• International journal of advanced smart convergence
• /
• v.10 no.2
• /
• pp.15-20
• /
• 2021

We constructed an air-lifted seawater propulsion system for decreasing fuel consumption of the ships. The system has a form of pipes which can be easily installed on the sides of the ship. Seawater mixed with air, will rise along within the pipe, and will be discharged downward. If the directions of inlet / outlet of the pipe are designed properly, a propulsive energy can be obtained. We tested the system with a model ship in Jangsa port at Sokcho-city with a water depth of 2.5 meters. The system was supplied regulated air at 6 bars during the 3 tests. The model ship was moving forward at a rate of 0.18 meters per second. In case of large ships equipped zfrom clean energy.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2017.05a
• /
• pp.198-200
• /
• 2017

An Auxiliary Power Unit (APU) is a small gas turbine engine that is mounted on an aircraft and serves to supply energy for ground and air starting of the main engine. APU also supplies emergency and auxiliary power for the aircraft. APU for aircraft is simple and compact in structure, but because it is mounted on manned aircraft, high reliability is required, so it must be proved its reliability through qualification procedure. The Korea Aerospace Research Institute and Hanwha Techwin successfully completed the design / analysis, fabrication, assembly, development test and certification test of APU for helicopter based on accumulated domestic R & D capability and experience from 2007 to 2012. In this paper, the development and certification process of auxiliary power unit for helicopter is summarized.

• Proceedings of the KIPE Conference
• /
• 1998.10a
• /
• pp.143-148
• /
• 1998

The Design criteria of the auxiliary resonant snubber inverter (ARSI) using a load-side circuit are discussed in relation to electric propulsion drives. In this regard, this paper attempts to develop a set of design criteria for the ARSI. First, the switching characteristics of IGBTs under soft-switching mainly in terms of dv/dt/, di/dt and switching losses are discussed and utilized for optimizing the selection of the resonant components in the system. After that, the proper control strategies of ARSIs are analyzed and simulated based on voltage space vector modulations. Later, the design, control and implementation of the auxiliary resonant circuit suitable for industrial products are analyzed and presented. And finally, other factors including power stage layout, packaging and the choice of current sensors are included. The detailed simulation and experimental results will be included based on a laboratory prototype. The proposed design criteria of the ARSI would help the implementation of an electric propulsion drive system.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.29 no.7
• /
• pp.566-569
• /
• 2018

A power line coupler that can apply high-frequency power to a railway overhead line structure was analyzed. It is difficult to supply auxiliary power to an overhead line in a high-voltage environment, and doing so requires a long-distance transfer. A method is proposed that utilizes the resonance on the Rogowski coil, which does not use a magnetic core. A simple overhead line structure was fabricated that consisted of a contact wire, messenger wire, and dropper. Couplers of various sizes were fabricated and deployed on the messenger wire, and the transfer characteristics of the two couplers were compared at a distance. As a result of applying the matching circuit to the coupler, the transmission efficiency was 53% at a distance of 2.5 m. The proposed method shows that it is possible to apply the auxiliary power by using the existing conductor in a special structure, such as the overhead line.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.19 no.1
• /
• pp.66-70
• /
• 2013

The input current of three phase rectifier which is mainly used in the propulsion system of the electric propulsion ship includes a variety of low order harmonics. To reduce these harmonics, the power conversion system, used in the large vessels which high power is required, is currently used the rectifiers of 12-pulse output, but it still has a problem that occurs $12{\pm}1$ harmonics. Also, in the case of the direct torque control technique which is widely used for the speed and torque control, the torque ripple is severe and the input current of motor has greatly included harmonics by the switching of the inverter. In order to reduce harmonics and improve the performance of torque control, this paper presents that the auxiliary supply assisted into the 12-pulse rectifier of the electric propulsion system using direct torque control technique. We confirm the validity of the proposed method through the simulation under the environment of a real vessel system.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2017.05a
• /
• pp.194-197
• /
• 2017

Aircraft engine and auxiliary power units are certified in processes of design, production according to airworthiness requirements. The aircraft engines shall demonstrate compliance with the design and production through the Type Certificate and the auxiliary power unit shall demonstrate compliance with the design and production through the Technical Standards Order Approval. MOLIT(Ministry of Land, Infrastructure and Transport) established the law and the airworthiness requirements for aircraft engines such as KAS Part 33 but didn't issue the Technical Standards Order for auxiliary power unit. In this paper, we proposed and explained the plan for improvement of our aircraft engines industry through building and expanding the certification infra-structure for aircraft engines and auxiliary power unit.

• Journal of the Korean Society for Railway
• /
• v.20 no.3
• /
• pp.339-348
• /
• 2017

Power supply for railway cars can be divided into propulsion system power supply and auxiliary power units (APU). The propulsion system power supply is for propulsion of railway cars, and regenerative braking; the APU provides power for the air compressor, lighting, car control and other auxiliary parts. According to high voltage and high current specifications, generally, an insulated-gate bipolar transistor (IGBT) is adopted for the switching component. For appropriate switching operation, a gate driver unit (GDU) is essentially required. In this paper, the technical trends of GDU for railway cars are analyzed and a design consideration for IGBT GDU is described.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.44 no.6
• /
• pp.512-519
• /
• 2016

Auxiliary Power Unit of FA-50 which provides energy other than propulsion is an important element to maintain airworthiness on aircraft. Also Inlet Guide Vane of Auxiliary Power Unit is a device that supplies appropriate airflow into the Auxiliary Power Unit after adjusting influent airflow into the load compressor. This report, based on the problems occurred the driving gears of Inlet Guide Vane, deals with cause of occurrence, troubleshooting, design improvement and result of test flight verification for FA-50 aircraft Auxiliary Power Unit lifespan.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.64 no.12
• /
• pp.1810-1817
• /
• 2015

The railway vehicle has an auxiliary power unit for supplying power to the associated electronic control devices and passenger service unit. Typically, input voltage from the catenary for rolling stock is highly fluctuating according to the substation capacity, vehicle propulsion and regeneration. Especially, the frost and freezing on contact wire in winter can cause a blackout inside vehicle, and also brings about electronic components damaging and the system down. To prevent this problem, a large filter and capacitor is used. But this is not a perfect solution, because it is increasing weight of the unit. In this paper, a new algorithm is proposed to suppress the disturbance without adding devices. Simulation and experimental results show that the proposed algorithm has performance to suppress the disturbance at the sudden input voltage variations.

• International Journal of Aeronautical and Space Sciences
• /
• v.18 no.1
• /
• pp.154-164
• /
• 2017

This work conducts a validation study for the XH-59A helicopter using a rigid coaxial rotor system in order to establish the techniques of the conceptual design and performance analysis for the lift-offset compound rotorcraft. As a tool for conceptual design and performance analysis, NDARC (NASA Design and Analysis of Rotorcraft) is used for the present study. An assumed mission profile is considered for the conceptual design of the XH-59A. As a validation result of the design, the dimensions and weight of the XH-59A are appropriately designed when compared to the target values since the relative error is less than 0.5%. Then, performance analyses are conducted for the designed XH-59A model with and without auxiliary propulsion in hover and forward flight conditions. The present analyses show good validity since the prediction results compare well with both the flight test and previous analyses. Therefore, the techniques for the conceptual design and performance analysis of the lift-offset compound helicopter are overall considered to be appropriately established. In addition, this study investigates the influence of the lift-offset on the rotor effective lift-to-drag ratio of the XH-59A helicopter with auxiliary propulsion. As a result, the improvement of the rotor effective lift-to-drag ratio can be obtained by appropriately increasing the lift-offset in high-speed flight.