The Next Wave in Solar Energy Cost Savings

Partnering with SolarEdge to deliver a critical breakthrough in solar energy.

SolarEdge, a global leader in solar energy inverters, power optimizers, and module-level monitoring services, has catapulted from startup to one of the industry leaders in the 10 short years since its founding. How? By thinking differently and finding disruptive solutions to some of the biggest challenges in solar energy advancement. Its latest breakthrough, the award winning HD-Wave Inverter, which uses a novel power conversion technology that is based on a distributed switching and powerful digital signal processing technology, has the potential to speed up solar energy proliferation compared to existing technology, enabling wider adoption of solar energy.

The Race to Grid Parity

Achieving “grid parity” - where renewable sources of energy are the same cost as traditional sources - has been the driving force in the evolution of renewable energy technologies over the past decade. Grid parity is thought to be the necessary tipping point for widespread adoption. For some, the environmental principles alone are enough to compel adoption, but for most the economics simply have to work. As with any commodity, the choice of energy source has much to do with cost and price. And while the experts disagree on when we’ll achieve grid parity (or whether we already have,) the principle remains - lower cost equals wider adoption, and wider adoption equals reduced dependency on fossil fuels. Better for the environment, better for energy independence, and increasingly better for our wallets.

From DC to AC to Leading-Edge

According to the Solar Energy Industry Association, the cost of solar energy has dropped 60% in the past 10 years, driven largely by reductions in the cost of solar panels. However, panel costs have hit a point of diminishing returns, meaning the next wave of savings will have to come from non-panel technologies. Enter the critically important power inverter.

Responsible for managing and monitoring energy production, consumption, and storage, the inverter is the brain of a solar power system. A central role of the inverter is to convert the direct current (DC) power produced by solar panels into an alternating current (AC) power, the standard delivered by utility grids to our homes and businesses.

In basic terms, traditional inverters work by using a series of high voltage switches to turn DC electricity into AC waveform. Because the waveform produced is initially rough, it must be correctly scaled and “filtered” to create a smoother wave that is more efficient and enables safe, reliable connection to the grid. This filtering is performed by magnetic components, which are heavy, bulky, and expensive, but is necessary for traditional switching technology. In addition, the energy lost in this imperfect process produces heat, which requires large cooling elements - more metal, more bulk, and more cost. So with roughly 50%-60% of the inverter cost tied up in these metal components, you might be surprised to learn that inverter technology has been relatively unchanged in the past 25 years. That’s something SolarEdge saw an opportunity to change, and in doing so unlocked significant potential for further cost reduction in solar energy. SolarEdge leveraged Analog Devices solutions to implement a new technology advancement.

Partnering for a Digital Revolution

SolarEdge realized that ridding the inverter of those heavy, bulky, metal components would require re-thinking the conversion process. While the emergence of new wide-bandgap switch technology such as Silicon Carbide (SiC) and Gallium Nitride (GaN) is expected to revolutionize the power switching design of next generation power conversion, existing silicon based technologies are equally contributing to this revolution through the deployment of sophisticated new multi-level switching topologies. However, to capitalize on these developments requires an advanced mixed-signal processing engine that can handle the significantly increased need for speed, accuracy, and capability. And that’s where SolarEdge leveraged Analog Devices technology.

The principal disruption in the HD-Wave design is that it trades traditional high-voltage switches for a larger number of low-voltage switches. This produces a smoother more efficient wave, hence requiring less magnetic filtering and cooling. The challenge is that this design requires highly sophisticated algorithms which need more processing power than previously available.

Most general-purpose processors are designed for broad marketability across a number of applications, and therefore have features and functions that are not critical for solar power inversion. This resulted in “wasted” processing power – constraining the system from performing at its maximum potential. So, to unlock the full potential, Analog Devices designed a highly specialized processor that would deliver the maximum possible processing power and performance to the switching operation.

“Designing something this specialized requires very deep domain knowledge and system-level design expertise,” comments Bill Slattery, head of the Renewable Energy group at Analog Devices. “In addition to working closely with SolarEdge, we bolstered our own expertise by hiring some of the very best system engineers in the power conversion and inverter space.” The result is Analog Devices’ growing power conversion portfolio, including the ADSP-CM40x family of mixed-signal control processors – two of which (ADSP-CM408) are at the heart of every SolarEdge HD-Wave Inverter. The industry’s first system-on-a-chip for solar inverters, they are the fastest ARM Cortex® M4 based control processors of their kind, and feature the industry’s most precise A/D converters, 16-bit accuracy, and a series of dedicated hardware accelerators.

HD Wave Single Phase Inverter NA

Here Comes the Sun. A New Era for PV Inverters.

The ultimate result of SolarEdge and Analog Devices’ collaboration is an inverter that’s half the size and weight of traditional inverters with a significant reduction in all that expensive metal. The immediate impact seems clear, but what may be even more important is that inverters can now better align their advancement with Moore’s Law - no longer as reliant on metal componentry which doesn’t show much hope of evolving.

"We believe the HD-Wave technology represents a significant milestone for solar inverters, akin to the transition from large glass tube TVs to the flat-screen," says Lior Handelsman, VP Marketing and Product Strategy of SolarEdge. "The digital processing enabled by Analog Devices’ Mixed-Signal Control Processors will allow us to continue improving inverter size, efficiency, and reliability at a much faster pace than the industry norm. Solar inverters can now evolve at the rate of electronics, not the rate of mechanics.”

To this end, Analog Devices has already announced the release of its next breakthrough in solar inverter processing, the ADSP-CM41x series, which combines the two physically isolated processors into a single controller using an innovative new “dual independent core” architecture and adds a set of dedicated hardware accelerators. These significant additions enable further performance, and cost efficiency without sacrificing safety.

ADI’s Power Conversion Platform Improves Safety, Reliability and Efficiency.

ADI’s “Precision Power Conversion Platform,” further enhances design simplicity - seamlessly integrating this mixed signal control processor with the other critical signal chain elements, including the AD740x isolated Sigma-Delta-based current sensor as well as the ADuM41xx series of isolated gate drivers featuring iCoupler® isolation technology.

So, with continued advances in solar technology and cost efficiency, the future seems bright for renewable energy. Collaboration between leading innovators like SolarEdge and Analog Devices will be critical to removing the term “alternative” from the energy discussion—and delivering groundbreaking solutions that are Ahead of What’s Possible.

You May Also Like These Stories.     See all >