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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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The Transactions of the Korean Institute of Power Electronics
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Journal DOI :
The Korean Institute of Power Electronics
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Volume & Issues
Volume 6, Issue 6 - Dec 2001
Volume 6, Issue 5 - Oct 2001
Volume 6, Issue 4 - Aug 2001
Volume 6, Issue 3 - Jun 2001
Volume 6, Issue 2 - Apr 2001
Volume 6, Issue 1 - Feb 2001
Selecting the target year
EMTDC Modeling of Cheju-Haenam HVDC System
The Transactions of the Korean Institute of Power Electronics, volume 6, issue 1, 2001, Pages 1~12
This paper deals with HVDC simulation. And the purpose of this paper is to reproduce measurements recorded at HVDC site and to verify the control gains and control actions. In this paper, the target of simulation study is Cheju-Haenam HVDC system. Because Cheju-Haenam HVDC system include analogue controller and digital controller, the detailed digital model considered nonlinear characteristics of analogue controllers is development for high accurate firing and control action. Finally the simulation results which is simulated by PSCAD/EMTDC is compared with measurement signals.
Proposal of the Current Mirror for the Circuit Design of CMOS Operational Amplifier
The Transactions of the Korean Institute of Power Electronics, volume 6, issue 1, 2001, Pages 13~20
In this appear, we proposed the new current mirror has large output resistance and excellent current matching characteristics. If supply voltage were lowered under the conventional CMOS operational amplifier, the wing of out put power could be restricted. So, the paper suggests a new way of differential operational amplifier circuit to solve the problem. The paper proposes that a new current mirror increases output swing and has a stable operation. We compare and verify characteristics of the proposed current mirror with the cascoded current mirror and the regulated current mirror through simulation.
Output Waveform Improvement of Double-Connected 3-Phase Voltage Source Inverter by Single-Phase Inverter
The Transactions of the Korean Institute of Power Electronics, volume 6, issue 1, 2001, Pages 21~26
This paper proposes a new double-connected 3-phase voltage source inverter with improved output voltage waveform. An auxiliary single-phase inverter injects a ripple voltage into the double-connected inverter to converter 12-step operation to 36-step operation. The KVA rating of the output phase-shifting transformer is reduced by employing a harmonic canceling reactor. The whole rectifier-inverter system including the proposed technique is introduced, and the experimental results are provided.
A DSP based Three Phase Power Quality Analyzer for Motor Drives
The Transactions of the Korean Institute of Power Electronics, volume 6, issue 1, 2001, Pages 27~33
This paper presents a digital instrument for a DSP based power quality analysis in three phase power system where current waveform is non-sinusoidal. it is based on stand alone type TMS320C31 DSP(digital signal processor)board and on a special high-speed data acquisition system. Power quality of low power motor drives are analyzed and processed by using a simple average power algorithm, and result of power analysis are displayed by LCD in the proposed system. This paper also goes on to discuss the performance of an instrument prototype, both in terms of accuracy and speed of measurement under the transient and steady state condition.
Improved Load Sharing Rate in Paralleled Operated Lead Acid Batteries
The Transactions of the Korean Institute of Power Electronics, volume 6, issue 1, 2001, Pages 34~42
A battery is the device that transforms the chemical energy into the direct-current electrical energy directly without a mechanical process. Unit cells are connected in series to obtain the required voltage, while being connected in parallel to organize capacity for load current and to decrease the internal resistance for corresponding the sudden shift of the load current. Because the voltage droop down in one set of battery is faster than in tow one, it amy result in the low efficiency of power converter with the voltage drop and cause the system shutdown. However, when the system being driven in parallel, a circular-current can be generated. The changing current differs in each set of battery because the system including batteries, rectifiers and loads is connected in parallel and it makes the charge voltage constant. It is shown that, as a result the new batteries are heated by over-charge and over-discharge, and the over charge current increases rust of the positive grid and consequently shortens the lifetime of the new batteries. The difference between the new batteries and old ones is the amount of internal resistance. In this paper, we can detect the unbalance current using the micro-processor and achieve the balance current by adjusting resistance of each set. The internal resistance of each set becomes constant and the current of charge and discharge comes to be balanced by inserting the external resistance into the system and calculating the change of internal resistance.
A Study on Design of the Compensation System for Wind Energy Generation by Power Storage Apparatus
The Transactions of the Korean Institute of Power Electronics, volume 6, issue 1, 2001, Pages 43~48
In conventional wind generation systems, since the blade rotates at low speed when the velocity of wind decreases their operations are possible only under limited conditions. Therefore they are in trouble of self-generation without the help of auxiliary generation devices outside. In addition, most of them have very low usage efficiency because of the characteristic changes of wind. For the solution of these problems and for enough generation regardless of districts and geographical features the rotation energy stored in a spring drives a compact generator and then electric power is stored at battery and supplied to the load continuously according to the lack of wind force. In this paper, the fabricated system consisting of a wind generator and power storage apparatus was introduced and its operation characteristics were analyzed.
A Study on the Control of AC Servo Motor for Machine Tools Cartesian Coordinate Type Using Neural Network
The Transactions of the Korean Institute of Power Electronics, volume 6, issue 1, 2001, Pages 49~56
This paper presents a new approach to the problem based on neural network methods. Instead of using general controllers, neural networks PID control are used to control AC servo motor. The most popular and widely used control method in servo system control loops is PID type. PID controller has the features of simple structure, stability and reliability. But it has limitations in complex system control and can not remain above virtues under the conditions of parameters uncertain and environment uncertainties. AC servo motor controller is designed for drive of the cartesian coordinate type for machine tools.
