Device for suppressing PID (potential induced attenuation) effect of photovoltaic assembly

Abstract

The invention discloses a device for suppressing the (potential induced attenuation) effect of a photovoltaic assembly. The device includes a virtual neutral point construction circuit, a direct-current power source and a control circuit; the virtual neutral point construction circuit is composed of a three-phase star connection inductor and a resistor; the three-phase star connection inductor is connected into a three-phase alternating-current line; and the resistor is connected in series between an inductance neutral point and a direct-current power source; and one end of the direct-current power source is grounded. Voltage at two ends of the resistor is detected, so that short-circuit current is calculated, and therefore, whether an electric leakage accident occurs can be judged; and the resistance of the resistor is limited within a certain range according to a formula provided by the invention, so that the short-circuit current can be limited in a safety range, and an electric leakage current sensor and a relay switch are not required. With the device of the invention adopted, the positive and negative voltage bias adjustment of the assembly and the electric leakage protection function of a whole power generation system can be realized. The device has the advantages of simple structure, high safety, low cost, low energy consumption and the like.

Description

technical field [0001] The invention relates to a device for suppressing the PID effect of a photovoltaic module, which belongs to the technical field of photovoltaic power generation. Background technique [0002] The potential potential induced decay (PID) effect refers to the phenomenon that the power generation performance of photovoltaic modules is reduced under the action of long-term negative bias voltage. [0003] The virtual neutral point clamping on the AC side of the photovoltaic inverter can affect the voltage of the positive and negative poles of the module to the ground, thereby solving the PID phenomenon (N-type photovoltaic modules need to make the bias voltage of the negative pole to the ground greater than 0V, and the P-type photovoltaic ground bias below 0V). The traditional way to realize the virtual midpoint through the three-phase star-connected load includes using three-phase inductors, three-phase capacitors, three-phase resistors, or three-phase res...

AI Technical Summary

Problems solved by technology

The traditional way to realize the virtual midpoint through the three-phase star-connected load includes using three-phase inductors, three-phase capacitors, three-phase resistors, or three-phase resistor midpoints and then series resistors. These methods have excessive short-circuit current or loss in practical applications. Disadvantages of being too high

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