J Jing Bao

Usage of the Inductive Energy Storage in the Field Winding for Driving the Variable Reluctance Motor

In automotive systems, reliability and cost are paramount for the success of electrical drive systems. Considering the switched reluctance motor (SRM), the power electronics cost dominates the total cost of the electrical drive. In this respect, especially the dc-link capacitor significantly contributes to the total bill of the material. This paper proposes the use of a dc-excited winding in an 8/6 SRM as a means of reducing the capacitor. The energy conversion of the motor is analyzed intensively. The control algorithm of the field winding is investigated and an active control algorithm is proposed to provide and absorb the energy in parallel with the dc-link capacitor. The effectiveness of this control method is confirmed by the cosimulation between the finite-element method and the Simulink.

Torque ripple minimization of variable flux reluctance machines by rotor skewing

Variable flux reluctance machines (VFRM) are an interesting candidate to substitute permanent-magnet synchronous machines in many applications, mainly owing to the absence of rare-earth permanent magnets and improved field weakening capability.

Optimization of the Force Density for Medium-Stroke Reluctance Actuators

This paper concerns the force density optimization for medium-stroke reluctance actuators applied in anti-vibration applications. The force density in a conventional E-core reluctance actuator is limited for medium strokes by the non-linear force-displacement characteristic. In this paper, different tooth topologies are analyzed to maximize the force density along the stroke using the finite element analysis. Teeth parameters are tuned in each topology to analyze the influences on the force density over a stroke of

Analysis and minimization of torque ripple for variable flux reluctance machines

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Field weakening capability of 12-stator/10-rotor-pole variable flux reluctance machines

12.5 mm. An analytic thermal model is used to estimate the surface temperature and is verified with finite element simulations. The optimal topology is validated by experiments on a prototype.

Torque Ripple Reduction for 12-Stator/10-Rotor-Pole Variable Flux Reluctance Machines by Rotor Skewing or Rotor Teeth Non-Uniformity

Variable flux reluctance machines (VFRMs) are permanent-magnet-free three-phase machines and are promising candidates for applications requiring low cost and robustness. This paper studies the torque ripple and minimization methods for 12-stator VFRMs. Starting with the analysis of harmonics in the self and mutual inductances of field and armature windings, instantaneous torque equations are derived by virtual work method, which give a clear view on the dominated torque ripple components in VFRMs. Afterwards, the influences of motor topology on harmonics of the inductances as well as the torque ripple are investigated, such as number of rotor poles and tooth arc, etc. On the basis of the aforementioned analysis, harmonic injections in field current and armature current are analyzed for torque ripple reduction. The effectiveness of these two methods is investigated for non-saturated and saturated 12/10 VFRMs based on 2D finite element analysis. The results show good performance of torque ripple minimization by harmonic armature current injection.

Comparison of 48V Rare-Earth-Free Reluctance Traction Motor Drives for Mild Hybrid Powertrain

Variable flux reluctance machines (VFRMs) are viable candidates for automotive applications. This paper investigates the field weakening capability of a 12/10 VFRM. Starting with voltage and toque equations, the paper reveals the relationship between torque-speed characteristics and the current arrangement (slot division) of both DC-field and armature windings. The method for expanding the working envelope by tuning DC or AC currents is discussed for different slot divisions. The results are validated by 2D finite element analysis.

Optimization of the force density for medium-stroke reluctance actuators

Variable flux reluctance machines (VFRMs) are interesting candidates to substitute permanent-magnet synchronous machines in many applications. However, they suffer from large torque ripple. In this paper two methods, stepped rotor skewing and rotor teeth non-uniformity, are researched to reduce the torque ripple of 12/10 (stator/rotor-pole ratio) VFRMs. Based on semi-analytic results and finite-element simulations, the effectiveness of these two methods is validated in both non-saturated and saturated machines.

Analysis of variable flux reluctance machines using hybrid analytical modelling

This paper provides a comparative analysis of three types of electrical drives with rare-earth- free reluctance motors for next-generation 48V mild hybrid automotive applications. The drives with switched reluctance motors (SRM), variable flux reluctance motors (VFRM) and synchronous reluctance motors (SynRM) are compared considering aspects like complexity of control algorithms and the structure of the power electronic circuits, construction of the motors and their performance characteristics, such as torque density, power factor, acoustic noise, and efficiency. The analysis is based on the results of simulation using 2D FEM and Simulink together with published research outcomes. The analyzed drives are compared to the internal permanent magnet motor (IPM) drive, selected as a benchmark.

Hybrid Analytical Modeling of Saturated Linear and Rotary Electrical Machines: Integration of Fourier Modeling and Magnetic Equivalent Circuits

This paper concerns the force density optimization for medium-stroke reluctance actuators applied in antivibration applications. The force density in a conventional E-core reluctance actuator is limited for medium strokes by the nonlinear force-displacement characteristic. In this paper, different tooth topologies are analyzed to maximize the force density along the stroke using the finite-element analysis. Teeth parameters are tuned in each topology to analyze the influences on the force density over a stroke of ±12.5 mm. An analytic thermal model is used to estimate the surface temperature and is verified with finite-element simulations. The optimal topology is validated by experiments on a prototype.