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In this paper the dynamic of capacitors voltage of flying capacitor multilevel inverter (FCMI) based on sine-sawtooth phase shift carrier pulse width modulation (PSCPWM) is investigated. By using the double Fourier series of PWM, the double Fourier series of PSCPWM is achieved. In continuous by applying the double Fourier series of sine-sawtooth PSCPWM, the linear state space equations of capacitors voltage of FCMI are obtained. The result is presented as a state space matrix. The presented method of this paper allows that the changes of parameters such as modulation index, carrier frequency, load resistance and load inductance be analyzed and investigated by using powerful strategies such as root-locus. By simulation of FCMI operation in PSCAD/EMTDC software, the validity of theoretical analysis is proved. [ABSTRACT FROM PUBLISHER]

The paper presents a new method for the simultaneous detection of signals occupying separate portions of an observed wide frequency band. The method is based on the subspace decomposition of the covariance matrix of the observed signal. The proposed method does not rely on the knowledge of the noise power and gives good results in terms of correct detections and false alarm rate, even for low SNR values. [ABSTRACT FROM PUBLISHER]

Comparing to GLRT which should have some prior information, eigenvalue-based spectrum sensing is a totally blind detection technique without knowing the information of signal, channel and noise power. Existing eigenvalue-based spectrum sensing techniques are based on the approximated methods to determine the threshold. The performance of this approach is satisfactory for multipath channels in low SNR environments, however, at the cost of a long detection latency and high computational complexity due to the fact that a large number of samples are required. To tackle this problem, the thresholds can be calculated by a joint eigenvalue distribution. Unfortunately, this kind of distribution functions hardly meet the requirements of signal detection. In this paper, we explore the usage of an exact probability density function (PDF) of Demmel condition number for complex Wishart matrices. We show that the potential gain obtained by using the proposed function is rather large compared to the traditional approximated methods with smaller size of samples. [ABSTRACT FROM PUBLISHER]

In the time of current trend of increasing energy consumption, the wind-power engineering may compensate considerable part of required electric energy. Rapid windpower engineering development is considered to be one of the important sources of human need satisfaction. Conventional wind turbine control strategies are dedicated to ensure high energy conversion efficiency under varying wind conditions. The challenge in wind power control engineering is to design an adaptive wind turbine control strategy, which provides the dynamic system stability and the effectiveness of energy conversion. Modern vector controlled wind turbine drives allow fast and accurate torque control on a wide speed range. The aim of this paper is to design and implement the control algorithm, which implies the electromagnetic torque control in order to adapt the optimal rotor speed and keep high energy conversion efficiency, taking full advantage of electrical drive performance. Wind turbine operation is considered in the partial-load regime. The stability of the purposed control system is studied using linear control theory concepts. The effectiveness of the wind energy conversion is proved by the simulation results in MATLAB Simulink environment. [ABSTRACT FROM PUBLISHER]

The purpose of this paper is to present some inequalities on majorization, trace, eigenvalue and singular for sum of complex, Hermitian and positive semidefinite matrices. [ABSTRACT FROM PUBLISHER]

Microgrid (MG) is composed of loads, Micro-Sources (MS) and Energy Storage Systems (ESS) operating as a single controllable system. In MGs, with high levels of Distributed Energy Resources, the stability becomes an important issue. The concept of “base-load” might not be considered in a typical MG, i.e., large load variations are expected to occur. Furthermore, different load conditions are effective on MG stability. In this paper, a typical MG is modeled completely and eigenvalues of the system are extracted based on small signal analysis in state equations. Thereafter, different load conditions are investigated and critical conditions of the loads are obtained. [ABSTRACT FROM PUBLISHER]

The paper addresses the application of finding key features within an image utilizing the process termed the Principal Components Analysis (PCA). Understanding this technique is critical for researchers within biometric fields and the larger cyber security field. Research, found in ASEE 2011 Conference Proceedings, titled “Edge Detectors in Engineering and Medical Applications,” develops the identification of edges within an image. That paper and this paper give the user two alternate approaches for comparing images. The PCA method was selected for analysis because it requires the use of many mathematical and statistical processes, such as means, standard deviation, variance, covariance, and eigenvalues, leading to a feature vector to compare images. The plan is to identify images, which will be termed authentic images and imposter images. Then the authentic and imposter images will be measured by th Euclidean norm to determine their authenticity. Developing software engineers and/or applied mathematicians using eigenvalues of a matrix can identify the authenticity of an image via that of an imposter image. This paper develops the key mathematical requirements to obtain a feature vector for a particular image. [ABSTRACT FROM PUBLISHER]

