Inverter efficiency monitoring method and system based on photovoltaic module level Internet of Things

Abstract

The invention mainly relates to an inverter efficiency monitoring method and system based on photovoltaic module level Internet of Things. Power is supplied to the inverter by a single battery pack string or a plurality of battery pack strings, each battery pack string comprising a plurality of photovoltaic modules connected in series. The power value and the voltage value of each photovoltaic module are measured for multiple times in any battery pack string, so that a series of power values and a series of voltage values are obtained at each measurement moment. Subtracting the sum of the series of power values at the previous moment from the sum of the series of power values at the next moment to obtain a power difference, and meanwhile, subtracting the sum of the series of voltage values at the previous moment from the sum of the series of voltage values at the next moment to obtain a voltage difference. If the ratio of the power difference to the voltage difference is not within the preset proportion range, it is considered that the inverter does not reach the expected efficiency, and otherwise, it is considered that the efficiency of the inverter is normal.

Description

technical field [0001] The present invention mainly relates to the field of photovoltaic power generation, and more precisely, relates to a method and system for monitoring inverter efficiency based on photovoltaic module-level IoT in a photovoltaic power generation system containing photovoltaic modules. It can ensure the safe and reliable operation of photovoltaic modules and realize the monitoring of photovoltaic inverters. Background technique [0002] Photovoltaic modules are an important core component of photovoltaic power generation systems, and their excellent performance directly affects the overall effect of the power generation system. However, in fact, photovoltaic modules are subject to many constraints. loss. Photovoltaic module arrays are generally series-parallel. If a battery module is affected by factors such as shadows, dust, occlusion, or aging, and the power is reduced, all other modules connected in series-parallel relationship may be affected by the ...

AI Technical Summary

Problems solved by technology

However, the PR value of the system energy efficiency is used to evaluate the performance of photovoltaic power plants. Months or years are usually regarded as time units. The evaluation indicators select factors such as geographical location, meteorological conditions, and light intensity that affect the performance of photovoltaic power plants, which are relatively more biased towards the normal operation of photovoltaic systems. However, it is not suitable for the evaluation of the performance loss caused by the failure of the internal components of the photovoltaic system.

[0006] Among the few evaluation methods for failure efficiency loss at present, AHP has become the preferred strategy for evaluation. However, when there are too many evaluation indicators, the amount of data statistics is large, and the calculation process is too cumbersome, which makes it difficult to determine the evaluation weight.

[0007] Therefore, there are certain deficiencies in the existing methods for the performance evaluation of photovoltaic inverters, especially for the evaluation of the performance loss of photovoltaic inverters under fault conditions.

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