Common-Mode Noise Canceling Circuit With Overcurrent Cutoff
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Solution Overview
Problem
Existing noise reduction technologies for power conversion devices are inadequate in effectively canceling common mode noise currents, leading to inefficiencies and potential interference in electrical systems.
Innovation Solution
A noise reduction circuit that injects a compensation current into the power line and ground to counteract common mode noise currents, utilizing a noise detection unit, coupling capacitors, transistors, and a cut-off unit to manage overcurrents, thereby reducing noise through feedback control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a noise reduction device with transistors and leakage current detector is used to cancel common mode noise, then common mode noise current is reduced, but the device complexity increases and overcurrent protection is lacking
Solution Approach 1:
The patent extracts and addresses the specific problem of overcurrent protection in noise reduction circuits by introducing a dedicated cut-off unit that operates independently of the main noise cancellation mechanism. This modular approach protects vulnerable components without requiring complete redesign of the noise reduction system.
Solution Approach 2:
The cut-off unit acts as an intermediary protective element inserted into the compensation current path. It monitors current levels and intervenes only when overcurrent conditions occur, allowing the main noise reduction circuitry to operate normally while providing automated protection against excessive currents that could damage transistors or other components.
2Object-affected harmful factors
If compensation current is injected to cancel common mode noise, then noise reduction is achieved, but overcurrent may damage the noise canceler circuitry
Solution Approach 1:
The cut-off unit is pre-configured in the compensation current path to provide protective cushioning against overcurrent conditions. By establishing this protective mechanism in advance, the circuit is prepared to automatically limit current flow before damage can occur to the noise canceler transistor or other sensitive components during abnormal operating conditions.
Solution Approach 2:
The cut-off unit provides automatic feedback control by monitoring the compensation current path and responding to overcurrent conditions. When excessive current is detected, the cut-off unit activates to limit current flow, creating a self-regulating protection system that maintains reliability without requiring external intervention or complex control algorithms.
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 solution effectively cancels common mode noise currents, enhancing the efficiency and reducing interference in power conversion systems by actively suppressing noise through compensation currents.
Implementation Method 1
noise canceler circuitry configured to generate a compensation current and inject the compensation current into a power line and ground to reduce a common mode noise current
Data Source
AI summary
A noise reduction circuit includes: noise canceler circuitry configured to inject a compensation current into a power line and ground to reduce a common mode noise current that flows through the power line and the ground into a commercial power supply from a power converter with a switching element connected to the commercial power supply; and overcurrent inhibitor circuitry provided on a compensation current path through which the compensation current flows, the overcurrent inhibitor circuitry being configured to inhibit application of an overcurrent to the noise canceler circuitry.