Wave Winding Stator Design for Electric Machine Efficiency
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Solution Overview
Problem
Existing electric machine wave windings face challenges in achieving high power and efficiency, particularly at high rotational speeds, due to frequency-dependent losses and equalizing currents caused by large conductor cross sections and uneven voltage induction across conductors.
Innovation Solution
A wave winding design for the stator with conductors interconnected in parallel or series, arranged in a sequence that allows for a predetermined winding pitch and transposed by at least one groove skip along the periphery, ensuring equal magnetic flux and uniform voltage induction across all conductors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conductors with large cross sections are used to satisfy torque and power requirements, then the machine can achieve high power output, but frequency-dependent losses increase at high rotational speeds
Solution Approach 1:
The wave winding is divided into multiple sets, with each set containing multiple conductors that can be arranged in series or parallel connections. This segmentation allows the total number of turns to be distributed across multiple conductors, enabling flexible configuration to achieve desired power output while managing current density and frequency-dependent losses.
Solution Approach 2:
The invention changes the winding parameters by introducing groove skips that transpose the sequence of conductors. This transposition modifies the electrical characteristics of the winding, allowing optimization of the number of turns and conductor arrangement to reduce frequency-dependent losses while maintaining power output requirements.
2Ease of manufacture
If conductors are arranged with uniform winding pitch, then the winding structure is simple and easy to manufacture, but unequal voltage induction occurs across parallel conductors causing equalizing currents and losses
Solution Approach 1:
The invention introduces asymmetric groove skips at specific positions in the winding sequence. These groove skips create deliberate asymmetries in the winding pattern that transpose the sequence of conductors, ensuring that parallel conductors experience equal voltage induction despite the overall asymmetric arrangement. This resolves the equalizing current problem while maintaining manufacturing feasibility.
Solution Approach 2:
The groove skip mechanism allows the winding to skip certain stator grooves strategically. By skipping grooves at specific positions, the conductor sequence is transposed to achieve equal voltage induction across parallel conductors. This skipping approach maintains relatively simple winding structure while eliminating the harmful equalizing currents.
3Loss of energy
If the number of conductors per groove is increased to reduce the cross section of individual conductors, then frequency-dependent losses are reduced, but the groove-filling ratio decreases and manufacturing complexity increases
Solution Approach 1:
The invention introduces dynamic flexibility in winding configuration through groove skips. The winding design allows different numbers of conductors per groove at different positions along the stator periphery. This dynamic arrangement enables optimization of conductor distribution to reduce frequency-dependent losses while maintaining acceptable groove-filling ratios and manageable manufacturing complexity.
Solution Approach 2:
Different regions of the winding can have different conductor arrangements. By applying groove skips at specific locations, the invention creates local variations in the number of conductors per groove. This local quality approach allows optimization of electrical characteristics in specific regions while maintaining overall winding feasibility and manufacturing practicality.
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 design reduces electrical power losses, enhances efficiency, and allows for a more compact and robust machine structure, while increasing the variability of configurations and power output, especially at high rotational speeds.
Implementation Method 1
ensuring equal magnetic flux and uniform voltage induction across all conductors
Implementation Method 2
uniform voltage induction across all conductors
Data Source
AI summary
A wave winding for a stator of an electric machine is configured to be placed in a series of stator grooves located along a periphery of the machine to increase power and efficiency of the machine by avoiding losses, particularly during upper rotational speed range operation. The wave winding has at least two conductors for one respective phase of the machine. The conductors are interconnected in parallel and/or series and can be disposed at a given winding pitch in a number of at least two successive stator grooves of each magnetic pole and each phase of the machine in a sequence predefined for each phase and for one respective magnetic pole along the periphery of the machine. The predefined sequence at least of the conductors interconnected in parallel is transposed by at least one groove skip in at least one position along the periphery of the machine.