Electric Compressor Inverter PCB Slit for Noise Grounding Stability
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Solution Overview
Problem
Conventional electric compressors face distortion issues in circuit boards due to variations in fastening positions, which can lead to damage and conductivity failures, especially when busbar and housing fastening holes are close, and there is a need to reduce noise components effectively while maintaining a compact design.
Innovation Solution
An electric compressor design featuring a circuit board with a slit between fastening holes to reduce distortion and enhance creepage distance, combined with a noise reduction circuit that effectively absorbs noise components into the housing, using a configuration that includes a multilayer board, busbars, and filter circuits to manage power and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the busbar fastening holes and housing fastening holes are located close to each other on the circuit board, then the noise reduction effectiveness is improved and the compressor size is reduced, but the circuit board distortion increases due to variations in fastening positions
Solution Approach 1:
The circuit board is divided into multiple regions by introducing reinforcement ribs that extend from the back surface toward the front surface. These ribs create segmented support zones between adjacent fastening holes, allowing each region to independently accommodate fastening position variations without transmitting distortion across the entire board. This segmentation enables close spacing of fastening holes while maintaining circuit board stability.
Solution Approach 2:
Reinforcement ribs are strategically positioned in specific local regions between adjacent fastening holes where distortion is most likely to occur. The ribs provide localized structural support and stiffness exactly where needed, allowing the circuit board to maintain stability in critical areas while remaining flexible enough to accommodate manufacturing tolerances. This local quality enhancement resolves the contradiction by providing support only where it is most needed.
2Stability of the object's composition
If the circuit board is fastened with bolts to reduce distortion, then the structural stability is improved, but the circuit board may still distort due to variations in fastening positions within tolerance
Solution Approach 1:
Reinforcement ribs are pre-installed on the circuit board before fastening operations. These ribs act as cushioning elements that absorb and distribute the mechanical stress caused by fastening position variations. By providing this preliminary structural support, the ribs prevent distortion from propagating through the circuit board during the fastening process, accommodating manufacturing tolerances without compromising stability.
Solution Approach 2:
The circuit board employs a composite structure combining the base circuit board material with reinforcement ribs made of structurally enhanced material. This composite construction provides both electrical functionality and mechanical stability, allowing the board to withstand fastening forces while accommodating position variations within tolerance ranges.
3Stability of the object's composition
If the distance between busbar fastening holes and housing fastening holes is increased, then the circuit board distortion is reduced, but the noise reduction effectiveness decreases and the compressor size increases
Solution Approach 1:
The reinforcement ribs segment the circuit board into independent support zones, allowing fastening holes to be positioned close together without causing cumulative distortion. Each rib creates a localized support structure that prevents distortion propagation, enabling compact layout while maintaining stability.
Solution Approach 2:
Instead of increasing the distance between fastening holes in the planar dimension to reduce distortion, the invention adds structural support in the vertical dimension through reinforcement ribs. This dimensional approach allows close spacing of holes while maintaining stability through thickness-direction support.
Data Source
AI summary
An electric compressor includes an inverter portion that includes a circuit board, a busbar fixed to the inverter housing and connecting an external power supply to the circuit board, a noise reduction circuit mounted on the circuit board, a first fastener fastening the circuit board to the inverter housing, and a second fastener fastening the busbar to the circuit board. The circuit board includes a first fastening hole through which the first fastener is inserted, a second fastening hole that is disposed adjacent to the first fastening hole and through which the second fastener is inserted, and a slit extending between the first fastening hole and the second fastening hole from a peripheral edge of the circuit board. The first fastener electrically connects the circuit board as a ground of the noise reduction circuit to the inverter housing.