Compressor Motor Rotor Structure for Stable Magnet Gap and Back-EMF
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Solution Overview
Problem
Reciprocating compressors using interior permanent magnet (IPM) motors face issues with increased motor excitation force and decreased back electromotive force compared to surface-mounted permanent magnet (SPM) motors, leading to inefficiencies and performance degradation.
Innovation Solution
A compressor motor design featuring a rotor core with axially stacked magnetic steel plates, seating grooves for magnets, and radially protruding features, along with a fixing member to secure the magnets, which reduces motor excitation force and enhances back electromotive force while maintaining a constant gap between the magnet and stator, improving safety and assembly efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
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 leading to efficiency degradation
Solution Approach 1:
The patent changes the geometric parameters of the rotor by introducing protrusions that radially protrude from the rotor core. This structural parameter change modifies the magnetic field distribution and flux path, thereby adjusting the motor's excitation force and back electromotive force characteristics to improve overall efficiency while maintaining structural reliability
Solution Approach 2:
The rotor structure is segmented into distinct components: the rotor core, multiple protrusions radially arranged on the rotor core, and magnets positioned on the protrusions. This segmentation allows independent optimization of each component's function, enabling the protrusions to serve as both structural support and magnetic flux guides, thus resolving the contradiction between structural stability and efficiency
2Productivity
If magnets are mounted on the surface of the rotor (SPM motor), then the motor excitation force is reduced and back electromotive force is maintained, but the structural complexity increases and assembly difficulty arises
Solution Approach 1:
The patent merges the functions of the rotor core, magnet mounting structure, and magnetic flux guidance into a unified design where protrusions extend from the rotor core to support the magnets. This integration reduces the number of separate components compared to traditional SPM motors, simplifying the overall rotor structure while maintaining the efficiency benefits of surface-mounted magnets
3Strength
If magnets are inserted into the rotor core (IPM motor), then the structural strength is improved, but the manufacturing precision requirements increase and assembly difficulty increases
Solution Approach 1:
The protrusions are pre-formed on the rotor core before magnet installation, creating predetermined mounting positions with precise geometry. This preliminary action establishes accurate reference surfaces and positioning features that guide magnet placement, thereby reducing the precision requirements during the actual assembly process while maintaining the structural benefits of embedded magnets
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 solution effectively reduces motor excitation force, increases back electromotive force, enhances safety, and lowers manufacturing costs by preventing magnet detachment and optimizing assembly, thus improving the overall performance and efficiency of the compressor motor.
Implementation Method 1
a motor 100, and a compression unit 200 configured to receive a rotational force of the motor 100
Implementation Method 2
a plurality of magnets 420 disposed on a radially outer surface of the rotor core 410
Data Source
AI summary
A compressor motor and a compressor including a compressor motor are provided. The compressor motor may include a stator and a rotor. The rotor may include a rotor core and a plurality of magnets disposed on a radially outer surface of the rotor core. The rotor core may include a plurality of seating grooves in which the plurality of magnets is respectively seated, and a plurality of protrusions that protrudes radially outward between the plurality of seating grooves. The magnet may slide axially between adjacent protrusions of the plurality of protrusions, an inner surface of the magnet may be seated in the seating groove, and at least a portion of a side surface of the magnet may contact a side surface of the protrusion. The side surface of the magnet may extend and protrude further radially outward than the side surface of the protrusion, and a fixing layer may be disposed in at least a partial area radially outward of the outer peripheral surface of the protrusion.