PV Module Voltage Balancing Circuit With Transformer Step-Up Control
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Solution Overview
Problem
Photovoltaic modules face challenges in maintaining consistent voltage output due to varying environmental conditions such as non-uniform illuminance from clouds, shadows, and debris, which affects the nominal output voltage across solar substrings.
Innovation Solution
A system comprising a power conversion circuit with a balancing section and a voltage control section, including windings and switches, that balances and modifies the voltage output across solar substrings using alternating polarity and modulation signals to maintain a target output voltage, employing maximum power point tracking techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If photovoltaic modules operate under varying environmental conditions (clouds, shadows, debris), then the nominal output voltage across solar substrings becomes inconsistent, but adding complex balancing circuitry increases device complexity
Solution Approach 1:
The solar array is divided into multiple substrings, each equipped with its own balancing circuit comprising switches and windings. This segmentation allows independent voltage balancing of each substring without affecting others, maintaining overall system reliability while keeping individual balancing circuits relatively simple.
Solution Approach 2:
The balancing circuit employs periodic switching of switches alternately connecting and disconnecting windings in series and parallel configurations. This periodic action dynamically adjusts voltage distribution across substrings, ensuring consistent output voltage without requiring complex continuous control mechanisms.
2Reliability
If voltage output is balanced across all solar substrings, then consistent energy delivery is achieved, but the system requires additional switches and windings increasing manufacturing complexity
Solution Approach 1:
The balancing circuit components (switches, windings, capacitors) serve multiple functions: they balance voltage across substrings, store electrical energy, and provide alternating current conversion capability. This multi-functionality reduces the need for separate dedicated components, simplifying manufacturing while ensuring consistent energy delivery.
Solution Approach 2:
The patent combines the balancing function with energy storage and voltage conversion functions into a single integrated circuit architecture. The windings serve both as balancing elements and as transformers for voltage conversion, while capacitors provide both filtering and energy storage, reducing overall component count and manufacturing complexity.
3Reliability
If alternating polarity switching is used to balance voltage, then voltage consistency is improved, but the switching control system becomes more complex
Solution Approach 1:
The controller monitors the voltage output of each substring and uses this feedback information to determine when and how to activate the balancing switches. This feedback mechanism enables simple binary switching decisions based on real-time voltage measurements, achieving stable voltage balance without complex control algorithms.
Solution Approach 2:
The balancing switches are controlled to operate periodically, alternately connecting and disconnecting windings in a predetermined sequence. This periodic switching pattern creates alternating polarity that balances voltage across substrings while simplifying control logic to basic timing-based switch activation rather than complex real-time calculations.
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 adjusts voltage output across solar substrings to maintain a target voltage, ensuring consistent energy delivery regardless of environmental conditions, thereby optimizing energy conversion and utilization.
Implementation Method 1
a first set of windings (132) arranged in parallel to a first set of solar substrings (110) and configured to balance voltage output across the first set of solar substrings (110)
Implementation Method 2
a first set of switches (135) coupled to the first set of solar substrings (110) and the first set of windings (132) and configured to alternate voltage polarity across the first set of windings (132)
Implementation Method 3
a second set of windings (142) arranged parallel to the first set of windings (132) and configured to step-up voltage across the first set of windings (132)
Implementation Method 4
a second set of switches (148) coupled to an output of the first set of solar substrings (110) and a fourth set of windings (147) and configured to alternate voltage polarity across the second transformer (145) to transfer energy to the output capacitor (150)
Data Source
AI summary
A system for balancing and converting voltage output from photovoltaic modules includes a set of solar substrings and a power conversion circuit. The power conversion circuit includes a balancing section configured to balance voltage output from the set of solar substrings. The power conversion circuit also includes a voltage control section including: a first transformer coupled to the set of solar substrings and configured to step-up voltage from the set of solar substrings; a second transformer arranged in series to the first transformer; and an output capacitor coupled to the second transformer. The system further includes a controller configured to: drive a set of modulation signals to the balancing section and the voltage control section; alternate voltage polarities across the first transformer and the second transformer; and modify output voltage of the power conversion circuit to a target output voltage.