Noise Shielding Plate Positioning for Power Conversion Device
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Solution Overview
Problem
In power conversion devices for electrically driven vehicles, miniaturization leads to insufficient noise shielding, resulting in increased conduction noise due to the reduced distance between noise sources and control circuits.
Innovation Solution
A power conversion device design featuring a noise shielding plate with strategically positioned connection points to the metal housing, where the shielding plate extends further over the power module than the ground layer, effectively reducing noise coupling with the control circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the device is miniaturized to reduce size, then the device volume is reduced, but the noise shielding becomes insufficient and conduction noise increases
Solution Approach 1:
The noise shielding plate extends in the vertical direction (z-axis) beyond the ground layer in the horizontal plane, creating a three-dimensional shielding structure. This vertical extension provides additional noise shielding capability without increasing the horizontal footprint, thus reducing device volume while maintaining effective noise protection against conduction noise
Solution Approach 2:
The noise shielding plate acts as an intermediary element positioned between the power module (noise source) and the control circuit (sensitive component). By strategically positioning connection parts closer to the power module, the shielding plate intercepts and redirects noise currents before they can couple into the control circuit, effectively reducing conduction noise in the miniaturized device
2Volume of moving object
If the distance between noise source and control circuit is reduced for miniaturization, then the device volume is reduced, but the electromagnetic noise coupling increases
Solution Approach 1:
The noise shielding plate serves as a mediator that physically and electrically separates the noise source (power module) from the control circuit. Even when the overall device is miniaturized and components are closer together, the shielding plate maintains an effective noise barrier by extending beyond the ground layer and providing alternative current paths that prevent electromagnetic coupling
3Volume of moving object
If the arrangement space of noise shielding member is restrained, then the device volume is reduced, but the noise shielding effectiveness decreases
Solution Approach 1:
The noise shielding plate utilizes the vertical dimension by extending beyond the ground layer in the z-direction. This three-dimensional configuration provides effective noise shielding without requiring additional horizontal arrangement space, thus maintaining noise shielding effectiveness while accommodating device miniaturization constraints
Solution Approach 2:
The noise shielding plate features non-uniform connection part positioning, with connection parts strategically placed closer to the power module than the ground layer edges. This local variation in geometry optimizes the shielding effectiveness in the critical region near the noise source, ensuring reliable noise protection even with limited overall arrangement space
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 configuration significantly reduces conduction noise by directing noise currents away from the control circuit, enhancing noise shielding and allowing for more compact device designs.
Implementation Method 1
a noise shielding plate which shields noise from the power module
Implementation Method 2
a capacitor module which smooths a DC current from a DC power source
Data Source
AI summary
A power conversion device possesses a capacitor module, a power module, a circuit board on which a control circuit is mounted and which has a ground layer formed in a control circuit mounting region, a noise shielding plate, and a metal housing. The circuit board is above the capacitor module, and the noise shielding plate faces the control circuit mounting region between the circuit board and the capacitor module, in which the noise shielding plate has a plurality of connection parts to be electrically connected to the metal housing. A first end part on the power module side of the noise shielding plate is on the power module side more than a second end part on the power module side of the ground layer, and the connection part which is the closest to the first end part is provided on the power module side more than the second end part.