Reduction of torque ripple in synchronous machines by quasi-skew-asymmetric rotor

2020 ◽  
Author(s):  
Ilya Petrov ◽  
Alvaro E. Hoffer ◽  
Juha Pyrhonen
Keyword(s):  
Torque Ripple ◽  
Synchronous Machines ◽  
Asymmetric Rotor

Torque ripple optimization for synchronous reluctance motors based on a virtual permanent magnet harmonic machine model

2021 ◽  
Vol 67 (3) ◽  
pp. 327-338
Author(s):  
Yixiang Xu ◽  
Chong Di ◽  
Xiaohua Bao ◽  
Dongying Xu
Keyword(s):  
Magnetic Field ◽  
Permanent Magnet ◽  
Torque Ripple ◽  
Air Gap ◽  
Analysis Model ◽  
Machine Model ◽  
Asymmetric Rotor ◽  
Rotor Flux ◽  
Air Gap Magnetic Field ◽  
Intermediate Variables

The torque ripple is affected by both the stator and the rotor magnetic field harmonics. In synchronous reluctance motors (SynRM), there are only rotor permeance harmonics existing on the rotor side for the absence of the rotor windings. Since the asymmetric rotor flux barriers are widely applied in the SynRM rotor, it is difficult to calculate the rotor permeance accurately by the analytical method. In this article, the effects of the rotor permeance harmonics on the air-gap magnetic field are studied by a virtual permanent magnet harmonic machine (VPMHM), which is a finite-element (FE) based magnetostatic analysis model. The air-gap flux density harmonics produced by the SynRM rotor are extracted from the VPMHM model and used as the intermediate variables for the torque ripple optimization. The proposed method does not need to solve the transient process of motor motion. Hence, the time of the optimization process can be significantly shortened. Finally, a full electric cycle is simulated by dynamic FE simulation, and the torque ripple is proved to be effectively reduced.

Reduction in Torque Ripple by Applying an Asymmetric Rotor to PMSM

2021 ◽  
Vol 141 (6) ◽  
pp. 445-452
Author(s):  
Makoto Ito ◽  
Shinji Sugimoto ◽  
Akeshi Takahashi ◽  
Shuichi Tamiya ◽  
Takatoshi Kushida
Keyword(s):  
Torque Ripple ◽  
Asymmetric Rotor

scholarly journals Predictive Trajectory Control with Online MTPA Calculation and Minimization of the Inner Torque Ripple for Permanent-Magnet Synchronous Machines

Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5327
Author(s):  
Simon Decker ◽  
Matthias Brodatzki ◽  
Benjamin Bachowsky ◽  
Benedikt Schmitz-Rode ◽  
Andreas Liske ◽  
...  
Keyword(s):  
Permanent Magnet ◽  
Real Time ◽  
Control Period ◽  
Torque Ripple ◽  
Trajectory Control ◽  
Synchronous Machines ◽  
Permanent Magnet Synchronous Machines ◽  
Flux Linkage ◽  
Maximum Torque ◽  
Dynamic Operation

This paper presents an extended predictive trajectory control scheme combined with an inner torque ripple minimization considering the current-, flux-linkage-, and voltage-planes of permanent magnet synchronous machines. The extension of a fundamental machine model with flux-linkage harmonics allows the calculation of the inner torque ripple and enables its minimization. For this, the control is divided in two cases: (1) The dynamic operation or large signal behavior which uses the maximal torque gradient for the trajectory strategy during each control period for fastest dynamic operation, and (2) The stationary operation or small signal behavior, utilizing a real time capable polynomial approximation of the rotor position dependent torque hyperbolas (iso-torque curves) of permanent magnet synchronous machines for the ideal torque to current reference values. Since dynamic and steady-state operation is covered, torque to current look-up tables, such as maximum torque per ampere (MTPA)/maximum torque per volt/voltage (MTPV) look-up tables, are not required anymore. The introduced, new control approach is implemented in Matlab/Simulink based on finite element analysis and measured data. Furthermore, test-bench implementations based on measurement data are presented to show the real-time capability and precision.

scholarly journals An Analytical Method for Generating Determined Torque Ripple in Synchronous Machines with Surface Magnets by Harmonic Current Injection

Machines ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 32 ◽  
Author(s):  
Matthias Vollat ◽  
Daniel Hartmann ◽  
Frank Gauterin
Keyword(s):  
Analytical Method ◽  
Electromotive Force ◽  
Permanent Magnets ◽  
Equation System ◽  
Torque Ripple ◽  
Synchronous Machines ◽  
Linear System Of Equations ◽  
Harmonic Currents ◽  
Asymmetrical Power ◽  
Phase Angles

In this paper, we present a new analytical method to calculate the required amplitudes and phase angles of the injected harmonic currents, to generate a determined torque ripple for synchronous machines with surface-mounted permanent magnets. First, we described the machine equations as a function of the phase current and the back electromotive force. We then introduced a new asymmetrical power system. After combining the equations, we established a linear system of equations. The solution of the equation system yielded the amplitudes and phase angles of the harmonic currents to be injected. Finally, we validated the method with several finite element method simulations. With this method, a previously defined torque ripple could be generated very accurately for synchronous machines with surface magnets.

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