A method and device for inverters to suppress the pid phenomenon of photovoltaic modules

Abstract

The invention discloses a method and device for suppressing a potential induced degradation (PID) phenomenon of a photovoltaic module through an inverter. The method comprises the steps that a bus negative electrode of a photovoltaic system is grounded after a resistor (1), an adjustable direct-current power source (2), a direct-current Hall sensor (4), a fuse protector (5) and a high-voltage relay (6) are connected to the bus negative electrode in series; the current monitored by the direct-current Hall sensor (4) is acquired through a controller (9), when the monitored current changes, the controller (9) adjusts the voltage of the adjustable direct-current power source (2) to improve the adjustment effect, and when the monitored current exceeds the preset protective current, the controller (9) controls the high-voltage relay (6) to open a circuit. The device further comprises a diode (3), a negative-electrode voltage monitoring circuit (7) and a positive-electrode voltage monitoring circuit (8), wherein the diode (3), the negative-electrode voltage monitoring circuit (7) and the positive-electrode voltage monitoring circuit (8) are connected with the controller (9). The phenomenon that the negative electrode is directly grounded is avoided, the voltage between the negative electrode of the system and the ground is boosted, usage of the photovoltaic system is not affected, and safety of the system and staff is better guaranteed.

Description

technical field [0001] The invention relates to a method and a device for an inverter to suppress the PID phenomenon of a photovoltaic module, belonging to a protection device in a solar photovoltaic power generation system. Background technique [0002] PID is Potential Induced Degradation. Photovoltaic modules under the action of high voltage for a long time will cause leakage current between the glass and the packaging material, and a large amount of charge will accumulate on the surface of the cell, which will deteriorate the passivation effect of the cell surface, resulting in a decrease in FF, Isc, and Voc, resulting in low module performance According to design standards, this phenomenon is called potential-induced decay, or PID phenomenon for short. Practice has shown that no matter whether it is a crystalline silicon module or a thin film module, there is a risk of PID under negative bias. When the PID phenomenon occurs in the module, it will seriously affect the p...

AI Technical Summary

Problems solved by technology

[0005] 2) Performance attenuation and shunting of semiconductor junctions: Ion migration will occur in the active layer, which will attenuate the performance of semiconductor junctions and cause shunting

Because the negative pole is grounded, the ground is at the same potential as the negative pole, so if a person touches the positive pole of the photovoltaic module by mistake, it will cause huge damage to the personal safety of the personnel.

At the same time, since the negative electrode of the photovoltaic system is grounded, a certain amount of circulation will be formed on the AC side and the DC side of the system, which is also unsafe for the photovoltaic system.

[0013] 2) Improve the dielectric strength of packaging materials: At present, various component factories are reducing the leakage current of components to the ground by increasing the dielectric strength of packaging materials. Facts have proved that improving the dielectric strength of packaging materials can indeed slow down the occurrence of PID phenomenon It is still very difficult to fundamentally eliminate the occurrence of PID phenomenon

Images