Capacitor Module Heat Dissipation Layout in Power Converters
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Solution Overview
Problem
In high-output-density power conversion devices, heat transfer from semiconductor power modules to capacitor elements via busbars leads to increased temperatures, reducing the lifespan of capacitor elements due to inadequate heat dissipation from the open-side electrode side and excessive heat reception from the semiconductor power module.
Innovation Solution
A power conversion device design featuring a capacitor module with a heat dissipation member connected to the sealing resin and located toward the opening side of the capacitor case, thermally connected to the power conversion device case, allowing efficient heat dissipation from both sides of the capacitor element, including the heat dissipation plate and the bottom wall of the device case.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If heat dissipation is improved from the bottom wall side only, then heat dissipation path is simplified, but heat dissipation from the open-side electrode side becomes insufficient
Solution Approach 1:
The heat dissipation function is segmented into two independent paths: one through the bottom wall to the heat dissipation member, and another through the open side to the semiconductor power module. This segmentation allows each path to optimize its own heat dissipation mechanism without interfering with the other, resolving the contradiction between structural simplicity and sufficient heat dissipation.
Solution Approach 2:
The invention transitions from single-direction (bottom wall only) heat dissipation to two-directional (bottom wall + open side) heat dissipation. By adding the open side as another dimension for heat dissipation, the system achieves more effective temperature control while maintaining reasonable structural complexity.
2Power
If high-output-density is achieved, then power conversion capability is improved, but heat generation and heat transfer to capacitor element increases
Solution Approach 1:
The heat dissipation member acts as an intermediary between the capacitor element and the cooling system. It provides a dedicated thermal pathway that mediates the heat transfer process, allowing heat to be efficiently removed from the capacitor element without requiring direct contact with the semiconductor power module, thus reducing harmful heat reception while maintaining high power capability.
Solution Approach 2:
The harmful heat transfer path from the semiconductor power module to the capacitor element is extracted and separated. By providing an independent heat dissipation path through the heat dissipation member, the invention removes the detrimental thermal coupling between high-power components and sensitive capacitive components, enabling high-output-density operation without compromising capacitor reliability.
3Ease of operation
If busbar thermal connection is used for heat dissipation, then electrical connection is maintained, but thermal resistance is high and heat dissipation efficiency is reduced
Solution Approach 1:
The electrical connection function and heat dissipation function are segmented into separate pathways. The busbar maintains electrical connection while the heat dissipation member provides a dedicated thermal pathway. This segmentation allows optimization of each function independently, reducing the thermal resistance penalty that would result from using the electrical connection path for heat dissipation.
Solution Approach 2:
The heat dissipation member serves as a thermal intermediary that provides a low-resistance heat transfer path independent of the electrical connection. This intermediary structure enables efficient heat dissipation without relying on the high thermal resistance busbar, thereby reducing energy loss while maintaining ease of electrical connection.
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 ensures uniform temperature distribution within the capacitor element, suppressing deterioration and improving heat dissipation efficiency, thereby extending the lifespan of the capacitor element.
Implementation Method 1
a heat dissipation member located toward an opening side of the capacitor case relative to the capacitor element and thermally connected to the sealing resin
Implementation Method 2
a cooler for cooling the semiconductor power module
Implementation Method 3
storing the capacitor element with sealing resin interposed therebetween
Data Source
AI summary
This power conversion device includes: a semiconductor power module including a module busbar; a capacitor module including a capacitor element, a capacitor case formed in a bottomed tubular shape and storing the capacitor element with sealing resin interposed therebetween and a capacitor busbar having one end electrically connected to the capacitor element and another end extending outward from the capacitor case and electrically connected to the module busbar; and a power conversion device case formed in bottomed tubular shape and storing the semiconductor power module and the capacitor module. An outer surface of a bottom wall of the capacitor case and an inner surface of a bottom wall of the power conversion device case are thermally connected to each other. The capacitor module has a heat dissipation member located toward an opening side of the capacitor case relative to the capacitor element and thermally connected to the sealing resin.