• Journal of Power Electronics
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• 제2권4호
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• pp.231-239
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• 2002

This paper describes the restructuring of power electronics and electric drives courses, sponsored by NSF, EPRI, NASA and the local utilities, which has significantly increased student enthusiasm, and the undergraduate enrollment in these courses at the University of Minnesota has tripled since 1997. The developed leaching approaches have been the subject of NSF-sponsored faculty workshops in 1994, 1997, 1998,2002, and 2003. In power electronics, the power-pole based building-block approach unifies analysis and control aspects of all converters. PSpice-based simulations aid in analysis and design, supported by a hardware laboratory. For electric drives, an integrative approach addressing all three aspects of electric drives - machines, power converters and control is being. used. Space vectors, introduced on a physical basis rather than purely mathematical ions, are used fur analysis of ac machines. This leads to a more physical understanding of machine operation and also makes it easier to address control aspects in the advanced course. The lecture materials are supported by a DSP-based laboratory.

• Journal of Electrical Engineering and Technology
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• 제4권2호
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• pp.266-271
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• 2009

In this paper, improved direct torque control(DTC) of five-phase induction motor(IM) is proposed. Due to the additional degrees of freedom, five-phase IM drives present unique characteristics. One of them is the ability of enhancing the torque producing capability of the motor. Also five-phase motor drives possess many others advantage compared with the traditional three-phase motor drives. Such as, reducing the amplitude and increasing of frequency of torque pulsation, reducing amplitude of current per phase without increasing the voltage per phase and increasing the reliability. The direct torque control method is advantageous when it is applied to the five-phase IM. Because the five-phase inverter provides 32 space vectors in comparison to 8 space voltage vectors by the three-phase inverter. The 32 space voltage vectors are divided into three groups according to their magnitudes. The characteristics and dynamic performance of traditional five-phase DTC are analyzed and new DTC for five-phase IM is proposed. Therefore, a more precise flux and torque control algorithm for the five-phase IM drives can be suggested and explained. For presenting the superior performance of the pro-posed direct torque control, experimental results is presented using a 32 bit fixed point TMS320F2812 digital signal processor

• 전기학회논문지
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• 제63권4호
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• pp.575-582
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• 2014

In this paper, a simulation model for 7-phase BLDC motor drives for an Autonomous Underwater Vehicles (AUV) is proposed. A 7-phase BLDC motor is designed and the electrical characteristics are analyzed using FEA program and the power electronics drives for the 7-phase BLDC motor are theoretically analyzed and the actual implementation has been accomplished using Matlab Simulink. PI controller is used for verifying the validity of the proposed model and the informative results are described in detail.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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• pp.400-403
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• 2001

In this paper, the classical Lyapunov synthesis method for designing controllers is extended to fuzzy logic. This control technique is then applied to the design of a novel tracking controller for reluctance motor drives. The main features of the method are small rule base, simplicity of construction, and low cost. The proposed controller has been simulated for a model case. In addition, its dynamic performances have been shown to be satisfactory. Capabilities of the proposed technique in controlling the highly nonlinear systems of reluctance motors with much simplicity are also verified.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제11권1호
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• pp.65-70
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• 2011

The increased disk rotational velocity to improve the data transfer rate has raised up many serious problems in its servo control system which should control the position and velocity of a spot relative to a rotating disk. This paper proposes gain-scheduling-based track-seek control for single stage actuator of hard disk drives. Gain scheduling is a technique that can extend the validity of the linearization approach to a range of operating points and one of the most popular approaches to nonlinear control design. The proposed method schedules controller gains to improve the transient response and minimize overshoot during the functions of the read/write head positioning servomechanism for the seek control. The validity of the proposed method is demonstrated through stability analysis and simulation results.

• 조명전기설비학회논문지
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• 제26권11호
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• pp.81-86
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• 2012

It is well known that the stator-flux-oriented induction motor drives are not dependent on parameter detuning in constant torque region except low speed range. This paper presents parameter detuning effects of stator-flux-oriented induction motor drives in constant torque region. The detuning effects of stator resistance, rotor resistance and rotor leakage inductance are analyzed.

• Journal of Power Electronics
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• 제9권3호
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• pp.481-490
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• 2009

This paper describes a SVPWM overmodulation scheme of NPC type three-level inverter for traction drives which extends the modulation index from MI=0.907 to unity. SVPWM strategy is organized by two operation modes of under-modulation and over-modulation. The switching states under the under-modulation modes are determined by dividing them with two linear regions and one hybrid region the same as the conventional three-level inverter. On the other hand, under the over-modulation mode, they are generated by doing it with two over-modulation regions the same as the conventional over-modulation strategy of a two level inverter. Following the description of over-modulation scheme of a three-level inverter, the system description of a vector controlled induction motor for traction drives has been discussed. Finally, the validity of the proposed modulation algorithm has been verified through simulation and experimental results.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.792-793
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• 2006

In the paper, the influence of different particle size $D:D>125{\mu}m$, $D<50{\mu}m$ and between on magnetic properties of a standardized dielectromagnetic is presented. The tests were taken at frequencies of between 50Hz, and 500Hz. Presented in the paper results provide important materials property data to allow the selection of the most appropriate dielectromagnetic particle size for different applications.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제2B권4호
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• pp.174-182
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• 2002

This paper presents a comprehensive study on reducing commutation torque ripples generated in brushless DC motor drives with only a single do-link current sensor provided. In such drives, commutation torque ripple suppression techniques that are practically effective in low speed as well as high speed regions are scarcely found. The commutation compensation technique proposed here is based on a strategy that the current slopes of the incoming and the outgoing phases during the commutation interval can be equalized by a proper duty-ratio control. Being directly linked with deadbeat current control scheme, the proposed control method accomplishes suppression of the spikes and dips superimposed on the current and torque responses during the commutation intervals of the inverter. Effectiveness of the proposed control method is verified through simulations and experiments.

• Journal of Power Electronics
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• 제2권2호
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• pp.130-138
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• 2002

The windup phenomenon appears and degrades control performance when a controller with integrating action is used and plant input is limited. An anti-windup integal-proportional(IP) controller is proposed for the variable-speed moter drives and it is experimentally applied to the speed control of a vector-controlled induction moter driven by a pulse width modulated (PWM) voltage source inverter (VSI). The consistency range of the IP controller is firstly derived and the intergal state is controlled to salisfy always the consistency range according to whether the the controller output is saturated or not. Although the operating condition like moter load or speed command is changed under the limited plant input, It is expermentally verified that the speed response has much improved performance, such as no overshoot and fast settling time, and the maximmum plant input is also effectively utilized.