The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform

Li Jian - One of the best experts on this subject based on the ideXlab platform.

  • The Slip Frequency Control System of Speed Sensorless based on DSP
    IEEE Transactions on Power Electronics, 2003
    Co-Authors: Li Jian
    Abstract:

    The paper describes a model reference adaptive system for the identification of induction motor speed from measured motor stator voltages and currents. We combine this system with the common inverter based on constant U/f control strategy to form a Slip Frequency control system without a speed sensor. Some experiments show that the system possesses better dynamic and static performance.

Slobodan N. Vukosavic - One of the best experts on this subject based on the ideXlab platform.

A. Shaltout - One of the best experts on this subject based on the ideXlab platform.

  • An Unsymmetrical Two-Phase Induction Motor Drive With Slip-Frequency Control
    IEEE Transactions on Energy Conversion, 2009
    Co-Authors: N. Abdel-rahim, A. Shaltout
    Abstract:

    This paper proposes a closed-loop control strategy to operate an off-the-shelf single-phase induction motor (IM) as a symmetrical two-phase IM. The proposed control strategy employs the SFC technique to independently control the stator currents of both the main and auxiliary windings, and make them follow a predefined sinusoidal waveform. Simulation and experimental results show that the proposed scheme is successful in operating the conventional single-phase IM as a symmetrical two-phase IM with fast dynamic and transient responses. In addition, the proposed control system achieves cost-effectiveness in both initial and running costs.

  • Analysis and Design of Photovoltaic Powered Air Conditioners Using Slip-Frequency Control Scheme
    Electric Power Components and Systems, 2007
    Co-Authors: N. Abdel-rahim, A. Shaltout
    Abstract:

    Abstract This article proposes a new scheme to drive an air conditioner powered by photovoltaic (PV) arrays. The main objective is to reduce the cost of the system, which is a major concern in PV applications. This is achieved by reducing both the initial and running costs of the PV system. Initial cost is cut down by reducing the required size of the PV array through (i) limiting the motor current during both startup and dynamic phases of operation, and (ii) extracting maximum power from the PV array under various metrological conditions by operating the PV array on the maximum power line. Reduction in the running cost of the PV system is achieved by controlling the motor speed such that its Slip is kept at a small value at various operating conditions, ensuring highly efficient operation of the system. This article outlines a procedure for sizing the photovoltaic array. Also, the article presents a control strategy that achieves acceptable levels of the motor current with good dynamic response. Simulati...

Zi-qiang Zhu - One of the best experts on this subject based on the ideXlab platform.

  • Investigation of Forces in Linear Induction Motor Under Different Slip Frequency for Low-Speed Maglev Application
    IEEE Transactions on Energy Conversion, 2013
    Co-Authors: Zi-qiang Zhu
    Abstract:

    The linear induction motor (LIM) applied in low-speed Maglev train produces not only the thrust force to drive the train, but also the normal force that affects the levitation system. Three finite element models are employed to investigate the influence of transverse edge effect, longitudinal end effect, transverse edge shape of secondary aluminum plate and its temperature, etc., on the force performance under different Slip Frequency. For the transverse edge effect, a precise correction factor is proved to be more suitable than the common Russell and Norsworthy's factor. An analytical method using an equivalent circuit model is improved based on an existing model for nonferromagnetic secondary LIM. The amendments account for the primary iron loss, the eddy current of secondary back iron, and the calculation of normal force. Based on this equivalent circuit model, the performance curves of thrust force, normal force, efficiency, and power factor against the train velocity are obtained for given Slip Frequency and thrust force. The influences of transverse edge, longitudinal end, and air gap length are also investigated. Analytically predicted results are validated by finite element models and measurements.

Hyung-soo Mok - One of the best experts on this subject based on the ideXlab platform.

