PV System Maximum Power Determination Without Irradiance Sensors

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Solution Overview

Problem

Existing methods for determining the maximum possible power of a regulated photovoltaic (PV) system are complex, require separate irradiation sensors, and result in significant power fluctuations and system curtailment, especially in highly regulated states.

Innovation Solution

A method that uses a PV module connected via a coupling unit to determine the maximum possible power by measuring short-circuit and no-load reference values, allowing for minimal power consumption and reduced system operation, thereby minimizing fluctuations and curtailment, without the need for separate sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If separate irradiance sensors are used to determine maximum possible power output, then measurement capability is provided, but device complexity and cost increase

Engineering Contradiction:
Improvemaximum possible power output determinationVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The PV module serves dual functions: generating power and acting as an irradiance sensor. By measuring the electrical characteristics (current, voltage, power) of a representative PV module, the system determines both the irradiance level and the maximum possible power output without requiring separate sensing components. This multi-functional approach eliminates the need for additional irradiance sensors while maintaining measurement capability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The PV system uses its own PV modules to generate measurement signals. The electrical characteristics of the PV modules themselves provide the information needed to determine irradiance and maximum power output, eliminating the need for external sensing systems. The system essentially measures itself through its operational parameters.

Inventive Principle:
Principle #25Self-service

2Measurement precision

If irradiance sensors are calibrated to specific PV modules, then measurement accuracy improves, but ease of operation deteriorates due to regular calibration requirements

Engineering Contradiction:
Improvesensor signal calibrationVSAvoidcalibration maintenance
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The PV module's electrical characteristics inherently reflect its own performance and the irradiance conditions. Since the measurement is based on the module's own operational parameters (current, voltage, power) rather than separate sensor signals, no calibration against reference sensors is needed. The module serves as both the test object and the measurement instrument, eliminating calibration requirements.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The invention extracts the measurement function from separate calibrated sensors and integrates it directly into the PV module's operational characteristics. By using the module's own electrical output as the measurement signal, the system removes the calibration layer entirely, simplifying operation while maintaining accuracy.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If PV system is curtailed to meet grid requirements, then grid compatibility improves, but power output is reduced

Engineering Contradiction:
Improvegrid complianceVSAvoidpower output
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system dynamically adjusts the power output based on real-time determination of the maximum possible power under current irradiance conditions. Rather than fixed curtailment levels, the system continuously calculates and adapts the allowable power output to match grid requirements while maximizing energy production within those constraints. This dynamic approach optimizes the balance between grid compliance and productivity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system uses feedback from the measured electrical characteristics of the PV modules to continuously determine the maximum possible power output and adjust the curtailment level accordingly. The control system receives information about current irradiance conditions and system capacity, then dynamically sets the appropriate power output limit to satisfy grid requirements while minimizing productivity loss.

Inventive Principle:
Principle #23Feedback

4Measurement precision

If sections operate without power limitation for maximum output determination, then measurement accuracy improves, but curtailment effectiveness worsens

Engineering Contradiction:
Improvemaximum output determinationVSAvoidcurtailment compliance
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The system determines maximum power output by measuring the electrical characteristics of individual PV modules or sections without requiring them to operate at full system power. By using partial measurements from representative modules and scaling to the total system capacity, the system achieves accurate maximum power determination while maintaining overall curtailment compliance. The measurement action is partial (individual modules) rather than requiring full system operation.

Inventive Principle:
Principle #16Partial or excessive action

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 simplifies the determination of maximum power, reduces power fluctuations, and allows for strong curtailment of the PV system while eliminating the need for separate sensors, resulting in a cost-effective and efficient method for regulating power feed into the energy supply network.

Implementation Method 1

The PV system comprises a PV generator with at least one string, wherein the at least one string comprises a series connection of PV modules

Methodology Applied
Scientific EffectPhotovoltaic effect: Photovoltaic Effect

Data Source

PatentEP3580826B1Method for determining the maximum possible output of a pv system, and pv system
Publication Date: 2022.04.27 SMA SOLAR TECH AG
  • EP3580826B1 patent drawingFigure 1
  • EP3580826B1 patent drawingFigure 2
  • EP3580826B1 patent drawingFigure 3a

AI summary

The invention relates to a method for determining the current maximum possible output (Pmax) of a photovoltaic (PV) system (1) operated in a decreased mode, having the following steps: - determining reference values for the PV module (5), comprising a reference MPP output (PMpp, Ref) and at least one value which is assigned to the reference MPP output (PMpp, Ref), from a near-short-circuit reference current (lsc, Ref) and/or a near-idling reference voltage (Uo, Ref) and - operating the PV system (1) in the decreased-mode state. A second current value (Isc, 2) which characterizes a near-short-circuit operating mode and/or a second voltage value (U0, 2) which characterizes a near-idling operating mode is determined for the PV module (5). Pmax is determined from the ISC, 2, the lsc, Ref, and the PMPP, Ref, or the U0, 2, the Uo, Ref, and the PMPP, Ref, or a combination of the ISC, 2, the lsc, Ref, the U0, 2, the Uo, Ref, and the PMPP, Ref.