Half-bridge Switch Arrangement with Vertical Busbar Stacking
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Solution Overview
Problem
Half-bridge switch arrangements in power converters face challenges with high DC link inductance and thermal impedance, making it difficult to cool effectively at high currents and switching frequencies, especially with the use of discrete semiconductor switching elements.
Innovation Solution
A half-bridge switch arrangement with parallel-connected discrete semiconductor switching elements, a heat sink with a recess and plateau sections for efficient heat dissipation, and busbars arranged close to each other to reduce inductive resistance, using copper busbars or printed circuit board layers for low inductance and thermal impedance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If discrete semiconductor switching elements are used in parallel connection to achieve high power scalability and high current levels, then power scalability and current levels are improved, but DC link inductance and total inductance of the commutation loop increase
Solution Approach 1:
The patent transitions from a planar busbar arrangement to a three-dimensional configuration where busbars are stacked vertically with alternating polarity (positive, negative, positive, negative) and connected via vertical vias. This vertical stacking in the third dimension reduces the horizontal current path length and minimizes loop area, thereby reducing inductance while maintaining high current capacity through parallel semiconductor elements.
Solution Approach 2:
The patent implements a nested structure where multiple busbars are integrated within a compact PCB footprint. The busbars are embedded in alternating copper layers of the PCB, with connection vias nesting through multiple layers to create a compact, multi-layered current path that minimizes inductance while accommodating parallel semiconductor switching elements.
2Power
If discrete semiconductor switching elements are used in parallel connection to achieve high current levels, then current levels are improved, but cooling difficulty increases due to high thermal impedance
Solution Approach 1:
The patent merges the electrical connection function and thermal management function into a single integrated structure. The busbars serve dual purposes: electrical connection between semiconductor elements and heat dissipation pathways. The low-inductance busbar design with vertical via connections provides direct thermal conduction paths from semiconductor junctions to external heat sinks, reducing thermal impedance while maintaining high current capacity.
Solution Approach 2:
The busbar structure performs multiple functions simultaneously: electrical connection, current distribution, and thermal conduction. The alternating polarity busbar arrangement creates efficient current loops while the vertical via connections provide direct thermal pathways to heat sinks, enabling the same structure to handle both electrical and thermal management for parallel semiconductor elements.
3Device complexity
If busbars are arranged close to each other to reduce inductive resistance, then inductance is reduced, but thermal management becomes more challenging
Solution Approach 1:
The patent resolves the thermal management challenge by moving heat dissipation to the vertical dimension. While busbars are arranged close together horizontally to minimize inductance, vertical vias provide direct thermal conduction paths from the busbar-current intersection points down to external heat sinks, separating the inductance optimization (horizontal arrangement) from thermal management (vertical heat pathways).
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 solution achieves low intermediate circuit inductance and thermal impedance, enabling effective cooling and high power scalability while maintaining low costs, allowing the switch arrangement to operate at high speeds and maintain desired junction temperatures.
Implementation Method 1
The heat sink has a recess or notch or groove and a first and a second plateau section or plateau area that are raised relative to the recess, with the recess being bounded by the first and the second plateau section... an outer surface of the individual semiconductor switching elements is expediently in thermal contact with the upper side of one of the plateau sections
Implementation Method 2
the heat sink can be fluid-cooled and have an inlet and outlet for a corresponding cooling fluid. The cooling fluid can comprise oil, water, air, etc.
Data Source
AI summary
A half-bridge switch arrangement has a high-side switch having a plurality of parallel-connected first semiconductor switching elements, a low-side switch having a plurality of parallel-connected second semiconductor switching elements, a positive busbar, to which a terminal of each of the first semiconductor switching elements of the high-side switch is electrically connected, a negative busbar, to which a terminal of each of the second semiconductor switching elements of the low-side switch is electrically connected, and a heat sink, the heat sink having a recess and two plateau sections which are located in an elevated position relative to the recess, the recess being bounded by the two plateau section, wherein the first semiconductor switching elements and the second semiconductor switching elements are arranged on an upper side of the two plateau sections, wherein the positive busbar and the negative busbar are arranged one above the other within the recess.