• Proceedings of the Korean Information Science Society Conference
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• 2007.10a
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• pp.259-260
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• 2007

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.6
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• pp.196-207
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• 2023

As part of measures to address the climate crisis, buses are also being converted to electric and hydrogen buses. Local authorities need to prioritize carbon emissions when allocating newly introduced and converted electric and hydrogen buses, and as a method, consider the introduction of Low Emission Bus Zones (LEBZ) to propose the reduction of pollution from specific links. To introduce LEBZ, it is necessary to compare the carbon emissions before and after its implementation, yet there is a shortage of studies that focus solely on buses or analyze the effects of introducing LEBZ to specific links. In this paper, we utilized bus information system data to calculate and compare the effects of introducing LEBZ to bus priority lanes in Jeju. We categorized scenarios into five groups, with scenarios 1 through 4 involving the introduction of LEBZ, and scenario 5 designating cases where LEBZ was not introduced. Comparative results confirmed that in scenarios with LEBZ introduction, the reduction per km reached a maximum of 0.097t per km, whereas in cases without LEBZ, it amounted to 0.022t per km, demonstrating higher efficiency. It underscores the significance of conducting carbon emission calculations and comparing the effects of LEBZ introduction using bus information system data, which can be directly applied by local authorities to make informed and rational decisions.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.6
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• pp.40-48
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• 2013

Recently, many types of electric vehicles including a heavy duty vehicle have been developed and released because of the better fuel economy and less gas products. In this study, research about an electric bus which utilizes the wheel motor drive system was conducted. The wheel motor is a motor connected to the wheel directly only with a simple gear so that the developer can utilize the space efficiently and the whole system efficiency will be better because of simple structure. However, because it is different from former types of vehicles which use the differential gear, the development of the integrated control logic is required in order to meet the vehicle stability and driving performance. The developed control logic is composed with direct yaw moment control, regenerative braking control and slip control logics. It is compared to the control logics which does not consist of direct yaw moment control and slip control when the vehicle is exposed in tough situations. For the unification of the control logic, a few maps were developed and applied to determine the output torque of each motor according to the driving status. As a result, it is shown that the developed control logic is more safe and well follow the target speed than the other control logic applied simulations.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.5
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• pp.170-175
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• 2003

A control algorithm is developed for highly efficient operation of auxiliary power unit (APU) that consists of a diesel engine and a directly coupled induction generator in series hybrid electric Bus (SHEB). In a series hybrid configuration the APU supplies the electric power needed for maintaining the state of charge (SOC) of the battery unit in various conditions of vehicle operation. As the rotational speed of generator does not depend on the vehicle speed, an optimized operation of engine-generator unit based on the efficiency map of each component can be achieved. The output torque of diesel engine can be controlled by the amount of fuel injection, and the power converted from mechanical to electrical energy can be adjusted by generate control unit (GCU) using the decoupling vector control of torque and flux. As for the given reference of the generating power, the multiply of speed and torque, many combinations of operating speed and torque are possible. The algorithm decides the new operating point based on the engine efficiency map and generator characteristic curve. During the transition of operating points, the speed controller saturation is avoided using variable limit and filtering of generator torque reference. A test rig and SHEB consist of a 1.5L diesel engine and a 30kw induction generator are constructed by Hyundai Motor Company.

• Journal of Electrical Engineering and Technology
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• v.10 no.1
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• pp.18-29
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• 2015

State Estimation (SE) is the basis of a variety of advanced applications used in most modern power systems. An SE problem formed with enough phasor measurement units (PMUs) data is simply a linear weighted least squares problem requiring no iterations. Thus, designing a minimum-cost placement of PMUs that guarantees observability of a power system becomes a worthy challenge. This paper proposes an equivalent integer linear programming method for substation-oriented optimal PMU placement (SOOPP). The proposed method uses an exhaustive search to determine a globally optimal solution representing the best PMU placement for that particular power system. To obtain a more comprehensive model, contingencies and the limitation of the number of PMU measurement channels are considered and embodied in the model as changes to the original constraints and as additional constraints. The proposed method is examined for applicability using the IEEE 14-bus, 118-bus and 300-bus test systems. The comparison between SOOPP results and results obtained by other methods reveals the excellence of SOOPP. Furthermore, practical large-scale power systems are also successfully analyzed using SOOPP.

• Proceedings of the KSR Conference
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• 1998.11a
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• pp.226-232
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• 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 Semiconductor & Display Technology
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• v.15 no.4
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• pp.61-66
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• 2016

This paper presents the implementation for a network structure of railway cars using a point to point communication. Most of network's representative specifications for a train are the FIP (Field Bus), MVB (Multifunction Vehicle Bus), CAN and WTB (Wire Train Bus) which is used by ALSOM, SIEMENS and BOMBADIER as major in this field. These networks in a physical layer use a multi-drop method, connected from $1^{st}$ car to $n^{th}$ car of a train through a cable without any extra services such as an electric part, amplifier. However waveforms which is passed through a long cable in the multi-drop are distorted by a capacitance or resistance of the cable or environments. Also since using a cable connected directly from $1^{st}$ car to $n^{th}$ car, if over two trains make double head, it isn't easy to distinguish ID for each railway cars. So by using the point to point network per each car, it is able to reduce a distortion. Also since reducing distortion, this communication speed can be been higher and transmit and receive any packets more stably. Using proposed token in a packet, this can make ID per each railway car automatically. Finally experimental results show the good performance and effectiveness of the proposed method.

• Proceedings of the KIEE Conference
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• 1997.07a
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• pp.373-375
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• 1997

In this paper, we present IGBT VVVF inverters as a 1C1M propulsion system for electric car. These 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 microcontroller. By using CAN-bus, high speed network is constructed within four control units. The stack is simplified and optimized by using plate bus and IGBT driver units of hybrid-type.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.6
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• pp.431-440
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• 2000

This paper analyses the dynamic performance of HVDC System connected to a weak AC system for various exciter characteristics of synchronous machines connected at the converter bus. Conventionally capacitors are used to supply reactive power requirement at a strong converter bus. But the installation of synchronous machine is essential in a isolated weak network to re-start after a shutdown of HVDC and to increase system strength. The dynamic performance of a synchronous machine depends on the characteristics depends of its exciter. In this paper, several exciter types are used to investigate their effect on the dynamic performance of the HVDC system and modifications to standard exciter topologies are suggested to mitigate observed problems.

• 한국태양에너지학회:학술대회논문집
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• 2012.03a
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• pp.102-107
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• 2012

The purpose of thesis is to improve output of solar cell module by enhancing transmission efficiency. To improve transmission efficiency, transmission interconnection ribbon which is used to connect solar cells and busbar which contacts with it has been improved. To secure reliability, comparison research on output of solar cell modules has been conducted by manufacturing PCB module formed by laminated metal with the same output. The result of this research is based on a output efficiency test of modules by comparing electric conductivity of soldering busbar and laminated PCV type of busbar.