An improved equivalent circuit model of a single-sided linear induction motor

The derivation of the equivalent circuit for a single-sided linear induction motor (SLIM) is not straightforward, particularly if it includes longitudinal end effects from the cut-open primary magnetic path, transversal edge effects from the differing widths between the primary lamination and secondary sheet, and half-filled primary slots. This paper proposes an improved series equivalent circuit for this machine. The longitudinal end effects are estimated using three different impedances representing the normal, forward, and backward flux density waves in the air gap, whose two boundary conditions are deduced by introducing the conception of magnetic barrier surface. The transversal edge effects are accounted for by correction coefficient K t̄ and air-gap flux density correction coefficient K b̄. Using the series circuit, the performance of the SLIM was assessed in a similar manner to a rotating induction machine. A 4-kW SLIM prototype was tested, which validated the simulation technique. © 2010 IEEE

Оптимизация параметров вторичного элемента односторонних линейных асинхронных электродвигателей с использованием генетического алгоритма

The article focuses on the use of genetic algorithms for the design of linear induction motors. Comparison of genetic algorithm with classical methods in the context of electrical machines designing has been carried out. The results of solving an optimization problem for two designs are presented, viz. a laboratory linear induction electric motor based on a three-phase SL-5-100 inductor and a traction single-sided linear induction electric motor of an urban transport system. The optimality criterion included maximizing the power factor and efficiency, as well as the rigidity of the mechanical characteristic while ensuring a starting traction force of at least a set value. The results of optimization of such parameters of the secondary element as the width and thickness of the conductive strip as well as the thickness of the magnetic circuit are described. The relevance of the problem of optimizing the parameters of the secondary element with unchanged parameters of the inductor is due to the fact that the same inductor can be used to build various structures, while the secondary element is created for each specific application and integrated directly into the working body of the mechanism or is a driven product. To calculate the traction and energy characteristics of linear induction electric motors, an electromagnetic model based on detailed equivalent circuits was used, taking into account longitudinal and transverse edge effects and providing a calculation time for one set of parameters of about 1 s. In accordance with this model, the electric motor is reduced to a set of three detailed equivalent circuits: a magnetic circuit, primary and secondary electrical circuits. The result of the optimization of these electric motors was an increase in the efficiency by 1.6 and 1.4 %, respectively, an increase in the power factor by 0.9 and 0.2 %, and an increase in the rigidity of traction characteristics and starting traction force. © Belarusian National Technical University, 2021

Оптимизация параметров вторичного элемента односторонних линейных асинхронных электродвигателей с использованием генетического алгоритма

The article focuses on the use of genetic algorithms for the design of linear induction motors. Comparison of genetic algorithm with classical methods in the context of electrical machines designing has been carried out. The results of solving an optimization problem for two designs are presented, viz. a laboratory linear induction electric motor based on a three-phase SL-5-100 inductor and a traction single-sided linear induction electric motor of an urban transport system. The optimality criterion included maximizing the power factor and efficiency, as well as the rigidity of the mechanical characteristic while ensuring a starting traction force of at least a set value. The results of optimization of such parameters of the secondary element as the width and thickness of the conductive strip as well as the thickness of the magnetic circuit are described. The relevance of the problem of optimizing the parameters of the secondary element with unchanged parameters of the inductor is due to the fact that the same inductor can be used to build various structures, while the secondary element is created for each specific application and integrated directly into the working body of the mechanism or is a driven product. To calculate the traction and energy characteristics of linear induction electric motors, an electromagnetic model based on detailed equivalent circuits was used, taking into account longitudinal and transverse edge effects and providing a calculation time for one set of parameters of about 1 s. In accordance with this model, the electric motor is reduced to a set of three detailed equivalent circuits: a magnetic circuit, primary and secondary electrical circuits. The result of the optimization of these electric motors was an increase in the efficiency by 1.6 and 1.4 %, respectively, an increase in the power factor by 0.9 and 0.2 %, and an increase in the rigidity of traction characteristics and starting traction force.Рассмотрено применение генетического алгоритма для проектирования линейных асинхронных электродвигателей, проведено его сравнение с классическими методами. Представлены результаты решения оптимизационной задачи для двух конструкций: лабораторного линейного асинхронного электродвигателя на базе трехфазного индуктора SL-5-100 и тягового одностороннего линейного асинхронного электродвигателя городской транспортной системы. Критерий оптимальности включал максимизацию коэффициентов мощности и полезного действия, а также жесткости механической характеристики при обеспечении пускового тягового усилия не менее заданного значения. Описаны результаты оптимизации таких параметров вторичного элемента, как ширина и толщина проводящей полосы, толщина магнитопровода. Актуальность задачи оптимизации параметров вторичного элемента при неизменных параметрах индуктора обусловлена тем, что один и тот же индуктор может использоваться для построения различных конструкций, при этом вторичный элемент создается под каждое конкретное применение и интегрируется непосредственно в рабочий орган механизма либо является приводимым в движение изделием. Для расчета тяговых и энергетических характеристик линейных асинхронных электродвигателей использовалась электромагнитная модель на основе детализированных схем замещения, учитывающая продольный и поперечный краевые эффекты и обеспечивающая время расчета для одного набора параметров около 1 с. В соответствии с данной моделью электродвигатель сводится к совокупности трех детализированных схем замещения: магнитной цепи, первичной и вторичной электрических цепей. Результатом оптимизации указанных электродвигателей стало повышение коэффициента полезного действия на 1,6 и 1,4 % соответственно, коэффициента мощности – на 0,9 и 0,2 %, увеличение жесткости тяговых характеристик и пускового тягового усилия

