차석원 교수

Thin film solid oxide fuel cells (TF-SOFCs) are one of the promising portable power sources in terms of rapid on/off, compact system volume, and high power density. This paper reviews fabrications, and designs of TF-SOFCs operating the temperature range of 300-500oC. The fabricating processes of both the electrolyte and the electrode via chemical vapor depositions and physical vapor depositions are discussed. The two platforms for designing TF-SOFCs are described: porous substrate and free-stand

Manufacturing paradigms have historically been shaped by social, economic, and technological aspect, including limitations and needs. Design for manufacturing (DFM) has been the main paradigm for last three decades since design is defined by the limitations of available manufacturing processes. Since reducing the time required for the development of new products has been one of the key issues for businesses, removing the gap between designers and manufacturers has been one of today’s main goals.

Optimal control is generally not possible without information about the future coming up, and it is not easy toobtain an optimal solution even though the information is given a priori. In this paper, a control concept based on Pontryagin’sMinimum Principle (PMP) is introduced as an efficient solution to generate an optimal control trajectory for Hybrid ElectricVehicles (HVEs) when the performance of the vehicles is evaluated on scheduled driving cycles at a simulation level. Themain idea of the

In the present paper, we fabricated and tested anode-supported solid oxide fuelcell(SOFC) with gadolinium-doped(GDC) and yttriastabilized zirconia (YSZ) electrolyte. The bilayer electrolyte thin film, consisting of a 8 μm thick YSZ layer and a 40 μm thick GDC layer, was prepared by a simple dry-pressing with simple spray coating process which is cost-effective method. The two electrolyte layers were sintered 1400oC together, and no crack and delamination at the interface were observed. An open-c

A speedy reinforcement learning (RL)-based energy management strategy (EMS) is proposed for fuel cell hybrid vehicles (FCHVs) in this research, which approaches near-optimal results with a fast convergence rate based on a pre-initialization framework and meanwhile possesses the ability to extend the fuel cell system (FCS) lifetime. In the pre-initialization framework, well-designed power distribution-related rules are used to pre-initialize the Q-table of the RL algorithm to expedite its optimiz

A transient numerical model of a lithium ion battery (LiB) pack with air cooled thermal management systemis developed and validated for electric vehicle applications. In the battery model, the open circuit voltage and the internalresistance map based on experiments are used. The Butler-Volmer equation is directly considered for activation voltage lossestimation. The heat generation of cells and the heat transfer from cells are also calculated to estimate temperature distribution. Validations are

In recent studies, various types of multi mode electric variable transmissions of hybrid electric vehicles have been proposed. Multi mode electric variable transmission consists of two or more different types of planetary gear hybrid powertrain system (PGHP), which can change its power flow type by means of clutches for improving transmission efficiencies. Generally, the power flows can be classified into three different types such as input split, output split and compound split. In this study,

In recent studies, various types of multi-mode electric variable transmissions for hybrid electric vehicles have been proposed. A multi-mode electric variable transmission consists of two or more different types of a planetary gear hybrid powertrain system (PGHP), which can change power flow type using clutches to improve transmission efficiency. Input split systems are generally used for the single-mode powertrain because of their overall superiority, but other power split systems such as outpu

In order to develop more practical vehicle controllers for hybrid vehicles, performance limitations of hybrid powertrain components need to be considered when constructing power management strategies. This paper introduces a Pontryagin’s Minimum Principle (PMP)-based power management strategy for fuel cell hybrid vehicles which considers not only the fuel consumption minimization but also the requirement on limiting battery state of charge (SOC) usage or on prolonging fuel cell system lifetime.

This paper presents a new energy management control strategy of a hybrid electric vehicle, using dynamic programming with preview driving cycle information. Dynamic programming is a promising solution for energy management problem of the hybrid electric vehicle, yet global optimality can only be achieved with preview driving cycle information due to its non-causal property. As recent driving cycle prediction algorithms facilitate the use of preview driving cycle information, rule-based energy ma

The powertrain of hybrid vehicles has been a major research issue due to the power distribution by the combination of mechanical energy. The power distribution of engines and motors have been determined by optimal control or rule-based control. However, the hybrid powertrain, which includes fuel cells, is a major research issue because the fuel cells and batteries support the motors. Recently, there have been many cases of using such fuel cell powertrains among construction machinery. In a fuel

An energy management strategy (EMS) plays an important role for hybrid vehicles, as it is directly related to the power distribution between power sources and further the energy saving of the vehicles. Currently, rule-based EMSs and optimizationbased EMSs are faced with the challenge when considering the optimality and the real-time performance of the control at the same time. Along with the rapid development of the artificial intelligence, learning-based EMSs have gained more and more attention

The Pontryagin’s Minimum Principle (PMP)-based energy management strategy is regarded as one of the most promising strategies for hybrid vehicles, given that it instantaneously provides optimal power distribution solutions between power sources. The real-time application of the PMP, however, is still difficult due to the heavy computational burden and the uncertainty of the future vehicle driving cycle. The driving characteristics of city buses, including the bus dwell time at bus stops and comp

In recent years, there has been growing consideration of renewable energy especially photovoltaic devices. A silicon (Si) based solar cell is the most popularly and frequently considered among the photovoltaic devices, but its bulk thickness issue lowers the performance and hinders widespread application due to the material cost. Also, this thick nature causes difference in length between minority carrier diffusion and sufficient light absorption. To mitigate the issues there have been many rece

It is very important to determine the specifications of components included in the drive-train of vehicles at the initial design stage. In this study, a component sizing process and a performance analysis for a plug-in hybrid electric transit bus (PHEB) as a series type hybrid system are discussed based on a certain system configuration and performance targets. Six types of driving cycles and various regeneration ratios (0 to 100%) are considered in order to estimate the battery capacity in an e