1. Field: 

Distributed photovoltaic inverters belong to the high-tech fields supported by the state: mechanical transmission technology, power electronics and control fields.

2. Project background: 

The world will mainly promote distributed projects in the next ten years. In 2015, global demand will reach 50GW, 15GW in China, 250GW in 2020, and 70GW in China. Photovoltaic inverters are the core components of distributed solar power generation systems and a very important unit of smart grids; the future has broad prospects.    

Distributed photovoltaic inverter technology has made certain development at home and abroad. Currently, the world is facing technical difficulties: electronic circuit topology, digital control and algorithms, monitoring, power grid regulation and stability control, energy storage, new devices and materials, etc., multidisciplinary emerging technologies.    

This project is based on global strategic needs and supported by major national research programs such as 863. In 2011, the company's inverter efficiency ranked seventh in the world in the test of PHOTO authoritative laboratory in Germany. It is the only one in China to enter the top ten in the world. Inverter manufacturer; The only company in China has received certification from mainstream countries such as German TUV, European CE, and American UL. It is also the first company in China to enter the North American and European markets, and has formed large-scale sales in the local area; It has broken through internationally recognized key technical difficulties.

3. The main scientific and technological innovations of the project will solve the following technical difficulties:

1) Break through multiple core algorithms (authorized invention patents: 201010216718.6 and 201010216727.5). Innovate the use of traditional two-level and three-level space vector modulation technologies to improve the conversion efficiency of high-power inverters, improve output current harmonics, and improve the common-mode voltage problem that medium-power products plague non-isolated inverters.

2) Breakthrough in all-digital control technology; solve problems such as product reliability, stronger anti-interference capabilities, and no device aging problems.

3)Innovating the single-phase inverter topology, the first single-phase asymmetric ultra-efficient inverter bridge circuit achieves three-level output voltage by changing the output filter inductor freewheel loop, making the inverter efficiency more than 98%, and eliminating the high-frequency common-mode voltage present in non-isolated single-phase inverters and the common-mode leakage current caused by it. (Invention patent: 201010232636.0).

4) Creatively make technical improvements to traditional active and passive devices. For example, medium power products use IGBT and MOSFET parallel technology to improve inverter efficiency to 98.5%; soft switching technology and three-level technology are used in small power products to reduce switching device losses; hybrid magnetic circuit technology and magnetic circuit integration technology are used to reduce magnetic components Cost and reduce losses; full-film capacitor design is used to achieve a product design life of up to 25 years; silicon carbide devices are used to improve efficiency and power density.

5) Breaking through the high reliability and safety of products and completing a series of innovative designs; for harsh outdoor applications, an invention patent was applied for on the structure: 201310180324.3; utility model patent: 201320265338.0; In view of the fire hazard caused by excessive contact resistance caused by insulation failure or poor joint overlap, a DC arcing detection device was proposed and passed UL1699B certification. The only inverter manufacturer in China to pass this certification.    

At present, it has obtained 30 patents and 8 inventions. The product has reached the international advanced level through performance indicators such as search, testing, novelty search, and international certification.

4. Promotion and application status, economic and social benefits With Yongchang 100MW, Jinchang 50MW, Italy, South Korea, the United States and other projects successively connected to the grid for power generation; successive breakthroughs in major technologies and rapid marketization have brought sales from 15.7 million yuan in 2010 to 700 million yuan in 2013, an annual growth rate of over 500%; the industry ranking soared to second place. In 2013, it was rated ninth in the world with the most competitive potential by the authoritative magazine GTM in the United States. It is estimated that in 2014, sales will reach 900 million yuan and foreign exchange will be US$50 million from exports; production capacity will be 3GW, annual electricity will be saved by 5 billion kilowatt-hours, and carbon emissions will be reduced by 600,000 tons. It has made significant contributions to the development of the country's western region, energy conservation and emission reduction, filling many technological gaps at home and abroad, training talents, and exploring the global market to obtain foreign exchange.