PCB-Less EMI Filter Layout for EV Traction Inverters
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Solution Overview
Problem
Electric vehicles generate electromagnetic interference (EMI) during the operation of power inverters, which can affect the performance and compatibility of other vehicle components.
Innovation Solution
An electromagnetic interference (EMI) filter is integrated within the inverter system controller housing, utilizing Y-capacitors and surface mount resistors without a printed circuit board, connected between the electric machine and battery to suppress EMI.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional EMI filter design with printed circuit board is used, then the EMI filtering function is achieved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent extracts and eliminates the printed circuit board from the EMI filter design. The filter components (capacitors, resistors, inductors) are mounted directly on the housing or chassis, removing the intermediary PCB layer and simplifying the overall device structure while maintaining EMI filtering functionality.
Solution Approach 2:
The patent merges the EMI filter components directly with the housing structure. The housing serves dual purposes as both structural enclosure and mounting substrate for filter components, combining previously separate functions into a unified structure that reduces complexity.
2Reliability
If a printed circuit board is used for EMI filter components, then electrical connections are established, but the manufacturing cost and assembly complexity increase
Solution Approach 1:
The printed circuit board is extracted and removed from the design. Electrical connections are established through direct mounting of components to the housing with solderless terminals or direct soldering to bus bars, eliminating PCB manufacturing and assembly costs.
Solution Approach 2:
The housing structure itself provides the mounting and connection functionality that would otherwise require a separate PCB. The housing serves as its own mounting substrate, eliminating the need for an additional component layer and reducing manufacturing steps.
3Reliability
If traditional EMI filter components are used, then EMI suppression is achieved, but the space occupied within the inverter housing increases
Solution Approach 1:
The EMI filter components are nested within the existing housing structure rather than occupying separate external space. Capacitors, resistors, and inductors are positioned in unused volumes and cavities within the housing, effectively utilizing available space without increasing overall device volume.
Solution Approach 2:
The filter components are merged with the housing structure, where the housing walls and internal structures serve as mounting surfaces and structural support, eliminating the need for separate filter housings and reducing total volume.
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 EMI filter effectively reduces interference, enhancing the operational efficiency and compatibility of the vehicle's power electronics and other components by minimizing electromagnetic noise.
Implementation Method 1
a capacitor disposed within and insulated from the housing
Implementation Method 2
a resistor having a first terminal connected to a terminal of the capacitor and a second terminal connected to the ground busbar
Data Source
AI summary
An inverter system controller for an automotive vehicle includes a housing and has disposed within the housing a Y-capacitor defining a terminal, a ground busbar, and a surface mount resistor in direct contact with the terminal and ground busbar to form an electromagnetic filter that lacks a printed circuit board.