Parallel Photovoltaic Modules on DC Bus
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Solution Overview
Problem
Existing photovoltaic systems with modules connected in series are inefficient because the least efficient module determines the overall efficiency, and each module requires a DC/AC converter, increasing complexity and cabling needs.
Innovation Solution
Photovoltaic modules are connected in parallel to a DC voltage bus, eliminating the need for individual DC/AC converters and reducing the impact of inefficient modules on overall efficiency, with a single inverter converting DC to AC for the mains grid, and using DC step-up converters and sensors for efficient voltage management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If photovoltaic modules are connected in series in a string, then the DC voltage is increased to match mains voltage levels, but the least efficient module determines the overall efficiency of the complete string
Solution Approach 1:
The patent divides the photovoltaic system into independent parallel-connected modules instead of series-connected modules. Each module operates independently and contributes its own current to the common DC voltage bus, so that the performance of one module does not constrain the others. This segmentation allows each module to operate at its own optimal efficiency point while collectively providing the required voltage level.
2Adaptability or versatility
If each photovoltaic module is provided with a DC/AC converter, then each module can independently convert DC to AC voltage, but the device complexity and cabling requirements increase significantly
Solution Approach 1:
The patent merges multiple independent DC/AC conversion functions into a single centralized inverter connected to a common DC voltage bus. Multiple photovoltaic modules in parallel feed their combined DC power to this single bus, which then connects to one inverter for AC conversion. This consolidation maintains the ability to convert DC to AC while dramatically reducing the number of converters and associated cabling infrastructure.
3Stress or pressure
If photovoltaic modules are connected in series, then the voltage adds up along the string, but inefficient modules reduce the total efficiency of the string
Solution Approach 1:
The patent creates a common DC voltage bus that acts as an equipotential reference for all parallel-connected photovoltaic modules. Each module operates at its own current level while contributing to the same voltage potential on the bus. This equipotential approach allows voltage accumulation without the efficiency penalties of series connections, as each module independently maintains its optimal operating point while collectively achieving the required 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
This configuration enhances overall efficiency by reducing the impact of inefficient modules, minimizes cabling, and allows for direct DC voltage supply to energy-demanding devices, improving operational simplicity and efficiency by up to 5%.
Implementation Method 1
a solar cell directly converting solar energy to electric energy
Implementation Method 2
DC step-up converters and sensors for efficient voltage management
Implementation Method 3
a single inverter converting DC to AC for the mains grid
Data Source
AI summary
An arrangement comprising at least a first photovoltaic module and a second photovoltaic module in a string is disclosed. The first photovoltaic module and second photovoltaic module are electrically connected in parallel and arranged to provide a DC voltage to a voltage bus. Also, an electrical connecting device configured for connecting to a photovoltaic module is disclosed. The electrical connecting device comprises first and second contacts for receiving a first DC voltage from the photovoltaic module and third and fourth contacts configured for electrically parallel connection to a DC voltage bus for providing a second DC voltage, dependent on the first DC voltage, to the DC voltage bus.