• Title/Summary/Keyword: Operating mode

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Synthesis and Implementation of a Multi-Port DC/DC Converter for Hybrid Electric Vehicles

  • Santhosh, T. K.;Natarajan, K.;Govindaraju, C.
    • Journal of Power Electronics
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    • v.15 no.5
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    • pp.1178-1189
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    • 2015
  • A non-isolated Multiple Input Converter (MIC) with an input port, two storage ports and a load port is proposed. The synthesis of the proposed four port converter with its switch realization is presented. A steady state analysis of each operating mode with a small-signal model is derived, and a stability analysis is done. A mode selection controller is proposed to automatically choose a specific operating mode based on the voltage levels of the different source and storage units. In addition, a voltage control loop is used to regulate the output voltage. A 200W prototype is built with a TMS320F28027 DSP controller to test the feasibility of the operating modes. Simulation and experimental results show the ability of the proposed converter to handle multiple inputs either individually or simultaneously.

Characteristics of Performance Parameters of Dual Mode(Ramjet-Scramjet Combined) Engine Based on the Analysis of The Operating limitations (작동한계 관점에서의 이중모드(램제트-스크램제트 연합 작동)엔진의 성능 인자 특성)

  • Sung, Hong-Gye;Byun, Jong-Ryul
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2006.11a
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    • pp.393-396
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    • 2006
  • This paper presents the characteristics of the performance parameters of dual mode(ramjet-scramjet combined) engine, inlet and combustor for wide range of flight Mach number, resulted from the analysis of its operating limitations. The transitional-critical flight Mach number from ramjet to scramjet and the performance of two types of combustors, such as constant pressure- and constant area- combustor, are conceptually evaluated.

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The Operating characteristics of Community Energy System(CES) with Grid connection and isolation (지역 에너지 시스템의 계통 연계 및 독립 운전 특성에 관한 연구)

  • Park, Y.U.;Kim, K.H.;Jang, S.I.
    • Proceedings of the KIEE Conference
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    • 2004.11b
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    • pp.258-260
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    • 2004
  • This paper analyse a operating characteristics when the Community Energy System (CES) is operated islanding mode. In the near future, CES might be one of major energy supply structures. The basic concept of CES is that it supplies electrical and thermal energy to the local customer loads through the islanded power network separated from the grid. The CES must be supplying local load with stable energy on the islanding mode, analysing necessary to thoroughly the operation feature. In order to show them, in this paper, we model the CES with 2.34 MVA DG and simulate the operating feature on the islanding mode of CES. The simulation results show that, in order to stability operate, the CES need the efficient load management and generation control schemes during the transition periods.

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A Study on the Adoption of Power Take Off Operation Mode and Fuel-Saving Effect in the Hybrid Electric Propulsion System for a Warship (전투함 하이브리드 전기추진 시스템의 PTO 운전모드 적용 및 연료절감 효과 연구)

  • Kim, So-Yeon
    • The Transactions of the Korean Institute of Power Electronics
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    • v.24 no.1
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    • pp.40-48
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    • 2019
  • Hybrid electric propulsion systems (H-EPSs) are an intermediate step for integrated full electric propulsion warships. H-EPSs are a dynamic combination of mechanical and electrical propulsion systems to achieve the required mission performances. The system modes could adapt to meet the requirement of the various operation conditions of a warship. This paper presents a configuration and operating modes of H-EPSs considering the operation conditions of a destroyer class warship. The system has three propulsion modes, namely, motoring mode, generating mode [power take off (PTO) mode], and mechanical mode. The PTO mode requires a careful fuel efficiency analysis because the fuel consumption rate of propulsion engines may be low compared with the generator's engines depending on the loading power. Therefore, the calculation of fuel consumption according to the operating modes is performed in this study. Although the economics of the PTO mode depends on system cases, it has an advantage in that it ensures the reliability of electric power in case of blackout or minimum generator operation.

