Transformer Noise Filter Using Opposite-Polarity EMI Compensation
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Solution Overview
Problem
Existing noise filters for power conversion devices, such as those using common mode transformers, face challenges in achieving enhanced noise reduction while maintaining a reduced size and weight, as they require increased turns ratios or higher voltage capabilities, leading to larger and heavier devices.
Innovation Solution
A noise filter design that includes a noise detector, a compensation signal applicator, and an injection voltage generator, which adjusts and applies compensation voltages across the transformer to reduce electromagnetic noise, allowing for enhanced noise reduction without increasing device size or weight by generating injection voltages with opposite polarities across the transformer's primary winding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If acoustic echo cancellation (AEC) and noise suppression algorithms are used to improve voice call quality, then call quality is enhanced, but battery power is consumed and device complexity increases
Solution Approach 1:
The patent extracts and processes audio signals separately at the microphone input stage, applying noise filtering and echo cancellation locally before the main signal processing chain. This early extraction approach reduces the computational burden on the processor, thereby lowering battery power consumption while maintaining call quality.
Solution Approach 2:
The audio processing system is segmented into multiple independent stages: physical noise filtering at the microphone capsule level, digital echo cancellation, and noise suppression. This segmentation allows each component to operate efficiently with optimized power consumption, preventing the need for continuous high-power processing of the entire audio signal.
2Object-affected harmful factors
If multiple microphones and complex signal processing are implemented to reduce noise, then noise reduction is improved, but device complexity and processing requirements increase
Solution Approach 1:
The patent implements noise filtering at the local level of each microphone capsule through physical design features (such as acoustic waveguides and filtering structures) rather than relying entirely on complex global digital signal processing. This local quality approach reduces noise early in the signal chain, simplifying subsequent processing requirements.
Solution Approach 2:
Noise filtering and signal conditioning are performed preliminarily at the microphone input stage before the audio signal enters the main processing chain. By performing noise reduction actions early, the system reduces the complexity of subsequent processing stages while achieving effective noise suppression.
3Object-affected harmful factors
If physical noise filtering structures are added to the microphone, then noise filtering is improved, but microphone structure complexity increases
Solution Approach 1:
The patent merges the noise filtering function directly into the microphone capsule structure itself, combining acoustic waveguide design with physical filtering elements. This integration achieves effective noise filtering without adding separate, complex external structures, as the filtering is embedded within the microphone's existing architecture.
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 noise filter achieves an enhanced noise reduction effect while maintaining a compact and lightweight design by optimizing the transformer configuration and voltage application, effectively addressing the limitations of previous designs.
Implementation Method 1
an acoustic waveguide, which filters ambient noise from the voice signal
Data Source
Figure 1~2
Figure 3~5
Figure 6~7
AI summary
A noise filter (50) includes: a noise detector (7) which detects voltage due to electromagnetic noise generated by a power converter (2) and outputs adjusted voltage (Vd) obtained by adjusting the detected voltage; a compensation signal applicator (75) which superimposes compensation voltage (Vcom) having a polarity opposite to the voltage due to electromagnetic noise, on an output or an input of the power converter (2) via a transformer (11); and an injection voltage generator 30 which generates, on the basis of the adjusted voltage (Vd), first output voltage (Vo1) and second output voltage (Vo2) having a polarity opposite thereto, for generating injection voltage (Vinj) between one end and another and of a primary-side winding (ml) of the transformer (11), and outputs the first output voltage and the second output voltage to the one end and the other end, respectively.