Intelligent photovoltaic array voltage compensator

Abstract

The invention discloses an intelligent photovoltaic array voltage compensator and belongs to the technical field of solar photovoltaic power generation. The intelligent photovoltaic array voltage compensator comprises a serial voltage sampling circuit, a PWM (Pulse-Width Modulation) control voltage compensation circuit, an on-off output control circuit, a keyboard circuit, an LCD (Liquid Crystal Display) display screen circuit and a main control CPU (Central Processing Unit) circuit. The intelligent photovoltaic array voltage compensator is characterized in that a sampling signal output port of the serial voltage sampling circuit is connected with a sampling signal input port of the main control CPU circuit; a control signal output port of the main control CPU circuit is connected with a control signal input port of the PWM control voltage compensation circuit and a control signal input port of the on-off output control circuit; a control signal output port of the keyboard circuit is connected with a control signal input port of the main control CPU circuit.

Description

technical field [0001] The invention belongs to the technical field of solar photovoltaic power generation, and in particular relates to a photovoltaic array intelligent voltage compensator. Background technique [0002] There are many forms of combined connection of solar panels in the photovoltaic array. The essence is that the output voltage of the DC terminal can be increased through the series connection of the solar panels, and the output current of the DC terminal can be increased through the parallel connection of the solar panels. In most photovoltaic power generation systems, the photovoltaic panels are first connected in series to a higher voltage, and then the series branches are connected in parallel to output a larger current. Due to the "barrel effect" of photovoltaic array power generation, if the voltage of one branch is reduced, the output voltage of all other branches connected in parallel will be reduced, thereby greatly reducing the output power of the e...

AI Technical Summary

Problems solved by technology

Due to the "barrel effect" of photovoltaic array power generation, if the voltage of one of the branches decreases, the output voltage of all other branches connected in parallel will decrease, thereby greatly reducing the output power of the entire array.

There are two main reasons for the drop in branch circuit voltage: the first is random reasons, including shadows caused by surrounding obstacles, snow cover in winter, hidden cracks inside photovoltaic panels, etc. The reduction of the range is irregular and accidental, which will cause one or several panels not to generate electricity, lower the branch circuit voltage, and further affect the output power of the entire array; the second is a fixed reason, in some cases due to objective conditions In the case of limitations, the number of panels in each series branch cannot be kept the same, or the number of panels in series is the same but the specifications of the panels are different. These reasons will cause each series branch connected in parallel to have a different working voltage , the voltage of each branch will be pulled down by the branch with the lowest working voltage

No matter what the reason is, the voltage reduction of the series branch will cause the strings in the array to fail to work at the maximum power point, which will directly cause the reduction of the power generation of the entire photovoltaic array.

There are two main methods to prevent the "barrel effect" of photovoltaic arrays: (1) reduce the loss of power mismatch by adding bypass diodes and blocking diodes. function, and will lead to multiple power peak points of the photovoltaic array, which often makes MPPT tracking fall into a local optimum point, and cannot make the array output the maximum power; (2) solve it by installing an optimizer on each panel, this method exists Problems such as high cost, complex installation, high failure rate, and high energy consumption of the optimizer

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