Experimental Study on the Performance Improvement of a Simultaneous Heating and Cooling Heat Pump in the Heating-main Operating Mode (난방주체 운전모드에서의 동시냉난방 열펌프 성능향상에 관한 실험적 연구)

  • Kang, Hoon;Jung, Hyen-Joon;Joo, Young-Ju;Kim, Yong-Chan;Choi, Jong-Min
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.20 no.4
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    • pp.245-251
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    • 2008
  • The cooling load in winter is significant in buildings and hotels because of the usage of office equipments and the high efficiency of wall insulation. Hence, the development of a multi-heat pump that can cover heating and cooling simultaneously for each indoor unit is required. In this study, the operating characteristics and performance of a simultaneous heating and cooling heat pump in the heating-main operating mode were investigated experimentally. The system adopted a variable speed compressor with four indoor units and one outdoor unit with R-410A. In the heating-main mode, the cooling capacity was lower than the design cooling capacity due to the reduction of the flow rate in the indoor unit for the cooling, with the increase of the heating capacity. To solve these problems, the performance characteristics of the simultaneous heating and cooling heat pump in the heating-main mode were investigated by varying the flow rate to the indoor unit for the cooling and the compressor rotating speed. In addition, the adequate control methods were suggested to improve the system efficiency.

Charging and Persistent-Current Mode Operating Characteristics of BSCCO Magnet Using High-Tc Superconducting Power Supply (고온 초전도 전원장치를 이용한 BSCCO Magnet의 충전 및 영구전류 운전 특성)

  • Jo, Hyun-Chul;Yang, Seong-Eun;Kim, Young-Jae;Hwang, Young-Jin;Yoon, Yong-Soo;Chung, Yoon-Do;Ko, Tae-Kuk
    • Progress in Superconductivity and Cryogenics
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    • v.11 no.1
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    • pp.30-34
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    • 2009
  • This paper deals with charging and persistent-current mode operating characteristics of BSCCO magnet load using high-temperature superconducting (HTS) power supply. The HTS power supply consists of two heater-triggered switches, an iron-core transformer with the primary copper winding and the secondary BSCCO solenoid, and a BSCCO magnet load. The magnet load was fabricated by double pancake winding and its inductance is about 21 mH. A hall sensor was installed at the middle of the magnet load to measure the current in the load. In order to investigate the efficient pumping characteristics, operating tests of heater-triggered switch with respect to dc heater current were carried out, and the electromagnet current was determined by considering saturation characteristics of its iron core. The saturation characteristics of charged current in the magnet load were observed with respect to various pumping periods: 12 s, 14 s, 24 s and 32 s. After charging the magnet load, the persistent current was measured. The operating characteristics of the persistent current mode were mainly determined by joint resistance and magnet load.

A High Performance Interleaved Bridgeless PFC for Nano-grid Systems

  • Cao, Guoen;Lim, Jea-Woo;Kim, Hee-Jun;Wang, Huan;Wang, Yibo
    • Journal of Electrical Engineering and Technology
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    • v.12 no.3
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    • pp.1156-1165
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    • 2017
  • A high performance interleaved bridgeless boost power factor correction (PFC) rectifier operating under the critical current conduction mode (CrM) is proposed in this paper to improve the efficiency and system performance of various applications, such as nano-grid systems. By combining the interleaved technique with the bridgeless topology, the circuit contains two independent branches without rectifier diodes. The branches operate in interleaved mode for each respective half-line period. Moreover, when operating in CrM, all the power switches take on soft-switching, thereby reducing switching losses and raising system efficiency. In addition, the input current flows through a minimum amount of power devices. By employing a commercial PFC controller, an effective control scheme is used for the proposed circuit. The operating principle of the proposed circuit is presented, and the design considerations are also demonstrated. Simulations and experiments have been carried out to evaluate theoretical analysis and feasibility of the proposed circuit.

