Rotor Position Detection Using Reference Angle Error Compensation
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Solution Overview
Problem
Conventional motor position sensors with a segment-like design face challenges in providing clear output signals over 360° due to mechanical tolerances and the need for additional error handling, especially after restarts.
Innovation Solution
A method for detecting a rotor position using a sensor signal that involves determining the first angular position, sensing position information, ascertaining error information based on the expected angle error, and calculating the rotor position within a rotational range, thereby improving accuracy beyond the sensor's measurement range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If segmented sensors are used to detect rotor position, then the sensor can be mounted on the end of the shaft, but the output signals are not clear over 360° and mechanical tolerances cause additional faults
Solution Approach 1:
A reference sensor is introduced as an intermediary component to detect a reference angular position that serves as a basis for calculating angular errors. This reference sensor mediates between the segmented sensor's limited measurement capability and the need for accurate full-range rotor position detection, enabling clear signal output over 360° despite mechanical tolerances.
Solution Approach 2:
The patent replaces direct mechanical contact-based segmented sensors with a hybrid approach that uses a reference sensor for mechanical position detection combined with electronic error compensation. The angular error calculated from the reference sensor's output is used to correct the segmented sensor's measurements, substituting mechanical precision requirements with electronic correction.
2Device complexity
If segmented sensors are used, then the sensor structure is simplified, but additional faults occur due to mechanical tolerances and the angular position becomes unknown after restart
Solution Approach 1:
The reference sensor is pre-configured to detect a reference angular position that establishes a known starting point for rotor position measurement. This preliminary detection of the reference position enables the system to calculate angular errors and determine accurate rotor positions after restart, eliminating the uncertainty that would otherwise occur.
Solution Approach 2:
The system implements feedback by continuously monitoring the reference angular position with the reference sensor and using this information to calculate angular errors. This feedback loop compensates for mechanical tolerances and ensures reliable angular position detection after restart, as the reference position provides a consistent basis for error calculation.
3Device complexity
If the sensor measures only a repeating subsection, then the sensor design is simplified, but the rotor position cannot be determined over the entire rotational range
Solution Approach 1:
The patent adds a temporal dimension to the measurement process by using the reference sensor to detect changes in the reference angular position over time. This allows the system to determine how many full rotations have occurred and calculate the absolute rotor position over the entire rotational range, even though the segmented sensor only measures a repeating subsection.
Solution Approach 2:
The reference sensor acts as an intermediary that bridges the gap between the segmented sensor's limited measurement range and the requirement for full rotational range position information. By detecting the reference angular position and calculating angular errors, the reference sensor enables reconstruction of the complete rotor position trajectory.
Data Source
AI summary
A method for detecting the position of a rotor element on the basis of a sensor signal of a sensor unit in order to detect a first angular position of the rotor element. The angular position relating to a repeating sub-section of a rotation of the rotor element within a rotational range. A computer program product and a sensor device are also provided.