EMI Suppression Circuit Using Phase Cancellation
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Solution Overview
Problem
Existing electromagnetic interference suppression technologies face challenges in effectively reducing conducted electromagnetic interference signals that exceed regulatory limits, particularly in applications where these signals have large magnitudes.
Innovation Solution
A circuit comprising a sensing circuit, an amplifier, and a controlled signal source is used to sense and amplify electromagnetic interference signals, with the controlled signal source further regulating the amplified signal to provide a suppression signal that reduces the interference. This circuit can include high pass filters and transformers to achieve effective suppression, and multiple stages can be cascaded to achieve substantial elimination of interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional electromagnetic interference suppression techniques are used, then some level of interference reduction is achieved, but conducted electromagnetic interference signals with large magnitudes above regulatory limits cannot be effectively suppressed
Solution Approach 1:
The sensing circuit detects the electromagnetic interference signal in advance, and the amplifier prepares the suppression signal by amplifying the sensed signal before it is injected back. This preliminary action allows the system to respond quickly to interference signals with large magnitudes, effectively suppressing them before they can cause harmful effects.
Solution Approach 2:
The invention converts the harmful electromagnetic interference signal into a beneficial suppression signal. The sensing circuit captures the interference signal, the amplifier amplifies it, and the controlled signal source injects the amplified signal back into the power lines in opposite phase, effectively canceling out the original interference and converting it into a useful suppression mechanism.
2Object-affected harmful factors
If the amplification factor is increased to suppress large magnitude interference signals, then suppression effectiveness improves, but the circuit complexity and power consumption increase
Solution Approach 1:
The invention divides the suppression function into three distinct modules: a sensing circuit for detecting interference signals, an amplifier for amplifying the sensed signals, and a controlled signal source for injecting the amplified signals back. This segmentation allows each module to be optimized independently, managing complexity while achieving effective suppression of large magnitude interference signals.
Solution Approach 2:
The amplifier serves multiple functions: it amplifies the sensed interference signal, prepares the suppression signal for injection, and works in conjunction with the sensing circuit and controlled signal source to achieve overall suppression. This multi-functionality reduces the need for additional dedicated components, managing circuit complexity while maintaining suppression effectiveness.
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 proposed circuit significantly reduces electromagnetic interference signals, often to below regulatory thresholds, by using amplification factors that result in suppression signals that are equal in magnitude and 180 degrees out of phase with the interference, effectively eliminating or minimizing the interference across power lines.
Implementation Method 1
The first sensing circuit is arranged to sense a first electromagnetic interference signal
Implementation Method 2
The first amplifier provides a first amplification factor and is operably connected with the first sensing circuit to amplify a signal sensed by the first sensing circuit
Implementation Method 3
The first controlled signal source provides a second amplification factor and is operably connected with the first amplifier to regulate or further amplify the amplified signal to provide a first suppression signal that reduces the first electromagnetic interference signal
Data Source
AI summary
A circuit for suppressing electromagnetic interference signal on power lines. The circuit includes a first sensing circuit, a first amplifier, and a first controlled signal source. The first sensing circuit is arranged to sense a first electromagnetic interference signal. The first amplifier is arranged to be powered by a power source. The first amplifier provides a first amplification factor and being operably connected with the first sensing circuit to amplify a signal sensed by the first sensing circuit. The first controlled signal source provides a second amplification factor and is operably connected with the first amplifier to regulate or further amplify the amplified signal to provide a first suppression signal that reduces the first electromagnetic interference signal. Multiple such circuits can be cascaded to form a mufti-stage electromagnetic interference suppression circuit.