Distributor Measuring Box for PV String Current Monitoring
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Solution Overview
Problem
Current string current measurement methods in photovoltaic systems are costly due to long cable lengths, generate thermal losses, and require additional components, leading to increased power consumption and production expenses.
Innovation Solution
A decentralized string current measuring system where a distributor measuring box with integrated measuring modules is attached directly to solar modules, reducing cable lengths and integrating current measurement components within the junction and connecting box, using sensors like magnetoresistive or Hall sensors for low-loss current measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If string current measurement is performed in a centralized generator control box, then current measurement capability is achieved, but cable lengths increase and costs increase
Solution Approach 1:
The patent divides the current measurement function from the centralized generator control box and distributes it to individual distributor boxes at each string level. Each distributor box contains its own current measuring module with shunt resistor and measurement electronics, enabling decentralized measurement. This segmentation eliminates the need for long cables running from each string to a central measurement point, as measurement occurs locally at each distributor box.
Solution Approach 2:
The patent transitions from a centralized vertical hierarchy (all strings connecting to one control box) to a distributed horizontal architecture where measurement occurs at multiple distributed points throughout the system. By placing measurement functionality at the distributor box level rather than concentrating it at the generator control box, the system achieves measurement capability without requiring long cable runs.
2Measurement precision
If multiple shunt resistors are used in generator control boxes for current measurement, then current measurement is achieved, but thermal output increases and cooling requirements arise
Solution Approach 1:
The patent extracts the shunt resistor and measurement electronics from the generator control box environment and relocates them to individual distributor boxes. This distribution of measurement components means that thermal output from shunt resistors is dispersed across multiple locations rather than concentrated in one box, reducing the cooling burden on any single location and eliminating the need for additional cooling fans.
3Reliability
If string current measurement components are protected from moisture in generator control boxes, then component protection is achieved, but cable lengths and costs increase
Solution Approach 1:
The patent segments the system into distributed measurement units at each distributor box, each self-contained and protected from moisture at its local installation point. By placing measurement components locally at the distributor box rather than centrally in the generator control box, the system achieves both protection (each box is sealed and mounted in a protected location) and reduced cable lengths (measurement occurs at the point of connection).
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces production costs, minimizes electrical losses, and enhances reliability by allowing redundant measurement capabilities, while maintaining system efficiency and reducing the need for additional cabling and cooling systems.
Implementation Method 1
the string current measuring module has a shunt resistor and a voltage measuring device at the shunt resistor
Implementation Method 2
using sensors like magnetoresistive or Hall sensors for low-loss current measurement
Implementation Method 3
using sensors like magnetoresistive or Hall sensors for low-loss current measurement
Data Source
AI summary
The present disclosure proposes: a distributor measuring box designed to be installed on a photovoltaic solar module, having a housing with a support section embodied to be supported on the solar module, an encompassing side wall, and a cover, and string line feedthroughs and/or string line connectors, and having a string current measuring module that includes a measuring component and an evaluation unit for measuring the string current in the distributor measuring box; a photovoltaic solar module having a plurality of solar cells, in which a distributor measuring box is mounted to the back of the solar module oriented away from the sun; and a photovoltaic system having a plurality of photovoltaic solar modules, having a plurality of string lines, having a generator junction box, and having at least one inverter for supplying the electrical power produced by the photovoltaic generator.