High-precision measurement method based on photovoltaic assembly data monitoring system

Abstract

The invention discloses a high-precision measurement method based on a photovoltaic assembly data monitoring system. A signal with a fixed input range is segmented; a single-chip microcomputer is used for controlling connection or disconnection of a switch; and thus a signal with a corresponding range passes through a corresponding channel. Before measurement, a complete signal is divided into a plurality of ones with small ranges; each range is bound with one switch group; and input signal segmentation is realized by connection or disconnection of a switch. Therefore, connection or disconnection of one switch group in an amplification circuit is controlled by the single-chip microcomputer; and other switches are in a disconnection state. Compared with the prior art, the method has the following advantages: the measurement accuracy is high; the fixed range is divided into several ranges; the more segments, the higher the measurement accuracy; with a differential amplifier circuit, a common mode signal is suppressed; and the anti-interference ability is good.

Description

technical field [0001] The invention relates to the field of photovoltaic module data monitoring, in particular to a high-precision measurement method based on a photovoltaic module data monitoring system. Background technique [0002] In recent years, distributed power stations have begun to develop rapidly. With the increase of the number of power stations, people pay more and more attention to the management of photovoltaic power stations; many companies have also begun to establish a complete set of photovoltaic module data monitoring systems, see image 3 , in this system, people upload the relevant data of components, combiner boxes, inverters, and weather monitors to the cloud, and then perform corresponding processing to realize the monitoring and management of the power station. [0003] In this photovoltaic module data monitoring system, one of the problems that needs to be solved urgently is the problem of low current measurement accuracy of the components. For dis...

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Problems solved by technology

[0005] In the currently commonly used component current measurement methods, for example, the collected current signal is converted into a voltage signal and then directly handed over to the microcontroller for processing. The data is optimized by software, which improves the measurement accuracy, but there are also some problems. For example, if the data If the quantity is large, this requires the data processing speed of the single-chip microcomputer. It is necessary to choose a single-chip microcomputer with fast processing speed and high AD accuracy, and the corresponding cost will increase. Secondly, if the accuracy of the data measured by the single-chip microcomputer itself is not high. If it is compensated by software, the error will be large; or the current output by the component is converted by the I / V conversion circuit, processed by the amplifier circuit, the voltage signal is amplified, and then measured; in this way, the input signal can be converted by the amplifier circuit Amplification eliminates the interference of some internal or external factors on the signal, and the accuracy of component current measurement is improved

[0006] But the problem is that once the amplifier circuit is fixed, the corresponding gain is often fixed. However, for the component, the flexible and changeable surrounding environment causes the output current range of the component to be not fixed. At this time, the range of use of the signal amplifier circuit is also limited There are limitations; at the same time, since the AD accuracy of the single-chip microcomputer is limited, if the input signal has a large range of values, at this time, the single-chip microcomputer with a fixed AD range is used to collect this signal, and the minimum measurement accuracy will be very low at this time. Then the measurement accuracy cannot be improved, and the previous measurement methods are not intelligent enough, or the anti-interference ability is weak

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