Gyu-Yeong Choe

An Optimal Design Methodology of an Interleaved Boost Converter for Fuel Cell Applications

In this paper, an optimal selection methodology for the number of phases will be proposed for an interleaved boost converter (IBC). Also, the analysis of the input current ripple according to CCM and DCM is carried out. The proposed design methodology will be theoretically analyzed, and its validity verified by simulation as well as with experimental results. Moreover, a comparison of cost and efficiency based on a 600W laboratory prototype using the Ballard NEXA 1.2kW PEMFC system is demonstrated.

Design and implementation of a high-efficiency on- board battery charger for electric vehicles with frequency control strategy

This paper presents a design and implementation of 3.3 kW on-board battery charger for electric vehicles or plug-in hybrid electric vehicles. A series-loaded resonant dc-dc converter and frequency control are adopted in consideration of efficiency, reliability, volume, cost, and so on. In order to obtain high efficiency and less volume within 6 liters, a prototype of the charger is designed and implemented by using high frequency of 80–130kHz and zero voltage switching method. The experimental result indicates 93% of the maximum efficiency and 5.84 liters in volume of the developed 3.3 kW on-board battery charger. Keywords-fuel cell electric vehicle; FCEV; low frequency current ripple; fuel cell; driving condition

DCM Analysis and Inductance Design Method of Interleaved Boost Converters

In order to use interleaved boost converters in the discontinuous conduction mode (DCM), the variation in the phase current and the input current ripple is analyzed theoretically. Based on the detailed analysis, a numerical formula for the input current ripple is deduced by including three criteria. Using the numerical formula, the optimized inductance that reduces the input current ripple and losses is deduced. The boundary conduction mode (BCM) is also compared with the discontinuous conduction mode to verify their strong points. In order to verify the analysis, simulation and experimental results are compared with theoretical data. The consideration of the BCM is also progressed by comparing with the DCM, and the results were different in terms of the efficiency and the input current ripple.

A Bi-directional battery charger for electric vehicles using photovoltaic PCS systems

In this paper, a new concept of bi-directional battery charger for PHEV/EV with photovoltaic generation system and operation algorithm of battery charger system is proposed. A novel battery charger system with photovoltaic generation is designed to have function of photovoltaic power conversion and battery charging/discharging. Also, considering sensitive photovoltaic source according to in the environment conditions, grid and battery characteristic, operation algorithms of the system is proposed and these algorithms are analyzed by four cases according to load conditions in detail. Moreover, it is applied to battery charging algorithm of hybrid constant current constant voltage control combined merits of constant current control and constant voltage control. Informative simulation using PSIM and experimental result using 3.3kW lab-prototype set are presented for performance verification.

A Parallel Operation Algorithm with Power-Sharing Technique for FC Generation Systems

In this paper, a parallel operation algorithm for high power PEMFC generation systems is proposed. According to increasing the capacity of fuel cell systems with several fuel cell stacks, the different dynamic characteristics of each fuel cell stack effect on imbalance of load sharing and current distribution, so that a robust parallel operation algorithm is desired. In this paper, a power-sharing technique is developed and explained in order to design an optimal distributed PEMFC generation system. In addition, an optimal controller design procedure for the proposed parallel operation algorithm is introduced, along with informative simulations and experimental results.

Design guideline of DC distribution systems for home appliances: Issues and solution

In this paper, 5kW DC distribution system test-bed is designed to prove feasibility of DC distribution system and find problems and solutions when DC distribution is introduced. And availability of spark reduction method using initial charging circuit and arc reduction method using freewheeling diode is verified. In conclusion, we conduct empirical research applying simultaneous and actual load to DC distribution test-bed.

Comparison of integrated battery chargers for plug-in hybrid electric vehicles: Topology and control

This paper studies battery charging methods utilizing the already available power electronics systems in plug-in hybrid electric vehicles (PHEVs) without an additional charger for charging the battery of PHEVs. Because inverter switch control and motor coils, which are used as the energy storage device for boosting, make the system the boost converter, it is possible to operate the existing system as a battery charger. The main advantages of these charging methods are that space, weight, and cost due to the additional charger are reduced. Various charging methods according to the system topologies and the configurations of the controller are analyzed and verified by PSIM simulation.

Comparative study of power sharing algorithm for fuel cell and photovoltaic hybrid generation system

In this paper, according to power sharing algorithm and types (2 Con & 2 Inv, 2 Con & 1 Inv, 1 Con & 1 Inv) of photovoltaic (PV) and fuel cell (FC) hybrid generation system, control algorithms of converter and inverter are presented. Almost algorithms of PV and FC hybrid generation system are performed and verified to use by technology for commercialization. Moreover, a comparative study are performed with respect to the efficiency, dc-link voltage variation, MPPT, output current, scalability and system size and cost. Base on these studies, selection guide line of PV-FC hybrid generation system is presented. In order to verify these, informative simulation and experiment are carried out.

Effect of Load Modeling on Low Frequency Current Ripple in Fuel Cell Generation Systems

In this work, an accurate analysis of low frequency current ripple in residential fuel cell power generation systems is performed based on the proposed residential load model and its unique operation algorithm. Rather than using a constant dc voltage source, a proton exchange membrane fuel cell (PEMFC) model is implemented in this research so that a system-level analysis considering the fuel cell stack, power conditioning system (PCS), and the actual load is possible. Using the attained results, a comparative study regarding the discrepancies of low frequency current ripple between a simple resistor load and a realistic residential load is performed. The data indicate that the low frequency current ripple of the proposed residential load model is increased by more than a factor of two when compared to the low frequency current ripple of a simple resistor load under identical conditions. Theoretical analysis, simulation data, and experimental results are provided, along with a model of the load usage pattern of low frequency current ripples.

A Feasibility Design of PEMFC Parallel Operation for a Fuel Cell Generation System

In this paper, the parallel operation for a FC generation system is introduced and designed in order to increase the capacity for the distributed generation of a proton exchange membrane fuel cell (PEMFC) system. The equipment is the type that is used by parallel operated PEMFC generation systems which have two PEMFC systems, two de/de boost converters with shared de link, and a grid-connected dc/ac inverter for embedded generation. The system requirement for the purpose of parallel operated generation using PEMFC system is also described. Aspects related to the mechanical (MBOP) and electrical (EBOP) component, size, and system complexity of the distributed generation system, it is explained in order to design an optimal distributed generation system using PEMFC. The optimal controller design for the parallel operation of the converter is suggested and informative simulations and experimental results are provided.