Photovoltaic inverter market changes

The photovoltaic inverter market has recently undergone catastrophic changes. On April 22nd, ABB announced the acquisition of Power One news for the vibration industry. People have speculated that this marriage of electrical equipment giants and the world's second largest PV inverter manufacturers will bring changes to the photovoltaic industry. Unlike the giants in the component market, which have cut meat and leave the market, the inverter market is indeed a frequent merger and acquisition. At the beginning of April, REFUsol, a German inverter manufacturer that was very eye-catching in Photon magazine, was acquired by American company Advanced Energy. At the end of last year, the industry’s first brother, SMA, acquired the domestic manufacturer of mega-Avos. The major manufacturers are making great strides toward greater and stronger direction. Together with photovoltaic leap forward in the western part of China, some domestic manufacturers have expressed that “small machines below one hundred kilowatts we do not do at all”.

Compared with the components, inverter technology innovation is more sluggish. In particular, the topologies, control methods, and switching devices of utility-scale inverters are all similar, but product stability and actual efficiency require long-term engineering design experience. On the other hand, to do this kind of large-scale project also needs localized technical support, market development, government relations, and financial support. It is not known who will be the winner in the future, but multinational giants have taken the initiative in many aspects.

It is another scene in the academic world. The inverters in the laboratory are getting smaller and smaller. Researchers conducting photovoltaic inverters should have read reviews by Professor Frede Blaabjerg of the University of Aalborg, Denmark, and his students on PV inverters. The article mentioned a development trend of inverters. Large-scale centralized inverters have been very mature in the past. At the time, (2005) was more popular as string inverters and AC components (ACs). Module)/micro-inverter. Future trends will be AC ​​components or even AC cells.

Prof. Frede Blaabjerg's over-inverter review articles have reached nearly 1,000 citations, which has been staggering in the field of power electronics. And in the past few years he served as chief editor of the IEEE Transactions on Power Electronics, photovoltaic inverter research has become a very hot area. I personally think that the prediction of the article is still very accurate. Since Enphase launched the first commercial product in 2008, the micro-inverter has begun to be recognized by people outside the academic circle. The company quickly expands and develops with its advantage in Silicon Valley. Fast, followed by several other brands to quickly follow up and compete. Several major brands have wait-and-see attitudes, and they have recently begun to lay out in the micro-reverse market. SMA, the industry leader, bought the OK4ALL, a product platform of the micro-reverse pioneer OKE-Services, and developed the SunnyBoy 240 micro-reverse product. This product is currently only visible on SMA's US site, and the exact time to market is unknown. Power One also launched its own micro-reverse product Aurora Micro in 2011.

Micro-inverters can increase system efficiency. Since each module is equipped with an inverter, the mismatch loss between components can be eliminated. However, due to the fact that the current price of micro-reversal is several times higher than that of string inverters, even if the total power generation is slightly higher, there is no advantage in the system's payback time. In fact, there is a great advantage of micro-reversing, that is, the installation is convenient and safe. According to some UNSW alumni who have done photovoltaic system design, the current Australian PV installation standard AS 5033 relaxes many requirements for the installation of micro-reverse, and at the same time, due to voltage With the lowering of grades, installers also feel safer. This may be the main advantage of this technology in opening up the market in the future.

When referring to the ease of installation, it is impossible not to mention the AC components that are very similar to the micro-inversion. The difference between the two is that the inverters of the AC components are directly mounted on the back of the components and are integrated with the components. This design greatly reduces the installation time. Currently Solarbridge is a leader in this field. The company's predecessor was a high-tech company founded by UIUC professor Philip Krein and his students, together with UIUC's associate professor Patrick Chapman. After the company grew up, Patrick Chapman resigned his tenure as the company’s CTO. In terms of technology, the power electronic equipment of AC components is directly installed behind the battery and needs to withstand more severe environmental tests. Solarbridge applies a unique topology to minimize components that are prone to aging and failure. The U.S. micro-insurance companies that have received venture capital support are actively expanding globally. The two large companies have unanimously started to develop the Australian market this year. Enphase has established a partnership with RFI Solar, a leading distributor in Australia, and Solarbridge is working directly with local Australian component manufacturers (Tindo and Solarland) to produce AC components.

Recently, major professors in academic circles have broken down the components and made great strides towards the exchange of batteries. In June 2013, the IEEE Power Electronics Journal was a special issue for the application of power electronics in the field of photovoltaics. Three of them invariably aimed at the submodule converter. They came from three power electronics companies respectively. Cattle group MIT, UIUC and U of Colorado. This technique divides the batteries in one module into three groups, and adds a maximum power tracker (MPPT) to each group so that the mismatch loss can be minimized. The size, efficiency, and stability of this type of technology device place high demands. The MIT team used a very high switching frequency converter to reduce the size of the energy storage device. This makes it easy to fit into the original assembly junction box.

Of course, the fiery academia does not necessarily equate to a high practical value, nor does it necessarily prove that it is the direction of future development. Large inverters and small inverters are different in topology, control methods, and switching elements, and there is no competition. At least in large-scale photovoltaic power plants, the value of any application cannot be seen at present. However, I personally think that the advantages of this technology in small distributed systems, such as high efficiency, easy installation, and flexible design, will make it stand out. Price factors can hinder the promotion of a product, but from a historical point of view, the price factor does not hinder the wide application of a technology.