Trunk Bus Connector Layout for Reliable Solar String Connections
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Solution Overview
Problem
Conventional methods for connecting solar panels to inverters are labor-intensive, prone to low-quality and inconsistent connections, and require extensive maintenance, especially with high-wattage solar panels, which increase costs and limit the number of trackers due to DC loss requirements.
Innovation Solution
A trunk bus system that eliminates the need for combiner boxes by using a trunk bus feeder made of 2 kV aluminum photovoltaic wire, allowing for efficient electrical connection of solar panels to inverters with a single, less-than-90-degree bend, reducing wire breaks and installation complexity, and accommodating larger sizes to support more trackers while maintaining DC loss requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional combiner box connection methods are used, then electrical connections can be established, but installation becomes labor-intensive and connection quality becomes inconsistent
Solution Approach 1:
The system segments the electrical connection architecture by replacing the centralized combiner box with distributed trunk bus connections. Each solar string connects independently to the trunk bus at multiple points along its length, dividing the connection function into modular segments rather than requiring convergence at a single location. This segmentation simplifies installation by eliminating complex combiner box assembly while maintaining reliable electrical connections.
Solution Approach 2:
The trunk bus acts as an intermediary element between solar strings and the inverter. Instead of directly connecting multiple solar strings to the inverter through combiner boxes, the trunk bus serves as a intermediate conductor that collects power from multiple strings along its length and delivers it to the inverter. This intermediary approach simplifies the connection architecture and improves installation ease while maintaining connection reliability.
2Loss of energy
If thick trunk bus cables are used to carry electricity from multiple solar panels, then DC loss requirements are met, but the number of trackers is limited
Solution Approach 1:
The system transitions from a single-point connection architecture to a distributed multi-point connection architecture along the trunk bus. By allowing solar strings to connect at multiple locations along the length of the trunk bus rather than at a single endpoint, the system effectively adds a spatial dimension to the electrical connection. This dimensional change enables better current distribution and reduced DC losses without requiring excessively thick cables, thereby increasing tracker capacity.
Solution Approach 2:
The system changes the electrical parameters along the trunk bus by distributing connection points at optimized intervals. This parameter change in connection distribution allows the trunk bus to maintain lower current density throughout its length, reducing I²R losses without requiring increased cable size. Consequently, the system can support more trackers while meeting DC loss requirements.
3Reliability
If copper string wire is used extensively, then electrical connections are reliable, but material costs increase
Solution Approach 1:
The aluminum trunk bus serves multiple functions simultaneously: it acts as the current collector from solar strings, provides mechanical support for connection points, serves as the main feeder to the inverter, and enables distributed connection architecture. This multi-functionality reduces the need for separate copper string wires at each connection point, lowering material costs while maintaining connection reliability through the robust aluminum trunk bus structure.
Solution Approach 2:
The system replaces expensive copper string wires with a standardized aluminum trunk bus that can be replicated and installed using consistent connection methods. By using the aluminum trunk bus as a universal connection medium that can serve multiple solar strings, the system eliminates the need for individual copper wire runs to each string, significantly reducing material costs while maintaining reliable electrical connections through standardized connection procedures.
Data Source
AI summary
A trunk bus connector for electrically coupling one or more branch cables to a trunk line may comprise a junction area where one or more stripped portions of the branch cable(s) can be secured against a stripped portion of the trunk line. The trunk bus connector may comprise an overmold substantially encapsulating the junction area and comprising a trunk line pathway to enable the trunk line to pass through the junction area. The overmold may comprise one or more branch entry pathways to enable the branch cable(s) access into the junction area. Each branch entry pathway may be angled with respect to the trunk line pathway such that the branch cable(s) enter into the junction area such that an angle at which each branch cable approaches the trunk line is between approximately 30 and 50 degrees.