Rotational Angle Sensing Using Two Sensors and 120° Phase Signals
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Solution Overview
Problem
Conventional rotational angle sensor devices for electric motors require precise placement of multiple magnetic field sensors to achieve phase offsets, which is labor-intensive and inefficient, especially for three-phase or multi-phase motors.
Innovation Solution
A rotational angle sensor device using a sensor arrangement with two magnetic field sensors capturing orthogonal magnetic field components, generating two first signals with a 90° phase offset, and a calculation apparatus generating at least three second signals with 120° phase offsets, allowing for motor control without the need for multiple sensors at different locations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple magnetic field sensors are placed at different locations to achieve phase offsets, then the measurement precision and reliability are improved, but the device complexity and installation effort increase
Solution Approach 1:
The patent combines multiple sensor functions into a single magnetic field sensor by using signal processing to generate multiple phase-offset signals (sin, cos, and intermediate phases) from one sensor's output. This merging approach maintains measurement precision while reducing device complexity by eliminating the need for multiple physically separated sensors.
Solution Approach 2:
The patent introduces an intermediary signal processing stage that takes the raw magnetic field sensor output and generates multiple phase-offset signals through mathematical transformations. This intermediary process acts as a mediator between the single sensor and the multiple signals needed for precise rotational angle measurement, avoiding the need for complex physical sensor arrangements.
2Reliability
If multiple sensors are used to generate phase-offset signals, then the control reliability of electric motors is improved, but the installation time and productivity decrease
Solution Approach 1:
The patent merges the functionality of multiple sensors into a single sensor system, where one magnetic field sensor generates all necessary phase-offset signals through signal processing. This dramatically improves installation efficiency by reducing the number of components to be installed while maintaining motor control reliability through mathematical generation of multiple phase signals.
Solution Approach 2:
The single magnetic field sensor effectively serves multiple functions by generating its own phase-offset signals through the signal processing unit. The system is self-sufficient, requiring no additional sensors or complex external arrangements, thereby improving installation productivity while maintaining reliable motor control.
3Measurement precision
If precise placement of multiple sensors is required, then the measurement accuracy is improved, but the ease of manufacture and assembly deteriorate
Solution Approach 1:
The patent combines multiple sensor placement requirements into a single sensor installation. The signal processing unit mathematically generates the necessary phase offsets, eliminating the need for precise physical placement of multiple sensors. This maintains measurement accuracy while dramatically improving ease of manufacture and assembly.
Solution Approach 2:
The patent replaces the mechanical system of multiple precisely-placed sensors with a single sensor plus signal processing system. Instead of relying on mechanical precision in sensor placement, the system uses mathematical transformations to achieve the required phase offsets, thereby improving ease of manufacture while maintaining measurement precision.
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
This solution simplifies the installation and operation of rotational angle sensors by reducing the number of sensors required, enabling effective control of electric motors with reduced installation effort and increased flexibility in sensor placement.
Implementation Method 1
a sensor arrangement which is configured to capture a modulated magnetic field and, based on the captured modulated magnetic field, to output two first signals which have a phase offset with respect to one another
Data Source
AI summary
A rotational angle sensor device and a corresponding method are provided. Two signals which have a phase offset with respect to one another are generated based on a modulated magnetic field using a sensor arrangement. Three signals which have a phase offset with respect to one another are generated from the signals.