Half-Bridge Busbar Coating for Compact Low-Inductance Inverters
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Solution Overview
Problem
Existing half-bridges and inverters for electric vehicles and hybrid vehicles require large distances between power connections and busbars to ensure electrical insulation, leading to a bulky design that contradicts the goal of compact electronic components in the automotive industry.
Innovation Solution
A half-bridge design where the busbar of the positive DC power connection and/or the negative DC power connection is at least partly covered by a current-isolating coating, extending the creepage path and ensuring reliable DC isolation, allowing for a reduced distance between busbars and a low-inductance inverter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If large distances are maintained between power connections and busbars to ensure electrical insulation, then DC isolation reliability is improved, but the inverter size and complexity increase
Solution Approach 1:
A coating layer is introduced as an intermediary between the positive and negative DC power connections. This coating extends the creepage path and provides additional insulation, enabling reliable DC isolation while reducing the physical distance between busbars and allowing for a more compact inverter design.
Solution Approach 2:
The insulation approach transitions from relying solely on spatial distance (one-dimensional separation) to utilizing a multi-dimensional solution that combines reduced spatial distance with an added coating dimension. This coating layer creates a new insulating dimension that compensates for the reduced distance, maintaining isolation reliability while enabling compactness.
2Reliability
If large distances are maintained between power connections and busbars to ensure electrical insulation, then DC isolation reliability is improved, but the inductance increases
Solution Approach 1:
The coating layer serves as a mediator that enables electrical insulation without requiring large distances. By providing the necessary creepage path extension and insulation properties, it allows the busbars to be positioned closer together, thereby reducing the loop area and minimizing inductance while maintaining DC isolation reliability.
3Volume of stationary object
If the distance between busbars is reduced to achieve compact design, then inverter size is reduced, but DC isolation reliability deteriorates
Solution Approach 1:
The coating layer acts as a compensating intermediary that makes up for the reduced distance between busbars. It provides the necessary creepage path extension and electrical insulation, ensuring that DC isolation reliability is maintained even when the physical distance between busbars is minimized for compact inverter design.
Solution Approach 2:
The solution changes the insulation parameter from relying on distance (spatial parameter) to relying on the coating layer properties (material parameter). By introducing the coating with appropriate thickness and material characteristics, the system achieves the required creepage path and insulation level without needing large busbar separations, thus enabling compact design while maintaining reliability.
4Use of energy by moving object
If the distance between busbars is reduced to achieve compact design, then inductance is reduced, but DC isolation reliability deteriorates
Solution Approach 1:
The coating layer serves as a mediator that decouples the relationship between distance and isolation reliability. It allows the system to achieve low inductance through reduced busbar distance while simultaneously maintaining DC isolation reliability through the coating's creepage path extension and insulation properties.
Solution Approach 2:
The solution transforms the insulation mechanism from a distance-dependent parameter to a material-dependent parameter. By specifying appropriate coating thickness and material properties, the system can minimize busbar distance for low inductance while ensuring sufficient creepage path and electrical insulation for reliable DC isolation.
Data Source
AI summary
A half-bridge having power connections and signal connections shaped from a leadframe, the signal connections electrically connected to semiconductor switching elements so that they can be switched by the signal connections, and the power connections are electrically connected to the switching elements in so that they switch an electrical power transmission between the power connections. The switching elements are embedded in a modular layer system including a contact-connection plane and a metallization for contact-connecting the switching elements, the signal connections and the power connections are arranged on a first surface of the substrate. The modular layer system, the signal connections and the power connections are potted with a potting compound, and external sections of the power connections and/or signal connections shaped in the leadframe extend out of the potting compound from a second surface orthogonal to the first surface, the external sections having ends that are perpendicular to the first surface.