Interior Permanent Magnet Motor Rotor Structure for Demagnetization Resistance
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Solution Overview
Problem
Existing interior permanent magnet motors face challenges in preventing demagnetization of arc-shaped permanent magnets due to electromagnetic forces, which can cause movement of the magnets within the magnet insertion holes, reducing demagnetization suppression effectiveness and magnetic resistance.
Innovation Solution
The design incorporates arc-shaped permanent magnets and magnet insertion holes with straight surfaces orthogonal to the magnetic pole center line, forming air gaps and ensuring contact between these surfaces to restrict magnet movement without abutment portions, maintaining magnetic resistance and preventing demagnetization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If abutment portions are formed by reducing the width of magnet insertion hole side end surfaces, then permanent magnet movement is restricted, but magnetic resistance increases and demagnetization suppression effect is reduced
Solution Approach 1:
The magnet insertion hole is segmented into different functional zones: the main body portion maintains a width that preserves magnetic resistance and demagnetization suppression, while the side end portions are selectively reduced to form abutment portions. This segmentation allows the hole to simultaneously provide mechanical restraint and magnetic protection, resolving the contradiction between restricting magnet movement and maintaining demagnetization suppression effect.
2Power
If arc-shaped permanent magnets are used, then magnetic efficiency is improved, but magnets may move inside magnet insertion holes due to electromagnetic forces
Solution Approach 1:
The magnet insertion hole is designed with asymmetric width distribution: the width at the side end surfaces is reduced to form abutment portions that prevent lateral movement, while the width in the main body is maintained to preserve magnetic efficiency. This asymmetric design allows the hole to simultaneously accommodate the arc-shaped magnet for high magnetic performance and provide mechanical restraint through the narrower abutment portions.
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 configuration effectively restricts permanent magnet movement, enhances demagnetization resistance, and maintains magnetic efficiency, allowing for reliable operation even in high-load regions without reducing the demagnetization suppression effect.
Implementation Method 1
at least one straight surface configured to suppress movement of the permanent magnet along the magnet insertion hole having the arc shape
Implementation Method 2
air gap portions are secured respectively between both side end surfaces that are both ends of an arc of each of the magnet insertion holes and both side end surfaces that are both ends of the arc of each of the permanent magnets
Implementation Method 3
the width of the magnet insertion hole is reduced so that the magnetic resistance is reduced
Implementation Method 4
an electromagnetic force generated during the drive of the motor
Implementation Method 5
When a large current flows through the stator to apply a demagnetizing field to the rotor
Data Source
AI summary
In an interior permanent magnet motor, each of permanent magnets has a radially-inner magnet contour surface, a radially-outer magnet contour surface, and a pair of side-end magnet contour surfaces. Each of magnet insertion holes has a radially-inner insertion hole contour surface, a radially-outer insertion hole contour surface, and a pair of side-end insertion hole contour surfaces. The radially-outer magnet contour surface and the radially-outer insertion hole contour surface are each formed by a first arc surface. The radially-inner magnet contour surface and the radially-inner insertion hole contour surface are each formed by a second arc surface and at least one straight surface configured to suppress movement of the permanent magnet along the magnet insertion hole having an arc shape.