Solis’ Various Generating Capacities of Single Axis Horizontal Tracker PV Power Station

“Double-sided PV module plus Single Axis Horizontal Tracker" is a new technology widely adopted by China's third batch of photovoltaic pioneer program. However, "double-sided PV module" is a new technology that started in 2017, and many people are not aware of the power generation effects of actual projects. Here’s how, Ginlong Solis describes the power generation gain from “Double-sided PV module plus Single Axis Horizontal Tracker” through the case study of Kubuqi desert in Inner Mongolia:

1. Project location

Kubuqi desert of Inner Mongolia, 40.26°N, 108.40°E, total radiation in the horizontal plane is 1762 KWH/m2.

2. Test conditions

Fixed Mounting Structure, installed with optimum angle of inclination:

Angle of Tilt Single Axis Horizontal Tracker: 12.5 °

Height of front pillar: 1.8 m, 

Height from peak of rotation axis’s center to the ground: 3.6 m

Rotation range of azimuth:  - 45 ° ~ plus 45 °

The pictures of the project are as follows:

3. Test time

July to August 2017, total of two months.

4. Test results

Two comparison tests were conducted:

1) Generation capacity of Tilt single axis tracker plus Single-sided PV module vs. fixed power generation. 

2) Generation capacity of Tilt single axis tracker plus Double-sided PV module vs. fixed power generation. 

The test results for July are shown in the figure below:

Tilt single axis tracker plus Single-sided PV module vs. fixed power generation

Tilt single axis tracker plus Double-sided PV module vs. fixed power generation

The test results for August are shown in the figure below:

 Tilt single axis tracker plus Single-sided PV module vs. fixed power generation

Tilt single axis tracker plus Double-sided PV module vs. fixed power generation

As it can be seen from the two comparisons:

Compared with the fixed power generation, the generation gain increased to 20.8% and 17.7% respectively from Tilt single axis tracker plus Single-sided PV module, and increased to 41.2% and 36.4% respectively from Tilt single axis tracker plus Double-sided PV module in the months of July and August.

This project was located at 40.26 °N, belonging to high latitude regions, and adopted the technology of Double-sided PV module plus Single Axis Horizontal Tracker or Tilt single axis tracker plus Single-sided PV module. Therefore, the power generation gain was obvious in summer, i.e. more than 35%. In contrast, the power generation gain was significantly reduced in winter, was about 10% to 15%. However, if Tilt single axis tracker plus Single-sided PV module was adopted in low latitudes, such as less than 35 ° latitudes, then the influence on the power generation gain of winter will be significantly reduced.

Somewhere in Inner Mongolia, 40.26 °N Somewhere in Guangdong, 21.2°N

This project which was invested by Elion Resources Group, turnkey system solutions charged by Xi’an Longi Clean Energy Co.Ltd, and the facilities were provided by Jiangsu Xietong new energy technology Co. Ltd. It took only 26 days from the launch day to the grid-connection.

In many applications, the Double-sided PV module, a new hotspot of the component recently, has good power-generation capacity i.e. high efficiency at the front side and multiple power generation at the back side. In order to lower the cost of electricity, to improve integrated generation capacity of the power plant and to reduce the cost of power generation, the double-sided PV module along with tracker and good quality inverter has become best project portfolio selection. 

Besides, the climatic characteristics of Kubuqi desert belongs to the typical Semi-arid plateau of continental climate with middle temperate zone, strong solar radiation, abundant sunshine and higher ratio of direct sunlight. Here, the combination of double-sided PV module and trackers are expected to increase the power generation more than 35%. However, as a typical desert power station project, the wind and sand factors affect the direct sunlight, especially the reflected light of the background and the scattered light surrounding. On the back of high frequency of variation of maximum power point of the double-sided PV module, MPPT of the inverter required to be efficient in tracking its maximum power point rapidly and with stability. Further, this characteristic of an inverter is a significant guarantee that the power generation from the double-sided PV module can be converted efficiently.

In addition, since the working environment of this project was at high-temperature in the desert area, this shows that system equipment will work properly in high-temperature environment for long time. So the equipment needs to have the operational capability of long-term reliability and stability in high-temperature environment. Otherwise, problem in any part of the system may arise and it will affect the integrated generation capacity of the system. Thus, inverters from Ginlong Solis ensure long-term reliability and stability in operation in a high temperature environment. With its greeat temperature protection capability, Solis inverter can perform normally under 45℃ ambient temmreperature, which key components temperature will rise up max to 150℃.

The variation of maximum power point of the Double-sided PV module is more complex than that of traditional components. This component receives direct sunlight to generate electricity from the front side, while the back side generates electricity by absorbing reflected light from the background and scattered light from the surrounding. Since, power generation on the back is significantly affected by the light intensity received on the back. So, it is required that the inverter must have a faster and more stable MPPT to adapt to this component, and the tracking frequency of MPPT should be higher. Here Ginlong Solis’50kW series inverter incorporates high-speed DSP chip having high computing speed and PWM resolution, and also adopts more advanced and precise MPPT algorithm, which can adapt to the fast changing sunlight intensity. It also has high tracking accuracy, which can match the complex variation of the maximum power point of the Double-sided PV module better.

According to the professional efficiency evaluation of EN5530, Static MPPT efficiency of Solis inverter is more than 99.5%, MPPT precision adjustment (<1V/S), this MPPT can ensure that the tracking power point is exactly stable near the maximum power point of the component, and more importantly, it can guarantee the conversion efficiency of the photovoltaic system, thus improving the power generation.

When compared with traditional components, the single block output power of double-sided PV module is larger and the range of power variation is wider. Therefore, the range of input and output power of the inverter is also required to be wider.

Thus, if the range of input and output of inverter is wider then more components can be accessed and the excess output capacity will be stronger. Further, Dc input power of Solis inverter can reach 1.2 times above of rated input and output power can reach up to 1.1 times of rated output. While ensuring DC ratio and power generation efficiency, the number of inverters can be reduced. Thereby saving costs and shortening the cycle of investment return.

How to convert and transmit the electricity smoothly? Project construction client finally chooses GCI_50k_HV inverter from Ginlong Solis after multiple comparisons.

Inverters from Ginlong Solis have the characteristics of high MPPT efficiency, low start-up voltage, low grid voltage, high switching frequency and high power generation efficiency. They can provide guarantee for high-quality and efficient transmission of solar power energy to this project in such climatic conditions. The high reliability of Solis inverter can also provide convenience for later operation and maintenance of this project. Meanwhile, this project has provided technical support for the application of photovoltaic pioneer program. 

Extended reading

The "photovoltaic pioneer program" is a special photovoltaic support program implemented by the national energy administration of China since 2015. The "pioneer program" will be implemented through the construction of demonstration bases for advanced photovoltaic power generation and demonstration projects for the application of new technologies.