3,330 research outputs found
Multiphase induction motor drives - a technology status review
The area of multiphase variable-speed motor drives in general and multiphase induction motor drives in particular has experienced a substantial growth since the beginning of this century. Research has been conducted worldwide and numerous interesting developments have been reported in the literature. An attempt is made to provide a detailed overview of the current state-of-the-art in this area. The elaborated aspects include advantages of multiphase induction machines, modelling of multiphase induction machines, basic vector control and direct torque control schemes and PWM control of multiphase voltage source inverters. The authors also provide a detailed survey of the control strategies for five-phase and asymmetrical six-phase induction motor drives, as well as an overview of the approaches to the design of fault tolerant strategies for post-fault drive operation, and a discussion of multiphase multi-motor drives with single inverter supply. Experimental results, collected from various multiphase induction motor drive laboratory rigs, are also included to facilitate the understanding of the drive operatio
Symmetrical six-phase induction machines: a solution for multiphase direct control strategies
Six-phase induction machines are considered an interesting multiphase option because they can benefit from the well-known three-phase converter technology. These multiphase machines can be classified according to the spatial distribution of
their windings into two main groups: asymmetrical and symmetrical six-phase machines. In the case of symmetrical sixphase
machines, some sets of voltage vectors show an important advantage from the point of view of the - current mitigation.
They provide an active production in the - plane with a completely null injection of - components. This fact is a desired
feature for direct control strategies, such as standard model predictive control (MPC), where a single switching state is applied
during the entire sampling period. Based on these statements, this work proposes an MPC strategy for symmetrical six-phase
induction machines using voltage vectors with null - voltage production in order to obtain the flux/torque generation with
minimum - currents. Simulated results have been included to validate the goodness of the developed control scheme.Universidad de MĂĄlaga. Campus de Excelencia Internacional AndalucĂa Tec
Model Predictive Control based on Dynamic Voltage Vectors for Six-phase Induction Machines
Model predictive control (MPC) has been recently
suggested as an interesting alternative for the regulation of
multiphase electric drives because it easily exploits the inherent
advantages of multiphase machines. However, the standard
MPC applies a single switching state during the whole sampling
period, inevitably leading to an undesired x y voltage production.
Consequently, its performance can be highly degraded when the
stator leakage inductance is low. This shortcoming has been,
however, mitigated in recent work with the implementation
of virtual/synthetic voltage vectors (VVs) in MPC strategies.
Their implementation reduces the phase current harmonic
distortion since the average x y voltage production becomes
null. Nevertheless, VVs have a static nature because they are
generally estimated offline, and this implies that the flux/torque
regulation is suboptimal. Moreover, these static VVs also present
some limitations from the point of view of the dc-link voltage
exploitation. Based on these previous limitations, this article
proposes the implementation of dynamic virtual voltage vectors
(DVVs), where VVs are created online within the MPC strategy.
This new concept provides an online optimization of the output
voltage production depending on the operating point, resulting
in an enhanced flux/torque regulation and a better use of the
dc-link voltage. Experimental results have been employed to
assess the goodness of the proposed MPC based on DVVs.Ministerio de Ciencia, InnovaciĂłn y Universidades RTI2018-096151-B-100
Predictive current control in electrical drives: an illustrated review with case examples using a five-phase induction motor drive with distributed windings
The industrial application of electric machines in variable-speed drives has grown in the last decades thanks to the
development of microprocessors and power converters. Although three-phase machines constitute the most common case, the
interest of the research community has been recently focused on machines with more than three phases, known as multiphase
machines. The principal reason lies in the exploitation of their advantages like reliability, better current distribution among phases
or lower current harmonic production in the power converter than conventional three-phase ones, to name a few. Nevertheless,
multiphase drives applications require the development of complex controllers to regulate the torque (or speed) and flux of the
machine. In this regard, predictive current controllers have recently appeared as a viable alternative due to an easy formulation
and a high flexibility to incorporate different control objectives. It is found however that these controllers face some peculiarities
and limitations in their use that require attention. This work attempts to tackle the predictive current control technique as a viable
alternative for the regulation of multiphase drives, paying special attention to the development of the control technique and the
discussion of the benefits and limitations. Case examples with experimental results in a symmetrical five-phase induction machine
with distributed windings in motoring mode of operation are used to this end
Impact of PWM strategies on RMS current of the DC-link Voltage Capacitor of a dual-three phase drive
