Three-phase PWM voltage-source inverters (VSI) are widely employed for distributed generation (DG) systems. Since the voltage at the point of common coupling should not be regulated by DGs, the current control strateg...
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Three-phase PWM voltage-source inverters (VSI) are widely employed for distributed generation (DG) systems. Since the voltage at the point of common coupling should not be regulated by DGs, the current control strategy of grid-connected inverters plays a dominant role in providing high quality power to electric grids. The authors have proposed two advanced SVPWM-based current controllers to improve the performance of grid-connected VSIs for DG systems. Three current control strategies, namely hysteresis current control, SVPWM-based PI control and SVPWM-based predictive control, have been developed, implemented, and studied on a 30kW three-phase grid-connected PWM VSI. Effective compensation for the grid harmonics and for the system nonlinearity due to control delay and switching dead time are investigated. The results of computer simulations and experimental tests are provided to verify and compare the performances of these three current control strategies
An efficient configuration of an adaptive power system stabilizer (PSS) based on the artificial neural network (ANN) and the linear optimal control (LOC) is presented in this paper. The proposed PSS combines the advan...
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An efficient configuration of an adaptive power system stabilizer (PSS) based on the artificial neural network (ANN) and the linear optimal control (LOC) is presented in this paper. The proposed PSS combines the advantages of conventional stabilizer (CPSS), optimizing LOC strategy and the quick response of ANN. The ANN was trained using the data generated by the optimal control stabilizer (LOC-PSS). Different PSSs are presented for performance comparison. MATLAB simulations prove that the proposed PSS significantly improves the dynamic response of the power system over various loading conditions, and different disturbances.
An approach for analyzing image sequences for motion parameter estimation is presented. A sequence of an arbitrary number of image frames is utilized to determine rotational and translational parameters. A dynamic sce...
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An approach for analyzing image sequences for motion parameter estimation is presented. A sequence of an arbitrary number of image frames is utilized to determine rotational and translational parameters. A dynamic scene model is developed in which image sequences are processed as a temporally correlated complex. The object motion is represented as a discrete-time time-varying system. The measurement consists of a sequence of image coordinates of three or more feature points in each frame. Using this model, measurement of the position of the object in a set of consecutive frames permits the estimation of motion as a function of time. An iterative parameter estimation technique is used to minimize the projection error. The technique is based on results from optimal control theory. Motion parameters are estimated from the sequences of image correspondences by modeling the motion dynamics using motion transformation and viewing projection. This methodology is suitable for processing a long sequence in situations where a high rate of imagery is available. Results are presented for general rigid-body motion in the context of synthesized images and real robot images.< >
Coated pits carry important information about plasma membrane and endosomes. They remove proteins and lipids from the plasma membrane and transport them to the endosomal compartment. It is of interest to get a thoroug...
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Coated pits carry important information about plasma membrane and endosomes. They remove proteins and lipids from the plasma membrane and transport them to the endosomal compartment. It is of interest to get a thorough understanding of these pits. In this paper, we consider two kinds of proteins in coated pits: clathrin and AP-2. We propose a detection method to extract as many coated pits trajectories as possible. It is observed that we can predict whether or not a pit will appear at certain "hot spot" at a certain time.
An efficient algorithm for merging two memory-resident sorted lists is described. The algorithm is based on a novel low-cost partitioning algorithm that is used to split the two lists among an arbitrary number of proc...
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An efficient algorithm for merging two memory-resident sorted lists is described. The algorithm is based on a novel low-cost partitioning algorithm that is used to split the two lists among an arbitrary number of processors in a way that ensures load balance during the merge. The algorithm has direct applications in memory-resident databases, as well as for handling record pointers in disk-resident databases. It may be used for parallel sorting, table access using multiple indexes, and parallel sort-merge joins. A feature of the partitioning algorithm is that it may itself be parallelized efficiently; the parallel implementation reduces partitioning time, which may become significant if the number of processors gets large. If p is the number of processors and N is the total number of elements in both runs combined, the serial and parallel versions of the partitioning algorithm require time O(p log (N/p)), and O(log p+log(N/p)), respectively.< >
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