The dual-mode photovoltaic inverter is capable of operating either in grid-connected mode or island mode, acting as a current source for the ac grid in the former and a voltage source for the load in the latter. Trans...
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ISBN:
(纸本)9781467371520
The dual-mode photovoltaic inverter is capable of operating either in grid-connected mode or island mode, acting as a current source for the ac grid in the former and a voltage source for the load in the latter. Transitioning from one mode to the next is non-trivial and can cause large deviations in voltage, current, and frequency because a mismatch in frequency, phase, and amplitude between the inverter output voltage and the grid voltage. This paper presents a model predictive control (MPC) for a single phase, grid-connected voltage source inverter (VSI) to support dual-mode operation and seamless transfer between the two. This technique uses decoupled power control in grid-connected mode and voltage control in island mode respectively. Seamless transfer is implemented through synchronization algorithm and smoothly changing weighting factor for the cost function of the MPC. Compared with PI based controller, the MPC controller is simpler to implement since there is only one parameter to tune, the weighting factor. Combined with second order generalized integrator (SOGI), the synchronization algorithm is used to achieve fast phase detection and improved disturbance rejection. The theoretical analysis, simulation and experimental results validate the effectiveness of the proposed control strategy.
a simple, low cost and robust OFDM-PON symbol synchronization technology is proposed and experimentally demonstrated. The main idea of this algorithm is to make use of the periodicity of the OFDM symbol to achieve sym...
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ISBN:
(纸本)9781479928606
a simple, low cost and robust OFDM-PON symbol synchronization technology is proposed and experimentally demonstrated. The main idea of this algorithm is to make use of the periodicity of the OFDM symbol to achieve symbol and frame synchronization at the receiver. This technology is applicable for the OFDM-PON system as some simple subtraction is required but without any multiplication. Using the proposed synchronization algorithm, a real-time OFDM-PON signal transmission at 2.5Gb/s over 25km standard single-mode fiber is achieved and the optical power of-12.5dBm corresponds to the system bit error rate of only 0.11634%. And most importantly, it provides the real time symbol synchronization for the point-to-point and point-tomultipoint OFDM-PON network.
OFDM (Orthogonal Frequency Division Multiplexing) has been applied in Vehicular Ad Hoc Networks (VANET) due to its ability to counteract the frequency-selective fading and its high spectral efficiency. For instance, O...
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ISBN:
(纸本)9781457714146
OFDM (Orthogonal Frequency Division Multiplexing) has been applied in Vehicular Ad Hoc Networks (VANET) due to its ability to counteract the frequency-selective fading and its high spectral efficiency. For instance, OFDM-based IEEE802.11 802.11p has been standardized for VANET. In OFDM-based VANET, synchronization of the carrier frequency at the receiver must be performed accurately to avoid performance degradation. This paper compares the effectiveness of three synchronization algorithms to estimate the carrier frequency offset (CFO) of OFDM signals in VANET. The simulation is conducted using the parameters of IEEE 802.11p and performed under several channel models including Additive White Gaussian Noise (AWGN) channel, Rayleigh channel, and COST 207 channel models.
In this paper, we gave a brief discussion of the expanded time and frequency OFDM (ETF-OFDM) system and its traditional synchronization method (the Schmidl's method). And then we present a rapid frame and symbol s...
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ISBN:
(纸本)9781629931357
In this paper, we gave a brief discussion of the expanded time and frequency OFDM (ETF-OFDM) system and its traditional synchronization method (the Schmidl's method). And then we present a rapid frame and symbol synchronization algorithm in this system for just detecting one training symbol instead of two training symbols in Schmidl's method. The algorithm has low calculation complexity and outperforms conventional synchronization methods.
The user interface made of a LCD (liquid crystal display) screen and a touch screen based on LPC2138 is presented in this paper. The hardware design of the LCD and the touch screen is introduced and the software flow ...
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ISBN:
(纸本)9783037852958
The user interface made of a LCD (liquid crystal display) screen and a touch screen based on LPC2138 is presented in this paper. The hardware design of the LCD and the touch screen is introduced and the software flow of the LCD and the touch screen is also described in this paper. And this paper proposes the synchronization algorithm which can achieve the LCD and the touch screen point by point with high accuracy and great reliability. On the basis of analyzing the principle of the embedded touch panel system, the working principle and control method of the dedicated controller DV320240GB touch screen are analyzed. The method for obtaining the coordinates of the touch screen and the synchronization algorithm of the LCD display are proposed to improve the efficiency of the touch screen and the LCD. The above-mentioned design has been successfully applied in ESR (erythrocyte sedimentation rate) detection system.
