Resolver Stator Interpoles Suppress Harmonic Waves
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Solution Overview
Problem
Existing resolver devices can only partially suppress third harmonic waves, leading to reduced reliability in rotation angle position detection.
Innovation Solution
A resolver device with a stator core and rotor core configuration that includes multiple stator main poles and interpoles arranged at specific electrical and mechanical angles, allowing for three-phase output signals shifted by 120 degrees and additional interpoles to suppress second and third harmonic waves through three-phase/two-phase conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a two-pole variable reluctance resolver with six stator teeth is used, then the second harmonic wave can be suppressed, but the third harmonic wave suppression is limited and detection reliability is reduced
Solution Approach 1:
The stator is segmented into multiple stator teeth (at least three stator teeth for three-phase output) with specific pole configurations. Each stator tooth has excitation windings and output windings arranged to create specific magnetic pole patterns that suppress third harmonic waves through controlled reluctance variations.
Solution Approach 2:
Different stator teeth have different winding configurations and pole arrangements optimized for their specific positions. The excitation windings and output windings are locally arranged to create the desired magnetic field distribution that suppresses third harmonic components while maintaining fundamental wave output.
2Measurement precision
If multiple rotor pieces are stacked and shifted by specified angles, then high harmonic wave components can be reduced, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The rotor is divided into multiple rotor pieces (first rotor piece, second rotor piece, etc.) that are stacked and shifted by specified angles relative to each other. This segmentation allows each rotor piece to contribute to harmonic suppression while maintaining a manageable structural complexity through systematic arrangement.
Solution Approach 2:
The rotor pieces are intentionally shifted by asymmetric angles (such as 30 degrees or 60 degrees) relative to each other in the turning angle direction. This asymmetric arrangement creates phase shifts in the reluctance variations that cancel out harmonic components while maintaining overall rotational symmetry for proper motor operation.
3Measurement precision
If unipolar resolver and multipolar resolver are installed together, then detection accuracy can be improved, but magnetic flux leakage causes electrical interference between the resolvers
Solution Approach 1:
A magnetic shield is introduced as an intermediary element positioned between the unipolar resolver and the multipolar resolver. This magnetic shield redirects and contains the magnetic flux from each resolver, preventing it from leaking into the other resolver's sensing region, thereby eliminating electrical interference while allowing both resolvers to operate simultaneously for improved detection accuracy.
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 configuration significantly improves the accuracy of angle information and reliability by canceling second and third harmonic waves, enhancing the precision of rotation angle detection.
Implementation Method 1
a two-pole variable reluctance resolver having a stator and a rotor configured such that reluctance in an air gap between a rotor iron core and stator teeth changes in accordance with a position of the rotor iron core
Data Source
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AI summary
A resolver device includes a stator core 11 and a rotor core 12 supported so as to be freely rotatable with respect to the stator core 11 and configured such that a reluctance component in a gap between the rotor core 12 and the stator core 11 changes in accordance with a relative angle position to the stator core 11. The stator core 11 includes stator main poles A1, A2, B1, B2, C1, and C2 and stator interpoles IA1, IA2, IB1, IB2, IC1, and IC2.