Integrated Capacitive Resolver-Rectifier for Low-Inertia Rotor Sensing

Solution Overview

Problem

Wound field synchronous machines require a system for rotor position sensing and power conversion, which can be complex and costly due to the need for separate mechanical encoders and rectifier assemblies, and also face challenges with rotational inertia and space efficiency.

Innovation Solution

Integration of a capacitive encoder and rectifier assembly into a single support structure, utilizing capacitive coupling for both power transfer and position sensing, reducing rotational inertia and cost by simplifying the design and allowing for a compact form factor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate mechanical encoders and rectifier assemblies are used, then position sensing and power conversion functions are provided, but device complexity and cost increase

Engineering Contradiction:

Improveposition sensing and power conversionVSAvoidseparate assemblies

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the encoder and rectifier assemblies into a single integrated rotor assembly. The encoder plates and rectifier components are mounted together on the same support structure, sharing common mechanical support and mounting infrastructure. This merging eliminates the need for separate mounting structures and reduces overall system complexity while maintaining both position sensing and power conversion functions.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The rotor assembly is designed to perform multiple functions simultaneously: it provides both encoder functionality for position sensing and rectifier functionality for power conversion. The capacitive plates serve dual purposes as both encoder elements for detecting rotor position and as components of the rectifier assembly for converting AC to DC power, thereby reducing the number of separate components needed.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If separate mechanical encoders and rectifier assemblies are used, then position sensing and power conversion functions are provided, but manufacturing cost increases

Engineering Contradiction:

Improveposition sensing and power conversionVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent combines the encoder and rectifier assemblies into a single integrated rotor assembly. The encoder plates and rectifier components are mounted together on the same support structure, sharing common mechanical support and mounting infrastructure. This merging eliminates the need for separate mounting structures and reduces overall system complexity while maintaining both position sensing and power conversion functions.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If separate mechanical encoders and rectifier assemblies are used, then position sensing and power conversion functions are provided, but rotational inertia increases

Engineering Contradiction:

Improveposition sensing and power conversionVSAvoidrotational inertia

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The patent combines the encoder and rectifier assemblies into a single integrated rotor assembly. The encoder plates and rectifier components are mounted together on the same support structure, sharing common mechanical support and mounting infrastructure. This merging eliminates the need for separate mounting structures and reduces overall system complexity while maintaining both position sensing and power conversion functions.

Inventive Principle:

Principle #5Merging (Combining)

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 integration simplifies the design, reduces costs, and enhances space efficiency while providing accurate rotor position sensing for Field Oriented Control, capable of operating during startup and varying rotor motions, and is resistant to rotational forces.

Implementation Method 1

each of the stationary and rotational supports having respective opposed electrical plates having a capacitive coupling adapted to provide a rotation signal indicating rotation of the rotor with respect to the stator

Methodology Applied

Scientific EffectCapacitive coupling: Capacitance

Implementation Method 2

A brushless AC power coupler communicates AC power to the rotor from a source stationary to the stator

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 3

a rectifier assembly is held on the rotational support communicating electrical power between the brushless AC power coupler and the electrical coil

Methodology Applied

Scientific EffectRectification: Diode

Data Source

PatentUS11990801B2Single substrate resolver/rectifier for brushless wound field synchronous machines

Publication Date: 2024.05.21 WISCONSIN ALUMNI RES FOUND

AI summary

An electrical rotating machine provides an integrated capacitive encoder for control of the stator field and enabling any of reduced size, reduced rotational inertia, and lower cost. The same structure may also support capacitive plates for capacitive power transfer to the rotor.