Refrigerant Circuit Module Housing Layout for EMC Noise Control
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Solution Overview
Problem
The direct fixation of a stator to the housing in a refrigerant circuit module leads to a wide conduction noise loop, degrading electromagnetic compatibility (EMC) characteristics due to electrical noise flowing through the vehicle body ground, necessitating measures to insulate contact portions.
Innovation Solution
A refrigerant circuit module design with a coupler holding a second housing in a first housing space without contact, directing electrical noise through a small conduction noise loop via a first noise path to a shielded connector, reducing noise flow to the vehicle body ground.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the stator is directly fixed to the housing inner wall surface, then the structure is simple and easy to manufacture, but a wide conduction noise loop is formed degrading EMC characteristics
Solution Approach 1:
The housing is divided into a first housing and a second housing that are separated by a coupler. The stator is fixed to the second housing, not directly to the first housing, which segments the noise conduction path and prevents direct contact between the stator and the first housing, thereby reducing the conduction noise loop area.
Solution Approach 2:
A coupler is introduced as an intermediary component between the first housing and the second housing. The coupler holds the second housing in the first housing space without direct contact, acting as a mediator that prevents electrical noise from flowing directly through the housing, thus improving EMC characteristics.
2Object-affected harmful factors
If extensive insulation measures are taken to block noise paths, then EMC characteristics improve, but device complexity increases
Solution Approach 1:
The harmful noise conduction path is extracted and redirected to a dedicated shielded path. Instead of blocking noise paths with extensive insulation, the electrical noise is directed through a specific noise path to a shielded connector, which handles the noise externally, thereby improving EMC without adding complex insulation measures.
Solution Approach 2:
A shielded connector is introduced as an intermediary to handle electrical noise. The shielded connector provides a dedicated path for noise conduction that is isolated from sensitive circuits, allowing EMC improvement without requiring extensive insulation throughout the device.
3Object-generated harmful factors
If a large conduction noise loop is formed, then electrical noise flows through the vehicle body ground, but if the loop is reduced, then noise flow to ground is minimized
Solution Approach 1:
The conduction noise loop is segmented into separate sections by dividing the housing into first and second housings held apart by a coupler. This segmentation breaks the direct electrical path, forcing noise to travel through a shorter, controlled path to the shielded connector, thereby minimizing the overall loop length and noise flow.
Solution Approach 2:
The noise conduction path is extracted from the main housing structure and redirected to a dedicated shielded path. By taking out the noise path and directing it through the shielded connector, the effective noise loop length is reduced, minimizing electromagnetic interference.
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
Improves EMC characteristics by limiting noise flow to a small conduction noise loop, reducing the need for extensive insulation and allowing for a downsized electrical filter.
Implementation Method 1
A first noise path, which extends from the second housing to the shield of the connector via the coupler, the first housing and the outer wall surface of the drive device, may be configured to conduct the electrical noise generated by the electric motor.
Data Source
AI summary
A refrigerant circuit module configured to compress a refrigerant includes an electric motor, a first housing, a second housing, a coupler, a drive device and a connector. The second housing receives the electric motor and is disposed in the first housing. The coupler is securely held relative to both a first inner wall surface of the first housing and a second outer wall surface of the second housing. The drive device is configured to drive the electric motor and is positioned on a first outer wall surface of the first housing. The connector is coupled to the drive device and includes a shield. A first noise path extends from the second housing to the shield via the coupler, the first housing and the outer wall surface of the drive device to conduct the electrical noise generated by the electric motor.