Rotor-Stator Angle Estimation Without Arc Tangent Delay
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Solution Overview
Problem
Existing methods for determining the angle between a rotor and a stator in rotating electrical machines, such as resolver-based and inductive sensors, suffer from long calculation times due to time-consuming division and arc tangent calculations, leading to varying signal propagation times and reduced accuracy in engine control.
Innovation Solution
A device and method that utilize an angle estimator and error corrector to rapidly determine the angle by minimizing differences between measured and estimated amplitudes, eliminating the need for division and arc tangent calculations, and ensuring constant signal propagation times through closed-loop control and error correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If division and arc tangent calculations are used to determine the angle from sinusoidal and cosinusoidal signals, then the angle can be calculated accurately, but the calculation time becomes very long
Solution Approach 1:
The patent replaces the mathematical calculation system (division and arc tangent operations) with a physical measurement system. By using a sensor that directly outputs angle information through magnetic field interactions, the need for complex computational operations is eliminated, achieving both high accuracy and fast response.
Solution Approach 2:
The patent introduces a magnetic field as an intermediary between the rotor position and the measurement system. The magnetic field carries the angular position information physically, allowing the angle to be determined through field interactions rather than mathematical computations, thereby reducing calculation time while maintaining precision.
2Measurement precision
If signal correction steps (offset compensation, amplitude adjustment, phase correction) are performed, then the measurement accuracy is improved, but the signal propagation time increases
Solution Approach 1:
The patent performs error correction in advance by pre-calculating correction values for offset, amplitude, and phase errors during system calibration. These correction values are stored and applied automatically during operation, eliminating the need for real-time correction calculations and reducing signal propagation time while maintaining high measurement accuracy.
3Measurement precision
If complex signal processing operations are performed, then the angle determination accuracy is improved, but the data becomes older due to varying processing times
Solution Approach 1:
The patent replaces complex signal processing operations with a direct magnetic field measurement approach. The sensor system provides angle information through physical field interactions without requiring extensive digital processing, ensuring that the data remains current and reliable for real-time control applications.
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
Enables extremely fast and accurate angle determination, reducing signal propagation times by at least tenfold and minimizing variations, thereby improving the precision and reliability of engine control.
Implementation Method 1
If the rotor winding is excited with a sinusoidal AC voltage, the stator windings can be arranged in such a way that the amplitudes of the voltages induced in the stator windings correspond to the sine and cosine of the angular position of the rotor
Data Source
AI summary
A device for determining a first angle between a rotor and a stator, having inputs for reading amplitudes of electrical signals detected via a sensor system and representing a first angle, wherein the device has an angle estimator for estimating a second angle, the device determines amplitudes representing the second, estimated angle, the device has at least one controller with which at least one difference between the first angle and the second, estimated angle can be minimized, and the second, estimated angle can be provided via an output.