Implementation of a motor control system for electric bus based on DSP

© 2017 IEEE. Motor control system may be the most important part of electric vehicles. To implement the control strategies, a lot of practical problems need to be taken into account. In this paper, an induction motor control system for electric bus is developed based on digital signal processor (DSP). The control strategy is based on field-oriented control and space vector pulse width modulation. Over-modulation, field weakening control, PI controller and fault diagnosis are also applied in this DSP algorithm. As a practical product running on a real electric bus with an 100 kW induction motor, communication with vehicle control unit (VCU) by controller area network (CAN bus), control system safety and PC software designed for experiment at lab are also discussed. The transient and steady-state performances of this motor control system are analyzed by experiments. Its performance is satisfactory when applied to the real electric bus

Electromagnetic optimal design of a linear induction motor in linear metro

An improved T-model equivalent circuit of a single-sided linear induction machine (SLIM) is proposed. The analysis utilizes a set of one-dimensional air gap flux linkage equations. The model takes longitudinal end and transversal edge effects into consideration. These have to account for primary terminal half-filled slots, secondary back-iron saturation and skin effect in the secondary conducting sheet. In the circuit, several coefficients are obtained by use of the dummy electric potential method in conjunction with consideration of the complex power equivalence between the primary and secondary sides. The coefficients derived include the longitudinal end effect coefficients K r and Kx, transversal edge effect coefficients C r and Cx, and skin effect coefficient Kf. The accuracy of the T-model is validated using comparison to a set of measured data under constant current - constant frequency conditions. These were taken from the Intermediate Capacity Transit System (ICTS) in Canada. An optimal design scheme for the SLIM is addressed. The application used for the optimization is a prototype propulsion system in a high temperature superconducting (HTS) maglev drive. The efficiency and primary weight are chosen as optimal objective functions while the thrust, power factor and other performance indexes are calculated. © 2010 IEEE

Traction system with on-board inductive power transfer

In traction applications based on long primary and short secondary type, contactless electrical energy transmission can offer distinct advantages over the conventional energy transmission based on catenary system to provide the required on-board power. In this paper, a linear brushless doubly fed machine with dual-primary windings and a reluctance secondary mover is proposed as a means of providing decoupled traction and on-board power. The machine primary contains two three-phase windings with different number of poles while an additional third winding is added around rotor saliencies forming a third output electric port to provide the required on-board power. A prototype machine is designed and simulated using 2D finite element analysis to verify the proposed concept.Qatar National Research FundScopu

Development of an advanced motor control system for electric vehicles

© 2019 SAE International. All Rights Reserved. Electric vehicles are considered as one of the most popular way to decrease the consumption of petroleum resources and reduce environmental pollutions. Motor control system is one of the most important part of electric vehicles. It includes power supply module, IGBT driver, digital signal processing (DSP) controller, protection adjustment module, and resolver to digital convertor. To implement the control strategies on motor control system, a lot of practical aspects need to be taken into accounts. It includes setup of the initial excitation current, consistency of current between motor and program code, over-modulation, field weakening control, current protection, and so on. In this paper, an induction motor control system for electric vehicles is developed based on DSP. The control strategy is based on the field-oriented control (FOC) and space vector pulse width modulation (SVPWM). Speed calculation, over-modulation, field weakening control, PI controller, and fault diagnosis are also applied in this DSP algorithm. As an industry product running on a real electric bus with a 100kW induction motor, communication with vehicle control unit (VCU) by CAN bus, control system safety and PC software designed for lab experiments are also discussed. This paper focused on how to develop the advanced motor control system for electric vehicles for industrial application. The steady-state and transient performances of this motor control system are analyzed by both test-bench experiments and road experiments. Its performance is satisfactory when applied to the real electric vehicle