Inverter Module Electromagnetic Shielding for Noise Interference
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Solution Overview
Problem
Integrated-inverter electric compressors for vehicle air-conditioners face noise interference and leakage due to directly accommodated high-voltage smoothing capacitors, which radiate electromagnetic noise affecting the power and control boards, leading to malfunction and size/weight challenges.
Innovation Solution
An inverter module with a resin module case, power, and control boards, where the smoothing capacitor is electromagnetically shielded by a metal case and connected to a ground earth terminal, preventing noise propagation and leakage by grounding the noise current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the smoothing capacitor is directly accommodated in the inverter module, then the inverter device can be made compact and assembly simplified, but the smoothing capacitor radiates electromagnetic noise causing interference and malfunction
Solution Approach 1:
A metal shielding case is introduced as an intermediary between the smoothing capacitor and the control board/power system board. This shielding case blocks electromagnetic noise from the capacitor while still allowing the capacitor to be integrated within the compact inverter module structure.
2Volume of moving object
If the smoothing capacitor is directly accommodated in the inverter module, then the inverter device can be made compact and assembly simplified, but the electromagnetic noise leaks out through control communication cable or power cable affecting other electric components
Solution Approach 1:
The metal shielding case acts as a mediator that contains electromagnetic noise within the inverter module, preventing it from leaking out through cables. The shielding case is connected to ground to provide a path for noise current, isolating the noise within the bounded shielding structure.
3Object-affected harmful factors
If electromagnetic shielding is added to block noise from the smoothing capacitor, then noise interference is reduced, but the device complexity increases
Solution Approach 1:
The electromagnetic shielding function is merged with the structural housing by forming the shielding case as an integrated component that combines noise blocking with mechanical support and mounting functions, reducing overall device complexity.
Solution Approach 2:
A thin metal shielding case is used to block electromagnetic noise while occupying minimal space within the inverter module, adding noise protection functionality without significantly increasing device complexity or size.
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 blocks electromagnetic noise, prevents malfunction, and reduces the size and weight of the inverter device, enhancing reliability and ease of installation by integrating the smoothing capacitor and shielding it within the module case.
Implementation Method 1
the smoothing capacitor is electromagnetically shielded by a metal case surrounding an outer periphery of the smoothing capacitor
Implementation Method 2
the metal case is connected to a ground terminal formed integrally with the module case by insert molding
Data Source
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AI summary
An inverter module and an integrated-inverter electric compressor using the same, which can eliminate noise interference, noise leakage, and the like attributable to a smoothing capacitor accommodated therein and which can be reduced in size and weight is provided. An inverter module (11) includes a resin module case (17); a power system board (15) provided on a bottom side of the module case (17); and a control board (19) provided on an upper side of the module case (17). A smoothing capacitor (18) connected to a power supply line for the power system board (15) is incorporated into the module case (17), and the smoothing capacitor (18) is electromagnetically shielded with respect to the power system board (15) and the control board (19).