Continuous DC Busbar Layout for EV Inverter Power Modules
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Solution Overview
Problem
Existing power modules for electric and hybrid vehicle inverters face challenges in heat dissipation and design complexity due to high current density in DC busbars, leading to increased power losses and manufacturing costs.
Innovation Solution
A power module design where the DC busbars are formed in one piece continuously along multiple half-bridges, reducing current density and eliminating the need for active cooling of the intermediate circuit capacitor, thereby simplifying the design and reducing heat generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If DC busbars are designed with separate segments for each half-bridge, then manufacturing flexibility and scalability are improved, but current density increases and heat dissipation becomes more difficult
Solution Approach 1:
The patent merges the DC busbars into a single continuous piece that spans multiple half-bridges, eliminating the need for separate segmented busbars. This consolidation reduces the total number of connections and contact resistances, thereby reducing power losses while maintaining manufacturing flexibility through the unified design.
2Loss of energy
If DC busbars are formed continuously along multiple half-bridges, then current density is reduced and heat generation is minimized, but manufacturing complexity increases
Solution Approach 1:
The continuous DC busbar serves multiple functions simultaneously: it provides electrical connectivity across multiple half-bridges, acts as a heat sink for intermediate circuit capacitors, and eliminates the need for separate cooling structures. This multi-functionality reduces overall design complexity while maintaining low heat generation.
Solution Approach 2:
The patent extracts the cooling function from separate active cooling systems and integrates it into the DC busbar structure itself. The continuous busbar design naturally dissipates heat from intermediate circuit capacitors through thermal conduction, eliminating the need for additional active cooling components and simplifying the overall design.
3Temperature
If intermediate circuit capacitor is actively cooled, then temperature control is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The intermediate circuit capacitor utilizes the DC busbar as a passive heat sink, allowing it to self-regulate temperature through thermal conduction without requiring active cooling systems. The busbar's large surface area and good thermal conductivity naturally dissipate heat from the capacitor, eliminating the need for fans, pumps, or temperature sensors.
Solution Approach 2:
The DC busbar acts as a thermal intermediary between the intermediate circuit capacitor and the environment. It conducts heat away from the capacitor and dissipates it through its extended structure, providing passive thermal management without requiring additional active cooling components.
4Adaptability or versatility
If segmented DC busbars are used for each half-bridge, then scalability and modularity are improved, but connection points and contact resistances increase
Solution Approach 1:
The patent combines multiple half-bridge connections into a single continuous DC busbar structure, reducing the number of connection points from multiple segmented joints to fewer welds or connections. This reduces total contact resistance and simplifies the manufacturing process while maintaining the ability to scale by extending the continuous busbar length.
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
This design reduces heat generation in the intermediate circuit capacitor, allowing for a simpler and more cost-effective manufacturing process while maintaining efficient electrical connectivity and isolation, thus enhancing the overall performance and reliability of the inverter.
Implementation Method 1
A first DC busbar is electrically connected to the positive DC power connection. A second DC busbar is electrically connected to the negative DC power connection.
Implementation Method 2
the DC busbars are formed in one piece continuously along multiple half-bridges, reducing current density and eliminating the need for active cooling of the intermediate circuit capacitor, thereby simplifying the design and reducing heat generation.
Data Source
AI summary
A power module includes a plurality of half-bridges, each including a substrate, a plurality of semiconductor switching elements, a positive DC power connection, a negative DC power connection, an AC power connection and a plurality of signal connections, wherein a respective DC busbar is connected to the respective DC power connection, wherein the two DC busbars extend from the half-bridges up to an intermediate circuit capacitor, wherein at least one of the two DC busbars is formed in one piece outside of the intermediate circuit capacitor with respect to the plurality of half-bridges.