• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.5
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• pp.595-602
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• 2017

In Korea, much research and development have occurred to enhance the technological competitiveness of tuna purse seining fisheries. Due to these efforts, fishing efficiency has been improved with the development of radar, sonar and global positioning systems for fish detection and revisions to the hull forms of tuna purse seiners. However, for skiff boats, net boats and speed boats, which are auxiliary working boats mounted on tuna purse seiners, technology has lagged behind relative to the modernization of the main vessel. In this study, the hull of an existing propeller-based net boat with steel wire net to protect tuna was changed to the hull of a water jet propulsion vehicle to reduce resistance and improve maneuverability. As a result, a prototype of a water jet propulsion option was produced according to the aluminum structure strength standards specified by the Ministry of Oceans and Fisheries, and safety was confirmed by performing a drop test. Moreover, through a sea trial test, an existing net boat was shown to have a speed of 12.0knots and a towing force of 2,545 kgf at 2,500 RPM. The prototype had a speed of 26.7 knots and a towing force of 2,011 kgf at 3,200 RPM, which satisfied the towing capacity standards of auxiliary working boats mounted on tuna purse seiners.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.11
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• pp.1628-1632
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• 2013

HEP(Head Electric Power) system, supplying 3-phase service power to the coach vehicles, is a kind of special auxiliary power equipment which is boarded on 8200 series electric locomotives in KORAIL. This equipment shares high voltage DC link with a main propulsion converter/inverter systems. It was difficult to use high frequency PWM technique so that GTO has been used as a power device same like the main power system. Due to low PWM frequency(300Hz) of HEP inverter, the output voltage has less power quality comparing to normal SIV(Static Inverter) system. In this paper, an optimal PWM strategy is presented for new IGBT type HEP inverter system. Several PWM techniques were investigated to improve output voltage quality under fixed lower filter inductance and not high PWM frequency. Finally PC simulations have been done to clarify its availability.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.638-641
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• 1997

This paper describes the electrical design, characteristic and test results of both VVVF Inverter system and a auxiliary power supply system for UTM-01. As the propulsion system for SLIMs, GTO type VVVF inverter is used. IGBT 3 level inverter is adopt in Auxiliary Power Supply system. The control of two systems is fully digitalized by DSP TMS320C31. So a performance of two systems is more improved.

• Journal of the Korean Society for Railway
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• v.19 no.3
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• pp.297-303
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• 2016

This paper introduces auxiliary power supply systems (APS) for railroad applications and proposes a new power conversion structure for highly-efficient and lightweight APS systems. The proposed structure focuses on an improvement of the power density in APS. It eliminates unnecessary power conversion stages in the conventional APS structure by modulating the dc/dc converter circuit and the structure of the system. The dc/dc converter circuit used in the proposed structure is based on a multi-level half-bridge converter, a widely used topology in railroad APS applications; a flying capacitor is newly added to the conventional circuit. The added capacitor is used not only to enhance the soft switching condition of the switches, but also so that the new pantograph will have a side voltage source of a battery charger in the APS structure. Since the battery charger uses the pantograph side voltage source in the proposed structure, rather than using the output of the main dc/dc converter in the conventional structure, the size and efficiency of the main dc/dc converter are reduced and increased, respectively. To verify the effectiveness of the proposed structure, simulation results will be presented with metropolitan transit APS specifications.

• Journal of the Korean Society for Railway
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• v.20 no.3
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• pp.329-338
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• 2017

A recent trend of technical development in auxiliary-power-supplies (APS) is to replace 60Hz low frequency transformers with isolated type dc/dc converters. This paper introduces the technical trend in APS structures and proposes a power converter circuit suitable for high-efficient and light-weight APS. By utilizing the resonant converter, which achieves ZCS, to reduce switching losses, various types of APS structures (1-stage and 2-stage) are reviewed, and they are verified by simulation. The full-bridge resonant LLC converter is designed with a 1-stage power converting structure; the resonant converter topology is designed with a 2-stage power converting structure that has a pre-regulator converter to compensate for the wide input voltage range. Both a step-down converter and a step-up converter are designed and compared for the pre-regulator in the 2-stage structure. Operational characteristics are compared with simulation results and loss analyses are presented to proposes appropriate system structure and topologies.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.8
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• pp.1103-1109
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• 2021

