Integrated Motor Resolver Position Feedback
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Solution Overview
Problem
Existing motor systems face challenges with high costs and limited temperature ranges due to the use of encoders for position, velocity, and acceleration measurement, as well as increased assembly complexity and cost when resolvers are added as separate components.
Innovation Solution
An integrated motor and position sensor design that incorporates a rotor assembly with alternately magnetized regions and a stator assembly with poles, where sensing coils intercept magnetic flux to provide position, velocity, and acceleration measurements, eliminating the need for separate position sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If encoders are used for position sensing, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The patent combines the motor and resolver into a single integrated structure where the resolver stator and rotor are formed as part of the motor stator and rotor, respectively. This merging eliminates the need for separate encoder components and reduces manufacturing complexity while maintaining position measurement precision through the resolver's magnetic field sensing mechanism
Solution Approach 2:
The motor windings serve dual functions: they generate the magnetic field for motor operation and simultaneously serve as the sensing windings for position detection. This multi-functionality eliminates the need for separate sensing components, reducing manufacturing cost while maintaining measurement capability
2Measurement precision
If encoders are used for position sensing, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The resolver is integrated directly into the motor structure with the resolver rotor formed as part of the motor rotor and the resolver stator formed as part of the motor stator. This consolidation reduces the number of separate components and simplifies assembly procedures while maintaining accurate position measurement through the integrated magnetic field sensing
3Measurement precision
If separate resolvers are added to motors, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The resolver components are merged with the motor components during the same manufacturing process. The resolver rotor is formed as part of the motor rotor assembly, and the resolver stator is formed as part of the motor stator assembly, eliminating the need for separate resolver assembly and reducing overall manufacturing cost while maintaining measurement precision
4Measurement precision
If encoders are used for position sensing, then measurement precision is improved, but temperature range is limited
Solution Approach 1:
The patent employs a resolver with magnetic field sensing that is inherently more robust to temperature variations compared to optical encoders. The magnetic field-based measurement mechanism maintains precision across a wider temperature range, effectively replacing the temperature-sensitive encoder components with a more thermally resilient sensing approach
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 reduces manufacturing costs and complexity, extends temperature ranges, and provides accurate position, velocity, and acceleration feedback without the need for additional sensors, enhancing motor performance and precision in closed-loop control systems.
Implementation Method 1
a plurality of sensing coils placed to intercept variations, uneven distributions or imbalances from symmetry in the magnetic flux between a plurality of the poles and the rotor assembly
Data Source
AI summary
An integrated motor and position sensor achieves motion between a moving portion and a stationary portion by electrically energizing poles to interact with magnetics respectively on the moving and stationary portions. The position sensor includes a plurality of sensing coils placed to intercept the magnetic flux between a plurality of the poles and the magnetics. The outputs from these coils are fed to a microprocessor or DSP through an internal or external A/D converter. The microprocessor or DSP decodes the measured voltages using resolver strategies to produce a position, velocity or acceleration measurement.