DC Link Capacitor Module Layout for Eddy Current Heat Reduction
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Solution Overview
Problem
Existing intermediate circuit capacitor modules in electric vehicles face challenges in achieving a compact design while maintaining improved thermal performance and reducing heat generation due to eddy current effects and current load.
Innovation Solution
The solution involves a DC link capacitor module with series-connected windings, a center tap, and a shielding plate thermally connected to a base plate, which dissipates eddy currents and reduces heat load, combined with oval cross-section windings for increased packing density and alternating current flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the DC link capacitor is designed to be compact, then the inverter size is reduced, but thermal performance deteriorates and heat generation increases
Solution Approach 1:
The DC link capacitor is divided into multiple windings (first winding, second winding, etc.) connected in series with center taps. This segmentation allows for better thermal management by distributing heat generation across multiple smaller units, each with its own cooling path to the base plate, thereby improving overall thermal performance while maintaining compact size.
Solution Approach 2:
The patent introduces a vertical stacking arrangement where windings are positioned at different heights above the base plate, with connecting plates and shielding plates creating a multi-layer structure. This three-dimensional configuration optimizes space utilization and thermal conduction paths, allowing heat to dissipate efficiently through the base plate while maintaining a compact footprint.
2Reliability
If connecting plates are used to connect windings, then electrical connection is achieved, but eddy current effects increase causing heat load
Solution Approach 1:
Shielding plates are introduced as intermediary elements between the connecting plates and the windings. These shielding plates serve multiple functions: they provide electrical connection continuity while blocking eddy currents from forming in the connecting plates, and they conduct heat away from the windings to the base plate, thereby reducing eddy current losses and heat generation.
Solution Approach 2:
The patent converts the potentially harmful eddy current effects into beneficial thermal management. The shielding plates, which could be sources of eddy currents, are instead designed to conduct heat away from the windings efficiently. The eddy current paths are controlled and directed through the shielding plates to the base plate, transforming energy loss into useful heat dissipation.
3Volume of moving object
If windings are arranged closely to reduce size, then compact design is achieved, but capacitive leakage currents increase
Solution Approach 1:
The patent employs asymmetric arrangement of windings with alternating polarity connections to adjacent connecting plates. This asymmetric configuration creates symmetrical current flow paths that balance electromagnetic fields, reducing capacitive leakage currents. The alternating connection pattern ensures that adjacent windings with opposite polarities are positioned symmetrically relative to the connecting plates, minimizing leakage.
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 achieves a compact inverter with reduced heat loss, minimized current paths, and symmetrical current flow, allowing for a smaller DC link capacitor and reduced capacitive leakage currents, thus enhancing thermal performance and efficiency.
Implementation Method 1
The shielding plate is thermally and electrically connected to a base plate. This effectively dissipates eddy current effects caused by the close current flow through the connecting plates to the base plate, thus reducing the resulting heat load in the windings.
Implementation Method 2
The shielding plate is thermally and electrically connected to a base plate... The base plate is preferably in thermal contact with, or incorporates, a coolant circuit.
Implementation Method 3
The base plate is preferably in thermal contact with, or incorporates, a coolant circuit.
Data Source
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AI summary
The invention relates to a DC link capacitor module (1) for an inverter (100), wherein the DC link capacitor module (1) has at least two windings (2) connected in series and having a central tap, wherein the windings (2) are connected to connecting plates (5, 6), wherein a first connecting plate (5) has terminals (7) for a positive contact (DC+) and terminals (8) for semiconductor switches (17) of the inverter (100), and the second connecting plate (6) has terminals (9) for a negative contact (DC-) and terminals (10) for semiconductor switches (17), wherein the windings (2) have a first end face (3) and a second end face (4) each with a contact, wherein the DC link capacitor module (1) has at least one shielding plate (19) arranged between the connecting plates (5, 6) and the outer surfaces of the windings (2).wherein the second end faces (4) of the adjacent windings (2) are connected to the shielding plate (19), wherein the first end faces (3) are connected to the connecting plates (5, 6), wherein the shielding plate (19) is thermally and electrically connected to a base plate (14), and an inverter (100) with such an intermediate circuit capacitor module (1).