• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.58 no.8
• /
• pp.1519-1525
• /
• 2009

This paper presents a novel passive converter for single phase SRM. The proposed passive converter has additional passive power circuit which is consisted by three diodes and one capacitor in the front-end of conventional asymmetric converter to supply a high negative bias during demagnetization. The high negative bias can reduce the demagnetization time and negative torque from tail current in single phase SRM. So, It can extend positive torque region by the extended turn-off position. In this paper, the structure and operating modes of a novel passive converter are introduced with mathematical model. The proposed single phase SRM using passive converter is verified by the computer simulation and experimental results.

• Journal of the Korean Institute of Telematics and Electronics D
• /
• v.34D no.10
• /
• pp.14-23
• /
• 1997

An MMIC downconverting mixer for cellular phone application has been successfully developed using an MMIC process including $1 \mu\textrm{m}$ ion implanted gaAs MESFET and passive lumped elements consisting of spiral inductor, $Si_3N_4$ MIM capacitor and NiCr resistor. The configuration of the mixer presented in this paper is single-ended dual-gate FET mixer with common-source self-bias circuits for single power supply operation. The dimension of the fabricated circuit is $1.4 mm \times 1.03 mm $ including all input matching circuits and a mixing circuit. The conversion gian and noise figure of the mixer at LO powr of 0 dBm are 5.5dB and 19dB, respectively. The two-tone IM3 characteristics are also measured, showing -60dBc at RF power of -30dBm. Allisolations between each port show better than 20dB.

• 전기의세계
• /
• v.25 no.4
• /
• pp.68-72
• /
• 1976

This study is initiated to solve the problem that the development of an electric machine to drive heavy horse-power load required in the rural district, where only single phase supply is available, is very urgent. As a method for this purpose, the single/three phase converter by single phase induction machine with a tapped auxiliary winding, running unloaded mechanically under single-phase source and supplying three-phase output to a loaded 3-phase induction motor, is devised and the pilot machine is put into test. Analysis based on hybrid equivalent circuit for the phase converter and symmertical component theory for the 3-phase load motor and practical experiment result in that optimum auxiliary winding ratio is to be 1.25 rather than theoretical .root.3/2 in order to keep the voltage unbalance ratio of 3-phase output from the converter as low as possible in both cases of starting and running the load motor.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.53 no.6
• /
• pp.396-401
• /
• 2004

Single phase induction motor(SPIM) is one of the most widely used type of low power AC motors in the world, especially for domestic or commercial applications where a three phase power supply is not available. Single phase induction motors have no starting torque their own. So there are several ways of starting single phase induction motors. The most common type is the starting capacitor installed in series with the auxiliary winding to increase the starting torque. In the conventional systems, this function is conducted by a centrifugal switch. But the mechanical centrifugal switch has many problems such as switch malfunction. This paper presents the auxiliary winding control using digital universal starting switch to overcome these shortcomings of centrifugal switch.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2007.10a
• /
• pp.242-245
• /
• 2007

To improve the efficiency of PDP TV, it should minimize the power losses transpired during AC-to-DC power conversion and PDP driving process. Generally the input power supply for PDP driving employes a two-stage power factor corrected converter, and it independently consists of sustain driver, which has high power consumption. However, such a circuit configuration has a difficulty for the PDP market requires low cost. To alleviate this problem, a new circuit composition is presented. It integrates input power supply with sustain driver in a single power stack. The input power supply of the proposed circuit has a single-stage structure to minimize power conversion loss, and it directly supplies power to the sustain driver so as to reduce the system size and cost.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.14 no.1
• /
• pp.72-81
• /
• 2009

This paper presents quasi-resonant type high power factor ac power supply for atmospheric pressure plasma cleaning system adopting three phase PFC boost converter and it's control method. The presented ac power supply consists of single phase H-bridge inverter, step-up transformer for generating high voltage and three phase PFC boost converter for high power factor on source utility. Unlikely to the traditional LC resonant converter, the propose one has an inductor inside only. A single resonant takes place through the inside inductor and the capacitor from the plasma load modeled into two series capacitor and one resistance. The quasi-resonant can be achieved by cutting the switching signal when the load current decrease to zero. To obtain power control ability, the propose converter controlled by two control schemes. One is the changing output pulse period scheme in the manner of PFM(Pulse Frequency Modulation) control. On the other, to provide more higher power to load, the DC rail voltage is directly controlled by the 3-phase PFC boost converter. The significant merits of the proposed converter are the uniform power providing capability for high quality plasma generation and low reactive power in AC and DC side. The proposed work is verified through digital simulation and experimental implementation.

