Modular Noise Filter Substrate Design for Compact EMI Suppression
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Solution Overview
Problem
Existing noise filter devices face challenges in balancing inductance and capacitance to effectively reduce noise while minimizing size and manufacturing costs, and current configurations make it difficult to adjust these parameters post-manufacturing or achieve compact designs.
Innovation Solution
A noise filter device comprising multiple substrates with varying characteristics for capacitors and choke coils, allowing users to select and combine substrates to achieve desired noise reduction effects and compact arrangements, with the second substrate attached vertically to the first substrate for electrical and mechanical connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the inductance of a common-mode choke coil is excessively increased to improve noise reduction effect, then the noise reduction performance is improved, but the coil becomes large-sized and manufacturing costs increase
Solution Approach 1:
The noise filter device is divided into a first substrate containing the common-mode choke coil and an input-side capacitor, and a second substrate containing the output-side capacitor. This segmentation allows the choke coil to be optimized for noise reduction while the capacitors provide additional filtering functionality, enabling effective noise reduction without requiring an excessively large choke coil.
2Reliability
If the capacitance of input-side and output-side capacitors is excessively increased to improve noise reduction effect, then the noise reduction performance is improved, but the capacitors become large-sized and leakage current increases
Solution Approach 1:
Different capacitors are placed at different locations in the circuit with different capacitance values optimized for their specific positions. The input-side capacitor on the first substrate and the output-side capacitor on the second substrate are configured with appropriate capacitance values that provide effective noise reduction without requiring excessively large capacitance values that would increase size and leakage current.
3Manufacturing precision
If all components are soldered on a wiring board before product shipment to ensure manufacturing quality, then manufacturing precision is improved, but it becomes difficult to change the balance between inductance and capacitance on the user's side
Solution Approach 1:
The device is segmented into two separate substrates that are connected together. This segmentation allows each substrate to be manufactured with high precision through standard soldering processes, while also enabling users to select and combine different substrate configurations to adjust the balance between inductance and capacitance according to specific application requirements.
4Reliability
If the wiring board is formed to be considerably long to separate input-side and output-side circuits, then circuit separation is improved and noise reduction is enhanced, but the device becomes large-sized and manufacturing costs increase
Solution Approach 1:
Instead of achieving circuit separation through a long linear wiring board, the invention uses a three-dimensional configuration where the second substrate is attached vertically to the first substrate. This vertical arrangement provides effective circuit separation between input-side and output-side circuits while maintaining a compact overall device size, avoiding the need for a considerably long wiring board.
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
Enables adjustable noise reduction while preventing device enlargement, allowing for user-side optimization of noise filter performance, leakage current, and size, thereby reducing manufacturing costs and enhancing compact integration with motor drive systems.
Implementation Method 1
a common-mode choke coil, and an output-side capacitor are connected in this order between the alternating-current power supply and the motor drive device
Implementation Method 2
an input-side capacitor, a common-mode choke coil, and an output-side capacitor are connected in this order
Data Source
AI summary
A noise filter includes a first substrate on which a filter input terminal, an input-side capacitor, a common-mode choke coil, and a filter output terminal are mounted and a second substrate on which an output-side capacitor and a ground capacitor are mounted. The first substrate is selected from a plurality of first substrates including a substrate in which a characteristic of at least one of an input-side capacitor and a common-mode choke coil is different, the second substrate is selected from a plurality of second substrates including a substrate in which a characteristic of at least one of an output-side capacitor and a ground capacitor is different, and the second substrate is attached to an end of the first substrate so that the filter output terminal is electrically connected to the output-side capacitor and to be substantially vertical to the first substrate.