Brushless Doubly-Fed Motor Rotor Harmonic Control
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Solution Overview
Problem
Existing AC brushless double feed motors have performance limitations due to restricted rotor designs, which restrict their applicability and efficiency, particularly in generating both fundamental and slot harmonics magnetic forces with opposite revolving directions, leading to suboptimal speed control and increased volume.
Innovation Solution
The motor incorporates rotor windings with reversely connected coils, varying slot distributions, and multiturn coils to optimize slot harmonics, ensuring high winding factors for both fundamental and slot harmonics magnetic forces, while minimizing high-order harmonics by adjusting the number of slots and coil turns to enhance performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional rotor structures (reluctor or cage type short-circuit windings) are used, then the motor can be manufactured with conventional designs, but the rotor can only be applicable to certain number of poles and performance is greatly lower than common AC motor with larger volume
Solution Approach 1:
The patent changes the fundamental parameter of rotor structure from traditional reluctor or cage types to a winding rotor with specific coil configurations. By altering the rotor winding arrangement, connection patterns, and slot distributions, the motor achieves improved performance and reduced volume while maintaining manufacturability through conventional winding techniques.
Solution Approach 2:
The patent employs a composite approach by combining specific winding patterns with slot harmonics theory to create a hybrid rotor design that integrates the benefits of both traditional and innovative structures, achieving superior performance characteristics.
2Productivity
If rotor windings are designed to generate both fundamental and slot harmonics magnetic forces with opposite revolving directions, then speed control performance is improved, but the rotor structure becomes more complex with restricted applicability
Solution Approach 1:
The patent segments the rotor windings into distinct coil groups with specific connections, where some coils generate fundamental magnetic forces while others generate slot harmonics with opposite revolving directions. This segmentation allows independent optimization of each component's function while maintaining overall system performance.
Solution Approach 2:
The patent implements opposite revolving directions for fundamental and slot harmonics magnetic forces by using reversely connected coils. This inversion strategy enables the generation of two distinct magnetic fields rotating in opposite directions, improving speed control performance through dual-field interaction.
3Productivity
If high winding factors are achieved for both fundamental and slot harmonics magnetic forces, then motor efficiency is improved, but the number of slots and coils must be precisely controlled increasing manufacturing constraints
Solution Approach 1:
The patent optimizes specific parameters including the number of slots, coil turns, and winding patterns to achieve high winding factors for both fundamental and slot harmonics. By carefully selecting and controlling these parameters, the design maximizes motor efficiency while maintaining feasible manufacturing requirements.
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 design achieves improved speed control, reduced vibration and noise, and increased efficiency by maximizing first-order slot harmonics while minimizing high-order harmonics, resulting in better motor performance and applicability across various power sources.
Implementation Method 1
the induced current of rotor will generate P2 pole pairs of magnetic field besides P1 pole pairs of magnetic field
Implementation Method 2
the ' slot harmonics' hereafter means slot harmonics magnetic force generated when rotor windings are with current
Implementation Method 3
when windings of stator P1 is power-on, revolving magnetic field with P1 pole pairs is generated. the induced current of rotor will generate
Data Source
Figure 1a~3
Figure 4~6
Figure 7~8
AI summary
The invention disclose a type of winding rotator brushless double feed motor. This invention falls into motor technology field. The AC brushless double feed motor's rotator is equipped with two sets of three phase windings whose number of pole pairs is p1 and p2; the rotator is in manner of multiphase winding, number of pole pairs is P1 and P2, and rotator is of multiphase coil windings, number of phases m is: m = (p1 + p2) / mk in which , mk=1, when p1+p2 is odd; ; mk=2, when p1+p2 is even, , rotor slots are distributed around air gaps, the number of slots Z' is : Z' = n(p1 + p2) in which , n is a positive integer , coil of rotator windings is in structure of multi turn, number of coils of each phase is nmk, distance between each coil is even, but the number of turns of each coil is different, when number of phase winding coils is ≤nmk, all coils of phase windings will be short circuit connected after then are connected in series. The advantage of this invention lies in that, not only span of winding coils can be changed flexibly, the number of turns of each coil is different, in order to remove higher-order harmonics as possibly as.