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Fundamental frequency
About: Fundamental frequency is a research topic. Over the lifetime, 8941 publications have been published within this topic receiving 131583 citations.
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TL;DR: In this article, the authors focus on fundamental frequency simulations, also known as electromechanical transient simulations, where the network is represented as an impedance matrix and only the fundamental frequency component of voltages and currents is taken into account in order to reduce the computation time.
Abstract: Increasing numbers of wind turbines are being erected. In the near future, they may start to influence the dynamics of electrical power systems by interacting with conventional generation equipment and with loads. The impact of wind turbines on the dynamics of electrical power systems therefore becomes an important subject, studied by means of power system dynamics simulations. Various types of power system dynamics simulations exist and the approach depends on the aspect of power system dynamic behavior being investigated. In this paper, the focus is on fundamental frequency simulations, also known as electromechanical transient simulations. In this type of simulation, the network is represented as an impedance matrix and only the fundamental frequency component of voltages and currents is taken into account in order to reduce the computation time. This simulation approach is mainly used for voltage and angle stability investigations. Models of wind turbine generating systems that match the fundamental frequency simulation approach are presented and their responses are compared to measurements.
340 citations
TL;DR: In this paper, Laskar's analysis of the fundamental frequencies of a hamiltonian system was applied to the standard mapping of the solar system and the results showed that the golden curve does not survive for a = 0.9718 which is very close and compatible with Greene's value ac = 0971635.
335 citations
Patent•
12 Jul 2002TL;DR: In this article, a system and method for detecting emotional states using statistics is described, which assigns at least one emotional state from a finite number of possible emotional states to the speech signal.
Abstract: A system and method are provided for detecting emotional states using statistics. First, a speech signal is received. At least one acoustic parameter is extracted from the speech signal. Then statistics or features from samples of the voice are calculated from extracted speech parameters. The features serve as inputs to a classifier, which can be a computer program, a device or both. The classifier assigns at least one emotional state from a finite number of possible emotional states to the speech signal. The classifier also estimates the confidence of its decision. Features that are calculated may include a maximum value of a fundamental frequency, a standard deviation of the fundamental frequency, a range of the fundamental frequency, a mean of the fundamental frequency, and a variety of other statistics.
334 citations
TL;DR: In this paper, an active harmonic elimination method was proposed to eliminate any number of specific higher order harmonics of multilevel converters with equal or unequal dc voltages, and the simulation results showed that the method can effectively eliminate the specific harmonics, and a low total harmonic distortion (THD) near sine wave was produced.
Abstract: This paper presents an active harmonic elimination method to eliminate any number of specific higher order harmonics of multilevel converters with equal or unequal dc voltages. First, resultant theory is applied to transcendental equations characterizing the harmonic content to eliminate low order harmonics and to determine switching angles for the fundamental frequency switching scheme and a unipolar switching scheme. Next, the residual higher order harmonics are computed and subtracted from the original voltage waveform to eliminate them. The simulation results show that the method can effectively eliminate the specific harmonics, and a low total harmonic distortion (THD) near sine wave is produced. An experimental 11-level H-bridge multilevel converter with a field programmable gate array controller is employed to implement the method. The experimental results show that the method does effectively eliminate any number of specific harmonics, and the output voltage waveform has low THD.
322 citations
TL;DR: In this article, a two-wheel cart towed by a light truck is used to scan the fundamental frequency of vibration of a sustaining bridge, where the bridge vibration is received or scanned by an accelerometer installed in the cart.
320 citations