Partial Shadowing Detection in PV Generators via Impedance Resonance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for detecting partial shadowing in photovoltaic generators are complex and costly, often leading to energy losses due to difficulty in accurately inferring shadowing from impedance measurements and requiring additional components for each PV module.
Innovation Solution
A method that performs reference impedance measurements on multiple PV generators under uniform irradiation, determining resonant properties, and comparing these with operational measurements to detect and signal partial shadowing without deviating from the operating point, using differences in resonant properties to identify shadowing and compensate for production tolerances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If impedance measurements are performed to detect partial shadowing, then shadowing detection capability is improved, but measurement precision deteriorates due to difficulty in accurately inferring shadowing from impedance changes
Solution Approach 1:
The PV generator is divided into multiple partial PV generators (strings), and impedance measurements are performed separately on each partial generator. This segmentation allows direct comparison of impedance values between strings, making shadowing detection more accurate. When one string is shadowed, its impedance will differ from unshadowed strings, enabling precise identification of the affected string.
Solution Approach 2:
The method utilizes changes in impedance parameters (magnitude and phase) as indicators of shadowing conditions. By monitoring impedance parameter variations across different partial PV generators and comparing them against reference values or each other, the system can accurately detect shadowing events without requiring complex modeling or additional sensors.
2Reliability
If additional components are added to each PV module for shadowing detection, then detection reliability is improved, but device complexity increases
Solution Approach 1:
The impedance measurement system serves multiple functions: it detects shadowing, monitors generator health, and provides diagnostic information about PV module conditions. By using the existing impedance characteristics of the PV generator for multiple purposes, the system achieves high detection reliability without requiring additional dedicated components for shadowing detection.
Solution Approach 2:
The PV generator's own impedance characteristics are used to detect shadowing conditions. The system leverages the natural electrical properties of the PV modules themselves rather than requiring external sensors or additional components attached to each module. This self-service approach maintains reliability while minimizing added complexity.
3Productivity
If MPP tracker operates continuously without interruption, then energy production is maximized, but energy losses occur when operating at local maxima instead of global maximum
Solution Approach 1:
The impedance-based shadowing detection system provides feedback to the MPP tracker about shadowing conditions. When shadowing is detected through impedance measurements, the system can trigger a global maximum search or adjust tracking behavior to avoid local maxima. This feedback mechanism allows the MPP tracker to maintain high productivity during normal operation while minimizing energy losses when shadowing occurs.
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
Enables reliable and uncomplicated detection of partial shadowing, reducing energy losses by comparing PV generators directly and allowing for efficient operation without complex modeling, while also providing insights into defects and installation issues.
Implementation Method 1
performing a reference impedance measurement on each of the at least two partial photovoltaic generators
Implementation Method 2
determining at least one reference resonant property of each of the at least two partial photovoltaic generators from the reference impedance measurement
Implementation Method 3
Photovoltaic generators (called PV generators in abbreviated form below) produce electrical energy with the incidence of light
Data Source
AI summary
The disclosure relates to a method for signaling partial shadowing within a PV generator including at least two partial PV generators connected in parallel. The method includes performing a reference impedance measurement on each of the at least two partial PV generators in a state of uniform irradiation of the PV generator, and determining at least one reference resonant property of each of the at least two partial PV generators from the reference impedance measurement. Furthermore, impedance measurements are carried out on the at least two partial PV generators at a first operating point of the PV generator during operation of the PV generator. Resonant properties of the partial PV generators are determined from the impedance measurements. Partial shadowing within the PV generator is detected and signaled if a difference between the resonant properties of the partial PV generators at the first operating point differs from a difference between the reference resonant properties of the partial PV generators. The disclosure also relates to an apparatus suitable for carrying out the method.