PV Substring Voltage Balancing Circuit for Uneven Illuminance
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Solution Overview
Problem
Photovoltaic modules face challenges in balancing and converting voltage output effectively, particularly under non-uniform environmental conditions such as varying illuminance, which can lead to decreased nominal output voltage and inefficient energy transfer.
Innovation Solution
A system comprising a power conversion circuit with multiple winding and switch configurations, along with a controller that alternates between charging and discharging states to balance and modify voltage output, using modulation signals to maintain a target voltage across solar substrings, and includes diodes to manage leakage inductance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If photovoltaic modules operate under non-uniform environmental conditions, then the system can adapt to varying illuminance, but the voltage output becomes unbalanced and nominal output voltage decreases
Solution Approach 1:
The patent changes the operating parameters of solar substrings by independently controlling their duty cycles in the power conversion circuit. This allows each substring to operate at optimized voltage levels despite non-uniform environmental conditions, maintaining voltage balance while adapting to varying illuminance.
Solution Approach 2:
The system dynamically adjusts the duty cycle of each solar substring based on real-time voltage measurements and environmental conditions. This dynamic control enables the system to maintain voltage balance and nominal output voltage while adapting to changing illuminance levels across different substrings.
2Device complexity
If conventional power conversion circuits are used, then the structure is simple, but energy transfer efficiency decreases under non-uniform conditions
Solution Approach 1:
The power conversion circuit is segmented into multiple independent power conversion units, each handling a specific solar substring. This segmentation allows each unit to optimize energy transfer for its assigned substring independently, improving overall energy transfer efficiency while maintaining manageable circuit complexity through modular design.
Solution Approach 2:
The controller pre-configures the duty cycle ranges and operational parameters for each power conversion unit based on expected environmental variations. This preliminary setup enables the system to respond more efficiently to actual conditions, reducing energy losses during transient states and improving overall energy transfer efficiency.
3Power
If solar substrings are connected in series to increase voltage, then the nominal output voltage increases, but voltage imbalance between substrings worsens under non-uniform conditions
Solution Approach 1:
The system dynamically adjusts the duty cycle of each solar substring individually, even though they are connected in series. This dynamic control compensates for voltage imbalances caused by non-uniform environmental conditions, maintaining stable voltage composition across all substrings while preserving the high nominal output voltage benefit of series connection.
Solution Approach 2:
The patent changes the operational parameters (duty cycle) of each solar substring independently within the series connection. This allows each substring to contribute its optimal voltage to the series string, maintaining both high nominal output voltage and voltage balance despite non-uniform environmental conditions.
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
The system effectively balances and modifies voltage output across photovoltaic modules to maintain a target voltage regardless of environmental conditions, enhancing energy transfer efficiency and stability.
Implementation Method 1
A system for balancing and converting voltage output for photovoltaic modules includes a power conversion circuit with multiple winding and switch configurations
Implementation Method 2
System for balancing and converting voltage output for photovoltaic modules
Data Source
AI summary
A system for balancing and converting voltage output from photovoltaic modules includes a set of solar substrings, a power conversion circuit, and a controller. The power conversion circuit includes: a set of windings coupled in series and arranged in parallel to the set of solar substrings; a set of switches coupled in parallel and interposed between the set of solar substrings and the set of windings; and an output switch coupled in series to a first switch, in the set of switches, and an output capacitor. The controller is configured to: oscillate states of the set of switches and the output switch at a first duty cycle; balance voltages output from the set of solar substrings across the set of windings to a nominal output voltage; and modify the nominal output voltage to a target voltage directed to the target load based on the first duty cycle.