• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.22 no.4
• /
• pp.67-72
• /
• 2022

This study presents the design of power amplifier (PA) in 60 nm GaN/Si HEMT technology. A customized transistor model enables the designing circuits operating at W-band. The all matching network of the PA was composed of equivalent transformer circuit to reduce matching loss. And then, equivalent transformer is several advantages without any additional inductive devices so that a wideband power characteristic can be achieved. The designed die area is 3900 ㎛ × 2300 ㎛. The designed results at center frequency achieved the small signal gain of 15.9 dB, the saturated output power (Psat) of 29.9 dBm, and the power added efficiency (PAE) of 24.2% at the supply voltage of 12 V.

• Proceedings of the KIEE Conference
• /
• 2005.07c
• /
• pp.2345-2347
• /
• 2005

In this paper, impedance characteristics of overhead medium-voltage (MV) power lines is reported for power line communication (PLC) over an MV power line network. For analysis, a two-port equivalent network model of MV power lines is derived. By applying the transmission line theory, reflection behavior and impedance of power lines are investigated. For verification, impedance of power lines is measured at a test field for an MV PLC. The results show that impedance of MV power lines is between $200{\Omega}$ and $300{\Omega}$ and converges to a half of their characteristic impedance.

• The Transactions of the Korean Institute of Electrical Engineers A
• /
• v.53 no.9
• /
• pp.494-499
• /
• 2004

This paper presents to compute the power economic dispatch, an optimal power flow (OPF) computation algorithm, considering the load power factor limits constraint in developed. Efficient reactive power planning enhances economic operation as well as system security. Accordingly, an adequate level of power factor limits for the load busesshould be evaluated for economic operation. In this paper, the ranges of acceptable load power factors are portrayed as bandwidths of load power factor expressed as a function of load level. The load power factor limits are included and described into the OPF's objective function. The method Proposed is applied to IEEE 26 bus system.

• Proceedings of the KIPE Conference
• /
• 2001.10a
• /
• pp.698-702
• /
• 2001

In this paper, to solve the defect of stand-alone type power system in a remote area, a hybrid power system with photovoltaic/wind/diesel generators is proposed. A hybrid power system has a power-balanced controller to equilibrate generation power with a given load demand and which is composed of common DC power system. To execute a power-balanced control, a hybrid power system is assumed that all of power generators have the characteristics of an equivalent current-source and load sharing control technique must be needed at the same time. So this paper describes the algorithm of interactive technique for design of a hybrid power system.

• ETRI Journal
• /
• v.33 no.4
• /
• pp.648-651
• /
• 2011

This letter presents a highly efficient rack-level DC power architecture combined with a node-level DC uninterruptible power supply (UPS). The proposed system can provide almost the equivalent power efficiency of a high-voltage DC data center without any change in the existing power infrastructure. The node-level DC UPS combined with a power distribution board provides high power efficiency as well as lower UPS installation costs. Implemented on a rack, the entire power system can be monitored through a network.

• 유체기계공업학회:학술대회논문집
• /
• 1999.12a
• /
• pp.291-300
• /
• 1999

Currently under development is an airborne auxiliary power unit with 100 Kw equivalent power, which is composed of a centrifugal compressor, a reverse annular combustor, and a radial turbine. Air-foil bearings are used in this power unit to eliminate the oil supplying system, which can reduce the system complexity and weight. The high speed generator is adopted as an electric power generation and engine starting system, which can also eliminate the reduction gear system. Not only electric power but also pneumatic power is provided by bleeding the compressed air This power unit is aimed for the multi-purpose use such as a primary power unit In the army weapon system, an auxiliary power and environmental control unit in a next-generation tank, and a smoke generating unit.

• Proceedings of the KIPE Conference
• /
• 2002.11a
• /
• pp.181-185
• /
• 2002

This paper discusses power balance control of photovoltaic/wind/diesel hybrid generation system for remote area power supplies. There are many control methods for hybrid power system. Among others, it must be adopted that the control method to guarantee a stable balance between supply and demand, regardless of the fluctuation of generator power by atmospheric changes. In this paper, it Is proposed that a hybrid generation system has a power-balanced controller to equilibrate generation power with a load demand, which is composed of DC bus-type power systems. To execute power balance control, it is assumed that all of power generators have a equivalent current-source characteristics. Through the results of simulation, the proposed scheme was verified.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.27 no.2
• /
• pp.157-164
• /
• 2022

This study proposes an enhanced quadruple-Active-Bridge (QAB) converter that can solve power coupling problems. By adopting a multiple winding transformer, the equivalent circuit of a conventional QAB converter has power couplings between arbitrary output ports. This coupling is an unintended power relationship that complicates the regulation of output voltage of the multiple ports. The proposed converter can carry out power decoupling by changing the arrangement of the coupling inductor. Power transfer equations for the proposed converter and its operating principles are analyzed in detail. The power coupling caused by the transformer's leakage inductance is verified by using a proposed coupling factor that presents the relationship between inductance ratio and coupling power. In addition, the decoupling power control performance of the proposed converter is verified by simulation and a 3 kW prototype converter.

• Proceedings of the KIEE Conference
• /
• 1986.07a
• /
• pp.369-372
• /
• 1986

• Proceedings of the Korean Society of Marine Engineers Conference
• /
• 2011.06a
• /
• pp.194-194
• /
• 2011