synchronization method
Recently Published Documents


TOTAL DOCUMENTS

623
(FIVE YEARS 124)

H-INDEX

16
(FIVE YEARS 4)

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8194
Author(s):  
Tomasz Binkowski

This paper proposes a method for synchronizing a grid inverter with the voltage of an on-board high-frequency power grid. The described synchronization method belongs to the adaptive methods, which use fuzzy logic in the process of estimating the fundamental component of the voltage. The synchronization system has been tuned to achieve the primary goal of achieving synchronization in the shortest possible time. This is to allow for the efficient energy fed from photovoltaic sources into the on-board grid at 400 Hz. The proposed method was implemented in the field programmable gate array (FPGA) based power converter controller and static and dynamic tests for harmonic, interharmonic and subharmonic voltage disturbances were performed. Dynamic tests for phase jump, frequency jump and sag of the on-board voltage were also performed. To evaluate the effectiveness of synchronization with high-frequency voltage, the grid current control system in the grid tied inverter was elaborated. Proper current waveforms at the perturbed voltage were recorded while identifying the effectiveness of power ripple suppression. The results obtained were compared with the enhanced phase locked loop (EPLL) synchronization method. Satisfactory test results confirmed the suitability of the proposed method in systems coupling the photovoltaic source to the on-board high-frequency power grid.


Micromachines ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1292
Author(s):  
Fahu Xu ◽  
Dayong Qiao ◽  
Changfeng Xia ◽  
Xiumin Song ◽  
Yaojun He

MEMS-based LiDAR (micro-electro–mechanical system based light detection and ranging), with a low cost and small volume, becomes a promising solution for the two-dimensional (2D) and three-dimensional (3D) optical imaging. A semi-coaxial MEMS LiDAR design, based on a synchronous MEMS mirror pair, was proposed in our early study. In this paper, we specifically reveal the synchronization method of the comb-actuated MEMS mirror pair, including the frequency, amplitude, and phase synchronization. The frequency sweeping and phase adjustment are simultaneously implemented to accelerate the MEMS mirror synchronization process. The experiment is set up and the entire synchronization process is completed within 5 s. Eventually, a one-beam MEMS LiDAR system with the synchronous MEMS mirror pair is set up and a LiDAR with a field of view (FOV) of 60°, angular resolution of 0.2°, and frame rate of 360 Hz is obtained. The experimental results verify the feasibility of the MEMS mirror synchronization method and show a promising potential application prospect for the MEMS LiDAR system.


Information ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 422
Author(s):  
Yanming Guo ◽  
Yan Bai ◽  
Shuaihe Gao ◽  
Zhibing Pan ◽  
Zibin Han ◽  
...  

An ultrahigh precise clock (space optical clock) will be installed onboard a low-orbit spacecraft (a usual expression for a low-orbit satellite operating on an orbit at an altitude of less than 1000 km) in the future, which will be expected to obtain better time-frequency performance in a microgravity environment, and provide the possible realization of ultrahigh precise long-range time synchronization. The advancement of the microwave two-way time synchronization method can offer an effective solution for developing time-frequency transfer technology. In this study, we focus on a method of precise satellite-ground two-way time synchronization and present their key aspects. For reducing the relativistic effects on two-way precise time synchronization, we propose a high-precision correction method. We show the results of tests using simulated data with fully realistic effects such as atmospheric delays, orbit errors, and earth gravity, and demonstrate the satisfactory performance of the methods. The accuracy of the relativistic error correction method is investigated in terms of the spacecraft attitude error, phase center calibration error (the residual error after calibrating phase center offset), and precise orbit determination (POD) error. The results show that the phase center calibration error and POD error contribute greatly to the residual of relativistic correction, at approximately 0.1~0.3 ps, and time synchronization accuracy better than 0.6 ps can be achieved with our proposed methods. In conclusion, the relativistic error correction method is effective, and the satellite-ground two-way precise time synchronization method yields more accurate results. The results of Beidou two-way time synchronization system can only achieve sub-ns accuracy, while the final accuracy obtained by the methods in this paper can improved to ps-level.


2021 ◽  
Author(s):  
Yanming Guo ◽  
Yan Bai ◽  
Decai Zou ◽  
Feng Zhang ◽  
Shuaihe Gao ◽  
...  

2021 ◽  
Vol 12 (1) ◽  
pp. 37-44
Author(s):  
Ryszard Golański ◽  
Juliusz Godek

Adaptive Delta Modulation with Non-uniform Sampling (ANS-DM) is one of the waveform coding techniques, where a sampling instant and a quantization step size are adapted to the signal. The ANS-DM modulator produces an output binary stream, that carries information about the signal and includes necessary data of coder parameters (sampling instant and quantization step). In the demodulator, these values are recovered for proper signal reconstruction. The paper reports the problem of synchronizing clocks (transmitting and receiving) in the (ANS-DM) delta codecs systems. The original synchronization method, valuable in systems dedicated to the transmission of the bits with variable time duration was projected and experimentally verified. Performed measurements and observations have shown the elimination of the synchronization loss phenomenon.


2021 ◽  
Vol 30 (5) ◽  
pp. 956-968
Author(s):  
ZHENG Chen ◽  
DING Xuhui ◽  
LIU Dekang ◽  
BU Xiangyuan ◽  
AN Sining

Author(s):  
Young Soo Do ◽  
Min Ho Kim ◽  
Jae Wook Jeon

Sign in / Sign up

Export Citation Format

Share Document