  • Efficiency Improvement by Deriving the Optimal Operating Slip Frequency of a Linear-Induction-Style Maglev Train
    Energies, 2020
    Co-Authors: Sang-uk Park, Hyung-soo Mok, Jaewon Lim, Hyun-uk Seo
    Abstract:

    While urban maglev trains have the advantage of being optimized for urban environments where noise is low and dust is less generated, their driving efficiency is low when compared to rotary induction motors owing to the structural limitations of linear devices. To compensate for these disadvantages, various studies on train control schemes have been conducted. Representative control methods include improving the efficiency of using Slip Frequency by directly controlling the propulsion force using vector control. However, this method has limitations in its use as it relates to the normal force that affects the train’s levitation system. Therefore, in this study, mathematical analysis was conducted for each factor that mutually affects the control of the train. On this basis, the magnitude of the normal force related to the safety of the train is limited. Operating efficiency was improved by varying the Slip Frequency according to the operating conditions of the train. In addition, for verification, the effect was proved through a comparative experiment using an 18 ton class maglev train running at Incheon International Airport.

  • A study on efficiency of magnetic levitation trains using linear induction motor by Slip pattern
    2019 IEEE Energy Conversion Congress and Exposition (ECCE), 2019
    Co-Authors: Hyun-uk Seo, Sang-uk Park, Jaewon Lim, Hyung-soo Mok
    Abstract:

    Linear induction motors used in magnetic levitation (maglev) trains use a higher constant Slip Frequency operating scheme than rotary motors to meet thrust and normal force requirements. Thus, the constant Slip Frequency is used in all operation conditions, which reduces the efficiency of the propulsion system. In this paper, a varying Slip Frequency control is proposed for increasing the propulsion efficiency within the limit of vertical force disturbance. The operation pattern of the actual train is defined by the route travel plan, which is adopted in simulation. The proposed varying Slip Frequency control pattern is verified by the actual maglev train test. With the proposed algorithm, efficiency consumption is improved not only in the propulsion system but the total power in the maglev train operation.

  • A Study on Improvement of Operation Efficiency of Magnetic Levitation Train Using Linear Induction Motor
    International Journal of Railway, 2016
    Co-Authors: Sang-uk Park, Jaewon Lim, Doh Young Park, Chan Yong Zun, Hyung-soo Mok
    Abstract:

    In this paper, a study on the efficiency improvement of the magnetic levitation train using the LIM (Linear Induction Motor) was presented. The maglev train has the advantage of being environmentally friendly since much less noise and dust is produced. However, due to structural limitation, compared to a rotating induction motor, linear induction motor, the main propulsion engine of the maglev train has a relatively greater air gap and hence has the lower operation efficiency. In this paper, the relationship between the operating condition of the train and the Slip Frequency has been investigated to find out the optimum Slip Frequency that might improve the efficiency of the magnetic levitation train with linear induction motor. The Slip Frequency is variable during the operation by this relationship only within a range that does not affect the levitation system of the train. After that, the comparison of the efficiency between the conventional control method with the Slip Frequency fixed at 13.5[Hz] and the proposed method with the Slip Frequency variable from 9.5[Hz] to 6.5[Hz] has been conducted by simulation using Simplorer. Experiments of 19.5[ton] magnetic levitation trains owned by Korea Institute of Machinery and Materials were carried out to verify the simulation results.

  • Improvement of ATO efficiency by varying Slip Frequency for a magnetic lévitation propulsion system using a linear induction motor
    2016 IEEE International Conference on Renewable Energy Research and Applications (ICRERA), 2016
    Co-Authors: Seok Young Lee, Sang-uk Park, Jaewon Lim, Doh Young Park, Chan Yong Zun, Jae Hyuk Choi, Hyung-soo Mok
    Abstract:

    In this paper, the possibility of energy efficiency improvement of the maglev train with variable Slip operation other than constant one for the linear induction motor drive is discussed. Such novel operation pattern is considered to be plausible by applying proper operating sup to the linear induction motor when a certain acceleration/deceleration operation pattern is determined. Investigation of the relationship between normal force and tracking force has been conducted. The relationship between Sup Frequency and normal force and tracking force has been studied by comparing constant sup current control and variable Slip current vector control. It has provided the most efficient sup curve along with varying operation pattern after testing a band of possible sup/pattern combination. An algorithm is used to implement the variable sup control scheme. During simulation and field test, the algorithm of automatic train operation which applies the best Slip curve to different operation pattern has been proved to be efficient and feasible. However, the best efficiency sup curve has to consider the influence of the change of the levitation force since the levitation force tend to increase along with the decreasing Slip Frequency. Then the ATO system select the sup curve that provide best efficicncy under constraints due to safety to conduct the field test.