Flexible Capacitor Connections for Power Electronics
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Solution Overview
Problem
Power electronic systems face challenges with high power losses and mechanical stresses due to rigid connections between DC link capacitors and switching modules, leading to overheating and uneven expansion of components.
Innovation Solution
A capacitor arrangement using flexible, electrically conductive connections, such as metal strips or films, with isolation media to connect DC link capacitors to switching modules, allowing for low-inductivity and adaptable connections that compensate for thermal expansion and mechanical stresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If rigid connections are used between DC link capacitor and switching module, then mechanical stability is improved, but mechanical stresses due to thermal expansion increase and power losses increase
Solution Approach 1:
The patent applies flexible connection elements (metal strips or films) instead of rigid connections to compensate for thermal expansion differences between the DC link capacitor and switching module. The flexible material can deform elastically to accommodate dimensional changes while maintaining electrical conductivity, thereby reducing mechanical stresses at the interfaces.
Solution Approach 2:
The patent changes the mechanical parameters of the connection elements from rigid to flexible by selecting materials with appropriate elastic properties. This allows the connection elements to dynamically adapt their shape and length in response to thermal expansion, maintaining mechanical stability while accommodating stress.
2Stability of the object's composition
If rigid connections are used between DC link capacitor and switching module, then connection stability is improved, but power losses increase due to high inductance
Solution Approach 1:
The flexible metal strips or films provide a low-inductance connection path due to their geometry and material properties. The direct, short connection path minimizes loop area, thereby reducing parasitic inductance and associated power losses during switching operations while maintaining connection stability.
Solution Approach 2:
The connection elements are designed with specific curved or bent geometries that optimize the current path to minimize loop area and inductance. The curvature is strategically designed to achieve low inductance while accommodating thermal expansion movements.
3Stress or pressure
If flexible connections are used between DC link capacitor and switching module, then mechanical stresses are reduced, but connection reliability may worsen
Solution Approach 1:
The flexible connection elements are made from high-conductivity, high-strength metals with appropriate elastic properties. These materials provide both flexibility to accommodate thermal expansion and sufficient mechanical strength to maintain reliable electrical connection under vibration and shock conditions.
Solution Approach 2:
The connection elements may utilize composite structures combining different metal layers or coatings to achieve optimal properties: high electrical conductivity, appropriate elasticity, oxidation resistance, and mechanical strength. This composite approach ensures both stress accommodation and connection reliability.
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 flexible connections reduce power losses, minimize mechanical stresses, and enable efficient cooling by allowing for a low-inductivity and mechanically stable connection between DC link capacitors and switching modules, improving the reliability and efficiency of power electronic systems.
Implementation Method 1
Not all of the components, however, warm up to the same extent. In addition, the different materials used expand to a varying degree. It is thus possible for mechanical stresses to result in the power electronic system
Implementation Method 2
The connection should preferably be implemented in a low-resistance and low-inductive manner and as short as possible, so that an overvoltage resulting at the power semiconductors during a switching operation remains small
Data Source
AI summary
The present invention provides a low-inductivity and mechanically stable connection between a DC link capacitor and a switching module for a power electronic system. To this end, the DC link capacitor and the switching module are connected to each other via an electrically conductive, flexible connection arrangement of electrically conductive strips or films. The individual strips or films are spaced from each other via suitable isolation media.