How to improve your own rooftop photovoltaic power generation efficiency?

How to improve your own rooftop photovoltaic power generation efficiency

Not all solar power plants have the same power generation efficiency. How can photovoltaic power plants improve power generation efficiency? In addition to factors such as the amount of solar radiation and the angle of inclination of photovoltaic modules, what are the influencing factors? Let’s take a look at it.

Solar radiation

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

The tilt angle of photovoltaic modules

The azimuth of the PV module is generally selected in the south direction to maximize the power generation per unit capacity of the PV power plant. As long as it is within ±20° of the south direction, it will not have much influence on the amount of power generation. If possible, it should be as far as 20°to the southwest.

PV module efficiency and quality

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

Component matching loss

In the case of series connection, current loss due to the component current difference, any parallel connection will result in voltage loss due to the component voltage difference. The loss may reach more than 8%. In order to reduce the loss of matching loss and 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 the consistent current; 2. The attenuation of the components should be as consistent as possible; 3. Isolation diode.

Temperature (ventilation)

Data show that the temperature rises by 1°C, the maximum output power of crystalline silicon PV modules drops by 0.04%. Therefore, it is necessary to avoid the influence of temperature on power generation and maintain good ventilation conditions.

The effect of dust can not be underestimated

The panel of the crystalline silicon component is tempered glass, which is exposed to the air for a long time, and naturally, there is 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 the component “hot spot” effects that can cause component damage.

Shadow and snow cover

In the process of site selection of photovoltaic power plants, it is necessary 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.

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.

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 and flame resistance of the cable, the moisture and light resistance of the cable, the type of cable core, and the size of the cable. All these factors should be carefully considered.

Inverter efficiency

The photovoltaic inverter is the main component and an important component of the photovoltaic system. In order to ensure the normal operation of the power station, it is particularly important to select the correct configuration of the inverter. In addition to the technical specifications of the entire photovoltaic 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. Overall efficiency; 4. Starting performance.