Yung-Ruei Chang

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In this study, a high-performance inverter, including the functions of stand-alone and grid-connected power supplies, is developed so that distributed generation units can operate individually or in a microgrid mode. In the stand-alone power-supply mode, the output ac voltage can supply to ac loads. In the gridconnected power-supply mode, the goal of power(More)
The recent literature showed that, in many cases, Ordered Binary Decision Diagram (OBDD)-based algorithms are more efficient in reliability evaluation compared to other methods such as the Inclusion-Exclusion (I-E) method and the sum of disjoint products (SDP) method. This paper presents algorithms based on OBDD to compute system failure frequencies and(More)
The theories of fault trees have been used for many years because they can easily provide a concise representation of failure behavior of general non-repairable fault tolerant systems. But the defect of traditional fault trees is lack of accuracy when modeling dynamic failure behavior of certain systems with fault-recovery process. A solution to this(More)
A simple photovoltaic (PV) system capable of operating in grid-connected mode and using multilevel boost converter (MBC) and line commutated inverter (LCI) has been developed for extracting the maximum power and feeding it to a single phase utility grid with harmonic reduction. Theoretical analysis of the proposed system is done and the duty ratio of the(More)
This paper mainly focuses on the development of a high-efficiency power conversion system for kilowatt-level stand-alone generation units with a low output voltage, such as photovoltaic modules, fuel cells, and small-scale wind generators, and it aims at having the same output ac voltage, i.e., 110 Vrms/ 60 Hz as the utility power for the utilization of a(More)
Algorithms for evaluating the reliability of a complex system such as a multistate fault-tolerant computer system have become more important. They are designed to obtain the complete results quickly and accurately even when there exist a number of dependencies such as shared loads (reconfiguration), degradation, and common-cause failures. This paper(More)
This paper presents an efficient approach based on OBDD for the reliability analysis of a multi-state system subject to imperfect fault-coverage with combinatorial performance requirements. Since there exist dependencies between combinatorial performance requirements, we apply the Multi-state Dependency Operation (MDO) of OBDD to deal with these(More)
The purpose of this research is to perform economic analysis, formulate an optimization model, and determine optimal operating strategies for smart microgrid systems. Microgrid systems are electricity supply systems that integrate distributed renewable energy production for local demand. Microgrids are able to reduce transmission losses and improve(More)