Stator Winding Outer Layer Placement to Reduce Leakage Current
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Solution Overview
Problem
Existing stator designs in electric rotating machines experience increased leakage current due to high average potentials at the outermost layer of the stator winding, leading to radio noise issues.
Innovation Solution
The stator design incorporates a cylindrical stator core with slots arranged in a circumferential direction and a stator winding comprising in-slot portions and turned portions, where the second winding is placed in the outermost layer position to reduce average potential and electrostatic capacitance, thereby minimizing leakage current. This is achieved by arranging the in-slot portions alternately in radial direction and using a stator winding made of flat wire with long sides perpendicular to the radial direction, increasing electrostatic capacitance and decreasing leakage current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the first winding (higher potential) is placed in the outermost layer position, then the electrostatic capacitance is increased, but the leakage current increases due to high average potential
Solution Approach 1:
The patent inverts the conventional arrangement by placing the second winding (lower potential) in the outermost layer position instead of the first winding (higher potential). This inversion reduces the average potential at the outermost layer, thereby decreasing leakage current while maintaining adequate electrostatic capacitance through the flat wire configuration
Solution Approach 2:
The patent changes the physical parameters of the wire from round to flat configuration, and alters the arrangement parameters by positioning the second winding in the outermost layer. These parameter changes optimize the balance between electrostatic capacitance and leakage current reduction
2Reliability
If flat wire is used with long sides perpendicular to radial direction, then electrostatic capacitance is increased, but device complexity increases
Solution Approach 1:
The patent changes the wire geometry parameter from round to flat, and optimizes the orientation parameter by positioning the long sides perpendicular to the radial direction. This configuration maximizes the surface area facing the stator core, thereby increasing electrostatic capacitance
Solution Approach 2:
The patent applies different orientations to different portions of the winding, with the long sides of the flat wire positioned perpendicular to the radial direction at the outermost layer, optimizing the local electrostatic capacitance where it is most needed
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 significantly decreases leakage current and radio noise by reducing the average potential at the outermost layer and increasing electrostatic capacitance, enhancing the performance of electric rotating machines.
Implementation Method 1
capacitors are created between each of the in-slot portions 320a and an inner wall of the slot of the stator core 310
Implementation Method 2
The average potential developed at the joint X will be, as demonstrated in FIG. 19, a one-half (1/2) of that developed at the end U. Thus, the winding portion A closer to the end U is higher in potential than the winding portion B
Data Source
AI summary
A stator which may be employed in an electric rotating machine. The stator includes a stator winding which includes in-slot portions disposed in slots of a stator core. The in-slot portions are arrayed in each of the slots in a form of multiple layers aligned in a radial direction of the stator core. The stator winding is made up of a first winding and a second winding which are connected together through a joint. The first winding is defined by a portion of the stator winding between the joint and an end of the stator winding which is to be connected to an external. The second winding includes the in-slot portion placed within at least one of the slots as an outermost layer that is one of the layers placed most outwardly in the radial direction of the stator core. This results in a great decrease in leakage current.