Voltage-Compensation Circuit for Photovoltaic String Power Optimization
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Solution Overview
Problem
Photovoltaic power harvesting systems face inefficiencies due to underperforming or partially shaded strings, leading to power losses and increased costs associated with high-power DC-DC converters, which also reduce system reliability.
Innovation Solution
The implementation of a voltage-compensation circuit connected in series with each photovoltaic string, utilizing a microprocessor-controlled DC-to-DC converter to adjust the compensation voltage and maintain optimal operating conditions for each string, ensuring maximum power point tracking and reduced power processing requirements for converters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high-power DC-DC converters are used to maximize power from each photovoltaic string, then power output is improved, but system cost and complexity increase
Solution Approach 1:
The system divides the photovoltaic array into multiple independent strings, each with its own compensation circuit. This segmentation allows each string to be optimized independently, enabling maximum power extraction without requiring a single high-power converter to handle the entire array.
Solution Approach 2:
A compensation circuit is introduced as an intermediary component between the photovoltaic string and the main DC-DC converter. This compensation circuit processes only the voltage difference or imbalance, reducing the power processing burden on the main converter and simplifying its design.
2Productivity
If high-power DC-DC converters are deployed to handle underperforming strings, then power harvesting is improved, but reliability decreases
Solution Approach 1:
By segmenting the power processing function into multiple independent compensation circuits for each string, the system avoids the reliability risks associated with single high-power converters. Each compensation circuit handles only its designated string, isolating potential failures.
Solution Approach 2:
The compensation circuits adjust voltage parameters of individual strings to optimize power extraction. By changing voltage parameters rather than relying on high-power conversion, the system achieves improved power harvesting with lower-stress components that have higher reliability.
3Loss of energy
If voltage-compensation circuits are added to each photovoltaic string, then power losses are reduced, but device complexity increases
Solution Approach 1:
The compensation circuit acts as an intermediary that adds minimal complexity by only compensating for voltage differences. Rather than completely redesigning the power processing architecture, it inserts a relatively simple compensation stage that reduces power losses without requiring major system changes.
Solution Approach 2:
The compensation circuits modify voltage parameters of individual strings to optimize power extraction. By making targeted parameter adjustments rather than complete system redesign, the solution reduces power losses with minimal added complexity.
4Productivity
If multiple DC-DC converters operate at high wattage levels, then maximum power point tracking is achieved, but installation and maintenance costs increase
Solution Approach 1:
The system segments the power processing function across multiple independent compensation circuits, each handling a portion of the total power. This segmentation enables maximum power point tracking for each string while using lower-wattage components that are cheaper to manufacture, install, and maintain.
Solution Approach 2:
Compensation circuits serve as intermediaries that reduce the power processing burden on main converters. By introducing this intermediate stage, the system achieves maximum power point tracking using lower-wattage components, reducing installation and maintenance costs.
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 maximizes overall power output while reducing the power rating and cost of converters, enhancing system reliability by allowing strings to operate at their maximum power points and minimizing power losses.
Implementation Method 1
Each string is connected in series with a voltage-compensation circuit. The voltage-compensation circuit adjusts the voltage output of each string
Implementation Method 2
A photovoltaic string includes a series-connection of photovoltaic panels
Data Source
Figure 1
Figure 2
Figure 3a
AI summary
A power harvesting system (30a) including multiple parallel-connected photovoltaic strings (109), each photovoltaic string (109) includes a series-connection of photovoltaic panels (101). Multiple voltage-compensation circuits (307) may be connected in series respectively with the photovoltaic strings (109). The voltage-compensation circuits (307) may be configured to provide respective compensation voltages (Vc) to the photovoltaic strings (109) to maximize power harvested from the photovoltaic strings (109). The voltage-compensation circuits (307) may be include respective inputs which may be connected to a source of power (Vs) and respective outputs which may be connected in series with the photovoltaic strings (109).