Non-Equidistant Stator Slot Placement for Harmonic Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electric motors experience significant harmonics due to stator winding and slotting, leading to increased vibration, noise, and power losses, which prior-art solutions have not adequately addressed, particularly in three-phase motors where odd harmonic terms like the 5th, 7th, 11th, and 13th harmonics cause detrimental effects.
Innovation Solution
The solution involves a dispersed placement of stator slots and/or pole cores on the rim of the stator, deviating from equidistant distribution, with a method that includes using a shape function incorporating a conversion function to determine non-equidistant positions, effectively reducing harmonics caused by the stator winding and slotting, thereby minimizing vibration, noise, and power losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If equidistant distribution of stator slots is used, then manufacturing is simple, but harmonics cause increased vibration, noise, and power losses
Solution Approach 1:
The patent applies asymmetry by deviating from the conventional equidistant distribution of stator slots. The slot positions are intentionally made non-uniform according to a specific mathematical function (e.g., f(θ) = θ + a·sin(kθ)), where a is the deviation amplitude and k is the harmonic order. This asymmetric arrangement disrupts the periodicity that generates harmonics, thereby reducing vibration, noise, and power losses while maintaining manufacturing feasibility through systematic positioning.
2Object-affected harmful factors
If dispersed placement of stator slots is implemented to reduce harmonics, then vibration and noise decrease, but manufacturing precision requirements increase
Solution Approach 1:
The patent employs parameter changes by introducing controlled deviations in slot positions based on mathematical functions with specific parameters (amplitude a, harmonic order k, phase angle). These parameters allow systematic adjustment of the dispersion pattern to optimize harmonic reduction while maintaining manufacturability. The deterministic nature of the parameter-based approach enables precise control over slot positions, balancing harmonic reduction with manufacturing precision requirements.
3Ease of manufacture
If conventional stator winding is used, then manufacturing is straightforward, but torque ripple and power losses increase due to harmonics
Solution Approach 1:
The patent applies asymmetry to the stator slot distribution to reduce harmonics generated by conventional windings. By positioning slots non-uniformly according to mathematical functions, the design disrupts the harmonic generation mechanism while preserving the simplicity of conventional winding techniques. This approach reduces power losses and torque ripple without complicating the winding manufacturing process.
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 approach significantly dampens harmonics to one-tenth of their original magnitude, resulting in reduced vibration, noise, and power losses while maintaining the fundamental wave's integrity, achieving a more even torque and improved motor performance.
Implementation Method 1
stator slots or pole cores, which possibly contain slots, are situated on the rim of the stator in a placement differing from equidistant distribution... significantly dampens harmonics to one-tenth of their original magnitude, resulting in reduced vibration, noise, and power losses
Data Source
AI summary
In the present invention the positions of the slots or poles of the stator of an electric motor are changed in order to reduce the harmonics caused by the stator winding and any vibration caused by these harmonics. In the present invention a shape function is defined according to the new placement positions for the stator slots and/or stator poles. A conversion function sums for the slot placement positions to be given to equidistant stator slotting placement. In one embodiment of the invention the conversion function is the sum of sinusoidal functions and in its amplitude small in relation to the distance between the slots.