• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.6
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• pp.301-308
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• 1999

According to the development of power electronic element(GTO, IGBT) and material for electrical machines(permanent magnet, super conductor), the technology for electrical machines is now a day rapidly developing. Here with, a novel electrical machine, based on the new conception of transverse flux configuration leads to a considerable increase in power density and enables simultaneously high efficiency. The designed and measured performance of transverse machine for railway traction system revealed a great potential of system improvements to reduce linear motor mass.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.3
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• pp.524-530
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• 2007

This paper presents a new and simple method for sensorless operation of matrix converter drives using a constant air-gap flux and the imaginary power flowing to the motor. To improve low-speed sensorless performance, the non-linearities of a matrix converter drive such as commutation delays, turn-on and turn-off times of switching devices, and on-state switching device voltage drop are modelled using PQR transformation and compensated using a reference power control scheme. The proposed compensation method is applied for high performance induction motor drives using a 3 kW matrix converter system. Experimental results are shown to illustrate the feasibility of the proposed strategy.

• Journal of Power Electronics
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• v.18 no.5
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• pp.1325-1335
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• 2018

This paper presents a discontinuous pulse width modulation (DPWM) method to reduce switching losses in an indirect matrix converter (IMC) drive. The IMC has a number of power semiconductor switches. In other words, it consists of a rectifier stage and an inverter stage for AC/AC power conversion, which are composed of 12 and 6 switching devices, respectively. Therefore, the switching devices of the IMC suffer from high switching losses in the IMC drives. Various topologies to reduce switching losses have been studied by eliminating a number of switches from the rectifier stage. In this study, in contrast to prior research, a DPWM method is presented to reduce the switching losses of the inverter stage. The effectiveness of the proposed method to reduce switching losses in IMC drives is verified by simulations and experimental results.

• Journal of Electrical Engineering and Technology
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• v.2 no.4
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• pp.500-504
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• 2007

In this paper, the induction motor rotor fault diagnosis system using current signals, which are measured using axis-transformation method, and speed, which is estimated using current information, are presented. In inverter-fed motor drives unlike line-driven motor drives the stator currents have numerous harmonics components and therefore fault diagnosis using stator currents is very difficult. The current and speed signal for rotor fault diagnosis needs to be precise. Also, high resolution information, which means the diagnosis system, demands additional hardware such as low pass filter, high resolution ADC, encoder and etc. Therefore, the proposed axis-transformation and speed estimation method are expected to contribute to low cost fault diagnosis systems in inverter-fed motor drives without the need for an encoder and any additional hardware. In order to confirm validity of the developed algorithms, various experiments for rotor faults are tested and the line current spectrum of each faulty situation using Park transformation and speed estimation method are compared with the results obtained from fast Fourier transforms.

• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.77-81
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• 2002

In many high performance engineering systems such as automated production system and transportation systems, AC-servo drives are employed as the most Important driving parts. And the faults of servo drives result in overall system performance deterioration or an unscheduled shutdown In critical situations. The real-time fault detection and isolation(FDI) scheme Is very useful to prevent them and to guarantee the desired reliability of the overall system. In this paper, the FDI schemes which can be applied to AC servo drives are introduced and some new results are presented.

• Journal of Power Electronics
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• v.12 no.3
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• pp.477-486
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• 2012

This paper proposes a novel current control scheme for vector-controlled induction machine (IM) drives in the overmodulation (OVM) range, with which the voltage utilization of the voltage-source inverter (VSI) can be maximized. In the OVM region, the original voltage reference is modified by changing its magnitude and angle, which causes the motor current to be distorted, resulting in a deterioration of the current control performance. To meet with this situation, the harmonic components in the feedback currents should be eliminated before being input to the PI current controllers. For this, a composite observer is applied to extract the fundamental and harmonic components from the distorted currents, which gives a good performance without a delay and the effect of a fundamental frequency variation. In addition, through a detailed analysis of the response of the PI current controllers in the OVM range, the effectiveness of using the composite observer is demonstrated. Simulation and experimental results for a 3-kW induction motor drive are shown to verify the validity of the proposed method.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.5B no.4
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• pp.392-398
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• 2005

This paper presents technologies that have strategic importance in future motor drives. The underlying strategic issue for motor drives is maintaining cost while increasing certain dimensions of functionality. The dimensions of functionality which should increase include reliability and added value features such as providing continuous energy optimization, providing sensing of the driven system suitable for application specific diagnostic purposes, and providing continuously optimal thermal utilization of the capability of the drive. This paper will address each of these issues and discuss the technology status for each case, with a focus on research needed to fully deliver the needed functionality.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.36 no.1
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• pp.3-8
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• 1987

The conventional autosequentially commutated current-fed inverter (ASCI) is widely employed with the induction motor drives for speed control. Howener, this inverter has a limit of high power and high frequency indution motor drives. One of the limitations is to be found in the commutation capacitors in the main circuit of this inverter. A new current-fed gate turn-off thyristor (GTO) inverter is developed. This inverter is composed of the main GTO bridge configuration and the improved energy rebound circuit (ERC)without the commutation capacitor. This inverter works stable at high frequency from light load to heavy one. The improved ERC is used not only to rebound the load reactive power to the dc link, but also to return the power in the load to the ac source. The new GTO inverter circuit and the characteristics of the inverter induction motor drives are explained and analyzed.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.9
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• pp.118-123
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• 2010

The selection of flux level in the maximum torque control of stator flux-oriented induction motor drives in the field weakening region is dependent on stator resistance and inductances. This paper presents parameter detuning effects of stator flux-oriented control drives in the field weakening region. The detuning effects of stator resistance and rotor leakage inductance are analyzed. The decrease of torque and the flux control lost by the detuning of inductance are shown in the simulation results.

• Journal of Power Electronics
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• v.4 no.2
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• pp.117-126
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• 2004

This paper focuses on the electrical modeling techniques of renewable energy sources and storage devices such as batteries, fuel cells (FCs), photovoltaic (PVs) arrays, ultra-capacitors (UCs), and flywheel energy storage systems (FESS). All of these devices are being investigated recently for their typical storage and supply capabilities for various industrial applications. Hence, these devices must be modeled precisely taking into account the concerned practical issues. An obvious advantage of electrically modeling these renewable energy sources and storage devices is the fact that they can easily be simulated in real-time in any CAD simulation program. This paper reviews several types of suitable models for each of the above-mentioned devices and the most appropriate model amongst them is presented. Furthermore, a few important applications of these devices shall also be highlighted.