Liquid Cooled Busbar for Power Module Thermal Management
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Solution Overview
Problem
High power density in power electronic applications has led to reduced space for heat sinks in power modules, necessitating an efficient cooling solution that also minimizes size and cost while avoiding electrical short circuits between components at different voltage levels.
Innovation Solution
A liquid cooled system comprising two current-carrying bars connected by an electrically non-conductive pipe, where one bar provides a first electric potential to the top of the power module and the other to the bottom, using an electrically conductive coolant with insulated channels to facilitate efficient heat exchange and reduce pressure drop, and integrated into a multilayer structure with embedded components for reduced parasitic inductance and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If power modules use high power density with wide band gap materials and increased switching frequency, then power density increases and passive component size reduces, but heat sink space becomes insufficient
Solution Approach 1:
The busbar is merged with the heat sink to form an integrated component that simultaneously performs electrical connection and thermal management functions. The busbar is directly coupled to the heat sink, eliminating the need for separate electrical connections and reducing overall module size while maintaining high power density
Solution Approach 2:
The busbar is designed to serve multiple functions: it provides electrical connection to the power semiconductor devices and simultaneously acts as a heat sink for thermal management. This multi-functional design reduces the number of separate components needed and optimizes space utilization in high power density applications
2Device complexity
If traditional busbars are used for electrical connection, then electrical connection is provided, but additional room is required and short circuit risk exists between bars at different voltage levels
Solution Approach 1:
An electrically insulating material is introduced between busbar segments at different voltage levels to prevent short circuits. The insulating material is integrated into the busbar structure, providing both mechanical support and electrical isolation, thereby reducing short circuit risk while maintaining compact design
Solution Approach 2:
The busbar is constructed using composite materials that combine conductive materials for electrical connection with insulating materials for electrical isolation. This composite structure allows different parts of the busbar to have different electrical properties, enabling safe operation at different voltage levels within a single integrated component
3Temperature
If liquid coolant with high electrical conductivity is used for cooling, then cooling efficiency increases, but short circuit risk between bars at different voltage levels increases
Solution Approach 1:
Electrically insulating layers are applied to the surfaces of the busbar channels that contact the liquid coolant. These insulating layers prevent electrical conduction through the coolant between bars at different voltage levels, allowing the use of highly conductive coolant without increasing short circuit risk
Solution Approach 2:
The busbar is designed with different electrical properties in different locations: the bulk material remains highly conductive for efficient current carrying, while the channel surfaces have insulating properties to prevent short circuits. This local differentiation of electrical quality allows simultaneous optimization of cooling efficiency and electrical safety
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 solution enables efficient cooling of power modules with reduced size and cost, increased heat exchange area, and minimized risk of short circuits, allowing for higher switching speeds and reduced switching losses while maintaining low inductance connections.
Implementation Method 1
the liquid cooled system is arranged to provide at least one electric potential to each power dies of the power module... the liquid coolant is electrically conductive and the channels surfaces are covered by an electrical insulation layer
Implementation Method 2
the channels being joint together by the pipe through which a liquid coolant flows... the heat exchange area is increased and the heat convection is increased between liquid coolant and cooler
Implementation Method 3
the liquid coolant is electrically conductive... the first bar provides a first electric potential to the power die and the second bar provides a second electric potential to the power dies
Data Source
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AI summary
The present invention concerns a system comprising at least one power module comprising at least one power die that is cooled by a liquid cooled system, the liquid cooled system is arranged to provide at least one electric potential to each power dies of the power module, characterized in that the liquid cooled system is composed of a first and a second current-carying bars connected together by an electrically nonconductive pipe, the first bar is placed on the top of the power module and provides a first electric potential to the power die and the second bar is placed on the bottom of the power module and provides a second electric potential to the power dies and the liquid coolant is electrically conductive and the channels surfaces are covered by an electrical insulation layer.