Sensor Signal Correction for Harmonic Angular Error Compensation
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Solution Overview
Problem
Existing methods for correcting measurement signals in sensor arrays are inadequate in minimizing angular errors caused by harmonics, particularly second and third electrical harmonic oscillations, leading to imperfect compensation.
Innovation Solution
A method using discrete Fourier transform to calculate correction coefficients that compensate for first and second-order electrical harmonic oscillations, allowing for angle-independent correction of measurement signals, which can be applied in sensor arrays with multiphase systems, and optionally combined with angle-dependent harmonic correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional correction methods are used, then offset, amplitude mismatch and orthogonality errors are corrected, but harmonics of first and second order in the angular error cannot be compensated
Solution Approach 1:
The patent applies preliminary action by calculating correction coefficients in advance using a Fourier transform of angular errors obtained during a calibration phase. These pre-calculated coefficients are then stored and applied during normal operation to compensate for harmonics without requiring real-time computation, thus achieving complete compensation while maintaining system reliability
Solution Approach 2:
The patent goes beyond conventional correction methods by not only correcting offset, amplitude mismatch and orthogonality errors but also compensating for harmonics of first and second order in the angular error. This excessive action ensures complete compensation of all significant error sources, achieving superior measurement precision and reliability
2Measurement precision
If correction coefficients are calculated using Fourier transform of sine and cosine signals, then offset, amplitude mismatch and orthogonality errors are minimized, but harmonics distort the correction coefficients
Solution Approach 1:
The patent extracts the harmonic components from the angular error signal using a Fourier transform and separates them from the fundamental measurement signal. By isolating and independently compensating for each harmonic order, the method prevents harmonic distortion from corrupting the correction coefficients for offset, amplitude mismatch and orthogonality errors
Solution Approach 2:
The patent performs preliminary calibration to calculate correction coefficients that account for harmonics, storing these pre-computed coefficients for use during normal operation. This preliminary action separates the coefficient calculation from real-time measurement, preventing harmonic distortion from affecting ongoing measurements
3Reliability
If angle-dependent harmonic correction is applied, then harmonic compensation is achieved, but correction becomes dependent on angular position
Solution Approach 1:
The patent transforms the correction approach by changing the parameter basis from angle-dependent to angle-independent correction coefficients. By using a Fourier transform to decompose angular errors into harmonic components, the method achieves harmonic compensation through parameters (correction coefficients) that do not vary with angular position, simplifying operation and control
Data Source
AI summary
A method is for correcting measurement signals which are provided by at least one sensor unit. Two processed measurement signals are generated based on at least two currently provided measurement signals, from which two corrected measurement signals are generated using angle-independent arithmetic operations and at least one correction coefficient, from which a corrected angle is calculated and output. A plurality of at least two measurement signals is provided in advance in order to determine the at least one correction coefficient, from which two conditioned measurement signals are generated. A corresponding angular error is calculated on the basis of the two conditioned measurement signals and a reference angle, which is subjected to a discrete Fourier transformation. The at least one correction coefficient is determined and stored.