Voltage Clipping Circuit for PV Modules
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Solar energy systems face inefficiencies due to maximum voltage limitations, leading to overdesign and increased balance of system (BOS) costs, as well as potential damage from reverse bias and hot spots in series-connected solar cells, which reduce performance and increase costs.
Innovation Solution
The implementation of a parallel current path with switches and controllers to bypass or clip voltage from solar cells, reducing the voltage output without the need for energy storage elements, thereby minimizing electromagnetic interference and allowing for safer operation by preventing reverse bias and hot spots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If series-connected solar cells are designed to accommodate maximum voltage (VOC), then system safety and reliability are improved, but the number of modules per string is reduced and BOS costs increase
Solution Approach 1:
The patent applies dynamics by making the voltage limitation adjustable rather than fixed. The controller dynamically adjusts the voltage clipping threshold based on operating conditions, allowing the system to adapt between safety requirements and performance optimization. This resolves the contradiction by enabling the system to be safe when needed while maximizing modules per string during normal operation.
Solution Approach 2:
The patent changes the voltage parameter dynamically through the clipping circuitry. By adjusting the clipping threshold voltage based on operating conditions (temperature, irradiance, cell performance), the system can accommodate more modules per string when safe while maintaining reliability when voltage limits are approached. This parameter change approach resolves the fixed design compromise.
2Productivity
If series-connected solar cells operate at high voltage to maximize power output, then energy harvest is improved, but the risk of reverse bias and hot spots increases
Solution Approach 1:
The patent applies preliminary anti-action by proactively clipping the voltage before it reaches levels that would cause reverse bias or hot spots. The controller monitors cell voltage and activates the clipping circuitry in advance to prevent harmful conditions, rather than reacting after damage occurs. This allows high voltage operation for maximum energy harvest while preemptively preventing reverse bias damage.
Solution Approach 2:
The voltage clipping circuitry acts as an intermediary between the solar cells and the load. It mediates the voltage output, allowing high voltage for energy harvest while preventing the extreme voltages that would cause reverse bias. The circuitry serves as a protective intermediary that enables beneficial high-voltage operation while blocking harmful voltage excursions.
3Reliability
If voltage clipping is implemented using traditional energy storage elements, then voltage control is achieved, but electromagnetic interference increases
Solution Approach 1:
The patent extracts and removes the energy storage elements (inductors and capacitors) from the voltage control circuitry. By eliminating these components, the system achieves voltage control through a different mechanism (resistive clipping or electronic switching) that does not generate electromagnetic interference. This extraction resolves the contradiction by maintaining voltage control while removing the source of EMI.
Data Source
AI summary
A photovoltaic (PV) module can include a plurality of solar cells and circuitry configured to switch between a first state in which output voltage from the PV module includes voltage from the plurality of solar cells and a second state in which the output voltage includes voltage from fewer that all the plurality of solar cells.