PV Module I-V Measurement Using In-Situ Operating Point Shifting
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Solution Overview
Problem
Current methods for measuring current-voltage (I-V) characteristics of photovoltaic (PV) modules in solar energy production systems often disrupt the power output and require module disconnection, limiting the ability to monitor performance metrics like soiling, irradiance, and degradation in-situ within PV arrays.
Innovation Solution
A device and system configured to measure I-V data of PV modules in-situ within a PV array, using a variable load and DC-DC switching power converter to shift operating points without disconnecting the module, allowing for minimal disruption to power output and enabling continuous monitoring of performance metrics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional I-V measurement methods are used, then I-V characteristics can be measured, but power output is disrupted and module disconnection is required
Solution Approach 1:
A current injection device is introduced as an intermediary component between the PV module and the load. This device can inject current into the module to shift its operating point without requiring disconnection, enabling I-V measurements while maintaining electrical connectivity and power flow through the module.
Solution Approach 2:
The measurement system dynamically adjusts the operating point of the PV module by controlling current injection levels. The system can transition between different measurement modes (e.g., standard I-V sweep, partial I-V, impedance measurement) by dynamically modifying the current injection, allowing flexible measurement approaches that minimize disruption to power output.
2Measurement precision
If module disconnection is required for measurement, then accurate I-V data can be obtained, but monitoring capability in-situ is lost
Solution Approach 1:
The current injection device serves as a mediator that enables accurate measurements while the module remains connected in its operational configuration. This allows in-situ monitoring of I-V characteristics, soiling, irradiance, and degradation metrics without removing the module from the array.
Solution Approach 2:
The measurement system is designed to perform multiple functions including standard I-V measurements, partial I-V measurements, impedance spectroscopy, and environmental parameter monitoring (soiling, irradiance). This multi-functionality is achieved while the module remains connected, enhancing adaptability for various monitoring scenarios.
3Productivity
If frequent measurements are performed, then performance metrics can be monitored, but power loss and disruption increase
Solution Approach 1:
The system dynamically selects measurement modes and durations based on operational conditions. For frequent monitoring, it can perform rapid partial I-V measurements or impedance measurements that require minimal current injection and time, thereby reducing power loss. For less frequent comprehensive assessments, full I-V sweeps can be performed.
Solution Approach 2:
The measurement system implements periodic measurement cycles with varying intensity. Routine monitoring uses low-intensity, fast measurements that minimally impact power output, while periodic more intensive measurements provide comprehensive performance assessment. This periodic variation in measurement intensity balances monitoring needs with power loss minimization.
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 efficient, uninterrupted measurement of I-V characteristics and performance metrics, such as soiling and irradiance, within PV arrays, improving monitoring and maintenance efficiency while minimizing power loss and disruption.
Implementation Method 1
using a variable load and DC-DC switching power converter to shift operating points
Implementation Method 2
current-voltage (I-V) characteristics of photovoltaic (PV) modules in solar energy production systems
Data Source
AI summary
In one respect, disclosed is a device comprising terminals or connections configured to connect to a first associated PV module, I-V measurement circuitry coupled to said terminals or connections and configured to measure I-V data of said first associated PV module, communication circuitry configured to communicate with at least one external device, and a processor coupled to said I-V measurement circuitry and to said communication circuitry, wherein said processor is configured to receive external data via said communication circuitry from said at least one external device, and wherein said processor is configured to determine a relative performance metric based at least upon said I-V data of said first associated PV module and said external data. In another respect, disclosed is a system comprising a first device configured to measure first I-V data of a first associated PV module and a second device configured to measure second I-V data of a second associated PV module, wherein said first device may be configured to receive said second I-V data and to determine a relative performance metric based at least upon said second I-V data and said first I-V data.