An alternative scheme to reduce torque ripple and mechanical vibration in direct torque controlled permanent magnet synchronous motor

Abstract

The direct torque control (DTC) technique of a permanent magnet synchronous motor (PMSM) has received increasing attention due to its simplicity and robust dynamic response compared with other control techniques. The classical switching table based DTC presents large flux, torque ripples and more mechanical vibrations in the motor. Several studies have been reported in the literature on classical DTC. However, the studies that actually discuss or evaluate the classical DTC are limited. This paper proposes, an alternative DTC method/switching table for PMSM, to reduce flux and torque ripples as well as mechanical vibrations. This is achieved by a simple modification in the classical DTC structure, by eliminating the two level inverter available in the classical DTC and replacing it with a three level neutral point clamped inverter. To further improve the performance of the proposed DTC, the available 27 voltage vectors are allowed to form different groups of voltage vectors such as Large - Zero, Medium - Zero and Small - Zero. Based on these groups, a new switching table is proposed. The proposed DTC is compared with the classical DTC and existing literature from the aspects of theory analysis and computer simulations. It can be observed that the proposed technique can significantly reduce the flux, torque ripples, and mechanical vibrations and improves the quality of current waveform compared with traditional and existing methods.

Adaptive steering‐based HDTC algorithm for PMSM

“…The comparison with previous methods is given in terms of the average commutation frequency, per unit flux ripple “ Ψ ripple ”, and per unit torque ripple “ T ripple ”. Flux and torque ripples are calculated using the formula given in () [11], while per unit values of the torque ripple and the flux ripple for different methods are calculated as given in (): …”

“…In Table 5, the results presented by [11] were conducted with a load of 3 Nm; it can be observed that there is no significant reduction in either torque ripple or flux ripple. In addition, the presented waveform of the torque performance in [11] suffers from serious fluctuations when the motor is loaded. The authors in [13, 14] succeed in reducing both torque and flux ripples compared to the traditional DTC.…”

“…A considerable number of researchers in recent times [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] have attempted to reduce some of the above mentioned drawbacks with a significant indication of continuous improvement. Additionally, the problems encountered with encoders in the FOC (to determine the rotor position) have shifted research directions toward sensorless direct torque control (DTC) of the PMSM.…”

A Ripple Rejection Inherited RPWM for VSI Working with Fluctuating DC Link Voltage

“…SPWM by its nature creates harmonics as cluster at switching frequency and its multiples. These carrier frequency harmonics are of dominant in magnitude and create mechanical vibration in the drive [37]. A host of PWM methods, named, RPWM have been researched and proved for distribution of harmonic power.…”

Modeling and active control of power-split hybrid electric vehicle launch vibration

“…8 A wellperforming motor can also help attenuate system vibration. 9,10 However, there is very limited published work available on the active control of driveline vibration of the Ravigneaux planetary power-split HEVs. Furthermore, most methods mainly focus on the vibration problems in EVs or conventional sedans instead of those in HEVs.…”