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• An exhaustive overview of the shipboard power system types, architectures, and load analysis • Various bus configurations, distribution schemes, and notable standards were discussed • Various energy storage devices and hybrid energy storage systems were introduced for their strengths in supporting shipboard power system load profiles • 4 unique control schemes to support a hybrid DC microgrid while...
This paper introduces a closed-loop control architecture for an impedance control network (ICN) resonant dc-dc converter that regulates the converter's output voltage while achieving soft-switching across wide operating ranges. This architecture is based on enhanced phase-shift control of the ICN converter, in which the inverter and rectifier phase-shifts are simultaneously controlled to regulate...
This paper presents the design process of a 13.56 MHz 10 kW and high efficiency inverter for wireless power transfer systems. The new 650V E-mode GaN is used in multiphase resonant topology to obtain high output power. The optimized efficiency design and the driver design are presented in detail. The circuit simulation results show that the inverter achieves 10 kW output power with the efficiency...
Wireless charging for electric vehicles is gaining more and more popularity recently. This paper analyzes the wireless power transfer (WPT) system with a constant-voltage source and a constant-current load, which is featured in series compensation in the transmitter and parallel compensation in the receiver. The source voltage and the load current are square waves with fixed amplitudes. The closed-form...
Frequency control is significant to maintain the stability and reliability of islanded microgrids. Generation side controls, e.g., virtual synchronous generator control and droop control, have been widely adopted to stabilize the frequency of islanded microgrid. However, this is not ideal method due to the capacity limitation and power fluctuation of distributed generation(DG). Meanwhile, energy storage...
In recent years, a demand of an isolated AC/DC converter for the grid connection increases. The authors have proposed an isolated three-phase AC/DC converter using soft-switching technique and the control. This paper presents a soft-switching parameter design for the isolated three-phase AC/DC converter. The effectiveness is verified by experiments.
This paper introduces a single-stage isolated 48V-to-1.8V point-of-load converter based on the impedance control network (ICN) resonant converter architecture. This point-of-load ICN converter achieves large step-down while maintaining high efficiency across a wide range of input voltage and output power. Large step-down is achieved through a combination of stacked inverters, a transformer and a resonant...
In recent years, wireless power transfer (WPT) technology has developed rapidly. In order to control power transmission and optimize efficiency, a large number of control methods have been proposed. Due to the unique inherent characteristics of the WPT system, the various control methods are faced to three challenges. First, transmission efficiency is significantly affected by the change in output...
In a magnetically coupled resonant (MCR) wireless power transfer (WPT) system, adding repeating coils is an effective way to lengthen transmission distance and improve the transferred power in a wide range. This paper investigated a 3-coil MCR WPT system. Based on fundamental harmonic analysis on the equivalent circuit model, the relationship between the transmission characteristics and the spatial...
DC microgrid has been drawing much attention in recent years. In DC microgrid, introduction of renewable energies to demand sides possibly causes power imbalance and reverse power flows on feeders. These problems cause increase of distribution losses and voltage rises in feeders. To overcome these problems, a power flow control method among multiple DC feeders (nodes) is required. We have studied...
A novel distributed adaptive droop coordination control system has been proposed in this paper to solve the economical dispatch problem (EDP) in DC microgrids. It comprises of tertiary and secondary controllers for scheduling the dispatchable distributed generation (DGs) output powers to ensure optimal load sharing between them and restore microgrid's average voltage as well. The controller of each...
The stability problems of power electronics interfaced distributed generators with low inertia and damping can be well solved by the virtual synchronous generator technologies. However, when the grid voltages become unbalanced, oscillations in both the real and reactive power will arise with unbalanced voltages and currents of VSG being noticed. This paper proposed a flexible power control method...
This paper proposes a new control method for two stage converters to realize the virtual synchronous generator (VSG) operation, which also can help eliminate circulating power between energy storage (ES) converters. It is proven in this paper that the proposed method shares stronger resemblances with synchronous generators (SGs) than traditional VSG in aspects of power conversion process and mathematical...
The well-known droop control and master-slave control methods are two dominant coordinative control schemes for inverter interfacing parallel distributed energy resources (DERs) in islanded AC microgrids. However, both these two control methods have some drawbacks and inherent limitations in practical application. After analyzing their complementary strengths and weaknesses, this paper proposed a...
The penetration of renewable power plants in the global electricity mix is reaching significant levels, and power system operators are adapting their grid codes, so that renewable generators do not alter the operation of the grid, preventing the introduction of additional disturbances and contributing to the control of the power system. In this context, hybrid solar plants arise as a tradeoff solution...
The dynamic characteristic, stability characteristic, and power sharing situation of the distributed system based on traditional droop control strategy are easily affected by uncontrollable power coupling and difference of line impedance of the distributed generator (DG) units in distributed system. In order to solve these drawbacks, an improved droop control strategy is proposed. It introduces the...
This paper presents a power-based droop controller for distributed energy resources converters in dc microgrids that are connected to the utility ac grid by a grid-interface converter. Typically, when dc microgrids are interfaced to ac power systems, the microgrid dc bus voltage can be affected by fluctuations caused, for example, by background harmonics present in the ac systems or by fluctuating...
This paper first shows efficiency maps of electric power train based on a two battery High Efficiency Energy Conversion System (HEECS) chopper. HEECS is based on the principle of partial power conversion, and the overall efficiency of HEECS chopper is high and over 99% [1]. The efficiency of this power train was measured in states of constant speed and constant torque by the motor test bench. Second...
This paper introduces the high voltage generation architectures derivation methodology and comparative evaluation of high voltage power generation architectures based on the key performance items such as efficiency, power density, high voltage pulse speed, high voltage pulse ripple, HV insulation and scalability for different output voltage and output power ratings. Based on comparative evaluation...
Due to the diversity of components, the multi-microgrid systems provide more optimization degrees of freedom for coordinated control of active distribution network among multiple sub-microgrids and various distributed generations within sub-microgrids. In this paper, a hierarchical energy optimization method for distributed system with multi-microgrids is proposed with multi-agents based on centralized-decentralized...
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