• Proceedings of the KSR Conference
• /
• 2004.10a
• /
• pp.1437-1443
• /
• 2004

In this paper, AC electric vehicle propulsion system(Converter/Inverter) using high power semiconductor, IPM(Intelligent Power module) is proposed. 2-Parallel operation of two PWM converter is adopted for increasing capacity of system and the VVVF inverter control is used a mixed control algorithm, where the vector control strategy at low speed region and slip-frequency control strategy at high speed region. The proposed propulsion system is verified by experimental results with a 1,350kW converter and 1.100kVA inverter with four 210kW traction motors.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2017.05a
• /
• pp.353-357
• /
• 2017

The research trends and major technologies of the divert attitude control system(DACS), which is the core of the anti-missile system, are described. The operating concept and characteristics according to the fuel used are summarized. The characteristics of typical weapon system applying solid(SM3 Block IB/IIA) and liquid(THAAD) fuels were discussed. In the future, it will be necessary to study various types of DACS in the strategic concept of the defense weapon system.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 1999.10a
• /
• pp.7-7
• /
• 1999

Thermal behavior of spacecraft propulsion system utilizing monopropellant hydrazine ($N_2$H$_4$) is addressed in this paper. The thermal-control performance to prevent propellant freezing in spacecraft-operational orbit was test-verified under simulated on-orbit environment. The on-orbit environment was thermally achieved in space-simulation chamber and by the absorbed-heat flux method that implements an artificial heating through to the spacecraft bus panels enclosing the propulsion system.

• Proceedings of the KSR Conference
• /
• 2005.05a
• /
• pp.800-805
• /
• 2005

In this study, control schemes are proposed for a propulsion system of TTX(Tilting Train eXpress). In developed traction converter, unity power factor control, compensation method of dc link voltage have been applied. Output current of converter contains harmonic ripple at twice input ac line frequency, which causes a ripple in the dc link voltage so that beatless control is developed in inverter system to reduce the pulsating torque current. This system is verified by the system modelling and prototype test.

• Proceedings of the KSR Conference
• /
• 1998.11a
• /
• pp.226-232
• /
• 1998

In this pager, we present IGBT VVVF inverters as a 1C1M propulsion system for electric car. This inverters are composed of high power IGBT's and controlled by compact control units. The control unit performs full digital control by using 32bit DSP and microconteroller. By using CAN-bus, high speed network is constructed within tow control units. The stack is simplified and optimized by using plate bus and IGBT driver units of hybrid-type.

• Journal of the Korean Society for Railway
• /
• v.13 no.2
• /
• pp.166-172
• /
• 2010

Currently, vector control is used for speed control of trains because induction motor has high performance is installed in Electric railroad systems. Also, control of the induction motor is possible through various methods by developing inverters and control theory. Presently, rolling stocks which use the induction motor are possible to brake trains by using AC motor. Therefore model of motor block and induction motor is needed to adapt various methods. There is Variable Voltage Variable Frequency (VVVF) as the control method of the induction motor. The torque and speed is controlled in the VVVF. The propulsion system model in the electric railroad has many sub-systems. So, the analysis of performance of the speed control is very complex. In this paper, simulation models are suggested by using Matlab/Simulink in the speed control characteristic. On the basis of the simulation models, the response to disturbance input is analyzed about the load. Also, the current, speed and flux control model are proposed to analyze the speed control characteristic in the train propulsion system.

• Journal of the Korean Society for Railway
• /
• v.13 no.4
• /
• pp.363-370
• /
• 2010

This paper describes the evaluation of structural integrity and dynamic characteristic of inertial load test equipments for performance test of railway vehicle propulsion control system. The propulsion control system of railway vehicle has to be confirmed of safety and reliability prior to its application. Therefore, inertial load test equipments were designed through theoretical equation for performance test of propulsion control system. The structural analysis of inertial load test equipments was conducted using Ansys v11.0 and the dynamic characteristic was evaluated using Adams. The results showed that the structural integrity of inertial load test equipment was satisfied with a safety factor of 10.2 on the bearing part under combined load. Also, the structural stability of flywheel according to dynamic simulation was secured by the maximum oscillation displacement within 0.83mm.

• 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.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.18 no.6
• /
• pp.34-41
• /
• 2014

A feasibility study of thrust control of hybrid propulsion system for lunar exploration is presented. The thrust control experiments were performed by controlling the oxidizer mass flow rate where the thrust modulation is carried by using a ball valve and a stepping motor. The gaseous oxygen (GOX) and the HDPE (High Density PolyEthylene) were used for the oxidizer and solid fuel, respectively. It was found that the thrust levels were stable without much fluctuation during the modulation period, and that the thrust was exactly controlled with target thrust modulation ratio of 53% and 32%.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.28 no.3
• /
• pp.451-458
• /
• 2022

In Korea, five major ports have been designated as sulfur oxide emission control areas to reduce air pollutant emissions, in accordance with Article 10 of the "Special Act on Port Air Quality" and Article 32 of the "Ship Pollution Prevention Regulations". As regulations against vessel-originated air pollutants (such as PM, CO2, NOx, and SOx) have been strengthened, the Ministry of Oceans and Fisheries(MOF) enacted rules that newly built public ships should adopt eco-friendly propulsion systems. However, particularly in diesel-electric hybrid propulsion systems,the demand for precise control schemes continues to grow as the fuel saving rate significantly varies depending on the control strategy applied. The conventional Power Take In-Power Take Off(PTI - PTO) mode control adopts a rule-based strategy, but this strategy is applied only in the low-load range and PTI mode; thus, an additional method is required to determine the optimal fuel consumption point. The proposed control method is designed to optimize fuel consumption by applying the equivalent consumption minimization strategy(ECMS) to the PTI - PTO mode by considering the characteristics of the specific fuel oil consumption(SFOC) of the engine in a diesel-electric hybrid propulsion system. To apply this method, a specific fishing vessel model operating on the Korean coast was selected to simulate the load operation environment of the ship. In this study, a 10.2% reduction was achieved in the MATLAB/SimDrive and SimElectric simulation by comparing the fuel consumption and CO2 emissions of the ship to which the conventional rule-based strategy was applied and that to which the ECMS was applied.