IGBT is popular in the photovoltaic industry

Under the background of "carbon neutrality", it is a general trend to vigorously develop clean energy industries such as solar photovoltaics. According to the latest report of the China Photovoltaic Industry Association, my country's new photovoltaic installed capacity reached 54.88GW in 2021, a year-on-year increase of 13.9%, a record high. The investment in photovoltaic power generation in Europe and the United States is also increasing. In 2021, the global average annual new photovoltaic installed capacity reached 170GW.

As an important component of photovoltaic inverters (DC to AC), IGBT is widely used in photovoltaic and other fields. With the continuous growth of photovoltaic installed capacity, the demand for IGBT has also risen rapidly. Recently, there have been reports in the market that IGBTs from international manufacturers are out of stock. This situation also provides a favorable opportunity for the development of the domestic IGBT industry.

The photovoltaic IGBT market size will reach 10 billion yuan in 2025

In recent years, the photovoltaic industry has been booming. In 2021, my country's new photovoltaic power generation installed capacity reached 54.88GW, ranking first in the world for nine consecutive years. The China Photovoltaic Industry Association also predicts that my country's new photovoltaic installed capacity will reach 75G~90GW in 2022, and my country's average annual new photovoltaic installed capacity will reach 83GW~99GW from 2022 to 2025. At the same time, the export market is also growing. A few days ago, the European Union released an energy independence roadmap, striving to get rid of its dependence on energy imports from Russia by 2030, starting with natural gas. On March 15, the European Council adopted the "Carbon Border Adjustment Mechanism (CBAM)". Experts believe that Europe is likely to accelerate the layout and application of photovoltaics, and the new photovoltaic installed capacity of the European Union this year may exceed expectations.

Under this circumstance, the market space for IGBT, a core component of photovoltaic inverters, has also been greatly expanded. In this regard, Xiang Jie, chairman of the board of directors of Sunking Technology, pointed out that countries around the world have reached a consensus on the severity and urgency of climate warming, and many countries, including China, have successively introduced "carbon neutrality" goals. In order to achieve this goal, relevant measures need to be taken in power generation, transmission and distribution, and electricity consumption. This requires building a sustainable green energy development system in many aspects such as energy and industrial structure, technology and standards, and supporting policies. As a core component in photovoltaic inverters, IGBT will definitely be directly driven by the development of this market.

Infineon Technologies' relevant person in charge also said that in the next decade, electrification and digitalization will become important driving forces for industrial and social development. Electrification involves all links in the power value chain, including power generation, transmission and transformation, energy storage, and power consumption, and photovoltaics is one of the power generation links. Power semiconductors, including IGBTs, play an important role in the entire power value chain. With the advancement of electrification, the market size of power semiconductors will continue to grow in the future.

It is reported that the photovoltaic inverter is the core component of the solar photovoltaic system. It can convert the direct current generated by the solar cell into alternating current that meets the power quality requirements of the power grid and is used in conjunction with general AC-powered equipment. The performance of the photovoltaic inverter can affect the stability, power generation efficiency and service life of the entire photovoltaic system. In the inverter circuit, semiconductor power devices with switching characteristics such as IGBT are required to control the various power devices to turn on and off in turn, and then step up or down the voltage through the transformer coupling, and finally realize the conversion of AC to DC.

It is worth noting that the service life of electronic components such as IGBT in inverters is generally 10-15 years, while the operating cycle of photovoltaic modules is 25 years, so the inverter needs to be replaced at least once during the life cycle of photovoltaic modules. This has further expanded the use of IGBT in photovoltaic systems.

Xiang Jie estimated that the demand for IGBTs in the Chinese photovoltaic market in 2021 will be about 1.5 billion yuan. If the demand for inverter exports from Chinese inverter manufacturers is included, the scale will be nearly 4 billion yuan. As the market demand for renewable energy increases, the demand for IGBTs will continue to grow. It is expected that by 2025, the demand for IGBTs for new installed capacity plus replacement installed capacity will reach 10 billion yuan.

