Motor Busbar Layout for Symmetric Phase Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Brushless DC motors with internal rotor designs often exhibit asymmetries in phase resistances due to uneven distribution of electrical connections, leading to undesirable phase currents and inefficiencies.
Innovation Solution
The motor design features a stator with busbars arranged in a specific angular pattern and contact scheme, where each pair of windings is connected to three busbars with power source terminals located adjacent to each other, and the busbars are offset by 120°, ensuring symmetrical electrical resistances despite asymmetrical arrangements, and the first busbar is divided into sections to adjust resistance values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If electrical connections are concentrated at one point in the stator, then the device complexity is reduced, but the phase resistances become asymmetrical leading to undesirable phase currents
Solution Approach 1:
The patent applies asymmetry principle by intentionally designing the first busbar with an asymmetric contact scheme (three contact points in one section, one contact point in another section) to compensate for the inherent asymmetry caused by concentrated connection arrangement. This deliberate asymmetric design achieves symmetric phase resistances despite the simplified concentrated connection structure.
2Manufacturing precision
If busbars are designed with different contact schemes, then phase resistance symmetry is achieved, but the device complexity increases
Solution Approach 1:
The patent applies local quality principle by making each busbar have different contact schemes tailored to its specific position and function. The first busbar has a unique contact scheme with two sections to achieve proper resistance matching, while the second and third busbars have identical simpler contact schemes. This localized differentiation achieves overall symmetry without unnecessary complexity.
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 reduces asymmetry in the circuit diagram, maintaining low asymmetry values in phase resistances at a lower cost, enhancing motor efficiency and performance.
Implementation Method 1
the three busbars each including a power source connection terminal to electrically contact the busbar with a power source
Implementation Method 2
the first busbar, on the other hand, has a different contact scheme, the first busbar including a first section and a second section... With the first busbar different from the second and third busbars, the electrical resistances of the busbars can be symmetrical
Data Source
AI summary
An electric motor with stator includes pairs of windings. Winding wire ends of the pairs of windings are electrically contacted at end surfaces with three busbars to define three phases. The three busbars include power source connection terminals which are located adjacent to one another, and the second and third busbars extending over an angular range of approximately 210°, having a same contact scheme with four contact points following one another in the circumferential direction to contact the winding ends and are offset from one another by approximately 120° in the circumferential direction, and the first busbar has a different contact scheme. The first busbar includes a first section and a second section, three contact points located in the first section, a further contact point being located in the second section.