Hybrid PM Rotor Layout for Lower Magnet Use and Back-EMF
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Solution Overview
Problem
Existing permanent magnet motors require significant amounts of magnet materials, leading to increased manufacturing costs and potential IGBT breakdown due to excessive open circuit counter-electromotive force, which affects driving safety.
Innovation Solution
A hybrid permanent magnet motor rotor design with alternating first and second magnetic pole parts, where the second pole part uses more magnets than the first, and a unique magnetic circuit arrangement to reduce magnet consumption while maintaining torque and controlling counter-electromotive force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If consequent pole type rotor is used to reduce magnet materials, then magnet consumption is reduced by half, but reluctance torque is reduced to 50% causing total torque to drop and requiring increased magnet amount again
Solution Approach 1:
The patent applies local quality by differentiating magnet placement between two types of magnetic poles: one type uses conventional magnet placement while the other type uses consequent pole structure without magnets. This local differentiation allows the motor to achieve both reduced overall magnet consumption and maintained torque output by strategically positioning magnets only where needed for optimal torque generation.
Solution Approach 2:
The rotor is segmented into two distinct types of magnetic poles: conventional poles with embedded magnets and consequent poles without magnets. This segmentation allows independent optimization of each pole type's magnetic flux generation mechanism, enabling the motor to reduce total magnet material while maintaining sufficient magnetic flux and torque through the combined contribution of both pole types.
2Power
If magnet amount is increased to compensate for reduced reluctance torque, then target output torque can be achieved, but open circuit counter-electromotive force increases by 20% causing IGBT breakdown risk
Solution Approach 1:
The patent changes the magnetic circuit parameters by introducing two types of magnetic poles with different magnet placements. This parameter change allows the motor to achieve the required output torque through optimized magnetic flux distribution rather than simply increasing magnet quantity, thereby controlling the open circuit counter-electromotive force within safe limits and preventing IGBT breakdown.
3Power
If conventional permanent magnet motor design is used, then sufficient torque is generated, but manufacturing cost increases due to high magnet material consumption
Solution Approach 1:
By applying local quality through differentiated magnet placement strategies for different magnetic pole types, the patent reduces overall magnet material consumption while maintaining sufficient torque generation capability. This localized optimization directly lowers manufacturing costs associated with magnet material procurement and installation without compromising the motor's torque 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
Reduces permanent magnet material usage by approximately 20%, lowers manufacturing costs, and maintains electromagnetic and reluctance torque levels, while preventing IGBT breakdown and ensuring safe driving.
Implementation Method 1
a plurality of magnet parts 112 embedded inside a plurality of magnet installation slots 114 respectively... the magnetic poles of the first magnetic pole part 20 and the second magnetic pole part 30 are arranged in opposite and alternately in the circumferential direction
Implementation Method 2
the reluctance torque is reduced... the magnetic flux is required to provide a magnetic flux similar to that of a general permanent magnet motor
Data Source
AI summary
A hybrid permanent magnet motor rotor rotates around a central axis, and includes: a rotor core provided with a plurality of magnet installation slots; and a plurality of magnet parts embedded inside a plurality of magnet installation slots respectively, wherein the rotor is provided with a plurality of first magnetic pole parts and a plurality of second magnetic pole parts, the magnetic poles of the first magnetic pole part and the second magnetic pole part are arranged in opposite and alternately in the circumferential direction, and the magnetic placement of the first magnetic pole part is different from that of the second magnetic pole part, the amount of magnets used in the second magnetic pole part is greater than that used in the first magnetic pole part.