Synchronous Reluctance Rotor Core Design for Self-Starting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Synchronous reluctance type rotary electric machines require an inverter for starting, which increases costs and efficiency losses due to harmonic currents and unnecessary weight from filling hollow parts with conductors, reducing their efficiency and manufacturing costs.
Innovation Solution
A rotor core design with multi-layered hollow parts and conductor bars positioned at specific distances from bridges to minimize harmonic flux linkage, allowing self-starting without an inverter, optimizing magnetic flux and torque generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the hollow parts are formed as close as possible to the outer circumferential surface of the rotor core to reduce leakage magnetic flux, then leakage magnetic flux is reduced, but harmonic current increases causing efficiency decrease
Solution Approach 1:
The patent applies local quality by making the conductor bar position different for the first hollow part versus other hollow parts. Specifically, the first conductor bar is positioned at a distance from the outer circumferential surface that is 0.05 to 0.15 times the rotor core width, while other conductor bars are positioned closer to minimize leakage flux. This localized differentiation optimizes both efficiency and harmonic current reduction.
2Force
If the entire hollow part is filled with a conductor to generate induced torque, then starting torque is improved, but rotor core weight increases unnecessarily
Solution Approach 1:
The patent applies partial action by positioning conductor bars at specific distances from the outer circumferential surface rather than filling the entire hollow part. The first conductor bar is positioned at 0.05 to 0.15 times the rotor core width from the surface, and other conductor bars are positioned at optimized distances, thereby generating sufficient induced torque without the unnecessary weight of complete filling.
3Device complexity
If a nonmagnetic conductor is provided in the hollow parts to generate induced torque for self-starting, then inverter cost is eliminated, but harmonic current flows through the conductor reducing efficiency
Solution Approach 1:
The patent applies parameter changes by optimizing the position parameters of conductor bars within hollow parts. The first conductor bar is positioned at a distance of 0.05 to 0.15 times the rotor core width from the outer circumferential surface, while other conductor bars are positioned at optimized distances. This parameter optimization enables self-starting capability while minimizing harmonic current and efficiency loss.
4Force
If conductor bars are positioned close to the outer circumferential surface to maximize magnetic flux linkage, then induced torque is maximized, but harmonic flux linkage increases causing efficiency loss
Solution Approach 1:
The patent applies local quality by differentiating the position of the first conductor bar from other conductor bars. The first conductor bar is positioned at 0.05 to 0.15 times the rotor core width from the outer circumferential surface to balance torque and harmonic flux, while other conductor bars are positioned at optimized distances. This localized differentiation maximizes induced torque while minimizing efficiency loss from harmonic flux linkage.
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 design enhances starting torque and driving efficiency while reducing manufacturing and commodity costs by eliminating the need for an inverter and minimizing conductor bar size, thereby improving overall performance and cost-effectiveness.
Implementation Method 1
a direction in which magnetic flux easily flows and a direction in which magnetic flux does not easily flow are formed in the rotor core. Thus, the synchronous reluctance type rotary electric machine rotates the shaft using a reluctance torque generated by the hollow parts.
Implementation Method 2
when an end portion on the outer circumferential surface side of the rotor core in the hollow part is filled with a conductor, since the magnetic flux pulsating according to a pitch of teeth of the stator links with the conductor, a harmonic current that does not contribute to rotation of the rotor flows through the conductor.
Data Source
AI summary
A synchronous reluctance type rotary electric machine of an embodiment includes, a rotor core, a plurality of conductor bars, short-circuit rings, a stator core, and multiphase armature windings. The rotor core includes multi-layered hollow parts having a convex shape toward a side radially inward formed for each pole in cross section, and a bridge formed between each of the hollow parts and an outer circumferential surface thereof. The plurality of conductor bars are disposed in the respective hollow parts. The short-circuit rings connect the plurality of conductor bars together. Then, in all of the hollow parts of a second layer and subsequent layers other than the hollow part of a first layer which is at a position farthest from the rotation axis of the rotor core, the conductor bars are disposed at both end portions thereof close to the bridge at a predetermined distance from the bridge.