Reluctance Machine Rotor Active Elements Torque Ripple
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Solution Overview
Problem
Reluctance machines experience significant torque ripple due to oscillations with slot frequency and pole pair frequencies, which current methods like skewing the stator or rotor have not adequately addressed, leading to inefficiencies and increased costs.
Innovation Solution
The design incorporates axially symmetrical active elements with specific angular configurations on the rotor, such as curved surfaces and offset pairs, to minimize magnetic resistance and reduce torque fluctuations, including the use of laminated electrical steel and strategic angle settings like α=(n+1/2)*α_n1 and α_3n1 to mitigate torque ripples at various frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If skewing the stator or rotor by a stator slot pitch is applied to reduce torque ripple, then torque fluctuations are partially mitigated, but additional costs are generated and the solution is insufficient
Solution Approach 1:
The patent changes the geometric parameters of the rotor active elements by defining specific angular positions using the formulas α=(n+1/2)*α_n1 and α_3n1, where α_n1=360°/N1. This parameter optimization reduces torque ripple at slot frequency and its harmonics without requiring skewing, thereby avoiding additional manufacturing costs while effectively mitigating torque fluctuations.
2Object-affected harmful factors
If the number of pole pairs is increased to reduce torque ripple, then torque fluctuations decrease, but the machine design becomes more complex
Solution Approach 1:
The patent applies local quality by optimizing the angular configuration of individual rotor active elements relative to the stator slots. Each active element is positioned at specific angles α and α_3n1 to locally minimize magnetic reluctance variations. This localized optimization reduces torque ripple without increasing the overall number of pole pairs, thereby avoiding increased device complexity.
3Reliability
If thin layers of non-magnetic material are arranged between laminations to increase magnetic resistance, then magnetic properties are improved, but manufacturing complexity increases
Solution Approach 1:
The patent introduces asymmetry in the angular positioning of rotor active elements using the formulas α=(n+1/2)*α_n1 and α_3n1. This asymmetric configuration creates optimal magnetic reluctance paths that reduce torque ripple without requiring additional non-magnetic layers between laminations. The asymmetric angular arrangement achieves improved magnetic resistance characteristics through geometric optimization rather than material modification, thereby reducing manufacturing complexity.
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 approach significantly reduces torque ripple, particularly at triple slot frequency, enabling the use of reluctance machines in applications previously limited by torque fluctuations, such as electric vehicles and production technology motors.
Implementation Method 1
A torque in the rotor is generated exclusively by a reluctance force, i.e. a force due to magnetic resistance. The system of stator and rotor strives for a minimum magnetic resistance, so that a rotational movement of the rotor of the reluctance machine is generated.
Data Source
Figure 1
AI summary
The utility model relates to a magnetic resistance motor (10) which is provided with a stator (11) and a rotor (12), wherein the rotor (12) is provided with a plurality of acting elements (41-44), each acting element is provided with at least one acting surface (45), and all the acting surfaces (45) respectively form a section of the rotor, face the stator (11) and play a role in reducing the torque vibration of the magnetic resistance motor (10).