Solar String Converter Topology for MPP Voltage Bucking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional string converters for solar PV systems face limitations such as reduced energy harvesting, diagnostic challenges at the module level, and regulatory voltage constraints, which restrict the number of modules that can be connected in a string, leading to higher costs and inefficiencies.
Innovation Solution
A novel string DC/DC converter operating at the Maximum Power Point (MPP) is introduced, allowing more modules per string by bucking open circuit voltages and maintaining efficient operation within regulatory voltage limits, thereby reducing the number of strings and combiner boxes needed, and enhancing energy harvesting and system efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional string converters are used with fixed voltage control, then the inverter can operate within regulatory voltage limits, but the number of modules per string is limited and energy harvesting is reduced
Solution Approach 1:
The patent implements dynamic voltage switching between series and parallel configurations based on operating conditions. The converter dynamically adjusts the connection topology of PV modules, switching between series connection (for higher voltage) and parallel connection (for lower voltage) to optimize energy harvesting while complying with regulatory limits, thereby resolving the contradiction between maximizing productivity and managing device complexity
Solution Approach 2:
The system changes the electrical parameters (voltage and current) by reconfiguring the module connections. By altering the connection configuration from series to parallel or vice versa, the system adapts to different operating conditions such as temperature variations and load requirements, enabling maximum power point tracking while maintaining compliance with voltage regulations
2Productivity
If more modules are added to increase power output, then energy harvesting improves, but the open circuit voltage exceeds regulatory limits
Solution Approach 1:
The patent employs dynamic reconfiguration of module connections that can switch between series and parallel arrangements. When more modules are needed to increase power output, the system dynamically switches to parallel configuration during operating conditions to keep the voltage within regulatory limits, thus allowing higher power output without violating voltage regulations
Solution Approach 2:
The system changes the electrical parameters by altering the connection topology. By switching from series to parallel connection, the voltage parameter is reduced while current increases, enabling the system to accommodate more modules for higher power output while maintaining compliance with regulatory voltage limits through parameter transformation
3Productivity
If series connection is used to increase voltage, then power output increases, but the wire size and inverter voltage rating must be increased
Solution Approach 1:
The patent implements dynamic switching between series and parallel module connections. Instead of permanently using series connection to increase voltage, the system dynamically switches to parallel configuration when high voltage is not required, thereby maintaining power output while reducing the requirements for wire size and inverter voltage rating, simplifying the overall system specifications
4Reliability
If parallel connection is used to reduce voltage, then regulatory compliance is achieved, but the number of modules per string is reduced
Solution Approach 1:
The patent utilizes parameter transformation by switching between series and parallel connections. The system uses parallel connection to reduce voltage for regulatory compliance, but compensates by enabling the addition of more module strings or by operating at maximum power point with optimized current, thereby maintaining or increasing the total number of modules deployed while ensuring regulatory compliance
Data Source
AI summary
The inventive technology, in certain embodiments, may be generally described as a solar power generation system with a converter, which may potentially include two or more sub-converters, established intermediately of one or more strings of solar panels. Particular embodiments may involve sweet spot operation in order to achieve improvements in efficiency, and bucking of open circuit voltages by the converter in order that more panels may be placed on an individual string or substring, reducing the number of strings required for a given design, and achieving overall system and array manufacture savings.