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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Power Electronics
Journal Basic Information
Journal DOI :
The Korean Institute of Power Electronics
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Volume & Issues
Volume 4, Issue 4 - Oct 2004
Volume 4, Issue 3 - Jul 2004
Volume 4, Issue 2 - Apr 2004
Volume 4, Issue 1 - Jan 2004
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Nonlinear Representation of Two-Stage Power-Factor-Correction AC/DC Circuits
Orabi Mohamed ; Ninomiya Tamotsu ;
Journal of Power Electronics, volume 4, issue 4, 2004, Pages 197~204
Two-stage Power-Factor-Correction (PFC) converters are the most common circuits for drawing sinusoidal and in phase current waveforms from an ac source with a good regulated output voltage. The first stage is a boost PFC converter with average-current-mode control for achieving the near-unity power factor and the second stage is a forward converter with voltage-mode control to regulate the output voltage. Stability analysis and design methods of two-stage PFC converters have previously been discussed using linear models. Recently, new nonlinear phenomena have been detected in pre-regulator boost PFC circuits and a new nonlinear model has been proposed for pre-regulated PFC converters. Therefore, investigation of two-stage PFC converters from the nonlinear viewpoint becomes important because the second stage DC/DC converter adds more complexity to the circuit. So, this paper introduces a study of the stability of two-stage PFC converters. A novel nonlinear model of two-stage PFC converters is proposed. Then, a stability analysis is made based upon this nonlinear model. The high correspondence between the simulated and experimental results confirms our analysis.
A Self-Excited Induction Generator with Simple Voltage Regulation Suitable for Wind Energy
Ahmed Tarek ; Nishida Katsumi ; Nakaoka Mutsuo ;
Journal of Power Electronics, volume 4, issue 4, 2004, Pages 205~216
In this paper, a three-phase induction machine-based wind power generation scheme is proposed. This scheme uses a low-cost diode bridge rectifier circuit connected to an induction machine via an ac load voltage regulator (AC-LVR) to regulate dc power transfer. The AC-LVR is used to regulate the DC load voltage of the diode bridge rectifier circuit which is connected to the three-phase self-excited induction generator (SEIG). The excitation of the three-phase SEIG is supplied by the static VAR compensator (SVC). This simple method for obtaining a full variable-speed wind turbine system by applying a back-to-back power converter to a wound rotor induction generator is useful for wind power generation at widely varying speeds. The dynamic performance responses and the experimental results of connecting a 5kW 220V three-phase SEIG directly to a diode bridge rectifier are presented for various loads. Moreover, the steady-state simulated and experimental results of the PI closed-loop feedback voltage regulation scheme prove the practical effectiveness of these simple methods for use with a wind turbine system.
A High-Performance Induction Motor Drive with 2DOF I-PD ModelFollowing Speed Controller
El-Sousy Fayez F. M. ;
Journal of Power Electronics, volume 4, issue 4, 2004, Pages 217~227
A robust controller that combines the merits of the feed-back, feed-forward and model-following control for induction motor drives utilizing field orientation control is designed in this paper. The proposed controller is a two-degrees-offreedom (2DOF) integral plus proportional & rate feedback (I-PD) speed controller combined with a model-following (2DOF I-PD MFC) speed controller. A systematic mathematical procedure is derived to find the parameters of the 2DOF I-PD MFC speed controller according to certain specifications for the drive system. Initially, we start with the I-PD feedback controller design, then we add the feed-forward controller. These two controllers combine to form the 2DOF I-PD speed controller. To realize high dynamic performance for disturbance rejection and set point tracking characterisitics, a MFC controller is designed and added to the 2DOF I-PD controller. This combination is called a 2DOF I-PD MFC speed controller. We then study the effect of the 2DOF I-PD MFC speed controller on the performance of the drive system under different operating conditions. A computer simulation is also run to demonstrate the effectiveness of the proposed controller. The results verify that the proposed 2DOF I-PD MFC controller is more accurate and more reliable in the presence of load disturbance and motor parameter variations than a 2DOF I-PD controller without a MFC. Also, the proposed controller grants rapid and accurate responses to the reference model, regardless of whether a load disturbance is imposed or the induction machine parameters vary.
