Sungrow's inverter conversion rate target rises to 99.5% Reducing photovoltaic costs requires integrated solutions

From October 17 to 19, 2017, the 2017 China Photovoltaic Conference and Exhibition (PVCEC2017) was held in Beijing. Hu Liang, senior manager of technical support of Sungrow Power Supply Co., Ltd., attended the Innovation Theater [Inverter] Forum on the afternoon of the 18th and gave a keynote speech. Hu Liang said that since last year, all of Sungrow's inverter products have achieved a conversion rate of more than 99%, and the next goal is 99.5%, because it is very difficult to increase by 0.1 percentage point above 99%. From the perspective of inverters, the spectrum is constantly enriched, and the application scenarios are now very segmented. Different inverter devices must be used in different scenarios. From the perspective of inverters, higher single-machine power is also a good solution. If photovoltaics want to reduce system costs, the unit price of inverters is very low now. If it is difficult to reduce the price per watt of photovoltaic inverters, we can only solve it through integrated system solutions. So now, whether it is string or centralized, everyone is moving in a bigger direction.

The following is the transcript of the speech:

Hu Liang: Good afternoon, distinguished guests. I am Hu Liang from Sungrow Power Supply. Today I am very honored to share with you Sungrow’s solutions and my understanding of the development trend of photovoltaics.

The speech is mainly divided into three parts. First, I will spend a minute to introduce the company. The second part is the main content about the current situation of photovoltaic systems and smart sunshine solutions. The third part predicts the development trend of photovoltaic systems.

Sungrow was founded in 1997, and it has been 20 years now. Next month on November 28th, the company will celebrate its 20th birthday. The company has several main business sectors, first of all, the photovoltaic inverter business and the photovoltaic power station business, including the wind turbine current transformer business exhibited here. This is an introduction to the company's operating income. Sungrow has achieved a revenue of 6 billion since last year. We are a company based on inverters, and we expect our operating income this year to be more than 7.5 billion. This is the company's market situation. From the perspective of photovoltaic inverters, we have accumulated shipments of more than 50 GW so far. This year, before June 30, 2017, we had a good performance, with shipments reaching 10.9GW.

The second section introduces the main solutions of Sungrow. The current situation of domestic photovoltaic power generation is more in the following three forms: the first is the leader, the second is distributed power generation, and the third is photovoltaic poverty alleviation. President Xi is very concerned about photovoltaic poverty alleviation. He conducted research in Anhui last year and gave a lot of guidance on poverty alleviation projects in Anhui Province. For the current situation, there may be three major challenges. The first is the grid parity, which has higher and higher requirements for the cost of electricity per kilowatt-hour, so the system solution needs to be continuously optimized. The second challenge is that the proportion of new energy intervention is getting higher and higher, which brings higher and higher penetration, and puts higher requirements on inverters, including the power quality of the entire photovoltaic system. In the third section, the early power stations were relatively less intelligent. In the future, we will see the development of intelligence and efficient operation and maintenance.

Therefore, we at Sungrow have always mentioned eight words to address the three major challenges at present: adapting to local conditions and scientific design. This is the spectrum of our Sungrow inverter product family. You can see that the products are very comprehensive, from the smallest 3,000-watt string inverter to the largest 2.5-megawatt solution. There are also larger power, 3-megawatt solutions overseas. At the same time, there are corresponding products for intelligent operation and maintenance and photovoltaic communications, including data collection. It can be said that in the inverter sector, Sungrow has the most comprehensive products and is the earliest and most professional to enter this industry.

This is the selection guide for our solution. We have the best solutions for different scenarios and terrains. First, let me introduce the inverter sector, which is the string inverter. The development trend of string inverters has been increasing in recent years. We can introduce several characteristics of the string type. The first is that the power of a single machine is constantly increasing. At present, the mainstream inverter on the market is still 50 kilowatts. The next generation may have to enter the 80 kilowatt string inverter, which is equivalent to a small centralized inverter in the past. In the early days, it was about 100 kilowatts. The third is that Sunshine Power uses intelligent air cooling. This is the design of the 80-kilowatt system. You can see that after coming out of the inverter, it can be directly connected to the low-voltage test, which is also a solution that cancels the AC box. In addition, the Sunshine power string inverter is divided into two, including all circuit boards are sealed in the front cavity, which can ensure that my components get a lower operating temperature. From here we can see a comparison. Why has Sungrow always insisted on using air cooling? There are different technical routes in the industry and there are controversies. Some claim natural heat dissipation, but we have always insisted on air cooling, which can reduce the operating temperature of all components by 10 to 25 degrees, ensuring a longer lifespan.

Another benefit of wind is that it can ensure that in high temperature scenarios, especially in southern China, including Southeast Asia, there will be no derating under high temperature, so that better power generation benefits can be obtained. At the same time, there are some disputes in the industry. After using air cooling, is the failure rate of the fan relatively high? What should we do if the fan fails? The operation and maintenance will be more troublesome. We can see from these amplitudes that the fan with high protection level of IP68 is used. The PCP and coil are potted. Even if a failure occurs, it can be replaced online in one minute. Sungrow Power Supply has proposed a 20-year warranty. We are very confident in the service life of the fan. In addition, our inverter, such as the 80-kilowatt inverter, supports a maximum of 16 DC channels, so the DC side can be considered for a step of over-allocation in some areas with poor lighting. Our component configuration is connected according to the 47.6 DC side. From this curve, the highest point is 41.13 kilowatts, and the inverter has no such situation of being trapped.

