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For a grid-connected Voltage-Source Converter (VSC), dynamics of the grid synchronization plays an important role in affecting the converter performances and stability. Due to its significance, this paper gives a comparative analysis about some basic grid synchronization schemes, through viewpoint of dynamic performances, which appeared as the impacts of voltage perturbation on the estimated angle...
This, paper proposes a method to eliminate the dc component in the measured three-phase grid voltage as the input signals of phase-locked loop (PLL). The dc component in the input signals of PLL causes a low-frequency oscillation of grid frequency. The dc component elimination can be achieved by replacing the integrator in the second-order generalized integrator (SOGI) with a differentiator, named...
In this paper, a fast-synchronization between grid and inverter based on virtual synchronous converter (VSCon) technique is achieved in single-phase inverter. Consequently, this technique is designed and simulated in Matlab/Simulink platform to perceive the significances during variation of grid load parameters. The VSCon is implemented for inverter output control that has a behavior of grid voltage...
This paper introduces the advanced synchronization method second order general integrator phase locked loop modified especially for voltage synchronization exclusively for traction active rectifier. Designed synchronization is characterized by resistance to interfaces and especially quick response to frequency fluctuations. The behavior of designed synchronization method was analyzed by simulations...
This paper introduces a novel design of phase locked loop (PLL) based oscillatory neural networks (ONNs) to mitigate the frequency clustering phenomenon caused by transmission delays in real systems. Theoretical analysis of the ONN reveals that transmission delays can produce frequency clustering that leads to synchronization and convergence failure. This paper describes the redesign of ONN dynamics...
A method for achieving frequency synchronization between two distantly positioned high frequency oscillators is presented. The method is based on using GPS disciplined 10 MHz reference sine waves and phase locked dielectric resonator oscillators. In order to be able to measure the frequency difference between high frequency sources precisely, frequency down-conversion by a mixer is implemented. The...
Due to the increasing penetration of single-phase distributed generations into the utility grid the need of an improved and efficient controller to control the distributed power generating systems (DGs) is also increasing. Therefore the grid synchronization techniques plays a major role in order to maintain the grid requirements in terms of power quality and the frequency of the grid voltage. The...
Deep space communications could be advantageously accomplished by using distributed multiple-input, multiple-output (DMIMO) satellite links, as it has been outlined in the recent literature. One of the most critical issues is related to synchronizing both the carrier phase and frequency, affected by Doppler shift and frequency offset at local oscillators. In this work a solution for intermittent carrier...
This paper proposes a new closed-loop synchronization algorithm, PLL (Phase-Locked Loop), for applications in power conditioner systems for single-phase networks. The structure presented is based on the correlation of the input signal with a complex signal generated from the use of an adaptive filter in a PLL algorithm in order to minimize the computational effort. Moreover, the adapted PLL, due to...
In this paper, a single-phase self-synchronized inverter that mimics synchronous generators (Synchronverter) without a dedicated synchronization unit is investigated. It offers a mechanism for power systems to control distributed renewable energy sources. It can synchronize itself with the grid before connection and track the grid frequency very well after connection without a phase-locked loop (PLL)...
The Microgrid voltage may deviate from the grid voltage when it operates in islanded mode, which will result in unexpected large inrush currents during the re-connection process. This paper proposed a new self-synchronization control strategy for synchronverter with local loads which utilizes the reference phase angle of synchronverter as the reference angle in the rotating frame. A compensation quantity...
This paper presents an innovative DFIG which has autonomous frequency control for stand-alone operation. When the wind farm is islanded, such DFIGs synchronize to form a reliable wind farm frequency source which does not collapse when member DFIGs fail. The frequency enables frequency droop control to be implemented for load sharing. The wind farm can provide fast reserve, ready to support a weakened...
The control of power electronic grid interfaces as Virtual Synchronous Machines (VSMs) is emerging as a suitable approach for converters in distributed power systems. VSM implementations including an internal model of a virtual inertia can also inherently allow for both grid-integrated and standalone applications. Thus, such control systems are suitable for Microgrids and other power system configurations...
Synchronous reference frame phase-locked loop (SRF PLL) is extensively employed for grid converter synchronization applications. When the input contains the fundamental positive sequence (FPS) component alone, it performs exceedingly well. However, with harmonic contamination and unbalance in the input, its performance degrades. For this purpose, many structural modifications are proposed. In this...
In the paper a new method based on feedforward carrier estimation circuit is described for BPSK carrier synchronization. Simulation of model based on proposed method shows comparable performance with square-law and Costas loop feedback circuits in small frequency shift conditions in AWGN channel, but operates in a frequency range up to 10% of symbol rate with slowly degrading BER comparing to maximum...
Common time-scale enables a wide range of applications and functionalities of a sensor networks. This paper proposes a clock synchronization method fulfilling the requirement of high precision and low energy consumption for large-scale sensor networks. It uses DAC embedded in microcontroller and voltage-controlled oscillator (VCXO) to act as local variable clock source which has the same frequency...
A broadband YIG tuned oscillator (YTO) frequency sweeping signal generator based on the DDS-PLL method is introduced. A linear sweep frequency sinusoidal signal generated by DDS is used to a reference signal of the YTO PLL (Phase-Locked Loop), and the other input of PLL is the linear frequency sweep signal of the YTO, the resulting error correction signal drives the YTO FM coil. Error correction signal...
This paper describes the design and performance analysis of a new approach for frequencysynchronization and transfer over packet networks. The proposed system utilizestimestamps-based with raised cosine pulse shaping first order adaptive zero-crossing digital phase-locked loop (AZC-DPLL). The system is designedto recover frequency as well as packets, independently of the input signal level in the...
In grid-side converter control in direct drive wind power generation system, grid voltage oriented vector control strategy is used. The fast and precise detection of the amplitude and phase of the fundamental frequency voltage components is a crucial issue in the design of grid synchronization of grid-side converter. Because the dynamic performance of the phase-locked loop based on the single synchronous...
Distributed beamforming is a form of collaborative communication, in which wireless nodes adjust the phases of their transmitted signals so that the signals are combined coherently at the destination. This enhances the received signal power and extends the communication range. In this paper, we propose a transmit beamforming method that does not require any explicit feedback information from the receiver...
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