Integrated Filter for Servo Motor Noise Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Servo and similar motors generate electrical noise and high-frequency currents due to sharp rise and fall times in drive pulses, causing reliability issues, bearing damage, and electromagnetic interference, which existing filters fail to address effectively in terms of space and cost efficiency.
Innovation Solution
A combination filter using common-mode inductors in the ground line and differential inductors on power lines, along with a choke on the ground wire, reduces high-frequency currents and integrates both motor and AC filters into a single enclosure to minimize space and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If separate motor filter and AC filter are used, then noise filtering effectiveness is improved, but device space and cost increase
Solution Approach 1:
The patent combines the motor filter and AC filter into a single integrated filter device. The filter housing contains both the motor filter section (with common-mode inductors and capacitors for motor noise filtering) and the AC filter section (with common-mode inductors and capacitors for power line noise filtering), allowing both filtering functions to be performed in one compact unit rather than requiring separate filter enclosures.
2Object-affected harmful factors
If separate motor filter and AC filter are used, then noise filtering effectiveness is improved, but device cost increases
Solution Approach 1:
The patent combines the motor filter and AC filter into a single integrated filter device. The filter housing contains both the motor filter section (with common-mode inductors and capacitors for motor noise filtering) and the AC filter section (with common-mode inductors and capacitors for power line noise filtering), allowing both filtering functions to be performed in one compact unit rather than requiring separate filter enclosures.
3Speed
If sharp rise and fall times in drive pulses are used, then motor response speed is improved, but electrical noise and bearing damage increase
Solution Approach 1:
The patent applies preliminary anti-action by placing the filter device between the servo controller and motor to pre-counteract the harmful effects of sharp drive pulse edges. The common-mode inductors and capacitors in the filter circuit actively suppress high-frequency noise and bearing currents before they can damage the motor, allowing the motor to operate with sharp rise and fall times for fast response without suffering the usual harmful effects.
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 reduces ground currents and electromagnetic interference, prevents bearing damage, and fits two filters into a compact space, reducing costs and improving reliability.
Implementation Method 1
one or more common mode inductors in a ground line between a motor and a motor controller
Implementation Method 2
differential inductors on power lines
Implementation Method 3
a separate noise-suppressing choke on a ground wire
Data Source
AI summary
A device and method for reducing ground currents and electromagnetic interference in pulsed signal devices are described. In one embodiment, the device may include, in addition to regular filtering components and circuits, a separate noise-suppressing choke in the ground wire to reduce current in the ground wire that causes damage to bearings and electrical overstress. Such choke may be of a saturation type that offers high inductance and good noise-blocking properties in normal operating conditions and sufficiently low impedance at fail currents which provides proper tripping of safety circuits.