Resolver Stator Coil Winding for Noise Cancellation
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Solution Overview
Problem
Reluctance type resolvers face reduced angle detection accuracy due to interference from magnetic flux and external magnetic fields affecting both excitation and detection coils, with existing technologies unable to effectively negate inductive noise passed to detection coils.
Innovation Solution
The stator and resolver design involves matching the number of windings between excitation and detection coils by arranging coils such that electrical wires connecting them run in the same direction, with coil groups formed by serially connecting coils wound in opposite directions around adjacent magnetic pole teeth, and connecting end windings in a manner that opposes the start winding direction, thereby reducing external magnetic field influence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If coils are wound in the same direction around magnetic pole teeth, then the winding process is simple and consistent, but magnetic flux from excitation coils interferes with detection coils causing reduced angle detection accuracy
Solution Approach 1:
The patent applies the inversion principle by winding excitation coils and detection coils in opposite directions around adjacent magnetic pole teeth. Specifically, if excitation coils are wound clockwise around certain teeth, detection coils on adjacent teeth are wound counter-clockwise. This opposite winding direction causes magnetic flux from excitation coils to generate voltages with opposite polarity in adjacent detection coils, enabling noise cancellation when the signals are combined.
2Volume of moving object
If excitation coils and detection coils are positioned close to each other to reduce size, then device compactness improves, but inductive noise from excitation coils affects detection coils
Solution Approach 1:
The patent converts the harmful inductive noise from excitation coils into a beneficial effect by utilizing the opposite winding direction arrangement. The magnetic flux that would normally create interference instead generates opposing voltage signals in the detection coils. When these signals are processed, the noise components cancel out, transforming the harmful electromagnetic coupling into a noise-rejection mechanism.
3Measurement precision
If coils are wound with varying numbers of turns to optimize performance, then detection sensitivity improves, but manufacturing precision and consistency become difficult to maintain
Solution Approach 1:
The patent applies local quality by allowing different winding configurations for excitation coils and detection coils on different magnetic pole teeth. Each coil can be optimized independently for its specific function - excitation coils for magnetic field generation and detection coils for signal sensing - while maintaining overall system consistency through the opposite direction winding pattern.
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 effectively negates inductive noise from external magnetic fields, enhancing angle detection accuracy by ensuring consistent winding patterns across all coils and reducing undesired gaps in turns, leading to improved rotational position detection precision.
Implementation Method 1
a resolver provided with this stator and a rotor, for detecting a rotational position of a rotating shaft by detecting variations in reluctance between the rotor and the stator
Implementation Method 2
a plurality of coils formed by respectively winding electrical wire around the plurality of magnetic pole teeth
Data Source
AI summary
Coils are formed into a coil group for a single phase by serially connecting a plurality of coils so that the resulting magnetic flux distribution is a sine wave distribution. The coil group for a single phase is constituted by a plurality of coil sets, formed from two coils that are wound around two adjacent magnetic pole teeth, connected in series. Each coil set includes coils of the two magnetic pole teeth constituting that coil set wound in opposite directions to each other looking from the inside of the stator. An electrical wire extending from an end winding of each coil is turned back so as to run in a direction opposite to an electrical wire connection to a start winding of that coil, and is connected to either a start winding of the next coil or a connection terminal.