Component evaluation method and system for photovoltaic power station

Abstract

The invention provides a component evaluation method and system for a photovoltaic power station. The method comprises the steps of determining a voltage value and a current value of each bypass diodein a to-be-evaluated photovoltaic string of the photovoltaic power station; calculating first power of the to-be-evaluated photovoltaic string when no current flows through each bypass diode in the to-be-evaluated photovoltaic string; moreover, when current flows through at least one bypass diode in the to-be-evaluated photovoltaic string, calculating the second power of the to-be-evaluated photovoltaic string according to the voltage value and the current value of each bypass diode in the to-be-evaluated photovoltaic string, and finally, using the difference value obtained by subtracting thesecond power from the first power as the mismatch loss of the to-be-evaluated photovoltaic string. Therefore, the to-be-evaluated photovoltaic string is used as a node, the series mismatch loss inside the photovoltaic modules and between the photovoltaic modules in the to-be-evaluated photovoltaic string can be calculated, the mismatch loss calculation is accurate to the module level, and the evaluation precision of the photovoltaic power station is improved.

Description

technical field [0001] The invention belongs to the technical field of photovoltaic power generation, and more specifically relates to a component evaluation method and system of a photovoltaic power station. Background technique [0002] At present, in order to solve the current mismatch problem of series photovoltaic modules, a bypass diode is usually connected in antiparallel to each photovoltaic substring in the photovoltaic module to form a bypass section, which can provide a low impedance path for energy dissipation. In this way, under normal circumstances, the bypass diode is reverse-blocked, and when some solar cells are affected by shadows or dust, the photo-generated current is smaller than the series current of the system, and the bypass diode branch will forward the residual current. [0003] In addition, each photovoltaic module can also be connected to a power optimizer. Each photovoltaic module is an independent whole compared to the photovoltaic array. Its ou...

AI Technical Summary

Problems solved by technology

This kind of calculation accuracy is relatively low, and the individual power is also based on the inverter or combiner box as the node, which can only be accurate to the string level, and the series mismatch loss inside the module and between modules cannot be calculated.

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