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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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The Korean Institute of Power Electronics
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Volume & Issues
Volume 14, Issue 6 - Dec 2009
Volume 14, Issue 5 - Oct 2009
Volume 14, Issue 4 - Aug 2009
Volume 14, Issue 3 - Jun 2009
Volume 14, Issue 2 - Apr 2009
Volume 14, Issue 1 - Feb 2009
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Nonlinear Controller Design for Noise Reduction and State Estimation in the Photovoltaic Power Generation System
Kim, Il-Song ;
The Transactions of the Korean Institute of Power Electronics, volume 14, issue 4, 2009, Pages 261~267
Due to the measurement noise or system noise, the performance of photovoltaic power generation system can be degraded. If this noise is contained in the solar array voltage measurement signal, the correct operation of the maximum power point tracker can not be guaranteed. The application of the extended Kalman filter to the photovoltaic system can obtain enhanced states estimation result. The Kalman filter provides a recursive solution to optimally estimate from random noise signals. Additionally, as a consequence of Kalman filter, the unmeasurable state such as inductor current can be estimated without current sensor. The methods for system modeling and extended Kalman filter design are presented and the experimental results verify the validity of the proposed system.
Speed Control of PMSM using DTC-PWM Approach
Lee, Dong-Hee ; Choo, Young-Bae ;
The Transactions of the Korean Institute of Power Electronics, volume 14, issue 4, 2009, Pages 268~277
This paper presents an DTC-PWM (Direct Torque Control-Pulse Width Modulation) of PMSM (Permanent Magnet Synchronous Motor). The proposed DTC-PWM method combines a conventional DTC and PWM approach for switching signal generation. The actual torque is estimated by the torque estimator in conventional method, but the switching signal is generated by PWM method according to the switching rules and torque error. A effective voltage vector and zero vector are used to generate the switching signals and asymmetric switching method is applied. A simple calculation of PWM without any complex determination of space vector can assure the constant switching frequency with an constant torque and flux. The proposed torque control scheme for PMSM is verified by experimental results.
Firing Angle Control of Thyristor Converter using PID Controller with Parallel Data Loop
Lee, Jae-Sung ; Jang, Jin-Seok ; Choo, Young-Bae ; Lee, Dong-Hee ;
The Transactions of the Korean Institute of Power Electronics, volume 14, issue 4, 2009, Pages 278~284
This paper presents a firing angle controller of a thyristor converter for DC power supply using PID controller with parallel data loop to improve the dynamic response. The proposed parallel data loop for firing angle controller of 3-phase semi-converter, generates pre-measured firing angle according to reference voltage and load current. With the approximated firing angle according to operating conditions, the output voltage can fast keep the reference value with small voltage error. And the PID controller compensates the output voltage error from the firing angle of parallel data loop. In order to reduce the sudden changing of the data from current ripple, a simple digital low pass filter is used to determine the output data. The proposed control scheme is verified by the experimental test of a practical 50[A] grade thyristor converter system.
Analysis of Common Mode Voltages at Diode Rectifier/Z-Source Inverter System
Tran, Quang-Vinh ; Chun, Tae-Won ; Lee, Hong-Hee ;
The Transactions of the Korean Institute of Power Electronics, volume 14, issue 4, 2009, Pages 285~292
In this paper, when ac motors are driven by the diode rectifier/Z-source inverter system, the common-mode voltages of system are analyzed in details under both the shoot-through state and non-shoot-through state through equivalent circuits. Then a modified space vector modulation strategy is suggested for attenuating the negative common-mode voltage by eliminating the zero voltage vector, and also controlling the shoot-through time. Through the simulation studies with PSIM and experiments with 32-bit DSP, it is verified that the negative common-mode voltage can be reduced by more than 50%.
Variable Gain Current Controller Considering Inductance Variations after the Connection of DFIG Stator to the Grid
Shin, Soo-Cheol ; Yu, Jae-Sung ; Hong, Jung-Ki ; Suh, In-Young ; Song, Seung-Ho ;
The Transactions of the Korean Institute of Power Electronics, volume 14, issue 4, 2009, Pages 293~298
This paper presents a variable gain current control algorithm for the stabilized grid connection between the grid and a doubly fed induction(DFIG) as a wind power generator. The performance of a RSC current controller depends highly on accurate machine parameters, and especially requires a fast and robust response regardless of the disturbances such as voltage sag. However, parameter variations of a DFIG occur at the point of grid connection, which affects the current controller gains based on DFIG parameters after a DFIG is connected to the grid. Thus, performance degrades when actual machine parameters depart from values used in the control system. In the proposed algorithm, current controller gains of the rotor side converter(RSC) are changed after a DFIG is connected to the grid. The simulation results and experimental results for a 750kW are shown to illustrate the feasibility of the proposed algorithm.
