Stator Assembly Asymmetric Current Distribution for Noise Reduction
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Solution Overview
Problem
Electric vehicle stators experience resonance-induced acoustic noise and hot spots due to balanced current distribution in winding paths, which limits cooling efficiency.
Innovation Solution
A stator assembly with a stator core and bar conductors arranged in a parallel circuit configuration, where electrical jumpers connect bar conductors to balance current flow through different winding paths, creating phase shifts and reducing impedance differences, thereby minimizing acoustic noise and thermal hot spots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bar conductors are arranged in a balanced parallel circuit configuration, then current distribution is improved, but acoustic noise increases due to resonance
Solution Approach 1:
The patent applies asymmetry by intentionally creating unbalanced winding paths with different impedances. The controller deliberately distributes current unevenly across the parallel circuit arrangement, making some winding paths have higher current than others. This asymmetric current distribution prevents the resonant conditions that cause acoustic noise while still maintaining reliable operation of the electric device.
Solution Approach 2:
The patent changes the current distribution parameters dynamically through controller management. By adjusting the current magnitude in each winding path based on impedance characteristics, the system transforms from a balanced to an unbalanced operational state. This parameter change eliminates resonance-induced acoustic noise while preserving the benefits of the parallel circuit configuration.
2Reliability
If bar conductors are arranged in a balanced parallel circuit configuration, then current balance is improved, but thermal performance deteriorates due to hot spots
Solution Approach 1:
The patent applies asymmetry by creating unbalanced winding paths with different impedances and current distributions. This asymmetric design prevents uniform current flow that causes concentrated heating in specific areas. By varying the current through different paths, the thermal load is distributed more evenly across the stator assembly, eliminating hot spots.
Solution Approach 2:
The patent changes the current distribution parameters to optimize thermal performance. The controller adjusts current magnitudes in each winding path based on their impedance characteristics, transforming the thermal distribution pattern. This parameter optimization prevents localized overheating while maintaining overall system reliability.
3Object-generated harmful factors
If unbalanced winding paths are created, then acoustic noise is reduced, but current distribution becomes uneven
Solution Approach 1:
The patent accepts uneven current distribution as a necessary parameter change to eliminate acoustic noise. The controller deliberately operates the parallel circuit arrangement with unequal current magnitudes in different winding paths. This controlled parameter change prioritizes noise reduction while maintaining sufficient current distribution to ensure reliable device operation.
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 effectively reduces acoustic noise and improves thermal performance by balancing current flow and impedance across winding paths, enhancing the operational efficiency and cooling of the stator assembly.
Implementation Method 1
an amount of current flowing through the first winding path and the third winding path is substantially the same and an amount of current flowing through the second winding path is different from the amount of current flowing through the first and third winding paths
Data Source
AI summary
An electric device and a stator assembly for the electric device includes a stator core defining a plurality of slots spaced from each other. The stator assembly includes a plurality of bar conductors disposed in each of the slots and arranged to present a first winding path, a second winding path and a third winding path. A first set of the bar conductors of the first, second and third winding paths are configured to receive current in a parallel circuit arrangement. The stator assembly also includes a plurality of electrical jumpers electrically connected to a predetermined number of the bar conductors such that an amount of current flowing through the first winding path and the third winding path is substantially the same and an amount of current flowing through the second winding path is different from the amount of current flowing through the first and third winding paths.