Solar Module String Switching for Open-Circuit Voltage Reduction
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Solution Overview
Problem
The existing solar systems are limited by the open circuit voltage, which restricts the length of strings of solar modules and results in higher balance-of-system costs due to the need for significant voltage headroom, leading to underutilization of the system's voltage rating.
Innovation Solution
Incorporating a current shunting device or switching circuitry that reduces the open circuit voltage by either shunting current or electrically decoupling modules during open circuit conditions, allowing for longer strings of solar modules and reducing the number of inverters required.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the string length of solar modules is increased, then the balance-of-system costs are reduced, but the open circuit voltage exceeds the system voltage rating
Solution Approach 1:
The patent extracts and removes excess voltage from the system by connecting solar modules in parallel configurations during open circuit conditions, thereby reducing the overall open circuit voltage to comply with system voltage ratings while maintaining longer string lengths for cost efficiency
Solution Approach 2:
The patent employs dynamic switching circuitry that automatically reconfigures the solar module connections between series and parallel arrangements based on real-time voltage measurements, enabling the system to adaptively maintain voltage within rated limits while optimizing string length
2Productivity
If the open circuit voltage is reduced to comply with voltage ratings, then longer strings can be used, but the system operates with significant voltage headroom during normal operation
Solution Approach 1:
The switching circuitry dynamically reconfigures module connections based on operational state, operating in series during normal conditions to utilize voltage headroom efficiently and switching to parallel configurations only when open circuit voltage exceeds ratings, thereby optimizing both string length and voltage utilization
Solution Approach 2:
The patent changes the electrical configuration parameters of the solar module strings, switching between series and parallel connections to optimize the balance between string length for cost reduction and voltage headroom for efficient operation
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 enables the design of longer strings of solar modules, reducing balance-of-system costs and optimizing the use of the system's voltage rating, with the open circuit voltage being reduced by 150-200 Volts or at least 5% in some embodiments.
Implementation Method 1
Photovoltaic cells, commonly known as solar cells, are well known devices for direct conversion of solar radiation into electrical energy
Implementation Method 2
Incorporating a current shunting device or switching circuitry that reduces the open circuit voltage by either shunting current
Data Source
AI summary
Devices for reducing the open circuit voltages of solar systems are described. In one embodiment, a solar system includes a string of a plurality of solar modules having an open circuit voltage. The solar system also includes a device for reducing the open circuit voltage of the string of the plurality of solar modules during an open circuit configuration.