Consequent Pole Motor Vibration Reduction via Tooth Width Variation
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Solution Overview
Problem
Consequent pole permanent magnet motors face challenges in reducing radial vibration and maintaining magnetic performance while minimizing the use of rare-earth permanent magnets, leading to increased size and cost, particularly in motor vehicles.
Innovation Solution
A motor design featuring a soft magnetic annular rotor with a specific arrangement of permanent magnet poles and consequent poles, along with a full-pitch distributed winding armature, which optimizes the number of teeth and magnetic flux distribution to match the rotating magnetic field, reducing radial vibration and size while maintaining torque performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a consequent pole rotor is used to reduce the number of permanent magnet poles, then the usage of rare-earth permanent magnets is reduced, but radial vibration increases causing noise
Solution Approach 1:
The patent applies local quality by creating non-uniform tooth width distribution in the armature. Specifically, teeth are designed with different widths: first teeth have a first width, second teeth have a second width greater than the first, and third teeth have a third width greater than the first. This localized variation in tooth dimensions creates corresponding variations in magnetic resistance along the circumferential direction, which balances the magnetic flux distribution and reduces radial vibration in consequent pole motors.
Solution Approach 2:
The patent changes the parameter of tooth width to optimize magnetic flux distribution. By varying the width of teeth (first width, second width > first width, third width > first width) rather than using uniform teeth, the magnetic resistance is adjusted locally. This parameter change enables better matching between the rotating magnetic field and the armature structure, reducing radial vibration while maintaining the benefits of reduced permanent magnet usage.
2Reliability
If the number of teeth in the armature is increased to match the pole pair number, then magnetic performance is improved, but the size and cost of the motor increases
Solution Approach 1:
The patent applies local quality by creating non-uniform tooth width distribution in the armature. Specifically, teeth are designed with different widths: first teeth have a first width, second teeth have a second width greater than the first, and third teeth have a third width greater than the first. This localized variation in tooth dimensions creates corresponding variations in magnetic resistance along the circumferential direction, which balances the magnetic flux distribution and reduces radial vibration in consequent pole motors.
Solution Approach 2:
The patent uses partial action by implementing tooth width variations only in specific regions rather than uniformly across all teeth. The first teeth have a baseline width, while only certain second and third teeth have increased widths. This selective approach achieves the necessary magnetic flux balance and vibration reduction without requiring all teeth to be oversized, thereby controlling motor size and cost while maintaining improved magnetic performance.
3Ease of manufacture
If conventional tooth arrangement is used in consequent pole motors, then manufacturing is simplified, but magnetic flux distribution becomes unbalanced causing vibration
Solution Approach 1:
The patent applies local quality by creating non-uniform tooth width distribution in the armature. Specifically, teeth are designed with different widths: first teeth have a first width, second teeth have a second width greater than the first, and third teeth have a third width greater than the first. This localized variation in tooth dimensions creates corresponding variations in magnetic resistance along the circumferential direction, which balances the magnetic flux distribution and reduces radial vibration in consequent pole motors.
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 design effectively reduces radial vibration, increases magnetic flux, and minimizes the use of rare-earth permanent magnets, balancing performance and cost competitiveness in motor vehicles.
Implementation Method 1
a three-phase armature winding 2b wound in the armature core 2a in distributed, full pitch winding configuration... generates a rotating magnetic field that interacts with the rotor poles
Implementation Method 2
a soft magnetic rotor with a plurality of consequent poles and with a plurality of permanent magnet poles... the magnetic polarities of the plurality of permanent magnet poles cause the plurality of projections to be consequently magnetized
Data Source
AI summary
In a motor, an armature is provided to be opposite to a rotor member for generating a rotating magnetic field. In the armature, plural sets of teeth are arranged in a direction of rotation of the rotor member such that each set of teeth in the plural sets of teeth is within one electrical angular cycle of the rotating magnetic field. The one electrical angular cycle corresponds to one pole-pair pitch of the annular rotor member. A number of teeth in the plurality of teeth within the one pole-pair pitch is set to 2k (k is a natural number), and a number of teeth facing each of the first magnetic poles in the plurality of teeth is set to be equal to or greater than the sum of k and 1.