A Study on the Developments of Emission Correction Formula and Emission Characteristics of Greenhouse Gas by 5-Cycle Mode (5-cycle 모드 특성에 따른 온실가스 배출특성 및 배출량 보정식 개발 연구)

  • Park, Jin-Sung;Lim, Jae-Hyuk;Lee, Min-Ho;Kim, Ki-Ho
    • Journal of Power System Engineering
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    • v.21 no.6
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    • pp.94-100
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    • 2017
  • Due to the environmental problems caused by the greenhouse effect, regulation of $CO_2$ emissions is getting stronger day by day. In paricular, regulations of automobiles $CO_2$ emissions are being strengthen. However, existing $CO_2$ measurement methods do not reflect the environment and operating conditions on actual roads. Emissions of $CO_2$ can be increased by various conditions such as environmental condition(temperature and humidity) and driver's tendency(aggressive and passive). Therefore it is necessary to reflect the conditions of various actual roads such as 5-cycle test method on behalf of the existing $CO_2$ emission measurement method. The 5-cycle measurement method has five test modes; FTP-75, HWFET, US06, SC03, Cold FTP-75. The method reflects the following three environments and operating conditions as compared to conventional method; Using heater at low temperature, Aggressive driving such as rapid acceleration or deceleration, Using air conditioner at high temperature. Because of these various conditions of each test cycle, the 5-cycle method can reflect actual environments and operating conditions. This paper attempt to analyze $CO_2$ emission characteristics based on the results measured through the 5-cycle mode and develop the correction formula that can derive the results of the 5-cycle test method using existing test methods. As a result, the developed correction formula is expected to reduce $CO_2$ emissions and cut down expense for testing 5-cycle mode.

A Study on High-Efficiency MPPT Algorithm Based on P&O Method with Variable Step Size (가변 스텝 사이즈를 적용한 P&O 방식 기반의 고효율 MPPT 알고리즘 연구)

  • Kim, Bongsuck;Ding, Jiajun;Sim, Woosik;Jo, Jongmin;Cha, Hanju
    • The Transactions of the Korean Institute of Power Electronics
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    • v.24 no.1
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    • pp.1-8
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    • 2019
  • In this study, a maximum power point tracking (MPPT) algorithm based on the perturb and observe (P&O) method with variable step size is proposed to improve the dynamic response characteristic of MPPT, using the existing P&O method. The proposed algorithm, which we verified by simulation and experiment, can track the maximum power point (MPP) through duty control and consisted of three operation modes, namely, constant voltage mode, fast mode, and variable step mode. When the insolation is constant, the voltage variation of the operating point at the MPP is reduced through the step size reduction of the duty in the variable step mode. Consequently, the vibration of the operating point is reduced, and the power generation efficiency is increased. When the insolation changes, the duty and the photovoltaic (PV) voltage are kept constant through the constant voltage mode. The operating point then rapidly tracks the new MPP through the fast-mode operation at the end of the insolation change. When the MPP is reached, the operation is changed to the variable step mode to reduce the duty step size and track the MPP. The validity of the proposed algorithm is verified by simulation and experiment of a PV system composed of a PV panel and a boost converter.

A study on an error recovery expert system as a part of man-robot system (Man-robot system의 일환으로서 에러회복 전문가시스템에 관한 연구)

  • 이순요;김창대
    • 제어로봇시스템학회:학술대회논문집
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    • 1988.10a
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    • pp.518-523
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    • 1988
  • A Teaching and Operating Expert System (TOES) was designed in order to perform a task effectively which is inaccessible to man. Once an error occurs in the middle of the task operation, the automatic mode is converted into a manual mode. After recovering the error by the manual mode, the manual mode should be converted into the automatic mode. It was necessary to improve the manual mode in order to increase the availability of a man-robot system, a part of the human interface technique. Therefore, the Error Recovery Expert System must be constructed and developed.

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