The main idea of conventional control methods for series active power filter (SAPF) is to control the SAPF as frequency-selective impedance or voltage source. In these conventional control methods, a real-time instant...
详细信息
ISBN:
(纸本)9781424406548
The main idea of conventional control methods for series active power filter (SAPF) is to control the SAPF as frequency-selective impedance or voltage source. In these conventional control methods, a real-time instantaneous harmonics detection algorithm is essential and comparatively complex, which is usually implemented with a digital signal processor (DSP) therefore makes the control circuit complicated and high cost. Furthermore, the time delay caused by the harmonics detection and its digital implementation will deteriorate harmonics compensation performance. In this paper a new control method for SAPF is proposed. The idea of the proposed control is to control the compensation voltage injected by SAPF to trace the multiple of whole line current to achieve current harmonics suppression. Since the control reference signal directly utilizes the detected line current without calculating harmonics, the proposed control actually eliminates the harmonics detection process. In addition, the DC-side voltage control is indispensable in this control to maintain the active power balance for the proper operation of the SAPF system. Compared to traditional control methods, the proposed control is therefore much simpler and easier to implement at low cost. And the time delay caused by complicated harmonics calculation does not exist any more. Simulation and experimental results are presented to verify the validity of the proposed control method and the performance of the SAPF.
Detecting densely connected subgroups in graphs such as communities in social networks is of interest in many research fields. Several methods have been developed to find communities but most of them have a high time ...
详细信息
ISBN:
(纸本)9780769530260
Detecting densely connected subgroups in graphs such as communities in social networks is of interest in many research fields. Several methods have been developed to find communities but most of them have a high time complexity and are thus not applicable for large networks. Inspired by the clustering algorithm incremental DBSCAN we propose a density-based graph clustering algorithm DENGRAPH that is designed to deal with large dynamic datasets with noise and present first experimental results.
Described is a new range finder using the diode laser. We use some detection method, named the Cumulative Binary detection Algorithm (CBDA). The CBDA make possible to detect very weak signal which reflect from small l...
详细信息
ISBN:
(纸本)9781424411733
Described is a new range finder using the diode laser. We use some detection method, named the Cumulative Binary detection Algorithm (CBDA). The CBDA make possible to detect very weak signal which reflect from small lambertian target like a person.
In this paper, we present a collision detection algorithm and a force response algorithm both for use in dynamic, rigid-bodied, highly-detailed, hapto-visual virtual environments in which the models' geometry is p...
详细信息
ISBN:
(纸本)9780769530116
In this paper, we present a collision detection algorithm and a force response algorithm both for use in dynamic, rigid-bodied, highly-detailed, hapto-visual virtual environments in which the models' geometry is point-based. Our collision detection algorithm partitions the virtual space into a modified octree in a preprocessing step. At runtime, collision detection involves querying the octree for the octant where the end-effector currently is, as well as the indices of neighboring octants. After the world space is narrowed down to a volume of interest, the algorithm checks to see if the end-effector falls inside any axes-aligned bounding box that is centered at the model surface points that reside in the aforementioned volume of interest. A collision is defined as the haptic end-effector being found inside an axes-aligned bounding box centered at a model surface point. After a collision is detected, the force response algorithm calculates a force vector that starts at the end-effector's current position and ends at the model surface point closest to the end-effector. This is an adaptation of the common god/proxy-object approach but for use in point-based models.
Distributed Generation (DG) systems based on inverters connected to low-voltage electrical grids, such as low power PV systems in buildings, require reliable islanding detection algorithms in order to determine the el...
详细信息
ISBN:
(纸本)9781424407545
Distributed Generation (DG) systems based on inverters connected to low-voltage electrical grids, such as low power PV systems in buildings, require reliable islanding detection algorithms in order to determine the electrical grid status and operate the inverter properly. Passive and active islanding detection methods are local detection techniques which have been presented and analyzed in literature. The first approach is based on current and voltage measurements at the inverter side of the point of common coupling (PCC) between the electrical grid, the local load and the DG system. Active methods introduce a disturbance at the PCC in order to reveal the islanding condition. This paper proposes a new hybrid detection algorithm based on monitoring of high-frequency components of the DG system output power due to PWM, the output LCL filter and the employed current controller. Wavelet analysis is applied to obtain time localization of the islanding operation mode. Simulation results show the performance of the proposed detection algorithm.
