Rotor Position Sensor Signal Correction for Motor Control
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Solution Overview
Problem
Existing motor control systems face challenges in accurately determining rotor position due to errors in inductive position sensor signals, which can lead to inefficient motor control and loss of mechanical dynamics, especially when error frequencies overlap with desired spectral content.
Innovation Solution
A method that converts rotor position signals to angles with error, tracks these angles to retain mechanical dynamics, transforms them into rotating reference frames, filters these signals, and then converts them back to stationary frames to produce a corrected motor control angle, using a speed state filter and low-pass filtering to minimize errors while maintaining accurate torque control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If filtering is applied to remove error frequencies from rotor position sensor signals, then measurement precision is improved, but mechanical dynamics information is lost
Solution Approach 1:
The patent segments the rotor position signal processing into multiple frequency components using Fourier analysis. By identifying and separating error frequencies from valid mechanical dynamics frequencies, the system can selectively filter only the harmful error components while preserving the useful mechanical dynamics information in the frequency domain
Solution Approach 2:
The patent applies partial filtering by targeting only specific error frequency ranges rather than applying broad filtering. The system identifies error frequencies that are spectrally close to the desired signal and removes only those specific frequency components, avoiding excessive filtering that would eliminate valid mechanical dynamics information
2Measurement precision
If error correction is applied to rotor position sensor signals, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex hardware-based error correction mechanisms with software-based signal processing algorithms. By using Fourier analysis and digital filtering techniques in the controller, the system achieves error correction without adding complex mechanical or electrical hardware components
Solution Approach 2:
The patent introduces an intermediary signal processing stage that transforms the rotor position signals into the frequency domain, applies error removal, and then transforms back. This intermediary frequency domain representation serves as a mediator that simplifies the error correction process by separating error frequencies from valid signal frequencies
Data Source
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AI summary
A motor control system (15) includes a shaft configured to be rotationally driven by a motor (14). A rotor position sensor (22) is configured to detect rotation of the shaft and output a rotor position signal. A controller (20) is in communication with the motor (14) and the rotor position sensor (22). The controller (20) converts the rotor position signal to an angle with error, tracks the angle with error to provide an angle that retains mechanical dynamics as stationary reference frame signals, transforms the stationary reference frame signals and the angle with mechanical dynamics to rotating reference frame signals, filters the rotating reference frame signals, transforms the filtered rotating reference frame signals to provide filtered stationary frame signals, and takes an arctangent of the filtered stationary reference frame signals to create a corrected motor (14) control angle. The controller (20) commands the motor (14) based upon the corrected motor (14) control angle.