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This paper presents three-phase converter topologies for four-wire systems. The converters are series connected by three-phase transformers with accessible neutral. They possess a common dc-link, which is the power supply of the system, and two or more converters, where one of them is connected directly to the ac system, and the others cascaded through three-phase transformers. The three-phase transformers...
An AC microgrid system model is created to assess transient and steady state stability during periods of separation from the grid. A secondary control is constructed to dispatch energy sources according to user selected setpoints and participation factors. Two sources — an energy storage device and synchronous generator — are controlled to share active and reactive load burdens. A system load models...
To interface low-voltage dc-output power sources to ac grid, the split dc-bus dc-ac inverters driven by step-up isolated dual-output dc-dc converters can be a solution. When the split dc-bus dc-ac inverter is loaded with single-phase ac or unbalanced three-phase ac, current ripples will propagate through the dc-dc converters at frequencies that are related to the ac side fundamental. For the dc-dc...
Switched power systems are inherently difficult to simulate, due to the significant sensitivity of the simulation algorithm to the timing of the switching events as well as the potentially complex dynamics of the components. Numerical simulation techniques, while flexible, are not well suited for large time scale simulation of such systems. Methods for increasing the accuracy of numerical simulation...
Resonant power converters have become ubiquitous to efficiently process electrical energy, however, their complicated structure challenges linear controllers in anticipating their large signal performance. Since small-signal modeling techniques do not provide sufficient information regarding the large signal behavior of power converters, nonlinear geometric controllers can be employed to tackle the...
In this paper, it is described how the circulating current flows between inverters which have isolated DC-link such as Cascaded H Bridge (CHB) topology, when they operating in parallel. In this case, Zero Sequence Circulating Current (ZSCC) flowing through shared DC-link cannot flow between inverters in parallel. However, circulating current is provoked by asynchronous switching instant of devices...
In this paper, a 25-kW Wireless Power Transfer (WPT) system is considered for in-motion charging of an electric bus. The goal of this research is to derive a control strategy for the primary side of a wireless Electric Vehicle (EV) charger, with the objective to achieve fast dynamics and full control over the primary coil current and the amount of transferred power. To this aim, a dual-loop controller...
This paper presents a physics based comprehensive dynamic model of a future power distribution system, termed as the FREEDM system, for plug-and-play interface of distributed renewable energy resources and distributed energy storage devices. The system allows for high penetration of renewable generation with energy storage at the distribution level. FREEDM system consists of an energy router, which...
Voltage dips or sag creates useless conflict at the customer side as well as utility side. In this paper, dynamic voltage restorer device based on voltage source converter (VSC) topology is used to compensate voltage sag. Dynamic Voltage Restorer (DVR) is a power electronic device that is utilized to improve voltage stability i.e. to reduce the power quality problems in electrical power system network...
With more and more distributed and renewable energy sources connected to the utility network, it will introduce different dynamics to the system, and power electronics interfaces are needed to enable efficient and flexible interconnections among different players. Based on Internal Model Principle, sinusoidal denominator can be included in the cascaded controller for DC-AC inverter to achieve the...
The application of inverter power supply is introduced and defects and shortcomings of traditional inverter control method. The advantages and disadvantages of the control method are analyzed through the study of the double closed-loop control method and the repetitive control method, according to the characteristics of the control method, a compound control method is proposed, the simulation model...
This paper analyzes the single event transient (SET) response of a single event latchup (SEL) protection switch (SPS) designed in the 130 and 250 nm bulk CMOS technologies. The analysis has been conducted through the SPICE simulations, using the standard double exponential current source as the SET model. It has been confirmed that the 130 nm SPS cell is more susceptible to SETs than the 250 nm version,...
Distributed energy resources (DERs) and smart loads have the potential to provide flexibility to the distribution system operation. A coordinated optimization approach is proposed in this paper to actively manage DERs and smart loads in distribution systems to achieve the optimal operation status. A three-phase unbalanced Optimal Power Flow (OPF) problem is developed to determine the output from DERs...
Power systems are under a huge transformation because of the growing penetration of renewable sources. In this sense, microgrids may become a reality, since local sources and manageable loads and batteries may help the system to be self-sustainable under emergency conditions. This paper proposes a three phase power flow for microgrids which considers the droop method. Hence, frequency and voltage...
One solution towards a resilient electric distribution system during extreme weather conditions and other natural disasters is microgrid with distribution automation. This low voltage bottom-up black start capability and feeder reconfiguration capability allow true realization of the full potentialities of distributed generation. This paper exploits the black start of a low voltage network supported...
The paper proposes a control strategy for managing the load associated to the HVAC system of a building. The idea is to use the thermal energy stored into the building to contribute to frequency response during emergency conditions and improve islanding transition. The frequency dynamics of a Microgrid, following a disturbance on the main grid, can be improved using load response. A test network model...
Many distribution utilities are facing with the challenge to integrate increasing amounts of photovoltaic (PV) systems. Battery energy storage systems (BESSs) can be used for supporting producers and distribution system operators to give more flexibility to the network in terms of dispatching capability of PV, load shifting, peak shaving, ancillary services. This paper proposes to support locally...
Renewable energy based microgrids are emerging as a potential solution to augment the utility grid energy. However, their inherent dependency on static power electronic inverters lesions utility grid equivalent rotational inertia, which effects the system resiliency during uncertainties. This degrades voltage-quality, frequency-stability, and self-healing capacity of the microgrid. This typical challenge...
Growing complexity and nonlinear structure of modern aircraft electric power systems with extensive nonlinear loading made available state-space averaging models inadequate for accurate analysis and characterization of such systems. In this paper, the Generalized State-Space Averaging (GSSA) model recently developed by the authors is applied for the modeling, control, and characterization of high...
Demand of electricity is growing very rapidly for industrialization & urbanization of India. Renewable energy sources being available abundantly in nature can be considered as a better option over conventional energy sources. Solar and wind energy are available in large amount and can be considered as reliable source of power generation. Hybrid solar and wind energy systems can be used for rural...
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