Distributed Solar Inverter Architecture Using Deadband DC Waveforms
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Solution Overview
Problem
Current solar power generation systems face inefficiencies and high costs due to centralized string inverter systems, which are limited by weak modules, high voltage hazards, and inefficiencies in DC to AC conversion, while module-level architectures are costly and complex to install.
Innovation Solution
A solar power generation system utilizing distributed power converter nodes that convert DC power into a deadband DC waveform, which is then transmitted to a centralized grid interface box to produce AC power, reducing the need for extensive electronics and minimizing switching losses, and using power-with-Ethernet cables for efficient communication and synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If centralized string inverter systems are used to convert DC to AC power, then the system architecture is simplified and installation is easier, but switching losses increase and conversion efficiency decreases
Solution Approach 1:
The patent segments the inverter function by separating the DC-to-AC conversion (performed by centralized inverters) from the DC power conditioning (performed by module-level power converters). This segmentation allows each component to be optimized independently: module-level converters use low-voltage MOSFETs with minimal switching losses, while centralized inverters handle only the final AC conversion, reducing total system losses.
2Device complexity
If centralized string inverter systems are used, then fewer inverters are needed reducing component count, but the system becomes limited by the weakest module in the string reducing overall productivity
Solution Approach 1:
The patent implements module-level power converters that operate independently for each solar module or string, allowing each module to be optimized individually. This eliminates the 'weakest link' problem in centralized systems, as each module can operate at its maximum power point independently, increasing overall system productivity while maintaining manageable complexity through standardized modular units.
Solution Approach 2:
Each module-level power converter is optimized for local conditions at its specific module, allowing different modules to operate at different power levels based on their individual performance characteristics, shading conditions, and orientation. This local optimization ensures that no single module limits the performance of others in the string.
3Productivity
If module-level architectures are used with individual inverters for each module, then power generation efficiency is improved by avoiding the weakest module limitation, but system cost and installation complexity increase significantly
Solution Approach 1:
The patent segments the inverter function into two parts: simple DC power conditioning at module level (using low-cost, low-complexity converters with MOSFETs) and AC conversion at centralized level. This segmentation reduces module-level complexity compared to full microinverters, while still achieving the productivity benefits of module-level optimization.
Solution Approach 2:
The patent merges the advantages of module-level optimization with centralized AC conversion. Module-level power converters handle DC conditioning and synchronization, while centralized inverters handle AC conversion and grid interface functions. This merging reduces overall system complexity compared to fully distributed microinverter architectures.
4Device complexity
If conventional DC to AC conversion is used in centralized inverters, then system architecture is simplified, but high voltage hazards and arcing risks increase reducing safety
Solution Approach 1:
The patent segments the voltage transformation function: module-level power converters operate at low voltage (48V or lower) for DC conditioning, eliminating arcing hazards at the module level. Centralized inverters handle high voltage AC conversion, but only after receiving already-conditioned DC power. This segmentation isolates high voltage to a single centralized location with appropriate safety measures.
Solution Approach 2:
The module-level power converters act as intermediaries between the solar modules and centralized inverters. They condition the DC power at low voltage, converting it to a synchronized deadband waveform that is then transmitted to centralized inverters. This intermediary function reduces the voltage and energy available for arcing in the DC distribution system.
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 achieves improved efficiency and cost-effectiveness by reducing the need for costly electronics, minimizing switching losses, and enhancing safety through reduced arcing risks, while allowing for scalable and flexible power generation suitable for various applications.
Implementation Method 1
Solar panels are designed to use the photovoltaic effect to convert photons emitted by the sun into direct current (DC) power
Data Source
AI summary
A solar power generation system is provided for more efficiently and cost-effectively generating and delivering power. The solar power generation system includes a plurality of distributed power converter nodes each configured to convert DC power received from a solar module into a deadband DC waveform. The deadband DC power generated by each power converter node is then transmitted to a centralized grid interface box, which is configured to unfold the deadband DC waveform into an AC signal suitable for transmission to an electric power grid.