using the update can contact their Ampt representative for assistance. For additional information about String Optimizer and other Ampt products, visit their website.


— Solar Builder magazine

How optimizers bridge the gap to 1,500-volt PV systems

AmptV1000StringOptimizer - CUT 1

String optimizers, like this one from Ampt, put voltage and current limits on each string to achieve 100 percent longer strings without exceeding 1,000 volts.

The need to lower PV system costs is driving large-scale solar developers to consider changing from 1,000- to 1,500-volt DC systems. The United States PV market was able to lower the cost of PV systems by increasing the maximum system voltage from 600 to 1,000 volts a few years ago. A similar outcome is expected by raising the maximum system voltage again to 1,500 volts.

However, according to a recent report by GTM Research, the lower cost promise of 1,500-volt systems cannot be fully realized today due to the limited availability and higher cost of 1,500-volt components. In addition to the economic barriers, there are delays associated with the implementation of newly defined codes and standards. As the industry works through these challenges and the actual value of 1,500-volt systems is understood, there is a lower cost alternative using DC string optimizers. In fact, string optimizers complement both today’s 1,000-volt systems and tomorrow’s 1,500-volt systems to deliver more value than can be achieved by simply raising the maximum system voltage.

The 1,500-volt promise

Higher system voltages drive down costs by reducing the amount of electrical balance of system (EBOS) components and increasing inverter power density. Raising the system voltage by 50 percent allows string lengths to be increased by 50 percent. Longer strings mean fewer strings for a given power level, which means 33 percent fewer combiners and cables per kW. This reduces the amount of associated labor as well.

Raising the maximum system voltage increases the operational voltage of the system. Increasing the system’s DC voltage capability allows the inverter to deliver a higher output voltage at the same current to increase the rated output power of the inverter. Typically, 1,500-volt inverters can increase their rated output power by 10 to 40 percent to use fewer inverters per system.

While 1,500-volt systems use fewer EBOS components and inverters at a system level to lower cost, there are barriers preventing the full value from being realized.

Barriers to cost reductions

StringOptimizerVsTraditionalThe promise of 1,500-volt systems is worth pursuing; however, getting the full value of 1,500-volt systems will be delayed due to equipment cost and availability as well as the recognition and adoption of new standards and codes.

Equipment for 1,500-volt systems is more expensive since components must be redesigned to withstand higher voltages. As a result, the unit cost of PV modules, combiners and inverters goes up, which lessens the cost per watt savings. In addition, some manufacturers will initially be able to charge a premium due to the lack of availability.

According to GTM Research, the materials cost per watt of 1,500-volt systems is actually higher than 1,000-volt systems and today’s savings come from direct labor. The cost per watt of materials will remain higher for 1,500-volt systems until production scales and competition grows to squeeze the prices down over time.

While many of the codes and component standards have been defined for 1,500-volt systems, they still need to be recognized and adopted. Equipment manufacturers need to engineer products that meet the new standards. In addition, PV system designers, authorities having jurisdiction (AHJ) and installers need to learn how these new requirements impact their areas of expertise and develop new practices to operate accordingly.

Instead of navigating higher component costs, limited product availability and the complexities of new codes and standards associated with 1,500 volts, developers and EPCs can use string optimizers in 1,000-volt systems to realize more value.optimizer savings

DC string optimizers in 1,000-volt systems deliver greater cost savings than can be achieved today by 1,500-volt systems. String optimizers are DC/DC converters that manage power out in the array and more effectively address the same value drivers as 1,500-volt systems.

Like 1,500-volt systems, string optimizers in 1,000-volt systems increase string lengths, but instead of raising the maximum system voltage, string optimizers put voltage and current limits on each string to achieve 100 percent longer strings without exceeding 1,000 volts. Compared to traditional 1,000-volt systems, string optimizers eliminate 50 percent of the combiners, cables and associated labor. This is greater than the 33 percent reduction offered by 1,500-volt systems, which have the added disadvantage of using combiners that cost more per unit as well.

Also, like 1,500-volt systems, string optimizers increase the inverter power density. The increase in rated output power for 1,500-volt inverters is limited because they must operate over a wide voltage range to accommodate temperature extremes, whereas string optimizers allow the inverter to set a high and narrow DC operating voltage — even on hot days — to deliver a higher AC voltage at the same current. This typically translates to a 40 to 70 percent increase in inverter rated output power with little or no increase in unit cost. Again, 1,500-volt inverters typically increase rated output power by only 10 to 40 percent at the expense of higher unit costs and often with premium pricing.

By operating in 1,000-volt systems, string optimizers are used in a familiar environment where the codes and standards are well established, making this cost savings immediately available to markets world wide.

