Application background: With the continuous development of photovoltaic inverter and UPS technology and the continuous expansion of the market, the requirements for inverter efficiency have been more and more valued by manufacturers, and the three-level topology has emerged as the times require. Compared with the traditional two-level structure, the three-level inverter has the advantages of low voltage stress and loss of power devices, good output waveform quality, and high efficiency. It is a new direction for the development of photovoltaic inverter technology.

It has been three years since the COVID-19 epidemic, and working from home has become the norm for many engineers and scientific research scholars. The software simulation part can be carried out with a computer, but the high-performance test bench cannot be copied home. So when it is necessary to do hardware verification testing, is there a way to expand the connection between engineers and equipment, remotely operate testing equipment, and realize the seamless connection between online and offline work?

With the rapid development of the mobile communication industry, 5G has become a super hot topic in the world. Compared with 2G, 3G, and 4G, the status of 5G in the optical fiber communication industry in the future cannot be underestimated. In the 5G network era, no matter what kind of 5G bearer All solutions are inseparable from 5G communication optical modules. Diversified standard 5G communication optical modules are now considered to be the core technology of the next generation of high-speed and large-capacity optical networks.

A starter motor, also called a starter motor, is a motor used to start a diesel or gasoline engine. The starter motor can effectively reduce the trouble of manpower starting the engine, start more quickly, and can be used repeatedly. It is often used for starting automobile engines, starting generators, and starting large-scale construction machinery.

At the end of April 2021, China Satellite Network Group Co., Ltd. was officially established and formally participated in the global competition for high-speed Internet access services in space. Looking at the world, the Starlink project launched by Tesla founder Elon Musk, the British company OneWeb and the Amazon Group compete with each other in this field. According to incomplete statistics, nearly 30 companies around the world have announced the deployment of satellite Internet constellations, and they plan to launch more than 100,000 satellites.

Hydrogen energy, as an important way of efficient and clean production and utilization of electric energy, is steadily advancing in my country, and its application scenarios continue to expand. In the "Action Plan for Carbon Peaking Before 2030" issued by the State Council, 11 items involve the field of hydrogen energy, which points out the way in many aspects such as transportation application, technological research and development and innovation. In 2021, hydrogen energy will grow rapidly in the field of commercial vehicles, especially heavy trucks, and more than 1,000 hydrogen energy vehicles will be demonstrated in the Beijing Winter Olympics, basically all of which are passenger vehicles, covering buses and group shuttles.