Sensorles Vector Control to Improve Maintenance Problem in Wound Rotor Type Induction Motor Control System
The Transactions of the Korean Institute of Power Electronics, volume 6, issue 1, 2001, Pages 57~63
The wound rotor type induction motor(WRIM) control system which is widely used in the industry has many maintenance problem because of external resistors and magnetic contactors. In this paper, the simple sensorless vector control algorithm for WRIM is proposed without any additional devices except detecting rotor currents. Because the external resistors are disconnectd and the rotor slip rings are shorten, the power loss due to external resistors is removed and the maintenance problem is improved remarkably. Also, the vector control performance becomes better because the proposed sensorless vector control algorithm does not use the rotor resistance which is usually used to estimate the slip frequency in case of indirect vector control scheme. The proposed algorithm is verified by the digital simulation and the experiment.
Three Level DC/DC Converter Using Energy Recovery Snubber
The Transactions of the Korean Institute of Power Electronics, volume 6, issue 1, 2001, Pages 64~73
This paper presents a Zero Voltage and Zero Current Switching (ZVZCS) 3-Level DC/DC converter. This converter overcomes the drawbacks presented by the conventional Zero Voltage Switching(ZVS) 3-Level converter, such as high circulating energy, severe parastic ringing on the rectifier diodes, and limited ZVS load range for the inner switches. The converter presented in this paper uses a phase shift control with a flying capacitor in the primary side to achieve ZVS for the outer switches. Additionally, the converter uses an energy recovery snubber to reset the primary current during the free-wheeling stage to achieve ZCS for the inner switches. The proposed converters are analyzed and verified on 6kW, 39kHz experimental prototype.
Error Analysis of a Sensorless Position Estimation Considering Noise for Switched Reluctance Motor
The Transactions of the Korean Institute of Power Electronics, volume 6, issue 1, 2001, Pages 74~81
The sensorless scheme for Switched Reluctance Motor(SRM) drives must have the robustness and reliability because the noise and error are sensitive. These elements make electrically noisy environments due to the proximity of high current power circuits with small signal electronic circuits when SRM drives. Also, due to the leakage inductances and finite coupling capacitances, these can cause the noise on any low voltage current and voltage measurement circuit. The position estimate error occurs because the current and voltage including the noise are sued as the inputs of sensorless algorithm. In this paper the high robustness and resistance of input noise re described. The fuzzy logic based rotor estimation algorithm and the observer model are used to reduce the tolerance of input data.
Analysis of HVDC Inverter and Application of Objective Functions for the Optimal Filter Design
The Transactions of the Korean Institute of Power Electronics, volume 6, issue 1, 2001, Pages 82~89
This paper proposes several methods to analyze dynamic and static characteristics of HVDC inverter system. The characteristic analysis is essential of the controller and filter design of the HVDC inverter system. Dynamic characteristic can be analyzed with EMTP simulation and static characteristic can be obtained by solving newly proposed load flow equation which includes the filter and load characteristic. New simple per-phase-equivalent circuit is also proposed. In this circuit, HVDC inverter is considered as a current source depending on the on-off status of switch. Dynamic and static characteristic can be analyzed by the proposed per-phase-equivalent circuit. For the optimal filter design, various performance criteria are proposed. The performance index, based on the per-phase-equivalent circuit, is calculated. Voltage harmonics and filter power loss are selected as criteria. Optimization procedure is explained to find optimal passive filter parameters.
Improvement of Speed Control Performance using Acceleration Feedforward and Incrtia Identification for the Induction Motor
The Transactions of the Korean Institute of Power Electronics, volume 6, issue 1, 2001, Pages 90~97
In this paper, a novel speed control strategy using an acceleration feedforward compensation by the estimation of the system inertia is proposed. With the proposed method, the enhanced speed control performance can be achieved and the speed response against the disturbance torque can be improved for the vector-controled induction motor drive systems in which the bandwidth of the speed controller cannot be made large enough. The simulation and experimental results for induction motor drive systems confirm the validity of the proposed strategy.
Precision Speed Control of PMSM Using Disturbance Observer and Parameter Compensator
The Transactions of the Korean Institute of Power Electronics, volume 6, issue 1, 2001, Pages 98~106
This paper presents external load disturbance compensation that used to deadbeat load torque observer and regulation of the compensation gain by parameter estimator. As a result, the response of PMSM follows that of the nominal plant. The load torque compensation method is compose of a dead beat observer that is well-known method. However it has disadvantage such as a noise amplification effect. To reduce of the effect, the post-filter, which is implemented by MA process, is proposed. The parameter compensator with RLSM(recursive least square method) parameter estimator is suggested to increase the performance of the load torque observer and main controller. Although RLSM estimator is one of the most effective methods for online parameter identification, it is difficult to obtain unbiased result in this application. It is caused by disturbed dynamic model with external torque. The proposed RLSM estimator is combined with a high performance torque observer to resolve the problems. As a result, the proposed control system becomes a robust and precise system against the load torque and the parameter variation. A stability and usefulness, through the verified computer simulation and experiment, are shown in this paper.
Controller Performance Analysis of 3-level inverter STATCOM for balancing DC Link Voltage
The Transactions of the Korean Institute of Power Electronics, volume 6, issue 1, 2001, Pages 107~113
This paper describes dynamic performance analysis of a STATCOM based on 3-level inverter. Major attention is focused on the controller design for 3-level inverter, including regulator design for voltage sharing across the dc link capacitors. A detailed simulation model was developed with Matlab and a scaled hardware model was built and tested to verify the proposed approach. Both simulation and experimental results confirm that the developed controller can regulate the reactive power. The developed controller could be effectively applied to the actual hardware system for STATCOM.