• International Journal of Computer Science & Network Security
• /
• v.23 no.1
• /
• pp.147-152
• /
• 2023

Mostly in motor fault detection the instantaneous values 3 axis vibration and 3phase current in time domain are acquired and converted to frequency domain. Vibrations are more useful in diagnosing the mechanical faults and motor current has remained more useful in electrical fault diagnosis. With having some experience and knowledge on the behavior of acquired data the electrical and mechanical faults are diagnosed through signal processing techniques or combine machine learning and signal processing techniques. In this paper, a single-layer LSTM based condition monitoring system is proposed in which the instantaneous values of three phased motor current are firstly acquired in simulated motor in in health and supply imbalance conditions in each of three stator currents. The acquired three phase current in time domain is then used to train a LSTM network, which can identify the type of fault in electrical supply of motor and phase in which the fault has occurred. Experimental results shows that the proposed single layer LSTM algorithm can identify the electrical supply faults and phase of fault with an average accuracy of 88% based on the three phase stator current as raw data without any processing or feature extraction.

• Journal of Power Electronics
• /
• v.3 no.3
• /
• pp.185-196
• /
• 2003

In this paper, the single-phase static VAR compensator (SVC) is applied to regulate and stabilize the generated terminal voltage of the single-phase self-excited induction generator (single-phase SEIG) driven by a variable-speed prime mover (VSPM) under the conditions of the independent inductive load variations and the prime mover speed changes The conventional fixed gain PI controller-based feedback control scheme is employed to adjust the equivalent capacitance of the single-phase SVC composed of the fixed excitation capacitor FC in parallel with the thyristor switched capacitor TSC and the thyristor controlled reactor TCR The feedback closed-loop terminal voltage responses in the single-phase SEIG coupled by a VSPM with different inductive passive load disturbances using the single-phase SVC with the PI controller are considered and discussed herem. A VSPM coupled the single-phase SEIG prototype setup is established. Its experimental results are illustrated as compared with its simulation ones and give good agreements with the digital simulation results for the single-phase SEIG driven by a VSPM, which is based on the SVC voltage regulation feedback control scheme.

• The Journal of Information Technology
• /
• v.8 no.3
• /
• pp.143-158
• /
• 2005

The purpose of the paper is to analyze situations and its prospect of Single Window System for custom's one-stop service in Japan and to suggest effective application was to improve of in Korea's Customs systems. In response to the growing demand for lower trading costs and shorter and more predictable lead times with the advancement of the international trade supply chain, the Single Window System for import/export and port-related procedures was launched on 23 July 2003 in Japan. The concept of the Single Window System is to establish a comprehensive computer interface system that enables users to complete all import/export and port-related procedures required under different laws and regulations in a single input and single transmission. To realize the concept, the data elements and submission times of the various systems were harmonized, and manual procedures, such as quarantine and immigration, were computerized. Then, all the necessary systems, such as NACCS, Port EDI System, and Crew Landing Permit Support System, were interconnected as a Single Window System. Close cooperation among other governmental organizations and the private sector was a key factor in the successful development and smooth utilization of the System so that it fully met all parties' needs. It is anticipated that operating costs will be greatly reduced and trade facilitation will be enhanced as a result of the simplification of procedures. Korea Customs advocates the Single Window System as a best practice at ASEAN and WCO to contribute to the development of regional and international capacity building.

• ETRI Journal
• /
• v.26 no.6
• /
• pp.560-564
• /
• 2004

An analog front-end circuit for ISO/IEC 14443-compatible radio frequency identification (RFID) interrogators was designed and fabricated by using a $0.25{\mu}m$ double-poly CMOS process. The fabricated chip was operated using a 3.3 Volt single-voltage supply. The results of this work could be provided as reusable IPs in the form of hard or firm IPs for designing single-chip ISO/IEC 14443-compatible RFID interrogators.