Efficiency Of Hybrid Power System Research Articles

PHEV 시스템의 분석을 통한 신 PHEV 동력 시스템 제안

Abstract : In order to develop the PHEV(plug-in hybrid electric vehicle), the specific power transmission systems considering the PHEV system characteristics should be applied. A PHEV applied to series-parallel type hybrid power transmission system is a typical example. In this paper, the novel hybrid power systems are proposed by analyzing the existing PHEV system. The backward simulation program is developed to analyze the fuel efficiency of hybrid power system. Quasi-static models for each components such as engine, motor, battery and vehicle are included in the developed simulation program. To obtain an optimal condition for hybrid systems, an optimization approach called the dynamic programming is applied. The simulation is performed in various driving cycles. A weakness for the existing system is found through the simulation. To compensate for a discovered weakness, novel hybrid power systems are proposed by adding or moving the clutch to the existing system. Comparing the simulation results for each systems, the improved fuel efficiency for proposed systems are verified.

Development of Efficient Operational Mode for Wind-Diesel Hybrid System

Hybrid wind Diesel stand-along systems are considered economically viable and effective to create balance between production and load demand in remote areas where the wind speed is considerable for electric generation, and also, electric energy is not easily available from the grid. In Wind diesel hybrid system, the wind energy system is the main constitute and diesel system forms the back up. This type of hybrid power system saves fuel cost, improves power capacity to meet the increasing demand and maintains the continuity of supply in the system. Problem we face in this system is that even after producing enough power through wind turbine system, considerable portion of this power needs to be dumped due to short term oversupply of power and to maintain the frequency within close tolerances. As a result remaining portion of total energy supplied comes from the diesel generator to overcome the temporal energy shortage. This scenario decreases the overall efficiency of hybrid power system. In this study, efficient Simulink modeling for wind-diesel hybrid system is proposed and some simulations study is carried out to verify the feasibility of the proposed scheme.

Parameter optimization study on SOFC-MGT hybrid power system

This paper mainly studied the solid oxide fuel cell (SOFC)–micro gas turbine (MGT) hybrid power system. The key parameters that greatly influence the overall system performance have been studied and optimized. The thermodynamic potential of improving the hybrid system performance by integrating SOFC with the advanced thermal cycle system is analyzed. The optimization rules of main parameters of SOFC-MGT hybrid power system with the turbine inlet temperature (TIT) of MGT as a constraint condition are revealed. The research results show that TIT is a key parameter that limits the electrical efficiency of hybrid power system. With the increase of the cell number, both the power generation efficiency of the hybrid cycle power system and TIT increase. Regarding the hybrid system with the fixed cell number, in order to get a higher electrical efficiency, the operating temperature of SOFC should be enhanced as far as possible. However, the higher operating temperature will result in the higher TIT. Increasing of fuel utilization factor is an effective measure to improve the performance of hybrid system. At the same time, TIT increases slightly. Both the electrical efficiency of hybrid power system and TIT reduce with the increase of the ratio of steam to carbon. The achievements obtained from this paper will provide valuable information for further study on SOFC-MGT hybrid power system with high efficiency. Copyright © 2010 John Wiley & Sons, Ltd.