Magnetically Shielded Refrigerant Pipe for Common Mode Noise
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Solution Overview
Problem
In refrigeration apparatuses using a refrigerant jacket to cool power devices, high frequency currents leak due to increased capacitance, leading to common mode noise issues when the refrigerant jacket is grounded, whereas air-cooling heat sinks do not suffer from significant noise due to lack of grounding.
Innovation Solution
A refrigeration apparatus with a refrigerant jacket thermally connected to a power device, where the refrigerant pipe forms current paths for grounding the jacket, and magnetic bodies are attached to these paths to increase impedance, reducing high frequency current leakage and common mode noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a refrigerant jacket is used to cool the power device, then cooling efficiency is improved, but high frequency current leakage and common mode noise increase due to grounding
Solution Approach 1:
A magnetic isolation component is introduced as an intermediary element between the refrigerant jacket and the refrigerant pipe. This component provides magnetic isolation to block the grounding path for high frequency currents, thereby reducing common mode noise while maintaining the cooling function of the refrigerant jacket
Solution Approach 2:
The impedance characteristics of the refrigerant pipe are modified by attaching a magnetic isolation component. This changes the electrical parameter (impedance) of the grounding path, creating sufficient impedance to high frequency currents to prevent noise propagation while allowing the cooling function to continue
2Reliability
If multiple refrigerant pipes are used for grounding the refrigerant jacket, then cooling reliability is improved, but the number of magnetic isolation components required increases
Solution Approach 1:
Multiple refrigerant pipes are merged into a single grounding path configuration. By providing a common grounding path with a single magnetic isolation component, the design maintains cooling reliability through multiple pipes while reducing component complexity by sharing the isolation function
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
The solution effectively reduces high frequency current leakage and common mode noise by increasing impedance in the refrigerant pipe paths, making the noise reduction reliable and efficient, while also simplifying manufacturing by potentially reducing the number of magnetic bodies required.
Implementation Method 1
a magnetic body (90) which is attached to the current path (20a, 20b), and generates a predetermined impedance in the current path (20a, 20b)
Implementation Method 2
a refrigerant jacket (30) which is thermally connected to the power device (14), and in which a refrigerant for a refrigeration cycle flows, the refrigerant flowing in the refrigerant jacket (30) cooling the power device (14)
Data Source
AI summary
A refrigeration apparatus includes: an electrical circuit (10) including a power device (14); a refrigerant jacket (30) which is thermally connected to the power device (14), and in which a refrigerant for a refrigeration cycle flows; a refrigerant pipe (20) which carries the refrigerant flowing in the refrigerant jacket (30), and forms a current path (20a, 20b) for grounding the refrigerant jacket (30); and a magnetic body (90) which is attached to the current path (20a, 20b), and generates a predetermined impedance in the current path (20a, 20b).