Hairpin Winding Layout for Balanced Parallel Circuits
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Solution Overview
Problem
Existing electric machines with hairpin windings face challenges in achieving balanced parallel circuitry without producing circulating currents, which requires complex manufacturing and is difficult to achieve with rigid hairpins.
Innovation Solution
The electric machine design includes a stator core with fifty-four circumferentially arranged slots, featuring hairpin windings with three electrical phases, each composed of interconnected hairpins with varying crown and twist pitches, and atypical hairpins connected via jumpers to form balanced paths without unnecessary manufacturing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complex manufacturing methods are used to achieve balanced parallel circuitry, then circuit balance is improved, but manufacturing complexity increases
Solution Approach 1:
The patent introduces atypical hairpins with asymmetric configurations (different crown pitches and twist pitches) to balance the parallel circuits. Specifically, one hairpin in each group of three has different dimensions than the other two, creating intentional asymmetry that compensates for cumulative errors and achieves circuit balance without complex manufacturing processes
Solution Approach 2:
The patent changes the geometric parameters (crown pitch, twist pitch, leg length) of specific hairpins to achieve balanced parallel circuits. By adjusting these parameters in atypical hairpins, the invention creates intentional variations that balance the electrical paths while maintaining simple manufacturing processes
2Ease of manufacture
If rigid hairpins are used, then manufacturing simplicity is improved, but achieving balanced circuitry becomes difficult
Solution Approach 1:
The patent applies local quality by making most hairpins typical with standard dimensions for ease of manufacture, while introducing specific atypical hairpins with modified dimensions at critical locations. This localized variation achieves circuit balance without requiring all hairpins to be complex or flexible
3Ease of manufacture
If all hairpins have the same dimensions, then manufacturing is simplified, but unwanted harmonics increase
Solution Approach 1:
The patent introduces asymmetric hairpin configurations (atypical hairpins with different crown and twist pitches) to reduce unwanted harmonics. These intentional dimensional variations break the symmetry that causes harmonic distortion while maintaining manufacturing simplicity through standardized production methods
Data Source
AI summary
An electric machine includes a stator core and a hairpin winding. The stator core defines slots that are circumferentially arranged between an inner diameter and an outer diameter of the stator core. Each slot has a plurality of pin positions that is arranged in a direction that extends from the inner diameter toward the outer diameter. The hairpin winding has a plurality of electrical paths of interconnected hairpins disposed within the slots. Each of the plurality of electrical paths of interconnected hairpins has a plurality of typical hairpins and an atypical hairpin. Each typical hairpin has a crown pitch of eight, nine, or ten, slots and opposing outwardly extending twist pitches along each end of the typical hairpin of four and one half slots. Each atypical hairpin, has an outwardly extending twist pitch and an inwardly extending twist pitch on opposing respective ends of the atypical hairpin.