Electric Motor Filter Circuit with 3D Capacitor Bridge for EMC
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Solution Overview
Problem
Existing electric motor filter circuits fail to effectively suppress radio interference, leading to significant electromagnetic disturbances, particularly in battery-operated tools, due to the complexity of achieving improved electromagnetic compatibility (EMC).
Innovation Solution
A capacitor bridge with at least two interference suppression capacitors is placed on a circuit board between the electrical connections of the electric motor, with capacitors aligned in different spatial directions and mechanically mounted to enhance radio interference suppression, combined with the integration of chokes in the filter circuit for improved EMC.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional filter circuits are used with standard capacitor arrangements, then the circuit complexity remains low, but the radio interference suppression is insufficient
Solution Approach 1:
The patent applies dimensionality change by transitioning from a single spatial arrangement of capacitors to multiple spatial orientations. Specifically, capacitors are arranged with their longitudinal axes extending in different spatial directions (e.g., first, second, and third directions) rather than a single direction, creating a three-dimensional suppression field that effectively counteracts electromagnetic interference from multiple sources without requiring additional circuit stages
Solution Approach 2:
The patent employs asymmetry in the capacitor arrangement by positioning capacitors with different longitudinal axis orientations relative to the motor shaft and stator. This asymmetric spatial configuration ensures that interference suppression is effective across various interference directions and load states, rather than optimizing for a single symmetric arrangement
2Reliability
If multiple capacitor bridges are added to improve radio interference suppression, then electromagnetic compatibility increases, but the device complexity increases
Solution Approach 1:
The patent merges multiple capacitor bridges into a single integrated filter circuit unit that is combined with the motor's existing electrical connections. Instead of adding separate, independent capacitor bridges that would increase complexity, the design integrates multiple capacitors with different spatial orientations into one unified structure that achieves enhanced EMC while maintaining simplicity
Solution Approach 2:
The filter circuit design achieves multi-functionality by using a single capacitor bridge structure with capacitors oriented in multiple directions to simultaneously suppress interference from various sources (different load states, different interference directions) without requiring multiple separate circuits, thereby providing universal interference suppression
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 solution significantly increases radio interference suppression and electromagnetic compatibility by optimizing the electrical and mechanical arrangement of capacitors and chokes, reducing electromagnetic disturbances effectively.
Implementation Method 1
a capacitor bridge comprising at least two interference suppression capacitors is provided between the electrical connections of the electric motor
Implementation Method 2
the filter circuit is arranged on the connection end of the electric motor
Data Source
AI summary
The disclosure relates to a filter circuit on an electric motor which has electrical connections at a connection end for connection to a supply voltage (U). The filter circuit consists of at least one capacitor bridge arranged between the connections of the electric motor for radio interference suppression. For increased electromagnetic compatibility (EMC), the filter circuit is arranged on a circuit board and held on the connection end of the electric motor. The circuit board has a capacitor bridge with interference suppression capacitors, which is connected between the electrical connections of the electric motor, wherein an interference suppression capacitor has a longitudinal axis between its electrical connections in the longitudinal direction. The interference suppression capacitors are arranged on the circuit board with their longitudinal axes aligned in different spatial directions.