The objective of this paper is to identify the position of the nonlinearity, a custom designed multisine signal that can be used to excite the signal path of the mixer. This special random-phase multisine signal with ...
详细信息
The objective of this paper is to identify the position of the nonlinearity, a custom designed multisine signal that can be used to excite the signal path of the mixer. This special random-phase multisine signal with a random harmonic grid contains several carefully selected spectral lines that are left unexcited. These "holes" in the spectrum of the signal act as detectors for the presence and the location of the nonlinearities that deviate from the ideal. First the proposed detection algorithm was tested in a simulation to show that it can work in an ideally controlled environment. Afterwards, measurements are performed on a real mixer excited with a special odd random-phase multisine with a two-port large signal network analyzer (LSNA) and detect the position of the unwanted nonlinearities in the device model.
In the high-precision low-temperature experiments, noise immunity has long been an important issue. We consider the problem of measuring the slowly changing data in the presence of both white noise and sudden, short n...
详细信息
In the high-precision low-temperature experiments, noise immunity has long been an important issue. We consider the problem of measuring the slowly changing data in the presence of both white noise and sudden, short noise spikes. The Kalman filter is applied to attenuate the white noise and a spike detecting algorithm is applied to remove spikes resulting from the charged particles. Experimental data show that, with the Kalman filter, the RMS of the measurement noise in a 0.5 Hz bandwidth can be attenuated from 4 nK to 0.2 nK in the best case. A simple spike detecting algorithm worked effectively to remove spikes without increasing the random noise level.
In recent decades, implantable cardioverter defibrillators (ICDs) have improved substantially, becoming the treatment of choice for patients at high risk of life-threatening arrhythmias. Nevertheless, inappropriate sh...
详细信息
In recent decades, implantable cardioverter defibrillators (ICDs) have improved substantially, becoming the treatment of choice for patients at high risk of life-threatening arrhythmias. Nevertheless, inappropriate shock therapy for non-ventricular arrhythmias is still a problem. Extending the ICD battery lifetime demands very low power consumption, which is obtained at very low microprocessor clock frequencies. Currently, some high-performance algorithms remain beyond the computational capabilities of ICDs. Future ICDs with higher computing power will permit the implementation of computationally intensive algorithms, enhancing the discrimination performance and preventing inappropriate shock therapies. An ICD algorithm status review is presented from the point of view of signal processing techniques and their computational costs. Several examples of discrimination algorithms with increasing computational cost are analyzed. Whereas some of them are already used in commercial ICDs, other algorithms cannot be implemented yet in current ICDs. A solution based on dynamic adaptation of microprocessor power consumption to meet algorithm computational requirements is proposed. This solution allows implementation of complex discrimination algorithms in ICDs without significantly increasing the power consumption.
In this paper, a new method of detector generation and matching mechanism for Negative Selection Algorithm(NSA) is introduced with variable properties, which are called the Nsa-Vs-Detector. The detectors can be variab...
详细信息
ISBN:
(纸本)9780769530901
In this paper, a new method of detector generation and matching mechanism for Negative Selection Algorithm(NSA) is introduced with variable properties, which are called the Nsa-Vs-Detector. The detectors can be variable in different ways using this concept, the paper describes an algorithm when the variable parameter is the size of the detectors in real-valued space. The algorithm is tested with a synthetic datasets, the new method improves the NSA's efficiency and reliability without significant increase in complexity.
An earthquake is a calamity that can cause colossal damage to buildings, infrastructure, and environment, consequently leading to heavy casualties. It is therefore imperative for disaster, relief agencies and civil pr...
详细信息
An earthquake is a calamity that can cause colossal damage to buildings, infrastructure, and environment, consequently leading to heavy casualties. It is therefore imperative for disaster, relief agencies and civil protection bodies to assess the damage for planning purposes. Satellite Remote Sensing and Geographic Information Systems can help prepare initial damage assessment maps. This examines the preparation of damage assessment maps using decision tree-based expert systems. The inductive machine learning-based decision tree classification has correctly identified 61 % off the severely damaged buildings, and hence, is a viable option for preparing damage assessment maps.
暂无评论