Bipolar Induction Machine With Slotless Segmented Flux Paths
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Solution Overview
Problem
Existing electric machines suffer from issues such as large DC components, weight, slot harmonics, torque ripple, structural resonances, acoustic noise, and the need for sliprings and commutators, which affect efficiency and reliability.
Innovation Solution
A bipolar induction synchronous electric machine with axially segmented flux circuits, comprising a stator and rotor arrangement with concentrically arranged pole elements and bipolar field poles, inducing a correspondingly shaped emf waveform, and featuring a slotless design without sliprings or commutators, allowing for concentrated coils and improved cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If conventional electric machines use slot designs with windings, then they can achieve electromagnetic function, but they produce slot harmonics and torque ripple
Solution Approach 1:
The invention extracts and removes the slots from the magnetic circuit structure. The stator core is designed as a slotless structure where windings are placed on the stator surface rather than embedded in slots, eliminating slot harmonics and the associated torque ripple while maintaining electromagnetic functionality
Solution Approach 2:
The stator is segmented into multiple independent magnetic poles with windings distributed around the stator periphery. This segmentation allows each pole to function independently, eliminating the need for traditional slot structures while maintaining the required electromagnetic characteristics
2Reliability
If electric machines use sliprings and commutators for current delivery, then they can achieve rotor excitation, but they reduce reliability and require maintenance
Solution Approach 1:
The invention replaces the mechanical slipring and commutator system with a stationary field exciter coil that generates the magnetic field directly. This eliminates moving electrical contacts, improving reliability and eliminating maintenance requirements for rotor excitation
Solution Approach 2:
The field exciter coil is stationary and self-contained, generating the required magnetic field without requiring external mechanical connections. The system serves itself by creating the magnetic field at the source rather than requiring current delivery to rotating components
3Ease of manufacture
If electric machines use distributed windings in slots, then they can achieve electromagnetic function, but they produce slot harmonics and require complex manufacturing
Solution Approach 1:
The invention extracts windings from traditional slot structures and places them on the stator surface in a slotless configuration. This simplifies manufacturing by eliminating the need for complex slot winding installation while maintaining electromagnetic functionality and eliminating slot harmonics
Solution Approach 2:
The stator is divided into multiple magnetic poles with windings distributed around the periphery. Each pole can be manufactured and positioned independently, simplifying the manufacturing process while eliminating slot structures that cause harmonics
4Ease of operation
If electric machines use conventional rotor designs, then they can achieve magnetic field generation, but they produce cogging and torque ripple
Solution Approach 1:
The invention extracts and removes the traditional rotor structure with its associated cogging and torque ripple problems. The magnetic field is generated by a stationary field exciter coil, eliminating rotor-related torque irregularities while maintaining magnetic field generation functionality
Solution Approach 2:
Instead of generating the magnetic field in the rotor and inducing it in the stator, the invention inverts the approach by generating the magnetic field stationary in the stator and having the rotor respond to this field, eliminating rotor cogging and torque ripple
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 provides a machine with reduced weight, zero cogging, high efficiency, and ripple-free torque, while eliminating slot harmonics and requiring no special tools or skills for manufacturing, with a sinusoidal or triangular emf waveform for enhanced performance.
Implementation Method 1
bipolar field poles that induce a correspondingly shaped emf waveform (in the case of an electric alternator)
Implementation Method 2
the rotor arrangement rotates within the stator arrangement, the rotor arrangement inducing a predetermined emf waveform in the armature winding of the stator pole elements
Data Source
AI summary
A bipolar induction electric machine is provided comprising a stator arrangement comprising a plurality of circumferentially arranged stator modules, each stator module comprising a plurality of axially arranged spaced apart stator pole elements fitted with a concentrated armature winding and terminating in an inwardly facing, curved stator pole surface; and a rotor arrangement rotatably and concentrically accommodated within the stator arrangement, the rotor arrangement comprising a plurality of axially arranged rotor modules, each rotor module comprising at least one circumferentially arranged, curved bi-polar member comprising a pair of curved rotor pole elements that are axially displaced on either side of a stationary concentric field exciter coil accommodated within the stator arrangement. The curved rotor pole elements are concentrically arranged relative to the stator pole surfaces so as to define a uniform air-gap therebetween and thus provide a plurality of axially segmented multipolar flux circuits.