Accurate Torque Ripple Measurement for PMSM

Theoretically, the layout of fractional pitch permanent magnet motors should ensure the cancellation of most cogging torque harmonics. In reality, manufacturing errors lead to incomplete cancellation and higher than expected cogging torque. Two potential manufacturing errors are the variation in angle between successive magnets and the strength of the magnets.To determine the sensitivity of cogging torque to magnet strength and placement, a superposition technique is used. This technique is validated by first demonstrating that the total cogging torque can be reconstructed by summing offset versions of the torque from experimentally determined single-magnet/singleslot interactions.Following this validation, Monte Carlo simulations are conducted to statistically determine the sensitivity of cogging torque to magnet placement and strength errors. It is demonstrated that the mean RMS cogging torque increases by 4 % for every degree increase in magnet placement standard deviation and by 0.06% for every 1% increase in magnet strength standard deviation.

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“…Measurement was done on a specifically designed test rig where the torque was measured by a piezoelectric reaction torque sensor [12]. …”

Section: A Test Motormentioning

confidence: 99%

Superposition techniques for analyzing cogging torque sensitivity to manufacturing errors in fractional pitch PMSM

Heins

Thiele

2011

IECON 2011 - 37th Annual Conference of the IEEE Industrial Electronics Society

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“…It should be noted that the dynamometer used for driving the generator in the experimental set consists of an induction machine which has no cogging torque. Moreover, the torque measurement conducted by the torque sensor has some inertial loads added to the ripple due to minor variation in speed of the rotor [26]. However, controller induced torque ripples superimposed on the shaft torque was not filtered during these measurements.…”

Section: Experimental Validationmentioning

confidence: 99%

Cogging Torque and Torque Ripple in a Direct-Drive Interior Permanent Magnet Generator

Dutta¹,

Ahsanullah²,

Rahman³

2016

PIER B

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Abstract-This paper investigates the cogging torque and torque ripple in high pole number interior permanent magnet generators, designed for direct-drive applications. Two interior permanent magnet rotor topologies -flat-shaped and V-shaped were considered with distributed wound and fractional slot concentrated wound stators. A comparison of torque performances was made between distributed wound and fractional-slot concentrated wound generators. Cogging torque was minimized by finding an optimum magnet pole arc length and torque ripples were minimized by finding optimum slot-opening and flux barrier shape. Design analysis was carried out in finite element models. It was found that flat-shaped rotor topology in the fractional slot concentrated wound stator can provide the best torque performance regarding low cogging torque and torque ripple. This finding was verified in constructed prototype machine.

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“…In the latter case, a trade-off is critical between finer steps and ripple minimization. In the process, the practical issue of the accurate measurement of increasingly small torque pulsations came to the forefront [14].…”

Section: Vehicle Handling (Chassis) Electrificationmentioning

confidence: 99%

Automotive Electrification: The Nonhybrid Story

Lequesne

2015

IEEE Trans. Transp. Electrific.

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The electrification of the automobile has a long history. Electric and hybrid vehicles are actually only a small part of it, albeit presently the most visible and the one getting the most attention in popular media. This paper will focus on the rest of the story, that is, aspects of transportation electrification other than hybrid or fully-electric propulsion systems. Recent progress (last 10-20 years) and current work on the electrification of road transport, from chassis to powertrains, will be reviewed with a focus on electromechanical systems. In the process, the numerous challenges engineers have overcome or have yet to solve will be highlighted, thus illustrating the many different ways electrical engineering is making its mark in providing more performant, more efficient, safer, and more pleasant means of personal transportation.

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Accurate Torque Ripple Measurement for PMSM

Cited by 45 publications

References 17 publications

Superposition techniques for analyzing cogging torque sensitivity to manufacturing errors in fractional pitch PMSM

Superposition techniques for analyzing cogging torque sensitivity to manufacturing errors in fractional pitch PMSM

Cogging Torque and Torque Ripple in a Direct-Drive Interior Permanent Magnet Generator

Automotive Electrification: The Nonhybrid Story

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