Electric Motor Control Board Filter Layout for EMI Reduction
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Solution Overview
Problem
Existing electric rotating machine apparatuses require dedicated wiring boards and circuit-supporting structures for noise filters, hindering downsizing and increasing costs, particularly in electric power steering apparatuses.
Innovation Solution
An electric rotating machine apparatus with a control unit and electromagnetic shield that integrates a filter outside the shield's through hole, eliminating the need for dedicated wiring boards and circuit-supporting structures, while providing effective noise attenuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a filter is provided as a separate board or with a separate circuit-supporting structure, then noise attenuation is achieved, but device complexity and cost increase
Solution Approach 1:
The patent combines the filter circuit with the control circuit board by mounting filter components (capacitors, coils) directly on the control circuit board alongside the inverter driving circuit. This integration eliminates the need for separate filter boards or dedicated circuit-supporting structures, thereby reducing device complexity while maintaining noise attenuation functionality.
Solution Approach 2:
The control circuit board is designed to serve multiple functions: it acts as both the support structure for the inverter driving circuit and the mounting platform for the filter circuit. The board handles both signal processing and noise filtering functions, eliminating the need for dedicated separate structures and reducing overall device complexity.
2Object-affected harmful factors
If a dedicated wiring board or circuit-supporting structure is provided for the filter, then noise attenuation is achieved, but manufacturing cost increases
Solution Approach 1:
The patent merges the filter circuit with the control circuit board, eliminating the need for separate dedicated wiring boards or circuit-supporting structures. By mounting filter components directly on the existing control circuit board, the number of parts decreases, assembly steps are reduced, and manufacturing cost is lowered while noise attenuation performance is maintained.
3Object-affected harmful factors
If the filter circuit is disposed on a separate wiring board, then noise attenuation is achieved, but the apparatus size increases
Solution Approach 1:
The patent integrates the filter circuit onto the control circuit board, eliminating the need for separate wiring boards. This consolidation reduces the overall apparatus size by removing redundant structural elements and reducing the space required for separate filter mounting structures, while maintaining effective noise attenuation.
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 enables downsizing and cost reduction of the electric rotating machine and power steering apparatuses by integrating the filter within the electromagnetic shield, effectively reducing noise without additional components.
Implementation Method 1
a filter that is disposed outside the electromagnetic shield and is mounted on the protruding portion of the control circuit board so as to attenuate noise components that propagate to the external connection terminal
Implementation Method 2
an electromagnetic shield that surrounds the control unit and is provided with a through hole that is penetrated by the protruding portion of the control circuit board
Data Source
AI summary
In an electric rotating machine apparatus according to the present disclosure, noise-removal capability is secured by adopting a structure in which an external terminal is connected with a protruding portion, of a control circuit board in a control unit, that protrudes from a through hole of an electromagnetic shield and in which a filter unit is provided. Because a conventional dedicated wiring board for mounting the filter unit thereon is not required, the foregoing structure can contribute to downsizing and cost reduction. In addition, the foregoing structure can contribute to downsizing and cost reduction of an electric power steering apparatus equipped with the electric rotating machine apparatus according to the present disclosure.