IPM Synchronous Machine Flux Shift for Torque Optimization
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Solution Overview
Problem
Conventional reluctance-parallel-use magnet synchronous machines require a large amount of expensive rare-earth magnets to increase output torque, which is inefficient and costly.
Innovation Solution
A synchronous machine design with a rotor featuring magnetic salient poles and permanent magnets, where the magnetic flux is shifted by a predetermined angle to optimize the combination of magnet torque and reluctance torque, reducing the need for increased magnet usage by altering the distribution and phase of magnetic flux.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a larger amount of rare-earth magnet is used to increase output torque, then torque output is improved, but cost and material usage increase significantly
Solution Approach 1:
The patent changes the positional parameter of the magnetic flux by shifting it by a predetermined angle Δθ from the reference position between paired magnetic salient poles. This parameter change optimizes the harmonic component alignment between magnet torque and reluctance torque, enabling increased output torque without proportionally increasing magnet material usage
Solution Approach 2:
The patent introduces a dynamic optimization approach by adjusting the magnetic flux position angle to achieve optimal torque synthesis. The shift angle Δθ is determined to maximize the sum of harmonic components, creating a dynamic optimization of torque output relative to magnet material input
2Power
If magnetic salient poles are arranged at q-axis positions with permanent magnets at d-axis positions to increase q-axis inductance, then reluctance torque is improved, but the structure becomes more complex and magnet usage increases
Solution Approach 1:
The patent modifies the positional parameter of magnetic flux emission from permanent magnets, shifting it by angle Δθ from the conventional d-axis position. This parameter change optimizes the interaction between magnet torque and reluctance torque harmonics, improving overall torque output while maintaining a simpler rotor structure without requiring additional magnetic salient poles
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 enhances torque output while minimizing the amount of magnet material required, achieving higher efficiency and cost-effectiveness by aligning the harmonic components of magnet and reluctance torque, thus increasing synthesized torque without excessive magnet usage.
Implementation Method 1
permanent magnets embedded in the rotor; magnet-originating magnetic poles that generate magnet torque by using permanent magnets
Implementation Method 2
magnetic salient poles that generate reluctance torque; difference between q-axis inductance Lq and d-axis inductance Ld; magnetic resistance of a permanent magnet
Implementation Method 3
synchronous machine that generates magnet torque and reluctance torque; rotor that faces the stator and rotates on a shaft thereof
Data Source
AI summary
A synchronous machine comprises a stator and a rotor that faces the stator and rotates on a shaft thereof in a circumferential direction. The rotor has magnetic salient poles that generate reluctance torque and magnet-originating magnetic poles that generate magnet torque by using permanent magnets embedded in the rotor. The machine comprises means for shifting a magnetically substantial central position of magnetic flux emanating from the permanent magnets in the circumferential direction, by an electrical angle π/2 plus a predetermined angle Δθ, from a reference position taken as a central position between paired magnetic salient poles composing each magnetic pole of the machine among the magnetic salient poles. Hence a maximum amplitude of a sum between a harmonic component of the magnet torque and the reluctance torque is changed from that obtained at the reference position without the shift.