ECS is a control device so that the warship can perform the mission stably by controlling and monitoring the entire propulsion system. As the recent provisions of the warship, it's propelling system is complicated than past, as the demand performance and mission of the warships are diverse. In accordance with the complicated propulsion system configuration, the demand for automatic control function of the ECS is increasing for convenient and stable propulsion system control for convenient and stable. As a result, verification of ECS stability and reliability is required. In this paper, we develop an interlocking signal simulator for verifying ECS control logic and communication protocol for warship with CODLOG propulsion systems. The simulator developed was implemented to simulate a signal of gas turbine, propulsion motors, diesel generator and 11 kinds of auxiliary equipment. The reliability of ECS was verified through the ECS communication program and the I/O signal static test with the simulator.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.6
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• pp.1158-1166
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• 2012

Thus, all systems and sensors corresponding to navigation are integrated to an INS (Integrated Navigation System) or an IBS (Integrated Bridge System). Propulsion automation systems, propulsion systems, auxiliary systems, and power management systems are integrated to an ICMS (Integrated Control and Monitoring System), an IPMS (Integrated Platform Management System), and IMCS (Integrated Monitoring and Control System). This paper introduces the results of designing and implementing an Integrated Interface System which ties up diverse system interfaces via network and inversely converts network signals into a proper interface signal type connected to other systems.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.109-112
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• 2011

The result of design review and arrangement of a combustion chamber test facility(CTF) and a turbo-pump real propellant test facility(TPTF) is briefly described. The development/qualification tests of combustion chamber and turbo-pump for 75ton-class liquid rocket engine will be performed in CTF and TPTF. The critical design of hydraulic-pneumatic system, control and data acquisition system, test stand cell, and auxiliary facilities in CTF and TPTF was performed.

• Transactions of the Korean hydrogen and new energy society
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• v.25 no.3
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• pp.271-279
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• 2014

A 25kW-class polymer electrolyte membrane (PEM) fuel cell system has been developed for the propulsion of a leisure boat. The fuel cell system was designed to satisfy various performance requirements, such as resistance to shock, stability under rolling and pitching oscillations, and durability under salinity condition, for its marine applications. Then, the major components including a 30kW-class PEM fuel cell stack, a DC-DC converter, a seawater cooling system, secondary battery packs, and balance of plants were developed for the fuel cell system. The PEM fuel cell stack employs a unique design structure called an anodic cascade-type stack design in which the anodic cells are divided into several blocks to maximize the fuel utilization without hydrogen recirculation devices. The performance evaluation results showed that the stack generated a maximum power of 31.0kW while maintaining a higher fuel utilization of 99.5% and an electrical efficiency of 56.1%. Combining the 30-kW stack with other components, the 25kW-class fuel cell system boat was fabricated for a leisure. As a result of testing, the fuel cell system reached an electrical efficiency of 48.0% at the maximum power of 25.6kW with stable operability. In the near future, two PEM fuel cell systems will be installed in a 20-m long leisure boat to supply electrical power up to 50kW for propelling the boat and for powering the auxiliary equipments.

• Journal of the Korean Society of Propulsion Engineers
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• v.21 no.6
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• pp.83-90
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• 2017

Performance analysis of the turboshaft engines for combined rotorcraft was executed. A tip jet and a ducted fan aircraft were selected for combined rotorcraft application. Gasturb 12 software was used for turboshaft engine performance analysis. In the results, maximum required power for the tip jet engine is about 1,600 hp class and maximum required power for the ducted fan engine is about 1,000 hp class at the required aircraft mission. This is due to the additional power of the auxiliary compressor to get a bleed air mass flow rate for the tip jet operation. At the same time, fuel consumption of the tip jet aircraft is 2.8 times larger than ducted fan case. Therefore ducted fan type aircraft is more efficient than tip jet aircraft in terms of fuel economy.