The major drawback of usual dual three-phase AC machines, when supplied by a Voltage Source Inverter (VSI), is the occurrence of extra harmonic currents which circulate in the stator windings causing additional losses and constraints on the power component. This paper compares dedicated Pulse Width Modulation (PWM) strategies used for controlling a dual three phase Permanent Magnet Synchronous machine supplied by a six-leg VSI. Since the application is intended for low-voltage (48V) mild-hybrid automotive traction, an additional major constraint arises: the compactness of the drive related to the size of the DC-bus capacitor. Thus, the PWM strategy must be chosen by taking into consideration its impact on both, the motor and the RMS value of DC-bus current
Multiphase Machines and Drives-Revisited
Although the concept of a multiphase drive system dates back to the middle of the 20th century, the initial pace of development was rather slow, as witnessed by the first two surveys of the area published in the beginning of this century. However, considerably new developments have resulted in the last decade of the 20th century and the beginning of this century, leading to an authoritative survey of the asymmetrical six-phase drive control and subsequently of the review of the complete area. This also initiated the organization and subsequent publication of the first IEEE Transactions on Industrial Electronics "Special Section on Multiphase Machines and Drives" in May 2008, which commenced with another survey paper, and that contained 12 original research papers. Since the publication of this Special Section in May 2008, the level of interest and pace of developments in the area have further accelerated and substantial new knowledge has been generatedwith an ever-increasing number of published research papers and reported new industrial applications. Such a trend has been emphasized in a recent paper. It therefore seemed appropriate to revisit the area and organize this Special Section as a sequel to the first one. The call for the Special Section papers resulted in 51 submissions, almost twice as many as the total back in 2008, thus confirming a substantial growth of the area. Indeed, the amount of new knowledge acquired since the publication of the first Special Section in 2008 has meant that it was not possible to provide a complete and thorough survey of the field in a single review paper
Direct Torque and Predictive Control Strategies in Nine-phase Electric Drives Using Virtual Voltage Vectors
One of the main distinctive features of multiphase machines is the appearance of new degrees of freedom ( - voltages/currents) that do not exist in their three-phase counterparts. As a direct consequence, control approaches that apply a single switching state during the sampling period cannot achieve zero average - voltage production. In direct torque control (DTC) this implies that - currents are not regulated, whereas in finite-control-set model predictive control (FCS-MPC) an enhanced - current regulation is feasible only at the expense of disturbing the flux/torque production. Aiming to avoid these shortcomings, this work makes use of the concept of synthetic/virtual voltage vectors (VVs) to nullify/limit the - voltage production in order to improve the current regulation in the secondary planes. Two strategies using two and four virtual voltage vectors (2-VV and 4-VV, respectively) are proposed and compared with the standard case that applies a single switching state. Since standard MPC has the capability to indirectly regulate - currents, the improvements with the inclusion of VVs are expected to be more significant in DTC strategies. Experimental results validate the proposed VVs and confirm the expectations through a detailed performance comparison of standard, 2-VV and 4-VV approaches for DTC and MPC strategies
Model predictive Direct Flux Vector Control of multi three-phase induction motor drives
A model predictive control scheme for multiphase induction machines, configured as multi three-phase structures, is proposed in this paper. The predictive algorithm uses a Direct Flux Vector Control scheme based on a multi three-phase approach, where each three-phase winding set is independently controlled. In this way, the fault tolerant behavior of the drive system is improved. The proposed solution has been tested with a multi-modular power converter feeding a six-phase asymmetrical induction machine (10kW, 6000 rpm). Complete details about the predictive control scheme and adopted flux observer are included. The experimental validation in both generation and motoring mode is reported, including post open-winding fault operations. The experimental results demonstrate the feasibility of the proposed drive solution
Comparative Study of Predictive Control Strategies at Fixed Switching Frequency for an Asymmetrical Six-Phase Induction Motor Drive
Las tĂ©cnicas de control predictivo del modelo de conjunto de control finito se distinguen principalmente por una frecuencia de conmutaciĂłn variable que provoca ruido, gran voltaje y ondas de corriente a baja frecuencia de muestreo. Este trabajo presenta una comparativa estudio de dos tĂ©cnicas mejoradas de control de corriente predictivo con frecuencia de conmutaciĂłn fija aplicada a un motor de inducciĂłn asimĂ©trico de seis fases. Los resultados de la simulaciĂłn se desarrollan para demostrar la eficiencia de los dos algoritmos de control de corriente utilizando el error cuadrĂĄtico medio y la distorsiĂłn armĂłnica total como Ăndices de desempeño de calidad, concluyendo asĂ las ventajas y desventajas de cada tĂ©cnica en estados estacionarios y transitorios.CONACYT â Consejo Nacional de Ciencia y TecnologĂaPROCIENCI
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