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Accurate knowledge of motor position is required in the motor drive application where smooth torque performance is needed. The error in position causes ripple in the developed current and thereby produce torque ripple. This paper analyzes the various effects of position sensor error in the current developed and in the torque generated in a current controlled permanent magnet synchronous motor drive. This research is focused on analyzing effect of position error on smooth production of torque in an interior permanent magnet synchronous motor (IPMSM) drive due to various inaccuracies. The analysis is verified through simulation and test results by measuring torque and torque ripple performances of an IPMSM drive. The results can be easily extended to surface mount permanent magnet motor drive also. [ABSTRACT FROM PUBLISHER]

This paper presents a method of profiling the phase currents to minimize the torque ripple of switched reluctance machines (SRMs) operating in four-quadrant mode over the entire speed range of operation. The method is based on machine and controller design through coupled simulation of the finite-element-based machine model and the dynamic controller model. The method considers the mutual coupling effect between conducting phases. The research quantifies the effect of sensor error and manufacturing build variations on the level of torque ripple minimization. The mitigation processes to address the issues in mass production are also presented. [ABSTRACT FROM AUTHOR]

A model of permanent-magnet synchronous machine (PMSM), including the electromagnetically originated torque ripple, is presented in this paper. This unique representation of such equivalent circuit is highly critical to understand the torque ripple content and to develop an appropriate mitigation scheme for low torque ripple applications requiring four quadrant operations. This research proposes a method to quantify the various sources of torque ripple and modifies the existing dq-model to enhance the modeling capabilities for both surface-mount and interior PMSMs. Finite-element (FE) analysis is used for modeling various PMSMs to verify the lumped circuit model proposed in this research. The theoretical results obtained from analytical and FE analysis are validated using experimental test. [ABSTRACT FROM AUTHOR]

This paper provides a detailed finding of the mechanics of vibration in permanent magnet (PM) synchronous motors due to electromagnetic (EM) origins. Several fractional-slot PM topologies are investigated to quantify the vibration phenomenon that is influenced by motor slot/pole and winding configurations. This paper also sorts out the vibration mode order that is responsible for deformation and the resulting excitation frequency. A finite-element-based cosimulation in the EM and structural domain is used to find the radial forces and, hence, the displacement, to quantify the vibration/noise performance of these selected motors. The displacement and frequency are converted to the sound pressure level to show the relative differences in the noise levels among these motor topologies. The selected motors were experimentally tested to verify the theoretical findings. [ABSTRACT FROM AUTHOR]

This paper presents a novel method of profiling the phase currents to minimize the torque ripple of a switched reluctance machine. The method is a combination of machine design and control algorithm. The minimization is accomplished in three steps: The first step is to design a machine that has symmetric torque characteristics with an extended flat portion, the second step is to find the required current profile through simulation, and the third step is the fine tuning of the profile. The simulation is done to verify the method through a coupling of the finite-element-based machine model and the Matlab/Simulink-based dynamic controller model. The coupled simulation considers the nonlinearities, electrical loss, magnetic loss, and mutual coupling. Experimental verification validated the torque-ripple minimization procedure. [ABSTRACT FROM PUBLISHER]

Cogging torque minimization is necessary for low torque ripple applications such as precision tooling, robotics, etc. Various techniques are available but few techniques are proved to be effective in mass production under manufacturing tolerances/variations. The research provides a design approach to minimize cogging torque by making the motor robust to manufacturing variations and dimensional tolerances. Several control and noise factors are identified to apply the robust design technique. The quality of robustness is judged by the signal-to-noise ratio. A tradeoff is exercised to maximize output torque in selecting the control parameters. The research shows the effectiveness of such design techniques in designing motors for mass production without adding cost or complexity. Experimentation by modeling has been chosen using finite element analysis. Motors using the optimized parameters are built and tested thus verifying the design approach. [ABSTRACT FROM AUTHOR]

High-performance motor drive applications require smooth operation with minimum torque ripple. This paper is focused on identifying various design parameters in the stator and rotor that can be utilized to reduce the torque ripple of sinusoidally excited permanent-magnet synchronous motors. This paper investigates the sensitivity of various design parameters on torque ripple and torque linearity that must be considered at the design stage for low-torque-ripple applications. Only the torque ripple and torque nonlinearity due to electromagnetic origin are considered in this paper. Finite-element analysis along with experimental data is provided to validate the findings. Design techniques have been provided to minimize the overall torque ripple and increase the torque linearity. Tradeoff between magnetic flux per pole and electrical loading of the machine is needed for low-torque-ripple performance. This also provides superior torque linearity. [ABSTRACT FROM AUTHOR]