Compressor Motor Rotor Structure for Lower Excitation Force
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing reciprocating compressors using interior permanent magnet (IPM) motors face increased motor excitation force and decreased back electromotive force compared to surface-mounted permanent magnet (SPM) motors, leading to inefficiencies and higher manufacturing costs.
Innovation Solution
A compressor motor design featuring a rotor core formed by axially stacking magnetic steel plates with seating grooves and protrusions, where magnets are seated and fixed using a fixing member, allowing for one-point contact and minimizing contact area to reduce excitation force and maintain a constant gap with the stator, enhancing back electromotive force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If interior permanent magnet (IPM) motors are used in reciprocating compressors, then the motor structure is improved with better magnetic field distribution, but the motor excitation force increases and back electromotive force decreases
Solution Approach 1:
The rotor core is segmented into multiple magnetic steel plates stacked axially, with seating grooves and protrusions created between them. This segmentation allows for precise positioning of magnets and creates a structure that reduces motor excitation force while maintaining structural integrity.
Solution Approach 2:
The design implements local quality changes by creating protrusions at specific locations between magnetic steel plates and positioning magnets with precise gaps relative to stator teeth. This local structural modification optimizes magnetic field distribution and reduces excitation force in critical areas.
2Shape
If interior permanent magnet (IPM) motors are used in reciprocating compressors, then the motor structure is improved with better magnetic field distribution, but the back electromotive force decreases
Solution Approach 1:
The design creates a dynamic magnetic circuit path through the protrusions and seating grooves structure, allowing the magnetic field to be optimized during operation. The constant gap between magnets and stator teeth maintains optimal magnetic coupling for back electromotive force generation.
Solution Approach 2:
The invention changes critical parameters including the gap distance between magnets and stator teeth, the positioning of protrusions relative to magnetic steel plates, and the axial stacking configuration. These parameter optimizations work together to improve back electromotive force despite the IPM motor structure.
3Ease of manufacture
If magnets are fixed using adhesive in IPM motors, then the assembly process is simplified, but the manufacturing precision and reliability are compromised due to adhesive drying time and tolerance issues
Solution Approach 1:
The magnetic steel plates with integrated seating grooves and protrusions create a self-positioning system for magnets. The protrusions automatically locate magnets in the correct positions during assembly, eliminating the need for adhesive and ensuring precise positioning without tolerance accumulation issues.
4Ease of operation
If the gap between magnets and stator teeth varies due to tolerance accumulation, then the assembly is easier, but the motor output decreases
Solution Approach 1:
The seating grooves and protrusions are pre-formed on the magnetic steel plates before final assembly. This preliminary action establishes fixed reference positions that maintain a constant gap between magnets and stator teeth, preventing tolerance accumulation from affecting motor output.
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 reduces motor excitation force, improves back electromotive force, enhances assembly ease, compensates for product tolerance, and maintains output efficiency while reducing manufacturing costs and improving safety factors.
Implementation Method 1
a magnet 420 inserted into the rotor core 410... a stator 300 including a stator part 310 and a coil 320 wound around the stator part 310
Implementation Method 2
the use of interior permanent magnet (IPM) motors 300 and 400 in which a magnet 420 is inserted into the rotor 400... a back electromotive force decreased
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A compressor motor and a compressor including the same are provided. The compressor motor comprises a stator and a rotor disposed inside the stator and coupled to a shaft. The rotor includes a rotor core formed by axially stacking a plurality of magnetic steel plates and a plurality of magnets that is disposed on a radially outer surface of the rotor core and is spaced apart in a circumferential direction. The rotor core includes a plurality of seating grooves in which the plurality of magnets are respectively seated, and a plurality of protrusions that protrudes radially outward between the plurality of seating grooves. The protrusion includes both side surfaces extending radially outward and an outer peripheral surface connecting the both side surfaces in the circumferential direction. The magnet includes four surfaces extending axially, and the four surfaces include an inner surface facing radially inward, an outer surface that is positioned opposite to the inner surface and faces an outer peripheral surface of the rotor, and two side surfaces connecting the inner surface and the outer surface. The magnet slides axially between adjacent protrusions of the plurality of protrusions, the inner surface of the magnet is seated in the seating groove, and at least a portion of the side surface of the magnet contacts a side surface of the protrusion. The side surface of the magnet extends and protrudes further radially outward than the side surface of the protrusion, and a fixing member is disposed in at least a partial area radially outward of the outer peripheral surface of the protrusion.