Power Meter DC Offset Removal Without Non-Sinusoidal Distortion
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Solution Overview
Problem
Existing power meter technologies face challenges in accurately removing DC offsets, particularly for non-sinusoidal signals, which can result in distorted signal waveforms due to the use of high pass filters.
Innovation Solution
An apparatus and method that include an analog-digital converter, high pass filter, selector, determination block, and offset compensation unit to detect the signal pattern and selectively apply high pass filtering or compensation to remove DC offsets in real time, distinguishing between sinusoidal and non-sinusoidal signals using RMS values or DC period detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high pass filter is used to remove DC offset from the signal output from the ADC, then the DC offset is removed, but the signal waveform is distorted when the signal is non-sinusoidal
Solution Approach 1:
The patent implements a dynamic DC offset removal system that automatically adapts its method based on the detected signal pattern. The determination block identifies whether the signal is sinusoidal or non-sinusoidal, and the selector dynamically switches between HPF-based removal (for sinusoidal signals) and compensation-based removal (for non-sinusoidal signals), thereby preventing waveform distortion while maintaining DC offset removal effectiveness
Solution Approach 2:
The patent changes the DC offset removal parameter (method) based on the signal type. For sinusoidal signals, the system uses HPF with specific cutoff frequencies; for non-sinusoidal signals, it switches to compensation methods that calculate and subtract the DC offset component without affecting the signal waveform, thus adapting the removal technique to the signal characteristics
2Adaptability or versatility
If a high pass filter is used to remove DC offset, then the DC offset is removed for sinusoidal signals, but the method is not suitable for non-sinusoidal signals with DC offset
Solution Approach 1:
The patent creates a universal DC offset removal system that handles both sinusoidal and non-sinusoidal signals through a single apparatus. The determination block identifies the signal type, and the selector routes the signal to the appropriate removal method (HPF for sinusoidal, compensation for non-sinusoidal), making the system universally applicable to different signal types while maintaining high removal accuracy for each
Solution Approach 2:
The patent segments the DC offset removal process into two distinct paths based on signal type. One path uses HPF for sinusoidal signals, and the other path uses compensation-based removal for non-sinusoidal signals. This segmentation allows each method to be optimized for its specific signal type, ensuring high accuracy for both sinusoidal and non-sinusoidal signals
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
Enables accurate and real-time removal of DC offsets for both sinusoidal and non-sinusoidal signals, preventing signal distortion and improving power meter accuracy.
Implementation Method 1
an analog-digital converter converting an analog signal into a digital signal
Implementation Method 2
a high pass filter (HPF) removing the DC offset from the signal output from the analog-digital converter
Implementation Method 3
The determination block may use an RMS value of the input signal or determine whether a DC period of the input signal is detected so as to determine whether the received signal is the sinusoidal signal or not
Implementation Method 4
determine whether a DC period of the input signal is detected so as to determine whether the received signal is the sinusoidal signal or not
Implementation Method 5
an offset compensation unit disposed on a path bypassing the high pass filter, compensating the DC offset value calculated from the offset calculation block in the signal output from the analog-digital converter
Data Source
AI summary
Disclosed herein are an apparatus and a method for removing a DC offset in a power meter. The apparatus for removing a DC offset in a power meter according to exemplary embodiment includes: an ADC; a HPF removing the DC offset from the signal output from the ADC; a selector receiving the signals passing through the HPF and bypassing the HPF and outputting any one thereof; a determination block receiving a signal output from the ADC or from the selector and determining whether the received signal is a sinusoidal signal; an offset calculation block calculating the DC offset to be compensated from the signal input to the determination block or output from the selector; and an offset compensation unit disposed on a path bypassing the HPF, compensating the calculated DC offset value in the signal output from the ADC and outputting the compensated result to the selector.