Electric Machine Winding Systems Harmonic Reduction
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Solution Overview
Problem
Electric machines with concentrated windings face challenges in reducing undesired harmonic components of the magnetomotive force, leading to losses and acoustic impairments, which existing technologies have not effectively addressed.
Innovation Solution
The electric machine incorporates at least two winding systems with winding-free teeth, where each stator tooth is either wound with one coil from the first or second winding system, or both, and the winding systems are mechanically shifted relative to each other by a defined electric angle, effectively reducing higher and subharmonic harmonic waves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If concentrated windings are used in electric machines, then manufacturing is simplified and design is compact, but undesired harmonic components of the magnetomotive force increase causing losses and acoustic impairments
Solution Approach 1:
The winding system is segmented into multiple independent winding systems (first, second, and optionally third winding systems), each with its own set of coils and winding-free teeth. By dividing the single winding system into multiple segments that can be independently designed and positioned, the patent achieves cancellation of harmonic components while preserving the manufacturing simplicity of concentrated windings.
Solution Approach 2:
The patent introduces asymmetry by mechanically shifting the winding systems relative to each other by a defined electric angle (e.g., 30 degrees for two winding systems). This asymmetric positioning, combined with the segmentation into multiple winding systems, creates a configuration where harmonic components from different systems cancel each other out, while the fundamental operating wave is reinforced.
2Object-generated harmful factors
If multiple winding systems are combined to reduce harmonic components, then acoustic properties and losses improve, but device complexity increases
Solution Approach 1:
Each winding system is designed with local quality considerations, including specific arrangements of coils and winding-free teeth tailored to each system. The winding-free teeth are strategically positioned in each winding system to facilitate the mechanical shift and enable harmonic cancellation, while maintaining the concentrated winding structure that simplifies manufacturing.
Solution Approach 2:
The patent changes key parameters of the winding systems, including the mechanical shift angle between systems, the number of coils per phase per pole, and the positioning of winding-free teeth. By optimizing these parameters, the patent achieves harmonic reduction with minimal increase in complexity, as the same winding structure is reused across multiple systems with different positional parameters.
3Object-generated harmful factors
If winding-free teeth are introduced in winding systems, then harmonic components are reduced, but manufacturing complexity increases
Solution Approach 1:
The winding-free teeth are pre-positioned in the stator structure before the coils are inserted. This preliminary arrangement of the stator teeth provides a ready-made framework that guides the insertion of coils into the correct slots, simplifying the overall manufacturing process despite the presence of winding-free teeth. The mechanical shift between winding systems is also predetermined by the stator geometry.
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 significantly reduces undesired harmonic waves, improving the operational efficiency and acoustic properties of the electric machine by minimizing losses and enhancing manufacturing simplicity.
Implementation Method 1
The coils are inserted in slots of the stator in each case. Teeth are formed between adjoining slots of the stator and the coils are wound around said teeth.
Data Source
AI summary
The proposed principle relates to an electric machine having a stator (1) and a rotor (2) that can move relative to the stator. The stator (1) comprises a first and at least one second winding system (4, 5) that have coils, each of which is placed in stator slots (3) and is wound around stator teeth (6). The first winding system (4) and the second winding system (5) each have at least one tooth (7) around which no coil is wound. When combining the first and second winding system (4, 5), all teeth of the stator (1) have coils wound around them.