In this paper to improve the capacity and coverage of the channel in WCDMA with OFDM, a concatenation of Wideband Code Division Multiple access (WCDMA) and Orthogonal Frequency Division Multiple Access (OFDM) is used ...
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ISBN:
(纸本)9781457715808;9781457715839
In this paper to improve the capacity and coverage of the channel in WCDMA with OFDM, a concatenation of Wideband Code Division Multiple access (WCDMA) and Orthogonal Frequency Division Multiple Access (OFDM) is used as spreading code. synchronization error which degrades the OFDM system performance is reduced by implementing synchronization algorithm which is used to estimate the offset and by using compensation technique these offsets are reduced which improves the system performance. This concept is implemented in Multi-input Multi-output (MIMO) antenna to boost the capacity of the channel for high data rate transmission.
Time synchronization is one of core technologies in Distributed Systems and Communication Fields. The "Network Time Protocol" (NTP) is the current widely accepted standard for synchronizing clocks over the I...
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ISBN:
(纸本)9781424415304
Time synchronization is one of core technologies in Distributed Systems and Communication Fields. The "Network Time Protocol" (NTP) is the current widely accepted standard for synchronizing clocks over the Internet. NTP uses a hierarchical scheme in order to synchronize the clocks in the network. It mainly adopts a phase-locked loop technique to adjust the local clock. This paper develops a time synchronization algorithm based on frequency adjustment in distributed system, which has a better performance compared with current algorithm, which uses the method of phase adjusting time. Under the same accuracy requirement, the algorithm has much less time requests to the NTP server and higher stability in performance, which decreases a lot on the load of server. This algorithm is more effective and would have preferable value in application.
Time synchronization is one of core technologies in Distributed Systems and Communication Fields. The “Network Time Protocol” (NTP) is the current widely accepted standard for synchronizing clocks over the Internet....
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ISBN:
(纸本)9781424415304;1424415306
Time synchronization is one of core technologies in Distributed Systems and Communication Fields. The “Network Time Protocol” (NTP) is the current widely accepted standard for synchronizing clocks over the Internet. NTP uses a hierarchical scheme in order to synchronize the clocks in the network. It mainly adopts a phase-locked loop technique to adjust the local clock. This paper develops a time synchronization algorithm based on frequency adjustment in distributed system, which has a better performance compared with current algorithm, which uses the method of phase adjusting time. Under the same accuracy requirement, the algorithm has much less time requests to the NTP server and higher stability in performance, which decreases a lot on the load of server. This algorithm is more effective and would have preferable value in application.
in this paper,we proposed and analyzed a frame-level synchronization (FLS) algorithm for the UWB direct-sequnce transmitted-reference (DS-TR) receiver. In DS-TR systems, Symbol-level synchronization is not enough for ...
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ISBN:
(纸本)9780878492510
in this paper,we proposed and analyzed a frame-level synchronization (FLS) algorithm for the UWB direct-sequnce transmitted-reference (DS-TR) receiver. In DS-TR systems, Symbol-level synchronization is not enough for data modulation, the position of low duty cycle signal in each frame is still unknown. The algorithm which we proposed has a moderate accuracy but a very low complexity and fast synchronization speed compared with conventional approaches requiring subnanosecond-level accuracy. Detailed analysis of the algorithm is carried out based on our in-depth analysis.
Atrial flutter is a common supraventricular tachycardia that can be treated using radiofrequency catheter ablation, a procedure that is guided by electroanatomical mapping systems. In this paper, we propose an algorit...
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Atrial flutter is a common supraventricular tachycardia that can be treated using radiofrequency catheter ablation, a procedure that is guided by electroanatomical mapping systems. In this paper, we propose an algorithm for incorporating mapping data into computer simulations of atrial electrical activity with the purpose of creating a more accurate map of electrical activation. The algorithm takes as input the extracellular potential values recorded at a number of sites throughout the atria and estimates the activation time for the entire atrial domain. We test the algorithm using synthetic mapping data and an anatomically detailed atrial geometry with an activation pattern typical of atrial flutter. The results show that the algorithm performs well with synthetic mapping data with information from relatively few mapping sites and in the presence of modeling and measurement error.
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