Two-Layer Laminated Busbar for NPC Power Converter
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Solution Overview
Problem
In NPC three-level power converters, stray inductance increases voltage stress on semiconductor components, reducing reliability and requiring complex and costly laminated busbar structures with multiple layers, which complicates manufacturing and increases costs.
Innovation Solution
A laminated busbar structure with two layers, where one layer connects to the neutral-point potential and the other layer connects to DC and AC inputs/outputs, providing mirror symmetry for current flow to reduce stray inductance and simplify manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple layers of laminated busbars are used to achieve complicated electrical connections in NPC three-level circuit, then the electrical connection capability is improved, but the manufacturing cost increases and the structure becomes more complex
Solution Approach 1:
The busbar structure is segmented into an upper busbar layer and a lower busbar layer, with each layer handling specific electrical connections. The upper layer connects to positive DC bus, negative DC bus, and AC buses, while the lower layer connects to neutral point and semiconductor components, dividing the complex electrical connection task into manageable segments.
Solution Approach 2:
The patent utilizes vertical stacking to create a three-dimensional busbar configuration, transitioning from planar two-dimensional connections to three-dimensional spatial arrangement. This allows multiple electrical connections to be achieved through vertical layering rather than horizontal expansion, reducing overall structural complexity.
2Adaptability or versatility
If multiple layers of laminated busbars are used to achieve complicated electrical connections, then the electrical connection capability is improved, but the manufacturing cost increases
Solution Approach 1:
The busbar system is divided into standardized upper and lower layers with defined connection functions. This segmentation allows for modular manufacturing where each layer can be produced and assembled independently, reducing overall manufacturing complexity and cost compared to creating a single complex multi-layer structure.
Solution Approach 2:
Each busbar layer is designed with specific local characteristics optimized for its function. The upper layer has connection configurations optimized for DC and AC buses, while the lower layer has configurations optimized for neutral point and semiconductor connections, allowing each layer to be manufactured with targeted quality standards rather than requiring all layers to meet maximum complexity requirements.
3Adaptability or versatility
If the layer number of busbars is increased to achieve more connections, then the electrical connection capability is improved, but the stray inductance increases due to increasing thickness of insulating layers
Solution Approach 1:
The patent extracts and eliminates unnecessary insulating layers between the upper and lower busbar layers. By carefully designing the configuration where the lower layer connects to neutral point and semiconductor components while the upper layer handles DC and AC connections, the patent removes redundant insulation that would otherwise increase thickness and stray inductance.
Solution Approach 2:
The patent transitions from increasing the number of vertical layers to optimizing the spatial arrangement within two functional layers. By utilizing horizontal spatial distribution of connections within each layer and optimizing the vertical distance between upper and lower layers, the patent achieves comprehensive electrical connections without proportionally increasing insulating layer thickness, thereby controlling stray inductance.
Data Source
AI summary
The present application discloses a laminated busbar arrangement for use in a three-level power converter and a power converter. The laminated busbar arrangement comprises a first layer of busbar comprising a neutral-point sub busbar configured to make electrical connections between respective components in the three-level power converter and a neutral-point potential; a second layer of busbar comprising a plurality of sub busbars configured make electrical connections between the respective components in the three-level power converter and a positive direct current (DC) input, a negative DC input and an alternating current (AC) input/output in the three-level power converter, and between respective semiconductor switching components. The present application may effectively reduce stray inductance.