Redundant Resolver Radial Nesting Axial Dimension

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Solution Overview

Problem

Existing redundant resolvers face issues with increased axial direction dimension, worsened manufacturability, and cost due to stacking or duplicating components, while also compromising angle detection accuracy with non-ideal sinusoidal output signals.

Innovation Solution

A redundant resolver design that divides the stator in the circumferential direction, using a pair of stator and rotor with natural number output winding orders, maintaining equivalent axial dimensions to single-system devices, and improving manufacturability and cost efficiency while enhancing angle detection accuracy through sinusoidal magnetic flux interlinkage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If two resolvers are stacked in two tiers via shaft, then redundancy is achieved, but axial direction dimension increases twofold

Engineering Contradiction:
ImproveredundancyVSAvoidaxial direction dimension
Core Design Contradiction:
ReliabilityVSLength of moving object

Solution Approach 1:

The patent transitions from a stacked configuration (axial direction) to a radial configuration where the first and second resolvers are arranged in the radial direction with different diameters. This dimensional change allows redundancy to be achieved without increasing the axial dimension, as the resolvers share the same axial space while being differentiated radially.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent implements a nested structure where the first resolver and second resolver are concentrically arranged with different diameters, allowing one resolver to be positioned inside the other radially. This nesting approach enables both resolvers to occupy the same axial footprint while maintaining redundancy, effectively avoiding the twofold axial dimension increase that would result from simple stacking.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Reliability

If stator is duplicated with first system stator and second system stator, then redundancy is achieved, but manufacturability worsens and cost increases

Engineering Contradiction:
ImproveredundancyVSAvoidmanufacturability
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent designs the first and second resolvers to share common components including the same stator core structure, rotor core structure, and winding patterns. By making the resolvers universal in their design while differentiating only by winding connections and excitation signals, the patent reduces manufacturing complexity and cost while maintaining redundancy functionality.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the structural components of the first and second resolvers into a single integrated assembly, where both resolvers share common stator and rotor structures. This combining approach reduces the total number of separate components that need to be manufactured and assembled, thereby improving manufacturability and reducing cost while achieving redundancy through electrical differentiation rather than complete duplication.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If output windings are alternately wound around teeth, then redundancy is achieved, but output signal becomes non-ideal sinusoidal wave and angle detection accuracy worsens

Engineering Contradiction:
ImproveredundancyVSAvoidangle detection accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent applies local quality by differentiating the winding configurations of the first and second resolvers in specific local areas. Instead of alternating windings that create non-ideal signals, the patent uses identical winding patterns in both resolvers but differentiates them through local connection arrangements and excitation signal phase relationships, thereby maintaining ideal sinusoidal output signals and high angle detection accuracy while achieving redundancy.

Inventive Principle:
Principle #3Local quality

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

The solution restricts axial dimension increase, reduces manufacturing complexity and costs, and improves angle detection accuracy by maintaining sinusoidal output signals and magnetic flux interlinkage, effectively addressing the limitations of prior redundant resolver designs.

Implementation Method 1

a change in permeance in a gap between a rotor and a stator

Methodology Applied
Scientific EffectMagnetic flux interlinkage: Electromagnetic Induction

Implementation Method 2

change in permeance in a gap between a rotor and a stator

Methodology Applied
Scientific EffectPermeance change: Magnetic Reluctance

Data Source

PatentEP3730903B1Redundant resolver and rotation angle detection device using same
Publication Date: 2023.02.15 MITSUBISHI ELECTRIC CORP
  • EP3730903B1 patent drawingFigure 1
  • EP3730903B1 patent drawingFigure 2
  • EP3730903B1 patent drawingFigure 3

AI summary

A worsening of manufacturability and a cost increase are restricted, and angle detection accuracy is improved, while preventing an increase in an axial direction dimension caused by redundancy. A redundant resolver is configured of a stator (3) and a rotor (4) that form a pair, wherein the rotor (4) is a rotor with a shaft angle multiplier of Nx having Nx (Nx is a natural number) salient poles, the stator (3) is such that n teeth T1 to Tn, where n is a natural number, are disposed sequentially in a circumferential direction, configuring M systems by being divided into M in the circumferential direction, and having an angle of 360/M degrees when angles of the teeth configuring one system are totaled, a one-phase excitation winding and a two-phase output winding are wound around each of the teeth T1 to Tn, excitation signals of the same frequency are applied by differing excitation circuits to the respective excitation windings, an output order per system is Nout (Nout is a natural number), and an abnormality is detected based on output signals of the M systems.