GMR Sensor Rotor Angle Estimation via PLL Pulsation Removal
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Solution Overview
Problem
The high cost of expensive sensors like encoders and resolvers for measuring rotor angles in motors reduces price competitiveness, and existing methods struggle to effectively remove pulsation errors caused by magnetic flux interference or shaft misalignment.
Innovation Solution
A method using a low-cost giant magneto resistance (GMR) sensor to measure rotor angles, combined with a D-Q converter and phase-locked loop (PLL) block for proportional integral control, to convert and remove pulsation from the measured angle, thereby estimating the rotor angle accurately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If expensive sensors like encoders or resolvers are used to measure rotor angle, then measurement precision is improved, but device cost increases
Solution Approach 1:
The patent replaces expensive encoders or resolvers with a low-cost GMR sensor that uses giant magneto resistance effect to detect rotor angle. This substitution directly addresses the cost issue while maintaining measurement capability through alternative physical principles
Solution Approach 2:
The patent substitutes mechanical sensing systems (encoders with moving parts) with a magnetic field-based GMR sensor system. This replacement eliminates complex mechanical structures while achieving the same measurement function through magnetic field detection
2Ease of manufacture
If GMR sensor is used to reduce cost, then device cost decreases, but measurement precision deteriorates due to pulsation errors
Solution Approach 1:
The patent extracts and removes the pulsation component from the GMR sensor output signal through signal processing. By separating the unwanted pulsation error from the useful rotor angle information, the system recovers measurement precision while keeping the low-cost sensor
Solution Approach 2:
The patent implements a feedback mechanism where the estimated rotor angle is continuously refined by comparing the actual GMR sensor output with the expected signal pattern. This closed-loop approach compensates for pulsation errors and improves measurement accuracy
3Reliability
If traditional sensors are used, then measurement reliability is improved, but device complexity increases
Solution Approach 1:
The patent uses a simple GMR sensor instead of complex encoder or resolver systems, reducing device complexity while maintaining reliability through software-based compensation techniques
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 approach reduces the cost of motor systems by utilizing a low-cost GMR sensor while stabilizing motor control by effectively removing pulsation errors, enhancing the accuracy of rotor angle estimation and motor performance.
Implementation Method 1
a low-cost giant magneto resistance (GMR) sensor
Data Source
AI summary
Provided is a device for estimating a rotor angle in a motor. The device includes a sensor configured to measure a rotation angle “θin” of a motor including a pulsation, a D-Q converter configured to convert the rotation angle “θin” into a D-axis conversion angle, and a phase-locked loop (PLL) block configured to perform proportional integral control on the D-axis conversion angle according to a PLL algorithm to estimate a rotation angle “θout” from which the pulsation has been removed.