PV String Voltage Compensation for Shading-Related Power Loss
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Solution Overview
Problem
Existing photovoltaic power harvesting systems face inefficiencies due to underperforming or partially shaded photovoltaic strings, leading to power losses and increased costs.
Innovation Solution
The implementation of a power harvesting system that includes multiple parallel-connected photovoltaic strings, each equipped with a voltage-compensation circuit. These circuits provide compensation voltages to maximize power harvesting by adjusting for inter-string voltage mismatches and optimizing the operation of photovoltaic modules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If voltage-compensation circuits are added to each photovoltaic string, then power harvesting is maximized and system reliability is improved, but device complexity and installation costs increase
Solution Approach 1:
The system divides the photovoltaic array into multiple independent strings, each equipped with its own voltage-compensation circuit. This segmentation allows each string to be optimized independently, maximizing power harvesting from underperforming strings while containing the complexity within manageable modular units rather than requiring a complex centralized control system.
Solution Approach 2:
Voltage-compensation circuits are introduced as intermediary devices between the photovoltaic strings and the main power collection system. These circuits actively measure string voltages and inject compensating voltages to balance mismatches, enabling maximum power extraction without requiring complete system redesign or complex centralized control.
2Loss of energy
If voltage-compensation circuits are deployed to maximize power output, then energy losses are reduced, but installation and maintenance costs increase
Solution Approach 1:
The voltage-compensation circuits are designed to autonomously monitor their respective string voltages and automatically generate compensating voltages without external intervention. This self-service capability eliminates the need for complex centralized control systems and reduces maintenance requirements, as each circuit independently optimizes its string's power output while being relatively simple in design.
3Productivity
If photovoltaic strings operate at different voltages due to shading or underperformance, then individual string optimization is lost, but adding compensation circuits increases system complexity
Solution Approach 1:
Each voltage-compensation circuit is designed to operate independently on its local photovoltaic string, applying compensation tailored to that specific string's conditions (shading, underperformance, etc.). This local quality approach allows each string to be optimized according to its own characteristics without requiring complex inter-string coordination or centralized control.
Solution Approach 2:
The voltage-compensation circuits dynamically adjust the operating voltage parameter of each photovoltaic string to maximize power output. By actively modifying the voltage parameter in response to real-time string conditions, the system enables each string to operate at its optimal point despite variations in irradiation or performance, achieving overall system maximization through simple localized parameter control.
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 enhances the overall power output of the system by ensuring that all photovoltaic strings operate at their maximum power point, thereby reducing power losses and lowering installation and maintenance costs while improving system reliability.
Implementation Method 1
Photovoltaic (PV) power devices can be used to improve the performance and to reduce the cost of power generation systems including photovoltaic panels
Data Source
AI summary
A power harvesting system including multiple parallel-connected photovoltaic strings, each photovoltaic string includes a series-connection of photovoltaic panels. Multiple voltage-compensation circuits may be connected in series respectively with the photovoltaic strings. The voltage-compensation circuits may be configured to provide respective compensation voltages to the photovoltaic strings to maximize power harvested from the photovoltaic strings. The voltage-compensation circuits may be include respective inputs which may be connected to a source of power and respective outputs which may be connected in series with the photovoltaic strings.