Flexible Winding for Electric Motor Torque Consistency
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Solution Overview
Problem
Existing electric machine windings face challenges in achieving consistent torque across phases due to unequal magnetic fields, necessitating varying coil turns to compensate for radial position differences in slotless, brushless motors with a permanent magnet rotor and electromagnetic stator.
Innovation Solution
A flexible winding design using a 3-phase air gap winding with a stator back-iron structure, where the winding is laid out on a flat flexible printed circuit rolled into a cylinder with phases separated by 120 degrees, and utilizing two circuits with copper coils on either side of the flex to adjust the number of turns in each phase, ensuring consistent torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the winding is placed radially in an equivalent magnetic field, then the magnetic field distribution is uniform, but the torque consistency across phases deteriorates due to radial position differences
Solution Approach 1:
The patent applies local quality by varying the number of turns in coils of each phase according to their specific radial positions. Coils at different radii have different turn counts to compensate for the non-uniform magnetic field strength at different distances from the rotor, ensuring each phase produces consistent torque despite occupying different radial positions in the air gap.
2Reliability
If the number of turns in coils of each phase is varied to compensate for radial position differences, then torque consistency across phases is improved, but the winding structure complexity increases
Solution Approach 1:
The patent changes the parameter of coil turn count to compensate for radial position variations. By adjusting the number of turns as a variable parameter based on each coil's radial position, the system achieves torque consistency across phases. This parameter adjustment is implemented through a systematic design process that calculates optimal turn counts for different phases.
Solution Approach 2:
The winding structure is segmented into multiple phases with distinct coil configurations. Each phase is independently designed with specific turn counts tailored to its radial position requirements. This segmentation allows for optimized torque production in each phase while maintaining overall system coordination through the 120-degree phase separation.
3Ease of manufacture
If a flat flexible printed circuit is rolled into a cylinder, then the manufacturing ease and adaptability are improved, but the precision of phase separation and winding alignment becomes more difficult
Solution Approach 1:
The patent applies preliminary action by pre-defining the phase separation geometry and winding patterns on the flat flexible printed circuit before rolling. The 120-degree phase separation and coil configurations are precisely laid out in the flat state, ensuring that when rolled into a cylinder, the phases automatically achieve the correct angular separation and alignment without requiring post-assembly adjustments.
Solution Approach 2:
The patent transitions from a flat 2D circuit layout to a curved 3D cylindrical configuration. The flexible printed circuit is designed with predetermined curvature characteristics that, when rolled, naturally form the cylindrical stator structure with correct phase angles. This curvature transformation maintains manufacturing simplicity while achieving precise geometric relationships.
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 ensures consistent torque production across phases by varying the number of turns in each coil, enhancing the performance and efficiency of the electric machine by minimizing magnetic field disparities.
Implementation Method 1
an electromagnetic stator magnetic field wherein the stator field is produced by a 3-phase air gap winding
Implementation Method 2
a permanent magnet rotor magnetic field
Data Source
AI summary
A flexible winding, for a brushless, rotating motor, comprising a flexible substrate. A first winding circuit is disposed on a first side of the substrate. The flexible substrate is rolled into a substantially cylindrical shape such that the first winding circuit forms a winding suitable for an electric machine, such as a rotary motor.