With the advancement of mass production of 166, 182, and 210 modules, the stakeholders within the industry are having a continuous discussion involving various issues caused by changes in silicon wafer dimensions, including the electrical characteristics and dimensions of the modules, transportation, and raw material supply. We also discussed system adaptation issues with many well-known inverter manufacturers. The operating current and short-circuit current of the 210 module are significantly improved comparing with previous products. Are the inverters ready for this change?
It can be seen from the topology of the centralized inverter system that when module’s short-circuit current increases, high-current modules adaptation can be realized only by replacing the combiner box fuse and inverter DC fuse. The selection process is fairly flexible. At the same time, according to the actual situation of the power station, different combiner box input channels can be selected to meet the requirements of different projects for capacity ratio.
By taking Trina Solar's Vertex 550W module as an example, the maximum operating current at highest level of output is Impp17.17A, and the short-circuit current is Isc18.47A. According to the requirements of IEC62548, the corresponding fuse of each input of the combiner box is 30A, and it can be adapted to the back side gain of bifacial module.
The maximum input current of each MPPT circuit of the string inverter is the key to adapting to large modules. As the module short-circuit current increases, the maximum input current of each MPPT of the string inverter needs to be expanded accordingly. The keys to its expansion are mainly in the boost circuit and the IGBT heat dissipation after the expansion.
The current mainstream inverter manufacturers' Impp current has reached 26A to 30A, which meets the requirement of most applications. Except for the application of Trina Solar's Vertex 550W module, the inverter needs to be expanded to an Impp current of more than 40A.
How Are Inverter Manufacturers Preparing?
Sungrow States that “We Are Ready”
Since the 600W modules with 210 silicon wafers adopt low voltage and high current solutions, can the inverters be compatible? Zhang Yuehuo, the solution director of Sungrow Power Supply Co., Ltd. firmly said: "Of course, the answer is affirmative."
Zhang Yuehuo states that provided with the same 1500V system, modules of low voltage and high current have obvious advantages. Regarding today's high-power modules, whether they are a centralized type or a string type, Sungrow is ready for it.For adaptation solution of the string type, the maximum input current of a single channel can be increased to 20A, and the system capacity ratio can be increased to 1.6, which will significantly reduce the LCOE.
It is reported that Sungrow has started to deploy inverter solutions for high-current modules in 2019 to meet future market needs. It is expected that in the fourth quarter of this year, the SG225HX series with a short-circuit current of about 18.5A will be mass-produced, and the SG250HX series will also be mass-produced in the first half of next year. It can be said that Sungrow is ready for the Module 6.0 era!
Huawei Integrates with AI to Create a Lower LCOE Solution
Zhang Xianmiao, vice president of Huawei's AI Photovoltaic Department, states that the company has always maintained close cooperation and in-depth technical exchanges with mainstream photovoltaic module manufacturers to jointly explore the direction of future technological evolution. High efficiency and high power are the inevitable development trend of photovoltaic modules; this trend poses new challenges for inverters. As we all know, the low-voltage, high-current solution can accommodate the long-string design so to reduce the number of strings, thereby reducing the cost of PV DC cables. It is a significant aspect in reducing LCOE.
For 18A high-current modules, Huawei launched a corresponding AI string inverter, equipped with unique values such as multi-channel MPPT, high power generation, zero operation and maintenance, and intelligent standardization, effectively ensuring system reliability. According to reports, this inverter can be shipped on a small scale in the fourth quarter of 2020, with a production capacity of more than 50GW in 2021, and it can accommodate lower-current modules. Zhang Xianmiao alleged that Huawei upholds the value concept of high intelligence, high reliability, and high yield, and is committed to working with partners to promote the high-quality development of the photovoltaic industry in the era of grid parity.
Sineng Electric Co., Ltd. is Committed to being the Next Representative of 600W+ Era
“Inverter is considered as the brain of the entire power plant system, which determines the electrical solution of the system, and also serves as the connection between all the core components.” Wang Yuelin, general manager of the electrical solutions division of Sineng Electric Co., Ltd., pointed out that in the process of generalizing 600W+ in the entire photovoltaic industry, inverters can not be treated as an independent product; instead, inverters should be put in the whole system to study its future development direction.
Wang Yuelin states that low-voltage, high-current, and high-power module solutions will have an expansive market outlook in the future. As a leading inverter company in the industry, it is necessary for Sineng to increase R&D investment and provide the best inverter products and system solutions for such modules. Currently, the centralized inverter series from Sineng are compatible with high-power modules, to accommodate string inverters of high-current modules that are above 20A, and this series is expected to be mass-produced and shipped in the fourth quarter of this year.
Tebian Electric Apparatus Co., Ltd (Tbea) Will Launch a Single-Channel Current 45A High-Power Inverter
With the development of high-power modules, TBEA will launch high-power and high-current string inverters to perfectly respond to the characteristics of high-power modules. The preliminary proposing power section is 350kW (model TS350KTL-HV). The solution confirmation and key module selection is expected to be completed in December 2020, and the prototype proofing is expected to be completed in March 2021, and the testing and release are expected to be completed in second quarter of 2021.
Reports show that this new product has 12 channels of MPPT, each with a current of up to 45A, supports ultra-high capacity ratios, and can accommodate smart grid-connection.
SMA Perfectly Accommodates 600W+ Modules
According to Wang Ting, vice president of sales for Greater China, India and Southeast Asia of SMA Solar Technology (Shanghai) Co., Ltd., the Sunny Tripower CORE2 launched by SMA this year can perfectly accommodate 600W+ modules. First of all, the product has a flexible design, with a power of 110kW, 12 MPPT, and 24 outputs. Customers can use part of the MPPT or part of the string input according to projects requirements. Even in the high current application, 120-140kW can still be connected to meet the requirements of high capacity ratio and reduce BOS cost.
In addition, according to different setting requirements of the owners and EPC parties, Sunny Tripower CORE2 can be applied to large-scale industrial and commercial projects as well as small ground-based power station projects. It is understood that the order for this product has been scheduled to the end of this year, and it is extremely competitive in terms of price, application, and overall performance.
In a nutshell, mainstream inverter companies have already started the strategic planning for products to accommodate 210 size. The batch shipment timeline is distributed in fourth quarter of 2020 or the first quarter of 2021, which basically aligns with the launch time of the modules. It can even be considered that in the future, high-current inverters will achieve full iterations, and they are by no means so-called niche products.
It’s extremely important to strengthen the exchange of advanced technologies and solution compatibilities between all parts of the industrial chain, and jointly to promote the technological innovation of system solutions, in order to advance the future development of inverters. In July of this year, 39 entities throughout the upstream and downstream of the photovoltaic industry chain such as silicon wafers, cells, modules, inverters, brackets manufactures, testing and certification organization jointly formed the 600W+ Photovoltaic Open Innovation Ecological Alliance. So far the alliance has welcomed 61 members and will work together to jointly build products, systems and standards based on a new technology platform. It is believed that with their joint efforts, 600W+ ultra-high power modules and solutions can maximize the application value, and establish a new pattern of co-creation, symbiosis and win-win environment.
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