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Models for active devices operating in a nonlinear regime are an indispensable tool for modern RF-circuit design. A popular class of large signal models are X-parameters which offer an accurate description of nonlinear devices. However, they require a specialized measurement setup. Typically nonlinear vector network analyzers (NVNA), are used to conduct the measurements required for an X-parameter...
A modeling method for RF power transistor fingers and large discrete die is presented in order to evaluate, visualize, and optimize various performance parameters at the device finger level. The model is constructed using a combination of TCAD based active die model and passive interconnect models based on Wheeler's transmission line formulation. Active die model of a fraction of the total periphery...
This study investigates the effect of the tuning conditions and losses of a radiofrequency birdcage coil on the incident field generated in a phantom. Several numerical implementations of a birdcage body coil model with variable coil losses were studied. The results showed that magnetic field at the coil isocenter (||H||iso), normalized to the square root of the whole body specific absorption rate,...
Regarding the intermittent nature of photovoltaic (PV) connected to grid, there will be a change in the operational mechanism. The energy generated from PV is highly dependent on the solar radiation. There are differences between using PV Farm from PLN (State-Owned Electricity Company) and IPP (Independent Power Plant). Modelling PV Farm from PLN implies the large cost of installation but little charge...
Electricity in rural area of Indonesia is mostly in small-scale with diesel generator as the main power source. These diesel generators are mostly in the latter stage of operational age, thus have limited capability and poor performance. Microgrid has been introduced lately, as a system to integrate more renewable energy sources to the existing power system. Photovoltaic (PV) source is one of the...
Belitung island will be developed as one of tourism economic zone. Regarding to this situation, the electricity will increase the capability of supply by using non fossil fuel power generation. Integration of intermittent renewable energy such as photovoltaic farm become a main concern in this development. This paper deal with a mechanism to calculate a maximum penetration of PV farm in the Belitung...
In modern distributed energy systems (DES), there is a shift in focus from conventional centralized approach to more advanced distributed architecture. Modeling and analysis of these complex systems is more challenging, as multiple energy sources are connected with different loads through power electronics converters. Due to vastly different dynamic characteristics of these converters, it is necessary...
Due to the presence of power electronics interfaced generation, voltage stability is a key design goal for converter control systems, such as in Medium-Voltage DC in naval vessels. In the presence of power electronic converter interfaced loads that can display high-bandwidth constant power load (CPL) behavior, the nonlinearity of the negative incremental resistance can induce instability. This paper...
Multilevel current source converter (MCSC) is an effective way to increase the power rating of conventional current source-fed motor drive, especially its current rating. However, there are still several challenges existing in this configuration, which mainly focus on its modulation and control techniques, and the inherent DC current imbalance issue. In this paper, a model predictive control (MPC)...
This paper proposes a stochastic programming approach based on Conditional Value at Risk (CVaR) to measure the impact of prediction errors brought about by the renewable energy and load on DC-linked multi-microgrids coalition in the distribution network so that the system scheduling operator can achieve the lowest day-ahead scheduling cost at a certain risk. Due to the prediction errors of the renewable...
Microgrids rely on energy management levels to optimally schedule their components. Conventionally, the research in this field has been focused on the optimal formulation of the generation or the demand side management separately without considering real case scenarios and validated only by simulation. This paper presents the power scheduling of a real site microgrid under a price-based demand response...
In these years, the wind power integration capacity has increased a lot, and the issue of wind curtailment has become more serious for lack of adequate flexible energy sources. To find out whether the nuclear power plant (NPP) in the present power system can solve this issue, this paper proposes a joint operational optimization model that includes the NPP, wind power plant, thermal units and pumped-storage...
Multiple functions — Increasing Utility-Electrical Rates with lowering Energy (Solar) Costs — are influencing the decision of whether we should deploy solar for On-Grid Solutions. In this study, with a set of simulations, we look at what at the current considerations that can justify deploying Solar for On-Grid sites.
An energy management system of a microgrid (MG) has several basic objectives; e.g. to maximize the utilization of renewable energy resources (RES), to protect the internal components from overloading, and to ensure that the MG operates reliably under any operating conditions. Although many control techniques are available in the literature to monitor and control the energy flows among distributed...
In order to improve the robustness of fault diagnosis method based on model in the modular multilevel converter, an improved predictive model of the circulating current is established. A correction method is proposed to compensate for the uncertainties of the parameters and the measurement errors, and the disturbances are eliminated by using multi-step prediction method. The fault detection method...
This paper addresses the modeling and controller design of large scale dc microgrids with nonlinear loads. First, the dynamic models of the sources and loads are discussed in detail, placing particular emphasis on generators with passive rectification and Constant Power Loads (CPLs) with input filters. These models will be defined as source and load nodes which along with internal nodes, will be integrated...
To improve the reliability of modular multilevel converter (MMC), the fault submodules must be isolated rapidly. In this paper, a new fast fault diagnosis method is proposed containing two steps: fault detecting and fault locating. Fault detection step finds failures by improved predictive model which detects the fault by comparing the difference between the predictive value and the measured one of...
The symmetrical compensation is widely used in inductive power transfer (IPT) system due to the advantages of achieving good coupling coefficient when the coils are perfectly aligned and easy to design. This paper investigates a general tuning method for voltage-fed symmetrical higher-order resonant networks for achieving load-independent transconductance. With the proposed tuning method, a resonant...
This paper presents a new technique to optimize the efficiency of the Cascaded Buck-Boost (CBB) converters by using adaptive switching frequency selection algorithm. Such bidirectional DC-DC CBB topology is typically deployed in PV-Battery systems. A precise loss-model that accounts for component nonlinearities is developed in which an optimal switching frequency is chosen that corresponds to the...
The droop control technology, which can achieve an autonomous power sharing among distributed resources interface converters, provides the advantages of enhanced system reliability and reduced complexity. However, the reactive power sharing accuracy of the conventional Q — V droop method can be degraded due to its dependence on the line impedances. The Q — V droop control method was proposed to reduce...
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