Power Converter Controller Offset Removal
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Solution Overview
Problem
Existing power converters face inaccuracies in measuring input power due to significant dc offsets produced by sensing and signal-conditioning circuits, which are costly to calibrate and prone to thermal drift and environmental variations.
Innovation Solution
A controller that includes an analog/digital converter to sample rectified voltage and current waveforms, a processor to estimate the minimum value of the rectified voltage waveform, and remove offsets to obtain unbiased waveforms, thereby calculating accurate average power without the need for additional components or increased manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If calibration is performed to correct dc offsets in sensing circuits, then measurement precision of input power is improved, but manufacturing cost increases significantly
Solution Approach 1:
The system performs self-calibration by automatically detecting and compensating for dc offsets in the sensing circuits through software algorithms, eliminating the need for manual calibration procedures and external calibration equipment, thereby reducing manufacturing costs while maintaining measurement precision
Solution Approach 2:
The system dynamically adjusts measurement parameters by detecting the minimum value of the rectified voltage waveform to determine and remove dc offsets, transforming the measurement process into an adaptive system that automatically compensates for circuit imperfections without requiring physical calibration
2Measurement precision
If calibration procedures are implemented to eliminate dc offsets, then measurement accuracy is improved, but manufacturing complexity and time increase
Solution Approach 1:
The controller automatically performs offset compensation through embedded algorithms that detect waveform minimums and calculate offset values, eliminating the need for external calibration equipment and manual adjustment procedures, thereby simplifying the manufacturing process while maintaining accuracy
Solution Approach 2:
The system extracts and removes the dc offset component from the sensed waveforms through digital signal processing, separating the unwanted offset from the useful signal and eliminating the need for complex hardware calibration circuits
3Device complexity
If traditional sensing circuits are used to measure voltage and current, then device simplicity is maintained, but measurement accuracy deteriorates due to significant dc offsets
Solution Approach 1:
The system replaces hardware-based calibration mechanisms with software-based offset compensation algorithms, using digital signal processing to detect and remove dc offsets from sensed waveforms, thereby maintaining circuit simplicity while improving measurement accuracy
Solution Approach 2:
The controller acts as an intermediary between the simple sensing circuits and the power measurement function, processing the raw sensed signals through offset removal algorithms to produce accurate power measurements without requiring complex calibration hardware
Data Source
AI summary
A controller for estimating a power of a power converter and method of estimating the same has been introduced herein. In one embodiment, the controller includes an analog/digital converter configured to provide samples of a rectified voltage waveform corresponding to a rectified sensed voltage of the power converter. The controller also includes a processor configured to estimate a minimum value of the rectified voltage waveform in accordance with the samples and remove an offset from the rectified voltage waveform to obtain an unbiased rectified voltage waveform in accordance with the estimate of the minimum value. The controller is also configured to obtain an unbiased rectified current waveform corresponding to sensed current of the power converter and provide an average power of the power converter.