In-Vehicle Power Conversion System Shielding via GND Plane
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Solution Overview
Problem
In-vehicle power conversion systems face challenges in reducing size and cost while effectively shielding against high-frequency noise, which leads to increased component count, weight, and heat dissipation issues, as well as constraints in design freedom and productivity.
Innovation Solution
The use of a conductive housing with a multilayer printed wiring board having a GND plane that forms closed spaces to shield circuit units without additional shield members, allowing for independent GND planes for each space and reducing noise interference, thereby minimizing component count and size while improving heat dissipation and design flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional shield cases are used to shield circuit units from noise, then noise shielding effectiveness is improved, but the number of components increases and device complexity increases
Solution Approach 1:
The patent merges the shield case structure with the printed wiring board by integrating circuit units directly onto the PWB, eliminating the need for separate shield cases. The PWB itself serves as both the mounting substrate and the shielding structure, reducing component count while maintaining noise shielding effectiveness through the conductive nature of the board and its ground planes.
Solution Approach 2:
The printed wiring board is designed to serve multiple functions simultaneously: it acts as the mounting substrate for circuit units, provides electrical connections through its circuit traces, and functions as a shield case to protect against noise. This multi-functionality eliminates the need for dedicated shield cases while maintaining all necessary protective and functional capabilities.
2Object-affected harmful factors
If traditional shield cases are used to shield circuit units, then noise shielding is improved, but weight increases
Solution Approach 1:
By combining the shield case function with the printed wiring board structure, the patent eliminates the need for additional heavy shield case materials. The PWB, being a lightweight composite material, provides sufficient shielding capability without the extra weight that would result from adding separate metallic shield cases.
3Volume of moving object
If switching frequency is increased to reduce transformer and reactor size, then device size is reduced, but conductive noise and radiation noise increase
Solution Approach 1:
The patent converts the harmful high-frequency noise generated by increased switching frequency into a beneficial shielding effect. By designing the printed wiring board with integrated shielding structures and ground planes, the noise energy is contained and directed away from sensitive circuits, transforming the noise problem into an opportunity to demonstrate the effectiveness of the integrated shielding design.
Solution Approach 2:
The printed wiring board serves as an intermediary structure between the power system circuit and control circuits. It provides a controlled impedance path and shielding that mediates the interaction between noisy power switching and sensitive control signals, allowing high-frequency operation while protecting against noise interference.
4Volume of moving object
If switching frequency is increased to reduce component size, then device size is reduced, but heat dissipation becomes more difficult
Solution Approach 1:
The patent merges the heat dissipation function with the printed wiring board structure by providing direct thermal pathways from circuit units through the PWB to heat sinks or cooling structures. The integrated design allows efficient heat transfer without requiring additional heat dissipation components, maintaining compact size while managing thermal loads from high-frequency switching.
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 solution reduces the number of components, lowers costs, and enhances productivity by eliminating the need for separate shield members, while effectively shielding circuit units and improving heat dissipation, thus addressing the constraints of size reduction and heat management.
Implementation Method 1
the GND plane of the multilayer printed wiring board is electrically connected to the conductive housing to shield the circuit unit stored in the closed space surrounded by the conductive housing and the multilayer printed wiring board
Data Source
AI summary
An in-vehicle power conversion system, which can shield a circuit unit without using a particular shield member and can achieve reduction in cost and size, is obtained. Included are: a conductive housing having an opening; and a multilayer printed wiring board in which circuit units are mounted and one layer is a GND plane. The multilayer printed wiring board is assembled to an opening surface of an opening of the conductive housing to form a closed space; and the GND plane of the multilayer printed wiring board is electrically connected to the conductive housing to shield the circuit units stored in the closed space surrounded by the conductive housing and the multilayer printed wiring board.