Dynamically Reconfigurable Photovoltaic System for Adaptive Voltage
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Solution Overview
Problem
Energy harvesting photovoltaic (PV) systems in spacecraft and other applications face challenges in efficiently producing both low and high voltages, requiring separate voltage boost converters and struggling with inefficiencies when light sources are non-uniform or incoherent, such as laser beams, which can lead to reduced energy harvesting due to wandering light spots.
Innovation Solution
A dynamically reconfigurable PV system with sub-arrays of microsystem-enabled photovoltaic cells connected in series, parallel, or series-parallel configurations, along with programmable power management circuits and a power grid, allowing for adaptive voltage output and efficient energy harvesting regardless of light source coherence or position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a separate voltage boost converter is used to increase PV output voltage, then the required voltage levels can be achieved, but power efficiency decreases and heat dissipation problems arise
Solution Approach 1:
The patent implements a dynamically reconfigurable PV system where cell strings can be reconfigured between series and parallel connections based on operational requirements. This dynamic reconfiguration allows the system to natively produce different voltage levels without energy-lossy DC-DC conversion, directly resolving the contradiction between achieving required voltage levels and maintaining power efficiency.
Solution Approach 2:
The PV system is designed to perform multiple functions - it can operate in different configurations (series for high voltage, parallel for low voltage) to serve various power requirements. This multi-functionality eliminates the need for separate voltage boost converters, as the same PV array can adapt to different voltage needs, thereby maintaining power efficiency while achieving required voltage levels.
2Power
If traditional PV systems use fixed series connections to increase voltage, then voltage output is improved, but the system cannot adapt to wandering light spots or non-uniform illumination
Solution Approach 1:
The system employs dynamic reconfiguration capability that allows it to adapt its electrical connections in real-time based on illumination conditions. When light spots wander or illumination becomes non-uniform, the system can reconfigure cell strings between series and parallel connections to maintain optimal power extraction, directly addressing the adaptability issue while preserving voltage output capability.
Solution Approach 2:
The PV system is divided into multiple independently controllable cell strings that can be reconfigured. This segmentation allows different portions of the array to be optimized for different illumination conditions, enabling the system to adapt to wandering light spots by selectively connecting or disconnecting specific cell strings from the load.
3Power
If PV cells are connected in series to produce high voltage, then voltage output is increased, but the system loses flexibility in providing both low and high voltages simultaneously
Solution Approach 1:
The patent implements dynamic reconfiguration switches that allow cell strings to be connected in series for high voltage operation or in parallel for low voltage operation. This dynamic capability provides voltage configuration flexibility without requiring separate fixed circuits for different voltage levels, as the same hardware can adapt to different voltage requirements based on operational mode.
Solution Approach 2:
The system merges the functionality of multiple fixed voltage circuits into a single reconfigurable circuit. By combining series and parallel connection capabilities in one dynamic system, the patent achieves both high voltage and low voltage output capabilities without the complexity of maintaining separate fixed circuits for each voltage level.
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 reduces the need for separate voltage boost converters, enhances power efficiency, and maintains predetermined output voltage or power levels even with non-uniform light sources, improving energy harvesting efficiency and adaptability in various operational modes.
Implementation Method 1
dynamically reconfigurable energy harvesting photovoltaic (PV) system
Data Source
AI summary
A PV system composed of sub-arrays, each having a group of PV cells that are electrically connected to each other. A power management circuit for each sub-array has a communications interface and serves to connect or disconnect the sub-array to a programmable power grid. The power grid has bus rows and bus columns. A bus management circuit is positioned at a respective junction of a bus column and a bus row and is programmable through its communication interface to connect or disconnect a power path in the grid. As a result, selected sub-arrays are connected by selected power paths to be in parallel so as to produce a low system voltage, and, alternately in series so as to produce a high system voltage that is greater than the low voltage by at least a factor of ten.