Interior Permanent Magnet Motor Rotor Flux Control
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Solution Overview
Problem
Conventional interior permanent magnet motors focus on maximizing efficiency at high power without considering the operating range, leading to reduced saliency ratio, increased iron loss, and limited operation range due to the arrangement of permanent magnets.
Innovation Solution
The motor design includes a rotor with permanent magnets arranged such that the central magnet is thicker than the side magnets, with barriers of non-magnetic material to control magnetic flux, and stator teeth widths optimized to maintain magnetic circuit integrity, enhancing the saliency ratio by adjusting the inductance ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If permanent magnets are arranged in V-shape or U-shape with constant thickness to maximize cross-sectional area, then magnetic flux and maximum power efficiency are improved, but operation range is reduced and saliency ratio decreases
Solution Approach 1:
The patent applies local quality by varying the thickness of permanent magnets along the radial direction. The central permanent magnet has a first thickness while the side permanent magnets have a second thickness that is 0.05 to 0.15 times the first thickness. This local variation optimizes magnetic flux distribution in different regions, improving both maximum power efficiency and operation range simultaneously.
Solution Approach 2:
The patent changes the thickness parameter of permanent magnets from a constant value to a variable value. By setting the side magnet thickness to 0.05 to 0.15 times the central magnet thickness, the design achieves optimal balance between magnetic flux maximization and saliency ratio improvement, thereby expanding operation range while maintaining high power efficiency.
2Quantity of substance
If deep magnet arrangement is used to maximize permanent magnet cross-sectional area, then magnetic flux is maximized, but magnetic flux saturation of stator core increases
Solution Approach 1:
The patent applies local quality by varying magnet thickness radially - the central magnet maintains full thickness for maximum flux, while side magnets are reduced to 0.05 to 0.15 times that thickness. This prevents excessive flux concentration in stator core teeth, reducing magnetic saturation and associated iron losses while preserving overall magnetic flux quantity.
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 design improves low-speed efficiency, reduces input current, and expands the operational range by optimizing the saliency ratio, resulting in enhanced performance compared to conventional motors.
Implementation Method 1
a plurality of permanent magnets (40) disposed inside the rotor core (31)... two adjacent permanent magnets (40-1, 40-2) have different magnetic poles so that the two adjacent permanent magnets (40-1, 40-2) form a magnetic circuit
Data Source
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AI summary
An interior permanent magnet motor includes a stator comprising a hollow and a plurality of coils provided around the hollow; and a rotor rotatably disposed in the hollow of the stator and comprising a plurality of permanent magnets therein. Each of the plurality of permanent magnets of the rotor comprises a central permanent magnet; a pair of side permanent magnets provided at opposite ends of the central permanent magnet to be inclined toward an outer circumferential surface of the rotor; and a pair of barriers provided between the central permanent magnet and the pair of side permanent magnets, a thickness of each of the pair of barriers is equal to or greater than a thickness of the central permanent magnet. The thickness of the central permanent magnet is greater than a thickness of each of the pair of side permanent magnets.