String optimizers in 1,000-volt systems enable longer strings and higher power density inverters while using 1,000-volt components that are readily available and already offered at volume pricing. As a result, string optimizers uniquely enable both materials and labor cost savings to lower total upfront system cost. Plainly stated, string optimizers deliver greater EBOS savings in terms of both quantity and unit cost. And the net savings from day one, after paying for the optimizers, is greater than the savings of moving to 1,500 volts.

Performance benefits

In addition to the cost savings, a 1,000-volt system using string optimizers has a performance advantage over a 1,500-volt system without string optimizers. As the design block sizes increase, the maximum power point tracking (MPPT) resolution can decrease — that is, the MPPT per kW goes down. Lower MPPT resolutions diminish the system’s ability to recover energy loss due to mismatch. This problem is exacerbated as the system ages and degradation becomes more of a revenue inhibitor.

String optimizers allow for larger design blocks while putting MPP trackers on each string to track the maximum power point across 10s of modules compared to 1,000s of modules with central inverters alone. So, while the design block size increases in both 1,000-volt systems with string optimizers and 1,500-volt systems, only string optimizers simultaneously increase MPP resolution by orders of magnitude to deliver more energy over the lifetime of the system.

The value of placing MPP tracking closer to the source of energy generation is more desirable as long as the cost doesn’t offset the benefits. Using string optimizers in 1,000-volt systems actually lowers the total upfront system costs while producing more lifetime energy. String optimizers offer a true spend-less-get-more value proposition.

Enhancing 1,500-volt systems

DC string optimizers add more value to 1,000-volt systems by allowing longer string lengths, like the SolarEdge P700 power optimizers in this 1-MW Monticello, Fla., installation by Region Solar.

DC string optimizers add more value to 1,000-volt systems by allowing longer string lengths,
like the SolarEdge P700 power optimizers in this 1-MW Monticello, Fla., installation by Region Solar.

Once the barriers to 1,500-volt systems come down, developers and EPCs can shift from using string optimizers in 1,000-volt systems to using them in 1,500-volt systems to achieve even more value.

String optimizers in 1,500-volt systems achieve cost savings by doubling string lengths to eliminate 50 percent of the EBOS components and labor compared to traditional 1,500-volt designs without string optimizers. The operating voltage for 1,500-volt systems using string optimizers increases, which enables 1,500-volt inverters to have an even higher rated output power and a lower cost per watt. In addition to the cost savings, string optimizers distribute MPP tracking throughout the 1,500-volt array to improve lifetime system performance.

While the move to 1,500 volts is ultimately good for the PV industry, these cost savings are difficult to realize today. Developers and EPCs can avoid the higher material costs of today’s 1,500-volt systems by using string optimizers to bridge this value gap. DC string optimizers allow 1,000-volt systems to deliver more value than 1,500-volt systems without string optimizers by allowing longer string lengths, fewer EBOS components and higher power inverters to achieve an overall lower cost per watt. Moreover, string optimizers increase the MPPT resolution of the system to deliver more lifetime energy. As the cost and other barriers associated with 1,500-volt systems come down over time, string optimizers can be deployed in 1,500-volt applications to realize even greater cost savings.

Mark Kanjorski is the director of marketing at Ampt.

— Solar Builder magazine

Ampt LLC string optimizers delivering cent-per-watt value

Ampt LLC sent out a release noting that its string optimizers are being deployed in 600 volt PV solar systems at installed costs in cents per watt that rival that of 1,000 volt systems.

ampt string optimizersAmpt String Optimizers are DC-to-DC converters that are being deployed with 1,000 volt inverters at their full-rated power in 600 volt National Electrical Code (NEC)-compliant systems. These inverters are delivering 60 percent more power, translating to a 40 percent reduction in inverter cost. In addition, fewer inverters are used, so AC cabling costs and labor decreases proportionally.

Ampt’s patented String Stretch technology allows PV strings to be twice as long as in other NEC-compliant systems. Doubling the number of PV modules per string reduces the number of combiners, disconnects and associated labor by 50 percent.

Ampt’s combined savings on inverters and electrical costs lower total system cost.
600 volt systems continue to be deployed due to application type (like rooftops) or code adoption cycles across local jurisdictions. In some cases, 600 volt systems are used to take advantage of significantly lower cost 600 volt PV modules, or because they are grandfathered in under the 1603 Treasury Grant Program. Ampt significantly improves the economics of these systems.

“Our customers are choosing Ampt to remove 5 to 10 cents per watt in total system cost by deploying 1,000-volt inverters at their full-rated power in 600 volt systems,” said Evan Vogel, Ampt’s VP of sales and marketing. “This savings, coupled with increased energy generation from more granular MPPT, significantly increases their ROI.”

“Ampt has purposefully designed the String Optimizer to bring value to customers in a variety of applications and market segments,” said Levent Gun, Ampt’s CEO. “Whether integrators are creating 600-, 1,000- or 1,500-volt systems from small commercial to the largest utility-scale power plants, Ampt delivers the highest value.”

— Solar Builder magazine