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How to improve the efficiency of solar energy system generation?
- Jul 20, 2018 -

Not all solar systems have the same power generation efficiency. How can solar systems improve power generation efficiency? Besides the factors such as the amount of solar radiation and the tilt angle of photovoltaic modules, what are the influencing factors?

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1. Solar radiation

In the case where the conversion efficiency of the photovoltaic cell module is constant, the amount of power generated by the solar energy system is determined by the intensity of the solar radiation. Under normal circumstances, the solar system's utilization efficiency of solar radiation is only about 10%. So take into account solar radiation intensity, spectral characteristics, and climate.

2. Angle of tilt of photovoltaic cell components

The azimuth of PV modules generally chooses the south direction to maximize the unit capacity of the solar system. As long as it is within 20 degrees south of the south, it will not have much impact on power generation. If conditions permit, it should be as far as possible to 20 degrees southwest.

3. PV module efficiency and quality

Calculation formula: theoretical power generation = annual average solar radiation total * total battery area * photoelectric conversion efficiency, there are two factors of battery area and photoelectric conversion efficiency, the conversion efficiency has a direct impact on the power generation capacity of the power station.

4. Component matching loss

In the case of series connection, current loss due to component current difference, any parallel connection will result in voltage loss due to component voltage difference. The loss may reach more than 8%. In order to reduce the loss of matching loss, in order to increase the power generation capacity of the power station, we must pay attention to the following aspects: 1) Reduce the matching loss, try to use the series of components with consistent current; 2) The attenuation of the components should be as consistent as possible; 3) Isolation diode.

5. Temperature (ventilation)

Some data show that the temperature rises by 1 °C, and the large output power of the crystalline silicon photovoltaic module group drops by 0.04%. Therefore, it is necessary to avoid the influence of temperature on power generation and maintain good ventilation conditions.

6. The loss of dust can not be underestimated

The panel of the crystalline silicon component is tempered glass. In the long-term exposed air, there will naturally be organic matter and a large amount of dust accumulation. The surface ash blocks the light, which reduces the output efficiency of the module and directly affects the amount of power generated. It can also cause component "hot spot" effects that can cause component damage.

7. Shadow, snow cover

In the process of site selection, it is important to pay attention to the shielding of light. Avoid areas that may be obscured by light. According to the circuit principle, when the components are connected in series, the current is determined by the least one block, so if there is a shadow, it will affect the power generation of this component. Similarly, the snow in winter should be removed in time.

8. Maximum Output Power Tracking (MPPT)

MPPT efficiency is a key factor in determining the amount of PV inverter power generation, and its importance far exceeds the efficiency of the PV inverter itself. MPPT efficiency is equal to hardware efficiency multiplied by software efficiency. The hardware efficiency is mainly determined by the accuracy of the current sensor and the accuracy of the sampling circuit; the software efficiency is determined by the sampling frequency. There are many ways to implement MPPT, but no matter which method is used, the power of the component is measured first, and then the change is reacted. The key component of this is the current sensor. Its accuracy and linearity directly determine the hard efficiency, and the sampling frequency of the software is also determined by the accuracy of the hardware.

9. Reduce line loss

In the photovoltaic system, the cable accounts for a small part, but the influence of the cable on the power generation cannot be ignored. It is recommended that the line loss of the DC and AC circuits of the system be controlled within 5%. The cables in the system should be well prepared, the insulation performance of the cable, the heat-resistance and flame-retardant properties of the cable, the moisture-proof and light-proof performance of the cable, the type of the cable core, and the size of the cable.

10. Inverter efficiency

Photovoltaic inverter is the main component and important component of solar energy system. In order to ensure the normal operation of the power station, it is especially important to select the correct configuration of the inverter. In addition to the technical specifications of the entire solar power generation system and reference to the product sample manual provided by the manufacturer, the following technical indicators should be considered: 1) Rated output power; 2) Output voltage adjustment performance; 3) machine efficiency; 4) starting performance.