Electric Machine Control Calibration for d-q Axis Rotor Orientation
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Solution Overview
Problem
Existing electric drive systems face challenges in accurately determining the rotor angle and orientation of electric machines, leading to potential incorrect direction of rotation and safety-relevant malfunctions, especially in encoderless systems.
Innovation Solution
A method and apparatus that apply electrical test signals with predefined directions in the d-q coordinate system to measure rotor angle changes, allowing calibration of the control system by determining the orientation of the d-q coordinate system, thereby ensuring accurate direction of rotation and preventing malfunctions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If encoderless drive systems are used to reduce system costs and improve robustness, then system cost and space requirement are improved, but the ability to accurately determine rotor position and direction of rotation deteriorates
Solution Approach 1:
The patent applies preliminary calibration actions before normal operation to establish the correct orientation of the d-q coordinate system. Test signals are applied in advance to determine the rotor offset angle and verify the orientation, ensuring accurate rotor position determination is established beforehand without requiring continuous encoders during operation.
Solution Approach 2:
The patent introduces test signals as intermediary elements to mediate between the controller and the rotor position determination. These test signals serve as a temporary medium to extract rotor position information and verify coordinate system orientation, enabling accurate measurement without permanent encoder hardware.
2Device complexity
If the rotor offset angle is incorrectly determined or phase sequence is wrong, then system complexity remains simple, but the reliability of direction of rotation determination deteriorates
Solution Approach 1:
The patent implements feedback mechanisms where the measured rotor angle changes are fed back to verify the orientation of the d-q coordinate system. The controller compares the expected rotor response with actual measurements and adjusts the coordinate system orientation accordingly, ensuring reliable direction of rotation determination through continuous verification.
Solution Approach 2:
The patent performs preliminary verification of the rotor offset angle and phase sequence before normal operation. Calibration routines are executed in advance to ensure correct coordinate system orientation, preventing unreliable operation due to incorrect initial parameter determination.
3Measurement precision
If calibration methods are implemented to determine correct rotor position, then direction of rotation determination accuracy is improved, but the time and complexity of the calibration process increases
Solution Approach 1:
The patent applies partial calibration actions by focusing test signals on specific axes (d-axis and q-axis) rather than comprehensive multi-axis testing. This selective approach achieves sufficient calibration accuracy for direction of rotation determination without requiring exhaustive calibration procedures, reducing calibration time while maintaining necessary precision.
Data Source
AI summary
The invention relates to a method for calibrating the control of an electrical machine, comprising the steps of: applying at least one electrical test signal having a specified direction in a d-q coordinate system to the electrical machine; measuring the change in the rotor angle of a rotor of the electrical machine according to the applied at least one electrical test signal; and calibrating the control of the electrical machine, the control being carried out using the d-q coordinate system, and the orientation of the d-q coordinate system being determined on the basis of the measured change in the rotor angle of the rotor of the electrical machine.