DC Link Capacitor Differential Winding for EMC
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Solution Overview
Problem
Intermediate circuit capacitors face issues with parasitic inductances, inhomogeneous switching current distribution, and unfavorable acoustic properties, which affect EMC behavior, energy losses, and overall device quality.
Innovation Solution
A differential winding structure for intermediate circuit capacitors, featuring multiple wound capacitors with first and second connection poles, connected via first and second current tapping elements, arranged in specific rows to ensure even current distribution and opposing current flows, minimizing electric fields and electromagnetic interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional capacitor designs are used, then manufacturing is simpler, but parasitic inductances increase and current distribution becomes inhomogeneous
Solution Approach 1:
The capacitor is divided into multiple wound capacitors arranged in rows, with each winding having specific connection pole arrangements. This segmentation allows current to be distributed across multiple paths, reducing parasitic inductance and achieving more homogeneous current distribution while maintaining manageable manufacturing complexity.
Solution Approach 2:
The first and second wound capacitors are arranged with asymmetric connection pole configurations - first connection poles on one side and second connection poles on the opposite side. This asymmetric arrangement creates opposing current flows that cancel electromagnetic fields, improving EMC behavior without requiring complete redesign of the manufacturing process.
2Loss of energy
If traditional capacitor arrangements are used, then device complexity is lower, but switching current distribution becomes inhomogeneous increasing energy losses
Solution Approach 1:
Different regions of the capacitor assembly serve different functions - first wound capacitors handle current in one direction while second wound capacitors handle current in the opposite direction. This local differentiation optimizes current distribution across the entire structure, reducing ohmic losses by ensuring uniform current density throughout all windings.
3Object-affected harmful factors
If conventional capacitor designs are used, then manufacturing is easier, but acoustic properties deteriorate due to unfavorable switching behavior
Solution Approach 1:
The winding configuration is designed in advance to create opposing current flows that generate counteracting acoustic vibrations. By arranging first and second wound capacitors with opposite current directions, the design preemptively cancels out acoustic noise before it propagates, reducing the need for additional acoustic encapsulation measures.
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 improved EMC compatibility, reduced ohmic losses, and enhanced acoustic properties by ensuring uniform current flow and canceling out electric fields, leading to a more efficient and cost-effective device performance.
Implementation Method 1
arranged in specific rows to ensure even current distribution and opposing current flows, minimizing electric fields and electromagnetic interference
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
The invention relates to a DC link capacitor (100), which comprises: a plurality of wound capacitors (10), which have a first connection pole (13) and a second connection pole (14); a first current-tapping element (20), by means of which the first connection poles (13) are contacted; and a second current-tapping element (30), by means of which the second connection poles (14) are contacted. First wound capacitors (11) of the wound capacitors (10) are arranged in a first row (1), the first wound capacitors (11) being oriented in such a way that the first connection poles (13) are arranged on a first side (3) and the second connection poles (14) are arranged on a second side (4) of the DC link capacitor (100), the first side (3) and the second side (4) being opposite sides, and second wound capacitors (12) of the wound capacitors (10) are arranged in a second row (2), the first row (1) and the second row (2) being arranged parallel to each other in a common plane, the second wound capacitors (12) being oriented in such a way that the first connection poles (13) are arranged on the second side (4) and the second connection poles (14) are arranged on the first side (3).