Robust Current Control for Permanent Magnet Synchronous Motors by the Inverse LQ Method - An Evaluation of Control Performance Using Servo-Locks at Low Speed -
Takami Hiroshi ;
Journal of Power Electronics, volume 4, issue 4, 2004, Pages 228~236
This paper describes the optimal current-control of a permanent magnet synchronous motor by the use of robust and simple current controllers, based upon the analytical procedure known as the inverse LQ (ILQ) design method. The ILQ design method is a strategy for finding the optimal gains based on pole assignment without solving the Riccati equation. It is very important to keep the motor in robust servo-lock. By experiments and simulations, we will show that the ILQ optimal servo-system with servo-lock is more insensitive at low speeds to variations in armature inductance than the standard PI servo-system. Variations in armature inductance have the greatest influence on the responses of a servo-system.
A Flyback Transformer linked Soft Switching PWM DC-DC Power Converter using Trapped Energy Recovery Passive Quasi-Resonant Snubbers with an Auxiliary Three-Winding Transformer
Ahmed Tarek ; Chandhaket Srawouth ; Nakaoka Mutsuo ; Jung Song Hwa ; Lee Hyun-Woo ;
Journal of Power Electronics, volume 4, issue 4, 2004, Pages 237~245
In this paper, a two-switch high frequency flyback transformer linked zero voltage soft switching PWM DC-DC power converter implemented for distributed DC- feeding power conditioning supplies is proposed and discussed. This switch mode power converter circuit is mainly based on two main active power semiconductor switches and a main flyback high frequency transformer linked DC-DC converter in which, two passive lossless quasi-resonant snubbers with pulse current regeneration loops for energy recovery to the DC supply voltages composed of a three winding auxiliary high frequency pulse transformer, auxiliary capacitors and auxiliary diodes for inductive energy recovery discharge blocking due to snubber capacitors are introduced to achieve zero voltage soft switching from light to full load conditions. It is clarified that the passive resonant snubber-assisted soft switching PWM DC-DC power converter has some advantages such as simple circuit configuration, low cost, simple control scheme, high efficiency and lowered noises due to the soft switching commutation. Its operating principle is also described using each mode equivalent circuit. To determine the optimum resonant snubber circuit parameters, some practical design considerations are discussed and evaluated in this paper. Moreover, through experimentation the practical effectiveness of the proposed soft switching PWM DC-DC power converter using IGBTs is evaluated and compared with a hard switching PWM DC-DC power converter.
A Comparative Study of Simple Ac-Dc PWM Full-Bridge Current-Fed and Voltage-Fed Converters
Moschopoulos Gerry ; Shah Jayesh ;
Journal of Power Electronics, volume 4, issue 4, 2004, Pages 246~255
Ac-dc PWM single-stage converters that integrate the PFC and dc-dc conversion functions in a single switching converter have been proposed to try to minimize the cost and complexity associated with implementing two separate and independent switch-mode converters. In this paper, two simple ac-dc single-stage PWM full-bridge converters are considered - one current-fed, the other voltage-fed. The operation of both converters is explained and their properties are noted. Experimental results obtained from simple lab prototypes of both converters are presented, then compared and discussed.
A Signal Anti-reduction System for Power Line Communication
Ko Jong-Sun ; Kim Hyun-Sik ; Hong Soon-Chan ;
Journal of Power Electronics, volume 4, issue 4, 2004, Pages 256~260
A new communication system is suggested using a single-phase full-bridge inverter with high efficiency ferrite core for power line communication (PLC). The conventional system has a decreasing signal voltage problem due to internal resistance. The proposed system has almost zero internal impedance and replaces a linear amplifier.