Electronic Transformer Calibration Using Multi-Frequency Pole Fitting
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Solution Overview
Problem
Existing methods for calibrating the cut-off frequency of electronic transformers are inadequate for achieving precise measurements across a wide frequency range due to deviations in actual capacitance and resistance values, leading to significant measurement errors.
Innovation Solution
A method and apparatus that determine the amplitude gain factor and time constant of the signal acquisition unit by sampling different frequency signals, calculate the dominant pole and amplitude factor, and configure these for the digital signal processing unit to perform digital filtering, thereby aligning the digital filter with the actual cut-off frequency for precise measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the cut-off frequency is calculated based on the nominal value of the component in the signal acquisition unit, then the calculation is simple, but there is a deviation between the calculated cut-off frequency and the actual cut-off frequency, resulting in large measurement error
Solution Approach 1:
The patent changes the parameter basis from nominal component values to actual measured values. By measuring the actual amplitude and phase angle at different frequencies and using these measured parameters to determine the dominant pole and amplitude factor, the system achieves accurate cut-off frequency calculation that reflects the actual component characteristics rather than relying on nominal values.
Solution Approach 2:
The patent implements a feedback mechanism by measuring the actual amplitude and phase angle of the signal acquisition unit across different frequencies, then using these measurements to adjust and determine the dominant pole and amplitude factor. This closed-loop approach allows the system to compensate for component deviations and achieve precise cut-off frequency calculation.
2Ease of operation
If a same clock source signal and same current or voltage input signal are used for calibration, then the calibration process is straightforward, but the method is only suitable for calculating amplitude error and phase error at a specific operating frequency, cannot meeting measurement precision requirement in wide frequency range
Solution Approach 1:
The patent transitions from a static single-frequency calibration approach to a dynamic multi-frequency measurement approach. By measuring amplitude and phase angle across multiple different frequencies and using these dynamic measurements to determine the dominant pole and amplitude factor, the system achieves adaptability to a wide frequency range while maintaining operational simplicity.
Solution Approach 2:
The patent creates a universal calibration method that works across multiple frequencies. The determined dominant pole and amplitude factor serve as universal parameters that can be applied for digital filtering across the entire operating frequency range, making the calibration process versatile rather than frequency-specific.
3Productivity
If the digital signal processing unit calculates measured current or voltage based on the cut-off frequency, then the measurement process is simple, but the deviation in cut-off frequency causes large measurement error
Solution Approach 1:
The patent performs preliminary measurement of the actual amplitude and phase angle across different frequencies before the actual measurement process. This preliminary action determines the accurate dominant pole and amplitude factor, which are then used in the digital signal processing unit to ensure both measurement efficiency and high accuracy without requiring complex real-time calculations.
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
This approach ensures measurement precision of electronic transformers across a wide frequency range by correcting the impact of analog components and adapting the digital filter to the actual cut-off frequency, reducing measurement errors and meeting precision class 0.2 requirements.
Implementation Method 1
The induction unit generates an induction signal based on a to-be-measured current or voltage using an electronic technology and an electromagnetic induction principle
Data Source
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AI summary
This application provides an electronic transformer calibration method and apparatus. The electronic transformer calibration method includes: obtaining amplitudes and phase angles of sampled signals obtained by a tested signal acquisition unit by sampling different frequency signals, where the tested signal acquisition unit is a signal acquisition unit included in a to-be-calibrated electronic transformer; determining an amplitude gain factor and a time constant of the tested signal acquisition unit based on the amplitudes and the phase angles; determining a dominant pole and an amplitude factor of the tested signal acquisition unit based on the amplitude gain factor and the time constant; and configuring the dominant pole and the amplitude factor for a digital signal processing unit included in the to-be-calibrated electronic transformer, so that the digital signal processing unit performs digital filtering on an input signal based on the dominant pole and the amplitude factor, to obtain an output signal, where the input signal is obtained by performing analog-to-digital conversion on a signal output by the tested signal acquisition unit. According to this solution, measurement precision of the calibrated electronic transformer can be improved.