Photovoltaic IGBT has very high reliability requirements

At present, the automotive market and photovoltaic systems are the two largest application markets for IGBTs and are also the most concerned by the industry. IGBT technology is also constantly developing in line with the needs of these two markets. Xiang Jie said that in order to meet the lightweight and high power density of electric vehicle electric drive systems, automotive IGBTs need to achieve low power loss and high switching frequency. In addition, the topology of electric vehicles is a typical three-phase inverter bridge. Therefore, automotive electric drive IGBT modules generally use 6in1 module packaging or half-bridge module packaging.

Relatively speaking, the voltage of photovoltaic panels is diverse, so the topology used by photovoltaic inverters is also different. Micro inverters generally use IGBT single-tube discrete devices; 1000V string photovoltaic inverters use T-type three-level modules; 1500V string inverters use I-type three-level modules; 1500V centralized inverters use half-bridge modules to configure I-type three-level topology. In other words, when IGBT is used in different photovoltaic inverters, products with different characteristics and packaging need to be selected according to the actual needs of the system configuration.

Affected by the application end, IGBT also shows different technical trends. First of all, the reliability requirements of photovoltaic IGBT are very high. Photovoltaic is to invert DC to AC and then upload it to the power grid. "This line is not like the industrial control field. Because of the fear of overload, the industrial control field often uses IGBT modules at a reduced voltage. For example, the rated current of the module is 100A, which is reduced to 40A-50A. Photovoltaic inverter companies basically use the performance of IGBT modules to the extreme, so the reliability requirements for IGBT chips are also higher than those in the industrial control field." A relevant R&D personnel told reporters.

, for the development of photovoltaic power module technology, we can start from several aspects such as chip design, packaging and module manufacturing to ensure the reliability of the product. For chip technology, one is to optimize and upgrade the performance of silicon IGBTs and diodes; the other is to adopt new materials such as SiC, among which the demand for SiC diodes in string inverters has become more and more widespread. In terms of packaging, it is necessary to meet the reliability requirements, and it is also necessary to consider the adoption of new devices, such as low stray inductance packaging that allows SiC devices to fully exert their performance. In terms of module manufacturing, a strict manufacturing process is required to ensure the consistency and reliability of the module, and it is necessary to adopt green manufacturing processes and environmentally friendly materials to contribute to a sustainable society.

Another noteworthy trend is that with the rapid growth of the distributed photovoltaic market in recent years, higher requirements will be placed on IGBT single tubes. In May 2021, the National Energy Administration proposed that "under the premise of ensuring safety, household photovoltaic projects with conditions are encouraged to be equipped with energy storage" and "household photovoltaic power generation projects are guaranteed by power grid companies to be connected to the grid and absorbed." With the help of relevant policies, distributed photovoltaics and distribution storage are expected to usher in large-scale development. Distributed photovoltaics mainly adopt IGBT single tube solutions. Driven by demand, IGBT single tubes are expected to usher in a new wave of development.

Silicon carbide IGBT will become the darling of the market

In recent years, wide bandgap semiconductors such as silicon carbide have been increasingly widely used in solar photovoltaic systems. Markus Mosen, CEO of WeEn Semiconductor, told reporters that silicon carbide power semiconductor products will become the "darling" of the market in energy applications. With its technical advantages such as low power consumption, long life, high frequency, and small size, silicon carbide power semiconductors have strong replacement potential in photovoltaics and other fields.

At present, SiC MOSFET and SiC diode are increasingly used in the photovoltaic power generation market. Thanks to the low loss of SiC materials and the ability to effectively reduce the system cost of photovoltaic power generation, SiC diodes have been verified and applied in micro inverters and string inverters. With the reduction of SiC wafer costs and the improvement of yield, the cost of SiC MOSFET continues to decrease. In the foreseeable future, the application of SiC MOSFET will also expand to micro inverters and string inverters. In the next step, carbon carbide device manufacturers will develop high-voltage SiC MOSFETs suitable for photovoltaic inverter applications, so that the application field of SiC MEOSFET will be expanded to high-power string inverters and centralized inverters.