BLDC Stator Parallel Windings for Higher Power Density
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Solution Overview
Problem
Existing brushless motor assemblies for rotary tools face challenges in achieving high power density due to limitations in stator winding configurations and magnetic flux efficiency, leading to suboptimal torque output and electrical resistance.
Innovation Solution
The design incorporates a stator assembly with dual sets of windings wound in parallel on each stator tooth, utilizing smaller diameter magnet wires to increase slot fill and wire density, along with a circuit board that connects the windings in a delta-parallel configuration, optimizing the magnetic and electrical envelopes to enhance power output and reduce resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional single set of windings is used on stator teeth, then device complexity is low, but power density and torque output are insufficient
Solution Approach 1:
The stator windings are divided into multiple parallel sets (first set and second set) wound on each stator tooth. Each set operates independently but contributes to the same magnetic flux, effectively segmenting the current path to reduce resistance and increase power density without requiring a complete redesign of the stator structure.
Solution Approach 2:
The patent introduces a parallel dimensional configuration by winding multiple sets of coils in parallel on each stator tooth rather than using a single series winding. This multi-dimensional approach to winding arrangement increases the effective conductor cross-section and reduces electrical resistance, thereby enhancing power density.
2Power
If smaller diameter magnet wires are used to increase slot fill, then wire density and power output increase, but manufacturing precision requirements increase
Solution Approach 1:
The patent changes the wire diameter parameter to a smaller size, which increases the number of turns that can be packed into each stator slot. This parameter change directly increases the conductor cross-sectional area within the slot, improving slot fill factor and consequently increasing power output and reducing electrical resistance.
3Force
If dual sets of parallel windings are implemented, then electrical resistance decreases and torque output improves, but device complexity increases
Solution Approach 1:
The patent merges multiple parallel winding sets on each stator tooth into a unified magnetic circuit. The first and second sets of windings are connected in parallel and work together to generate additive magnetic flux in the air gap, effectively combining their contributions to produce higher torque output while sharing the same physical stator structure.
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 significantly increases the motor's power output density, achieving higher torque ratings and improved thermal efficiency while maintaining a compact size, outperforming conventional BLDC motors in terms of motor constant and power output.
Implementation Method 1
a stator assembly with dual sets of windings wound in parallel on each stator tooth
Implementation Method 2
utilizing smaller diameter magnet wires to increase slot fill and wire density, along with a circuit board that connects the windings in a delta-parallel configuration, optimizing the magnetic and electrical envelopes to enhance power output
Data Source
AI summary
A brushless direct-current (BLDC) motor includes a stator assembly and a rotor assembly including a rotor supporting permanent magnets rotatable relative to the stator assembly. The stator assembly includes a stator comprising a stator core and stator teeth radially extending from the stator core and defining slots therebetween. A first set of stator windings is wound on the stator teeth, and a second set of stator windings is also wound on the stator teeth such that, on each stator tooth, the first and second windings are provided in an electrically parallel configuration.