Photovoltaic inverter development faces three major challenges

From May 24 to 26, the SNEC 16th (2023) International Solar Photovoltaic and Smart Energy (Shanghai) Conference and Exhibition was held in Shanghai. Cao Renxian, Chairman of the China Photovoltaic Industry Association and Chairman of Sungrow Power Supply Co., Ltd. (hereinafter referred to as Sungrow Power Supply), said in his speech at the opening ceremony that with the depletion of traditional fossil energy and the continuous rise in prices, photovoltaic power generation will soon become the most economical form of electricity.

With the continuous advancement of the "dual carbon" goals and the acceleration of the global energy transformation, the photovoltaic industry is experiencing leapfrog development in terms of installed capacity and technological innovation. New formats, new models and new demands are constantly emerging, and photovoltaic power stations are also facing new challenges in development. As a bridge between photovoltaic power stations and power grids, photovoltaic inverters are connected to components on one end and to the power grid on the other. They not only determine how much electricity the power station can generate, but also adapt to and support the safe and stable operation of the power grid. Under the new development situation, what changes do photovoltaic inverters need to make to firmly pull both ends of the power station and the power grid? During the 2023 Shanghai SNEC exhibition, the reporter interviewed Zhang Xianli, vice president of Sungrow's photovoltaic storage group and president of the ground photovoltaic business unit.

The ability to support power grids needs to be improved

According to statistics from the Forward-looking Industry Research Institute, a think tank service agency, the proportion of photovoltaic power generation in my country's total electricity consumption has increased year by year from 2014 to 2022. In 2022, the proportion of photovoltaic power generation in my country's total electricity consumption has reached 5.1%. In the future, photovoltaic power will be one of the important engines driving my country's energy transformation.

In its White Paper on 5A Fusion-Ground Power Station Solutions, Sungrow cited data from industry organizations and predicted a broad future for photovoltaics. In 2023, the global photovoltaic installed capacity will exceed 350 GW, and by 2030, the installed capacity will be close to 700 GW.

In Zhang Xianli's view, the continuous increase in the scale of photovoltaic installed capacity and the proportion of power generation have put forward new requirements for the development of inverters. "In the past, photovoltaic power was small in scale and had little impact on the power grid. As the scale becomes larger and larger, its unique volatility and randomness will bring challenges to the safe and reliable operation of the power grid. How to improve the strength of the power grid will become a difficult problem in the future. To this end, we need to change our development thinking from passive adaptation to active support, and improve the support capacity of photovoltaic inverters for the power grid. This is also the recognized development direction of the photovoltaic inverter industry at present."

Zhang Xianli further explained: "Specifically, the power grid environment is also different. In some places, the power grid is strong, and in some places, the power grid is weak. The photovoltaic inverter needs to automatically adapt to the local power grid environment and always keep the system running stably. This places very high control requirements on the inverter."

The power plant operating environment is becoming increasingly complex

Ground photovoltaic power stations are the main force of photovoltaic installation. In 2021, my country launched the construction of the first batch of large-scale wind power photovoltaic base projects focusing on deserts, Gobi and desert areas, and the application scenarios of ground photovoltaic power stations are gradually developing in a diversified and complex direction.

"'Going up the mountains, down the sea and into the desert' has become a true portrayal of ground photovoltaic power stations. Not only deserts, Gobi, and wastelands, but even hills, tidal flats and offshore areas have become potential development sites for photovoltaic ground power stations in the future." Zhang Xianli said that ground photovoltaic power stations have large single-unit capacity and complex systems. The wind and sand intensity in deserts, Gobi and wastelands is strong, and the equipment is easily invaded by sand and dust, resulting in poor heat dissipation and damage to parts, affecting the reliable operation of the equipment. The high salt fog, high temperature and high humidity in tidal flats and offshore areas are prone to corrosion, which aggravates the aging and damage of power station equipment and affects its lifespan.

Zhang Xianli proposed that the upgrade of ground photovoltaic power station solutions needs to comprehensively consider multiple factors such as the application environment, design concepts and grid requirements of different regions, and scientifically design according to local conditions. "The application environment determines the upgrade direction of photovoltaic inverter products, and some differentiated needs will also emerge. We can adapt to various application scenarios through string and modular product combinations and technical solution innovations. For example, for mountains, hills and other undulating and scattered plots, we need to provide more flexible product solutions to make full use of the land and maximize land use. For desert projects, our products need to dissipate heat efficiently, isolate sand and dust, and ensure reliable operation of the power station."

Rapidly increasing demand for intelligent operation and maintenance

From the perspective of the development direction of photovoltaic inverter technology, Zhang Xianli believes that as the market's performance requirements for photovoltaic inverters become higher and higher, it is necessary to increase the innovation of product hardware and software. The two complement each other and develop together. Hardware starts from product quality and reliability, while software uses big data, algorithms and other technologies to achieve rapid and accurate identification and control, and achieve the purpose of power generation optimization and intelligent operation and maintenance.

Zhang Xianli used the operation and maintenance of photovoltaic inverters as an example to illustrate the positive role of hardware and software. "Traditional centralized inverters have high power per unit, and the power generation loss during failure is large, and generally require professional maintenance. After adopting modular design, each inverter unit is electrically independent of each other, and a single failure does not affect the power generation of other units. At the same time, we have also developed modular photovoltaic inverter intelligent IV diagnostic technology, which accurately identifies and locates faults through software technology upgrades. At present, 16 mainstream faults can be identified, which greatly shortens the operation and maintenance time and improves the operation and maintenance efficiency."

Looking ahead, Zhang Xianli believes that under the goal of building a new power system, the market will have higher and higher requirements for photovoltaic inverters. To do a good job in the innovation of photovoltaic inverters, it is necessary to fully connect the upstream and downstream of the supply chain and strengthen collaborative innovation with component companies and power grid companies, so as to play a good role as a bridge and effectively support photovoltaic power to become the main power source.