The second major sector is also the sector where Sungrow has always been very leading in China, which is the centralized inverter. This exhibition also launched such a product of 1.25 MW, which is the overall concept of centralized outdoor. The protection level of the entire outdoor unit has cancelled the container. The entire protection level is IP65, which is better than the traditional centralized solution. Currently, three-level technology is used, which is more efficient and can reach more than 99%. At the same time, dual windings are used to save transformers. The third feature is the integration of intelligent control units, which is equivalent to replacing the functions of the communication management level. The control unit itself can also integrate the functions of the ring network switch. The inverter is not only an inverter, but can also be connected to third-party equipment, and communicate and transmit to the outside world through a unified optical fiber.

In addition to the inverter, we can also propose the inverter and deep pressure flag, and the integration of inverter and deep pressure, because after integration, it can bring higher integration, lower cost, higher conversion efficiency, and a wider range of applications. At the same time, Sungrow has done some research and pilot projects on floating power stations in the past two years, using a 2.5-megawatt large-scale solution. It can be seen that such an inverter deep pressure integrated machine is used. A large floating platform is built in the middle of the entire array, which is an overall floating solution. Now for some deep-water projects, including the current leader coal mining subsidence area project, this solution can be considered. A special floating body factory has also been built in Huainan, Anhui to manufacture floating body materials. The manufacturers of these floating body materials do not have a deep understanding of photovoltaics, so Sungrow is a manufacturer that understands both photovoltaics and floating bodies in China. There are relatively few manufacturers.

In addition, Sungrow also has its own unique solutions for distributed systems. It can not only provide inverter return boxes and other equipment, but also provide power station automation systems, integrating primary and secondary equipment into the equipment, and providing owners with integrated solutions for large rooftop projects. This is our DAS1000 system, which is different from the traditional one. The traditional solution may build a primary and secondary flat cabinet, but there are some problems with distributed systems. The original distribution room has no space to add these devices, so we can provide an overall solution, which not only solves the problem of land occupation, but also reduces the overall system cost by about 30%.

The third section is to share with you some of our own views on the development trend of photovoltaic systems. From the perspective of devices, electronic devices are constantly innovating. Since last year, all of Sungrow's inverter products have achieved a conversion rate of more than 99%. The next goal is 99.5%, because it is very difficult to increase by 0.1 percentage point above 99%. From the perspective of inverter models, it is constantly enriched. The application scenarios are now very segmented. Different inverter devices must be used in different scenarios. From the perspective of inverters, higher single-machine power is also a good solution, especially last year there was a GW or 2.5 MW solution in the Indian market. We all know that if photovoltaics want to reduce system costs, the unit price of inverters is very low now. If it is difficult to reduce the price per watt of the inverter, we can only solve it through integrated system solutions. So now, whether it is string or centralized, everyone is moving in a bigger direction. The fourth trend is higher DC voltage. Currently, 1500V systems are rarely used in power stations. Sungrow has also made some attempts. We first built a 4MW power station in Golmud, Qinghai in 2015. This is the earliest application of 1500V in China. At the same time, we applied 1500V in the leader bid. This is the largest 1500V power station in China. Of course, we know that after the 1500V system voltage is increased, the entire system loss including its entire conversion efficiency will be improved, and the loss will be reduced. In summary, the system cost can be reduced. From the perspective of inverter, the inverter system of the component may only be able to achieve the MPPT tracking method of the group string level. Sungrow also launched such a product in February this year. At present, there are some test and verification data in some test projects. We plan to make a power hardening connection with two pieces, so that relatively speaking, the inverter does not need to do maximum power point tracking, and the inverter only needs to convert DC to AC.

In addition, from the perspective of the integration of multiple systems, photovoltaics can now also track and clean, including sensors for integration from multiple angles, including tracking brackets, providing power, and tracking systems to transmit these data through inverters. These can all be achieved through inverters. From the perspective of the entire monitoring, Sungrow can also provide a full set of management systems. At the same time, the group management system can also play a role in uploading and downloading in the future. It can communicate and dispatch with the underlying equipment of the power station, and can also transfer these data to third parties including government agencies.

This is the large screen display of Sungrow itself in the company's exhibition hall. The company has connected to more than 1 GW of power stations, including some self-sustaining power stations, including power stations for poverty alleviation projects. Operation and maintenance are difficult, and they are currently connected to our operation and maintenance platform. At the same time, the development trend I mentioned last time is the combination of photovoltaics and energy storage. Sungrow has always been able to provide energy storage inverters. It also has a cooperative factory with Samsung in South Korea. These are several typical cases of energy storage. The first one is the application of energy storage at the highest altitude last year. The second one is to solve the problem of power rationing in the west. Power rationing in the northwest is relatively easy. Considering that the electricity price of early power stations is relatively high, considering that adding a little energy storage can store the abandoned light electricity, we have calculated that it will recover the cost in about six or seven years. In addition, energy storage can be used in frequency regulation to smooth the impact of impact loads on the power grid.

The following is my brief summary today. Sungrow has always adhered to the idea of ​​scientific design based on local conditions to meet customers' needs for inverters in different scenarios. At the same time, we are constantly improving our inverter products and hope to provide more perfect solutions for each customer in the future. Thank you everyone, and this concludes today's speech.