Enphase Energy brings innovation to the solar inverter market

The solar inverter market enjoyed terrific growth in 2015, with almost 60 GW of new PV inverter capacity installed. Yole Développement recently published Inverter Technologies Trends & Market Expectations 2016, a report detailing the evolution of this promising market, and which forecasts 90 GW of new capacity installed by 2020. Within this high-growth environment the demand for micro-inverters is especially noticeable, and new inverter manufacturers have in the last few years joined the attractive residential business.

The micro-inverter segment accounts for almost 80% of the market in terms of units, but micro-inverters still face technical challenges for improving their conversion efficiency (they still use transformers) and drastically reducing their cost, since price pressure is huge in this particular market. In order to gain an even better understanding of where this market is heading, Yole Développement sat down with Martin Fornage, Enphase Energy Co-founder and Chief Technology Officer, to discuss PV inverter market trends and challenges, as well as his company’s positioning.

Yole Développement (YD): Let’s start by discussing Enphase Energy’s PV inverter business. How are you positioned? What is your “star” product?

Martin Fornage (MF): Enphase Energy is the world’s leading microinverter company in the solar industry, with more than 11 million units shipped to date and 460,000 residential and commercial PV installations worldwide. Our fifth-generation product is already on the market, with our sixth-generation suite set to debut in early 2017.

However, we are much more than a microinverter company—we are an energy technology company. In addition to the microinverters, the Enphase Home Energy Solution incorporates the Envoy-S communications hub and Enlighten monitoring software, providing an intelligent solar energy management solution. We collect terabytes of actionable data every day from our systems in the field. With our energy storage system featuring the Enphase AC Battery coming to market later this year, we will have a complete, smart grid-ready home energy solution. We also offer O&M services for solar assets in the United States, and our grid optimization services unit offers data acquisition and control solutions for utilities and other electric services providers, helping our clients turn their distributed energy resources into grid stabilizing assets.

Enphase AC Battery (Source: Enphase)

YD: Is your business global? What is your biggest market? In which region(s) are you planning to expand or reinforce your business?

MF: Enphase is a global company, with employees in 12 countries and systems deployed in more than 100 countries. Although the U.S. market makes up the vast majority of our business, about 15% of our annual revenues come from our international operations. We have gained or are gaining significant market share in Australia, New Zealand, France, the Netherlands, the U.K., and parts of Latin America and the Caribbean, for example. We are always looking at promising markets, but take a patient approach to expansion.

YD: How do you see the solar inverter market evolving? What are your predictions? (Yole forecasts almost 60 GW solar power installed in 2015, increasing to over 85 GW by 2020)

MF: In the inverter and power conversion sector, microinverters and other module-level power electronics have become the dominant inverter choice for residential and small to medium commercial solar installations in the U.S. and other regions. The necessity for intelligent energy management solutions, with the inverters serving as the “brains” of the systems, has become evident as more solar is deployed and the utility grids must handle larger and larger amount of distributed energy generation assets. Energy storage, which pairs well with solar, also requires smart electronics, and the leading inverter companies are well positioned to take advantage of this fast-growing new market segment. We have shipped nearly 3GW in microinverter systems since our inception, and are ready for exponential growth in the solar and storage sectors in the years to come.

Enphase M250 (Source: Enphase)

YD: What was the impact of the shutdown of Advanced Energy in the North American market? Who has benefited the most?

MF: While we don’t comment on specific competitors, we do see continued strong growth and consolidation in the North American solar market as well as many other established and emerging regional markets.

YD: What is the major technical challenge that PV inverters must overcome in the next few years?

MF: In the context of microinverters, we need to stay on a steep cost decline of more than 15% per year. This is accomplished by:

• Further integration of components in custom chips, removing unessential parts, reducing size and physical volume, and reducing transformation cost.
• Innovations in design that decrease both materials and the weight of materials used. For example, our next generation of microinverters will be double insulated, allowing us to move to a two-wire cable, saving copper.
• Efficiency needs to go up in order to reduce power dissipation. This in turn impacts the size of the unit, so it is more of a tactical requirement than a market requirement.

YD: Currently, SiC diodes are commonly used in the solar market. How do you see the integration of WBG devices? Do you think they will expand?

MF: So far, we have used well over 20 million SiC 1200V diodes, thereby making up a very large part of the market—if not being “the market.”

These diodes have performed extremely well in our application.?We are changing our microinverter topology, and because the new topology does not need high-voltage diodes, we are now using Si MOSFETs.?We decided to do this because inverters now have to provide four-quadrant capabilities (for reactive power and for storage), therefore we can’t have diodes in the power path. We think that both SiC MOSFETs and GaN HEMTs are extremely interesting in our application, assuming that both devices can demonstrate competitive cost and excellent reliability.

SiC is far better proven in volume than GaN and works better at higher voltages. Plus, we have seen a steep SiC cost decline—approximately an eightfold reduction in 10 years.

That said, we believe that GaN has two distinct advantages in our application:

• First, our topology uses bidirectional switches. We currently use back-to-back MOSFETs to achieve that function. GaN HEMTs have the capability to be natively bidirectional. This gives an inherent ~3X advantage over SiC or Si, due to the reuse of the same channel for both voltage blocking polarities.
• Second, a number of companies have emerged that are developing GaN integrated power circuits. This is one of the most interesting phenomena happening in our sector.

These advantages are specific to microinverters (or 100W-class power electronics) and likely do not port well to traditional inverters. We have found during the past 10 years that the technology set required for microinverters is totally different from what works in larger inverters.

YD: Are you feeling competition from Chinese players? What is their impact on the market?

MF: We believe that competition is good, whatever the country of origin, and that it pushes Enphase to work even harder to maintain our technological, quality and market leadership. Like all companies in the inverter space, we have felt the impact of global price pressures and have answered the challenge by leveraging our innovative strengths to lower our own costs, largely by reducing the part count and bill of materials used in our systems.

YD: What other technical evolutions do you foresee?

MF: Solar is transitioning from blindly injecting raw energy into the power grid to being smartly integrated with storage, energy management technologies, and the grid. Networking capabilities and remote control and monitoring of power electronics (both loads and generators) are fast becoming a “must.”?I predict that companies that neglect these trends will end up on the lower rungs of the commoditization ladder.

Martin Fornage, Enphase Co-Founder and Chief Technology Officer

Martin Fornage is a 20-year veteran of the telecom equipment industry where he designed a large variety of functions, ranging from power supplies and fiber optics to wireline and radio communications. He brings a wealth of practical experience designing high reliability, high volume and cost effective electronics susceptible to being deployed in harsh environments.

Martin co-founded Enphase Energy with Raghu Belur in March of 2006. He led the initial technology development at Enphase, focusing on the power train and its control as well as the communication system. He now focuses on advanced technologies at the company, and he holds over 25 US patents.

Martin received his “Ingénieur Diplômé d’État” degree from ENSEA, France in 1985.

Source: www.yole.fr  – enphase.com 

 

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