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Ronald A. Perez

Bio: Ronald A. Perez is an academic researcher from University of Wisconsin–Milwaukee. The author has contributed to research in topics: Microgrid & Control theory. The author has an hindex of 12, co-authored 35 publications receiving 706 citations.

Papers
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Journal ArticleDOI
TL;DR: In this article, the authors presented a survey regarding published papers on why the microgrid is required, and what the components and control systems are which constitute the actual microgrid studies, and proposed a standard microgrid for better power quality and optimizing energy generation.

284 citations

Journal ArticleDOI
TL;DR: In this paper, the authors present an overall description and typical distributed generation technology of a microgrid and provide a comprehensive study on energy storage devices, microgrid loads, interfaced distributed energy resources (DER), power electronic interface modules and the interconnection of multiple microgrids.
Abstract: Grid connection capability of distributed generation attracts researchers due to the cumulative demand for electricity and environment pollution concern as a new emerging technology for providing reliable and clean power supply. A microgrid comprises distributed generation, energy storage, loads, and a control system that is capable of operating in grid-tied mode and/or islanded mode. As operation modes are shifted, the microgrid should successfully manage the voltage and frequency adjustment in order to protect the grid and any loads connected to the system. Facilitation of the generation-side and load-side management and the resynchronization process is required. This paper presents an overall description and typical distributed generation technology of a microgrid. It also adds a comprehensive study on energy storage devices, microgrid loads, interfaced distributed energy resources (DER), power electronic interface modules and the interconnection of multiple microgrids. Details of stability, control and communication strategies are also provided in this study. This article describes the existing control techniques of microgrids that are installed all over the world and has tabulated the comparison of various control methods with pros and cons. Moreover, it aids the researcher in envisioning an actual situation using a microgrid today, and provides insight into the possible evolvement of future grids. In conclusion, the study emphasizes the remarkable findings and potential research areas that could enrich future microgrid facilities.

102 citations

Journal ArticleDOI
TL;DR: In this paper, a multi-input-multi-output (MIMO) controller is proposed to control temperature and ventilation of multiple zones in a building with a model predictive control (MPC) strategy.

100 citations

Journal ArticleDOI
TL;DR: A comprehensive review is presented on accomplished research work on stabilization of dc and ac microgrid system stabilization techniques, which can basically be classified as compensation done at feeder side; by adding intermediate circuitry; and at load side.
Abstract: Microgrid, because of its advantages over conventional utility grids, is a prudent approach to implement renewable resource-based electricity generation. Despite its advantages, microgrid has to operate with a significant proportion of constant power loads that exhibit negative incremental impedance and thus cause serious instability in the system. In this paper, a comprehensive review is presented on accomplished research work on stabilization of dc and ac microgrid. After reviewing these, microgrid system stabilization techniques are classified with required discussions. As found out in this paper, the stabilization techniques can basically be classified as compensation done: 1) at feeder side; 2) by adding intermediate circuitry; and 3) at load side. Finally, after analyzing the merits and drawbacks of each generalized technique, several infographics are presented to highlight the key findings of this paper.

82 citations

Journal Article
TL;DR: In this paper, a virtual impedance-based load side compensation technique is used to improve the stability of the microgrid system, a hybrid energy storage system (HESS), with a battery unit as well as ultracapacitor unit, is introduced to reduce the deficiency in the case of using either battery-only or ultracAPacitor-only storage system and offer the combined features with higher energy and higher power density.
Abstract: Microgrid systems have been adopted globally to implement the renewable energy-based electrification, but the CPL has caused instability issues. To improve the stability of the microgrid system, a virtual impedance-based load side compensation technique is used. In this paper, to implement this storage-based compensation technique, the hybrid energy storage system (HESS), with a battery unit as well as ultracapacitor unit, is introduced to reduce the deficiency in the case of using either battery-only or ultracapacitor-only storage system and offer the combined features with higher energy and higher power density. Here, the storage will provide high power density with quick charging/discharging time and the ultracapacitor will compensate the transient demand for a short period of time; therefore compensating the required power by the combined features of its constituents. Besides HESS is operated by a simple implementable algorithm, it improves overall efficiency, cost effectiveness, life span; reduce the energy storage size and stress on the battery. To verify the performance of the proposed system, necessary results performed at Matlab/Simulink platform are presented in this paper.

