Stator Winding Bend Balance for Electric Motor Efficiency
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Solution Overview
Problem
Existing electric rotating machines with stators using segment coils face inefficiencies due to circulating currents generated by phase-shifted induced voltages, which can lead to energy losses and reduced efficiency.
Innovation Solution
The stator design incorporates a cylindrical stator core with slots arranged in phase-shifted groups to accommodate segment conductors with bends, ensuring that induced voltages in each phase are balanced, preventing circulating currents by coupling segment conductors in series and parallel configurations, thereby matching the number of bends in each slot direction to optimize coil structure and reduce energy losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If segment coils are used to increase efficiency, then power output is improved, but circulating currents are generated causing energy losses
Solution Approach 1:
The stator winding is divided into multiple segment conductors that are inserted into slots and coupled in series. Each segment conductor has straight parts accommodated in slots and bends that protrude from the end face. This segmentation allows balanced induced voltages while maintaining high power output capability.
Solution Approach 2:
The patent ensures that the number of bends protruding from the end face in opposite circumferential directions are equal. This creates equipotential conditions that balance the induced voltages across different segments, preventing potential differences that would cause circulating currents and energy losses.
2Loss of energy
If segment conductors are coupled in series to balance induced voltages, then circulating currents are prevented, but device complexity increases
Solution Approach 1:
Multiple segment conductors are coupled in series to form phase windings, and multiple phase windings are coupled in parallel. This merging approach simplifies the overall structure while maintaining balanced induced voltages and preventing circulating currents through the series coupling configuration.
Solution Approach 2:
The segment conductors have different local configurations with straight parts inserted into slots and bends protruding from the end face. This local differentiation optimizes the magnetic field distribution and induced voltage balance across different regions of the stator, achieving energy efficiency without excessive complexity.
3Loss of energy
If bends are arranged to match numbers in opposite directions, then circulating currents are eliminated, but manufacturing precision requirements increase
Solution Approach 1:
The segment conductors are pre-formed with specific bend configurations before insertion into the slots. The bends are positioned to protrude from the end face in predetermined numbers and directions, ensuring that when assembled, the equal number of bends in opposite directions automatically balances the induced voltages without requiring high-precision adjustment during assembly.
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 enhances energy efficiency by eliminating circulating currents and optimizing the stator winding structure, leading to improved performance and reduced size of the electric rotating machine.
Implementation Method 1
An electric rotating machine, such as an electric motor or an electric generator, is provided with a stator that generates magnetic field
Data Source
AI summary
A stator includes a stator core and a stator winding. The stator core has a cylindrical shape and a plurality of slots. The stator winding includes a plurality of phase windings each including a plurality of segment conductors inserted into the slots and coupled to each other in series. Each of the segment conductors has a pair of straight parts and a bend. The pair of straight parts is accommodated in two of the plurality of slots. The bend protrudes from an end face of the stator core and couples the pair of straight parts to each other. In each of the plurality of slots, the number of the bends protruding from the end face of the stator core to extend in one of circumferential directions matches the number of the bends protruding from the end face of the stator core to extend in the other of the circumferential directions.