Active Filtering System for High Frequency Noise Cancellation

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Solution Overview

Problem

Current filtering systems, particularly passive filters, are inadequate for effectively addressing high frequency noise components generated by power conversion units, as they are bulky, introduce high losses, and are not feasible for filtering a range of frequencies without increasing footprint.

Innovation Solution

An active filtering system is introduced, comprising a filtering unit with multiple converters and inductors, where the converters are switched to generate output voltages with the same switching pattern, allowing for the cancellation of high frequency noise components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a passive filter is used to filter high frequency noise components, then the filtering function is achieved, but the filter becomes bulky and introduces high losses

Engineering Contradiction:

Improvefiltering functionVSAvoidlosses

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent replaces the traditional passive mechanical filter system (inductors, capacitors, damping resistors) with an active filtering system using PWM converters. The active filter generates compensating voltage signals electronically to cancel noise components, eliminating the need for bulky passive components and damping resistors that cause energy losses.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention changes the filtering approach from passive component-based frequency selection to active electronic signal generation and subtraction. By using PWM switching and digital signal processing, the system dynamically generates filtering components that match the noise characteristics, achieving frequency-independent filtering without the energy losses inherent in passive damping resistors.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If a passive filter is designed for a fixed value of frequency, then the filtering is effective at that frequency, but use of such a passive filter to filter high frequency noise components having a plurality of frequencies is not feasible without further increasing footprint of the filter

Engineering Contradiction:

Improvefiltering effectivenessVSAvoidfrequency range

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The active filtering system performs multiple functions: it filters noise across a broad frequency spectrum, adapts to different operating conditions, and maintains effectiveness for multiple frequency components simultaneously. The PWM converters and digital signal processor enable the system to handle various frequency ranges without requiring additional passive components, achieving universal filtering capability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The filtering system is dynamic rather than static. The PWM converters switch at variable frequencies, and the digital signal processor continuously adapts the filtering parameters based on the noise characteristics. This dynamic approach allows the filter to effectively handle a plurality of frequencies and adapt to changing operating conditions without increasing footprint.

Inventive Principle:

Principle #15Dynamics

3Reliability

If damping resistors are used in the passive filter, then the filtering function is achieved, but high losses are introduced

Engineering Contradiction:

Improvefiltering functionVSAvoidlosses

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent eliminates damping resistors by replacing the passive filtering mechanism with an active electronic system. The PWM converters generate compensating voltage signals that actively cancel noise components, removing the need for resistive damping elements that dissipate energy as heat.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

Instead of using resistors to dissipate noise energy as heat (harmful loss), the active filtering system converts the noise problem into a beneficial cancellation effect. The system generates opposing voltage signals that destructively interfere with the noise components, transforming the filtering function from energy dissipation to energy redirection and cancellation.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentUS9882464B1System for filtering high frequency noise components and an associated method thereof

Publication Date: 2018.01.30 GE PRECISION HEALTHCARE LLC

AI summary

A system including at least one first converter and a filtering unit coupled to the at least one first converter is presented. The filtering unit includes at least one second converter and a plurality of inductors coupled to the at least one second converter. The system further includes a controlling unit operatively coupled to the at least one first converter and the at least one second converter. The controlling unit switches the at least one first converter to generate a first output voltage and the at least one second converter to generate a second output voltage, where the first output voltage and the second output voltage have a substantially same switching pattern.