Resolver Back Yoke Width Optimization for Magnetic Saturation
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Solution Overview
Problem
Existing resolver designs fail to optimize the width relation between the back yoke of the stator and the salient pole of the rotor, leading to overcrowded magnetic flux and magnetic saturation, which deteriorates measurement precision and increases manufacturing costs.
Innovation Solution
A resolver design that incorporates a stator with a ring-shaped back yoke and teeth, and a rotor with salient poles, where the width of the back yoke is optimized to be between 0.66 and 8 times the width of the salient pole, ensuring proper magnetic flux flow and preventing saturation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the back yoke of the stator is designed to have a width smaller than a width of the rotor, then the device size is reduced, but magnetic flux becomes overcrowded excessively or magnetic saturation is generated to disturb a flow of the magnetic flux, thereby deteriorating the measurement performance
Solution Approach 1:
The patent applies parameter changes by establishing a specific width ratio relationship between the back yoke and salient pole (Wb≥0.66×Wr). This quantitative parameter optimization ensures sufficient magnetic flux path width to prevent saturation while maintaining compact device dimensions, directly resolving the contradiction between size reduction and measurement performance preservation.
2Volume of moving object
If the back yoke of the stator is designed to have a width smaller than a width of the rotor over a certain level, then the device size is reduced, but magnetic saturation is generated to disturb a flow of the magnetic flux
Solution Approach 1:
The patent prevents magnetic saturation by optimizing the width parameter of the back yoke relative to the salient pole. The specified relationship (Wb≥0.66×Wr) ensures adequate cross-sectional area for magnetic flux flow, eliminating the harmful effect of magnetic saturation while maintaining compact device size.
3Device complexity
If existing resolver designs are used without optimizing the width relation between back yoke and salient pole, then the design work is simpler, but measurement precision deteriorates and manufacturing costs increase
Solution Approach 1:
The patent introduces a specific parameter relationship (Wb≥0.66×Wr) that provides clear design guidance for engineers. This quantitative criterion simplifies the design process by eliminating the need for complex iterative optimization, while simultaneously ensuring high measurement precision and preventing manufacturing issues related to magnetic saturation.
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 optimization improves measurement precision, reduces manufacturing costs, and facilitates design work by preventing overcrowded magnetic flux and magnetic saturation, while maintaining a reasonable product size and weight.
Implementation Method 1
a stator having at least one excitation coil and at least one output coil
Implementation Method 2
the rotor rotating based on a rotary shaft to change a gap permeance with respect to the stator
Implementation Method 3
the back yoke of the stator and the salient pole of the rotor have a relation satisfying Equation 1 below: Wb≥0.66×Wr
Data Source
AI summary
Disclosed is a resolver, which includes a stator having at least one excitation coil and at least one output coil, and a rotor disposed at a center space in the stator with a predetermined gap from the stator, the rotor rotating based on a rotary shaft to change a gap permeance with respect to the stator, wherein the stator includes a back yoke having a ring-shaped body, and a plurality of teeth formed at an inner circumference of the back yoke so that the excitation coil and the output coil are wound thereon, wherein the rotor includes a ring-shaped body having a center hole into which the rotary shaft is inserted, and a plurality of salient poles formed at an outer circumference of the ring-shaped body.