Rotor Position Sensing With Odd-Harmonic Signal Compensation
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Solution Overview
Problem
Existing methods for determining the angular position of a rotor in rotary electric machines suffer from inaccuracies due to odd-order harmonics in the signals from Hall-effect sensors, which affect the control of the electric machine.
Innovation Solution
A device that dynamically processes signals from position sensors to compensate for odd-order harmonics by synchronous demodulation and low-pass filtering, improving the accuracy of the rotor position signal without requiring over-sampling or additional calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Hall-effect sensors are used to determine rotor position, then the rotor position can be measured, but odd-order harmonics in the sensor signals reduce the measurement accuracy
Solution Approach 1:
The patent extracts and removes the harmful odd-order harmonic components from the sensor signals through synchronous demodulation and low-pass filtering, separating the useful fundamental frequency components from the harmful harmonic distortions generated by the Hall-effect sensors
Solution Approach 2:
The patent introduces intermediary processing circuits including synchronous demodulators and low-pass filters that act as mediators between the raw sensor signals and the rotor position calculation, dynamically eliminating harmonic distortions without requiring additional physical sensors
2Measurement precision
If dynamic harmonic compensation is implemented, then signal accuracy is improved, but device complexity increases
Solution Approach 1:
The patent makes the processing circuits multi-functional by using the same synchronous demodulation and filtering architecture for multiple odd-order harmonic frequencies (5th, 7th, 11th, 13th harmonics), allowing a single processing block to perform multiple compensation functions rather than requiring separate circuits for each harmonic
Solution Approach 2:
The patent implements dynamic harmonic compensation where the processing circuits continuously adapt to varying harmonic content in real-time operation, using dynamic filtering and demodulation techniques that adjust to changing operating conditions rather than relying on static calibration
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
The solution enhances the accuracy of the rotor position signal, allowing for precise control of the electric machine, and adapts to variations over time due to temperature or aging, without static calibration.
Implementation Method 1
synchronous demodulation of the signal resulting from the signals delivered by the position sensors by a reference signal at said harmonic and in phase with the signal representative of the position of the rotor
Implementation Method 2
low-pass filtering
Implementation Method 3
reconstruct a signal at said harmonic on the basis of the reference signal at said harmonic in phase with the signal representative of the position of the rotor and using each signal representative of phase and amplitude generated beforehand, especially via synchronous modulation
Data Source
AI summary
A device for determining the angular position of a rotor of a rotary electric machine on the basis of signals delivered by a plurality of position sensors. The device includes a circuit that applies a control loop to estimate the position of the rotor, and that delivers as output a signal representative of the position of the rotor. Also included is at least one circuit for performing dynamic processing of an odd-order harmonic of a signal resulting from the signals delivered by the position sensors.