31 citations


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Journal ArticleDOI
TL;DR: Progress in reducing death rates and improving survival is limited for several cancer types, underscoring the need for intensified efforts to discover new strategies for prevention, early detection, and treatment and to apply proven preventive measures broadly and equitably.
Abstract: Background: The American Cancer Society (ACS), the Centers for Disease Control and Prevention (CDC), the National Cancer Institute (NCI), and the North American Association of Central Cancer Registries (NAACCR) collaborate to provide annual updates on cancer occurrence and trends in the United States. This Annual Report highlights survival rates. Methods: Data were from the CDC- and NCI-funded population-based cancer registry programs and compiled by NAACCR. Trends in age-standardized incidence and death rates for all cancers combined and for the leading cancer types by sex were estimated by joinpoint analysis and expressed as annual percent change. We used relative survival ratios and adjusted relative risk of death after a diagnosis of cancer (hazard ratios [HRs]) using Cox regression model to examine changes or differences in survival over time and by sociodemographic factors. Results: Overall cancer death rates from 2010 to 2014 decreased by 1.8% (95% confidence interval [CI] = –1.8 to –1.8) per year in men, by 1.4% (95% CI = –1.4 to –1.3) per year in women, and by 1.6% (95% CI = –2.0 to –1.3) per year in children. Death rates decreased for 11 of the 16 most common cancer types in men and for 13 of the 18 most common cancer types in women, including lung, colorectal, female breast, and prostate, whereas death rates increased for liver (men and women), pancreas (men), brain (men), and uterine cancers. In contrast, overall incidence rates from 2009 to 2013 decreased by 2.3% (95% CI = –3.1 to –1.4) per year in men but stabilized in women. For several but not all cancer types, survival statistically significantly improved over time for both early and late-stage diseases. Between 1975 and 1977, and 2006 and 2012, for example, five-year relative survival for distant-stage disease statistically significantly increased from 18.7% (95% CI = 16.9% to 20.6%) to 33.6% (95% CI = 32.2% to 35.0%) for female breast cancer but not for liver cancer (from 1.1%, 95% CI = 0.3% to 2.9%, to 2.3%, 95% CI = 1.6% to 3.2%). Survival varied by race/ethnicity and state. For example, the adjusted relative risk of death for all cancers combined was 33% (HR = 1.33, 95% CI = 1.32 to 1.34) higher in non-Hispanic blacks and 51% (HR = 1.51, 95% CI = 1.46 to 1.56) higher in non-Hispanic American Indian/Alaska Native compared with non-Hispanic whites. Conclusions: Cancer death rates continue to decrease in the United States. However, progress in reducing death rates and improving survival is limited for several cancer types, underscoring the need for intensified efforts to discover new strategies for prevention, early detection, and treatment and to apply proven preventive measures broadly and equitably.

1,103 citations

Journal ArticleDOI
TL;DR: In this paper, the authors present a literature review of model predictive control (MPC) for HVAC systems, with an emphasis on the theory and applications of MPC for heating, ventilation and air conditioning (HVAC) systems.

899 citations

Journal ArticleDOI
TL;DR: In this article, a review of microgrid drivers, real-world applications, challenges, and future prospects is presented, along with a multi-disciplinary portrait of today's micro-grid drivers.
Abstract: Microgrids are now emerging from lab benches and pilot demonstration sites into commercial markets, driven by technological improvements, falling costs, a proven track record, and growing recognition of their benefits. They are being used to improve reliability and resilience of electrical grids, to manage the addition of distributed clean energy resources like wind and solar photovoltaic (PV) generation to reduce fossil fuel emissions, and to provide electricity in areas not served by centralized electrical infrastructure. This review article (1) explains what a microgrid is, and (2) provides a multi-disciplinary portrait of today's microgrid drivers, real-world applications, challenges, and future prospects.

884 citations

Journal ArticleDOI
TL;DR: In this article, the authors present a comprehensive and significant research conducted on state-of-the-art intelligent control systems for energy and comfort management in smart energy buildings (SEB's).
Abstract: Buildings all around the world consume a significant amount of energy, which is more or less one-third of the total primary energy resources. This has raised concerns over energy supplies, rapid energy resource depletion, rising building service demands, improved comfort life styles along with the increased time spent in buildings; consequently, this has shown a rising energy demand in the near future. However, contemporary buildings’ energy efficiency has been fast tracked solution to cope/limit the rising energy demand of this sector. Building energy efficiency has turned out to be a multi-faceted problem, when provided with the limitation for the satisfaction of the indoor comfort index. However, the comfort level for occupants and their behavior have a significant effect on the energy consumption pattern. It is generally perceived that energy unaware activities can also add one-third to the building’s energy performance. Researchers and investigators have been working with this issue for over a decade; yet it remains a challenge. This review paper presents a comprehensive and significant research conducted on state-of-the-art intelligent control systems for energy and comfort management in smart energy buildings (SEB’s). It also aims at providing a building research community for better understanding and up-to-date knowledge for energy and comfort related trends and future directions. The main table summarizes 121 works closely related to the mentioned issue. Key areas focused on include comfort parameters, control systems, intelligent computational methods, simulation tools, occupants’ behavior and preferences, building types, supply source considerations and countries research interest in this sector. Trends for future developments and existing research in this area have been broadly studied and depicted in a graphical layout. In addition, prospective future advancements and gaps have also been discussed comprehensively.

689 citations

Journal ArticleDOI
Yasin Kabalci1
TL;DR: The smart metering and communication methods used in smart grid are being extensively studied owing to widespread applications of smart grid as mentioned in this paper, and the security requirements of hardware and software in a smart grid is presented according to their cyber and physical structures.
Abstract: The smart metering and communication methods used in smart grid are being extensively studied owing to widespread applications of smart grid. Although the monitoring and control processes are widely used in industrial systems, the energy management requirements at both service supplier and consumer side for individuals promoted the evolution of smart grid. In this paper, it is aimed to disclose in a clear and clean way that what smart grid is and what kind of communication methods are used. All components of a smart grid are introduced in a logical way to facilitate the understanding, and communication methods are presented regarding to their improvements, advantages, and lacking feature. The developing generation, transmission, distribution and customer appliances are surveyed in terms of smart grid integration. The communication technologies are introduced as wireline and wireless classification where the key features are also tabulated. The security requirements of hardware and software in a smart grid are presented according to their cyber and physical structures.

477 citations