Electrical Machine Air-Gap and Slot Winding Torque Density
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Solution Overview
Problem
Existing electrical machines with air-gap windings lack efficiency and torque density, particularly at high speeds, and require significant materials for construction, limiting their compactness and lightweight potential.
Innovation Solution
The integration of a meandering air-gap winding on the stator and a slotted winding within the stator's slots, where both windings are connected to form conductors in a meandering shape, allowing for synchronized operation with magnetic poles, reducing material usage and enhancing torque and power density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single air-gap winding is used, then the structure is simple, but the torque density and power density are low
Solution Approach 1:
The patent combines two different winding structures (air-gap winding and slotted winding) into a single electrical machine system. The air-gap winding is arranged in the air gap between stator and rotor, while the slotted winding is arranged in slots of the stator iron core. Both windings work simultaneously to generate torque, achieving 60-80% higher torque density and power density compared to single winding designs.
Solution Approach 2:
The patent utilizes two different spatial dimensions for winding arrangement: the air-gap winding is positioned in the radial air gap, while the slotted winding is positioned within the stator slots. This multi-dimensional arrangement allows both windings to contribute to torque generation without interfering with each other, maximizing space utilization and electromagnetic performance.
2Force
If more materials are used for construction, then the machine can generate higher torque, but the machine becomes heavier and less compact
Solution Approach 1:
By merging air-gap winding and slotted winding in a coordinated manner, the patent achieves higher torque output without proportionally increasing material usage. The two windings share the electromagnetic workload, allowing each to be optimized for efficiency rather than brute-force material quantity.
Solution Approach 2:
The patent optimizes the electrical parameters (number of turns, wire gauge, winding configuration) of both air-gap and slotted windings to achieve maximum torque density. This parameter optimization allows the machine to generate high torque with minimized copper and iron material, reducing overall weight and improving power-to-weight ratio.
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 increases torque and power density by 60-80% compared to single air-gap winding designs, results in a lightweight, compact, and efficient machine suitable for high-speed applications with reduced manufacturing costs and minimal weight addition.
Implementation Method 1
The magnetic field in the air gap acts on each current-carrying phase and generates a Lorentz force.
Implementation Method 2
The magnetic field in the air gap acts on each current-carrying phase and generates a Lorentz force.
Data Source
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AI summary
An electrical machine (1) has a primary part (2), a secondary part (3) and an air gap (6) between said primary part and secondary part, an air gap winding (4) with two phases (4a, 4b) being arranged on an iron core (7) of the primary part in the said air gap. Magnetic poles (9) alternate on an iron core (10) of the secondary part. A magnetic circuit (11) runs via two poles (9a, 9b), the iron core in the secondary part, the air gap (6) twice and the iron core in the primary part. For each pole and each phase (4a, 4b), a winding phase (12a, 12b) lies perpendicular to a magnetic flux density (11a, 11b) in the air gap. Alternating head pieces (12c, 12d) connect adjacent winding phases of a phase of the air gap winding to form a conductor. The primary part has a slot winding (5) with two phases (5a, 5b) in slots (8) of the iron core (7). For each pole and each phase (5a, 5b), a winding phase lies parallel to the winding phase of the air gap winding which is associated with the same pole. Alternating head pieces (14c, 14d) connect adjacent winding phases (14a, 14b) of a phase (5a, 5b) of the slot winding to form a conductor. The winding phases (12a, 12b) of the first phase (4a) of the air gap winding have a position offset (a), which is determined by the number of phases, in relation to the winding phases (14a, 14b) of the first phase (5a) of the slot winding. The air gap winding and the slot winding can be operated by an activation which is alternately synchronized with the position of the magnetic pole (9).