A Novel Flyback Converter for Low Standby Power Consumption
Chung, Bong-Gun ; Jang, Sang-Ho ; Kim, Eun-Soo ; Choi, Mun-Gi ; Kye, Moon-Ho ;
The Transactions of the Korean Institute of Power Electronics, volume 14, issue 4, 2009, Pages 299~306
Recently, although the power consumption of the flyback converter at the light load and standby power load was minimized by the burst mode operation of PWM IC, flyback converter has still the low efficiency characteristics by the high magnetizing current flowing through magnetizing inductance of transformer. This paper proposes a novel flyback converter with an improved efficiency characteristics and the reduced magnetizing current at the light load and standby power load. Prototype of the 70W multi-output flyback converter for an auxiliary power module of 50 inch PDP TV is built and the experimental results are described.
Modified Full-bridge based Inverter for Synthesizing Multilevel Output Voltage
Lee, Sang-Hyeok ; Kang, Feel-Soon ; Park, Sung-Jun ;
The Transactions of the Korean Institute of Power Electronics, volume 14, issue 4, 2009, Pages 307~314
In this paper, we proposes a multilevel inverter which can synthesize multi output voltage levels by adding DC voltage sources and switch components. In the proposed circuit topology, full-bride inverter determines the output polarity and the number of output voltage levels are defined by the operation of the additional switches. It can reduce the number of switch devices compared with the conventional approaches when they generate the same number of output voltage levels. To verify the validity of the proposed multilevel inverter, we present simulation and experimental results using a prototype.
A Non-isolated DC-DC Converter with High Step-up Ratio and Wide ZVS Range
Park, Sung-Sik ; Choi, Se-Wan ; Choi, Woo-Jin ; Lee, Kyo-Beum ;
The Transactions of the Korean Institute of Power Electronics, volume 14, issue 4, 2009, Pages 315~322
In the conventional boost converter, the actual duty cycle is limited as the output voltage increases due to increased voltage and current stress of the switch and diode and voltage surge caused by diode reverse recovery. In this paper a new non-isolated boost converter suitable for high gain applications is proposed. The proposed converter has voltage gain of around 6 when the duty cycle is 0.5. Since ZVS is achieved under CCM, the proposed converter has wide ZVS range. Also, voltage ratings of switch and diode are the same as one third of output voltage, and ratings of input and output passive components are reduced due to the interleaving. In addition voltage surge caused by diode reverse recovery is negligible due to ZCS turn-off of diodes. Operating principle of the proposed converter is described and validated through theoretical analysis, simulation and experiment.
Multi-Output LLC Resonant Converter
Kang, Seong-In ; Kim, Joo-Hoon ; Kim, Eun-Soo ; Park, Jun-Ho ; Lee, Jae-Sam ; Huh, Dong-Young ;
The Transactions of the Korean Institute of Power Electronics, volume 14, issue 4, 2009, Pages 323~332
In this paper, operating characteristics of multi-output LLC resonant converter are described and analyzed. Especially, voltage gain characteristics and an equivalent resonant frequency in the multi-output LLC resonant converter are changed by the influences due to the several load conditions and the secondary leakage inductances of multi-output transformer. Based on the theoretical analysis and simulation results considered the characteristics of voltage gain and load variation, prototype of the 540W 3-output LLC resonant converter for 42 inch PDP TV power module is built and the experimental results are described.
A Study on the Neutral Point Potential Variation under Open-Circuit Fault of Three-Level NPC Inverter
Park, Jong-Je ; Park, Byoung-Gun ; Ha, Dong-Hyun ; Hyun, Dong-Seok ;
The Transactions of the Korean Institute of Power Electronics, volume 14, issue 4, 2009, Pages 333~342
Three-level Diode Clamped Multilevel Inverter, generally known as Neutral-Point-Clamped (NPC) Inverter, has an inherent problem causing Neutral Point (NP) potential variation. Until now, in many literatures NP potential problem has been investigated and lots of solutions have also been proposed. However, under fault and fault tolerant control, distinctive feature for NP potential variation problem was rarely published from the standpoint of reliability. In this paper, NP potential is analytically investigated both normal and faulty conditions under carrier based PWM. Subsequently, relation between fault detection time and size of capacitor is analyzed. This information is explored by simulation and experiment results, which contribute to enhance the reliability of inverter system.