Motor and compressor comprising the motor
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Solution Overview
Problem
Existing rotary direct-current variable-frequency compressors with built-in permanent magnet motors suffer from significant armature iron loss and vibration noise due to strong stator armature reaction and composite magnetic field harmonics, which are difficult to reduce through targeted design.
Innovation Solution
A rotor design with specific slit configurations and permanent magnet arrangements, including non-coincident extension lines and optimized slit angles, reduces armature iron loss and vibration noise by enhancing the air gap magnetic field harmonics and counter-electromotive force waveform.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If higher power density is designed to improve cost performance, then power density is improved, but armature iron loss increases
Solution Approach 1:
The patent changes the geometric parameters of the rotor structure by introducing slits with specific angle ranges (α1 and α2 where α1 + α2 > 180°) and positioning them asymmetrically relative to the d-axis. This parameter modification optimizes the air gap magnetic field distribution, reducing harmonic components that cause armature iron loss while maintaining high power density design
Solution Approach 2:
The patent employs asymmetric arrangement of slits on the rotor core, where slits are positioned at specific angles relative to the d-axis rather than symmetrically. This asymmetric configuration creates an optimized magnetic field distribution pattern that reduces harmful harmonics and armature iron loss, while the permanent magnets are also arranged with non-coincident extension lines to achieve similar asymmetric optimization
2Loss of energy
If slits are arranged to reduce armature iron loss, then energy efficiency is improved, but manufacturing complexity increases
Solution Approach 1:
The patent integrates the slits directly into the rotor core structure, creating a composite rotor design that combines magnetic material with air gaps in a unified structure. This approach, while geometrically complex, can be manufactured as an integrated component, reducing the need for separate assembly steps and potentially offsetting the manufacturing complexity through design integration
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 rotor design effectively minimizes armature iron loss, improves energy efficiency, reduces vibration noise, and enhances the performance of compressors by optimizing the air gap flux density harmonics and counter-electromotive force.
Implementation Method 1
a permanent magnet arranged in the installation recess to form a magnetic pole, wherein the permanent magnet comprises a first permanent magnet and a second permanent magnet
Implementation Method 2
the action of stator armature reaction is stronger, so that the rotor structure of the motor has a great armature iron loss
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A rotor, a motor, a compressor, and a refrigeration apparatus. The rotor (1) comprises: a rotor iron core (10) having multiple installation recesses (12) arranged in a circumferential direction of the rotor iron core (10); permanent magnets provided in the installation recesses (12) to form magnetic poles; multiple slits arranged at the rotor iron core (10) and positioned at respective sides of the installation recesses (12) away from a rotation axis of the rotor (1), a connection line between central points of two end portions of the slit close to and away from the installation recess (12) forming a direction line of the slit within a cross-section perpendicular to the rotation axis of the rotor (1), wherein the slits include a first slit (14) and a second slit (16) positioned at the same side of d axis, extension lines of the direction lines of the first slit (14) and the second slit (16) intersect at an intersection point not on d axis, and a central line of any magnetic pole passing through a central axis of the rotor iron core (10) is set as d axis. The above arrangement can reduce air gap flux density harmonics of the rotor (1), reduce fluctuation of torque of a motor, and increase a counter-electromotive force of the rotor (1), thereby enhancing energy efficiency of a compressor.