Based on the analytical solutions obtained for the electric and magnetic field components in a rectangular closed waveguide with metal walls and two longitudinally disposed dielectric layers, the paper discusses the guide eigenvalues, field patterns, wavelength, impedance and transmitted power. The practical mode of excitation in the dominant and higher TE modes is established for some numerically analyzed cases. [ABSTRACT FROM PUBLISHER]

In this paper, the modeling of distribution network with Doubly Fed Induction Generator (DFIG) is done in a different way where the resistances of the line are considered. Based on this modeling, this paper presents an analysis to investigate the critical parameters for distribution systems stability where DFIG is used as distributed generation. In order to analyze the critical parameters, the system is linearized about an operating point by using Taylor series expansion method. The critical parameters are investigated through the concept of eigenvalues and participation factors. This paper also shows the graphical output for different states by varying the line resistor. Finally, a Linear Quadratic Regulator (LQR) controller is proposed to improve the parameters disturbances in the distribution network with DFIG. [ABSTRACT FROM PUBLISHER]

Voltage stability is a very important subject in power system operation. In the literature there is a number of works proposing a variety of methods and techniques for the analysis of voltage stability problem. Into these ones, there is a family of methods based on load flow formulations, which aim to be consistent in predicting if voltage is stable or unstable. In this paper, three load flow-based methodologies are applied to a very simple power systemand concluding remarks are made by comparing their results. [ABSTRACT FROM PUBLISHER]

The problem of the poorly damped low-frequency (0.1–0.4 Hz) oscillations of power systems has been a matter of concern to power engineers for a long time, because they limit the power transfer capability in power systems. The power systems stability is also affected by these poorly damped oscillations and can lead to the system instability. The paper presents a design PSSs based on μ-controller to enhance power systems stability and improve power transfer capability. MATLAB dynamic model was developed for a power system and lead-lag PSS structure is considered in the model. Damping torque technique is applied to tune the PSS parameters. The results of this technique have been verified by eigenvalue analysis and time-domain simulations. The optimal sampling time was determined for transferring the s-domain of PSS model to digital (z-domain) model and then it was implemented on μ-controller chip. The peripheral interface controller (PIC) μ-controller type was used and the developed MATLAB model was interfaced with the μ-controller. The simulations results show that the system time responses under different operating conditions are well damped with the designed PSS. Moreover, the proposed PSS based μ-controller is relatively simple and suitable for real-time applications in the future smart power grid where the stabilizing signals to the PSSs will be provided by wide-area measurement signals using the new technology of synchrophasors. [ABSTRACT FROM PUBLISHER]

Voltage stability has been well investigated for the traditional power system using bifurcation analysis: saddle-node bifurcation (SNB) and hopf bifurcation (HB). This paper studies the impacts of distributed generators (DGs) on the voltage stability of power system. The bifurcations analysis is applied on the steady state three-phase load-flow Jacobian-matrix of unbalanced distribution system. The analysis of the eigenvalues is used to study distribution system behavior under different operating conditions. 10-bus radial distribution system is used as the study system. Different case studies and loading scenarios are presented to trace the eigenvalues of the Jacobian-matrix. The eigenvalues were calculated and the worst point, which is the nearest point to the imaginary axis, was registered for every case. The loci of these points with different load unbalance and location of DGs were plotted. Maximum loading point (MLP) was calculated at different ratings and locations of DGs. Results show that bifurcation analysis can clearly explain the voltage stability of the distribution systems. It also, explains the effect of introducing DGs on the voltage stability of the unbalanced distribution systems. Distribution of the eigenvalues helps in choosing the best location and rating of the required DGs. [ABSTRACT FROM PUBLISHER]

This paper proposes a novel master-slave scheme to control active power of an HVDC system with multiple voltage-source converters. The total active power generated by three offshore wind farms (OWFs) based on doubly-fed induction generator is delivered to two onshore AC grids through the proposed HVDC system. The total active power sent to the two onshore AC grids can be equally shared by the proposed control scheme of the HVDC system under various operating conditions. Calculated system eigenvalues of the studied system at the nominal operating point are analyzed. Transient responses of the studied system subject to a three-phase short-circuit fault at one of the two power grids are also carried out. It can be concluded from the eigenvalues and transient simulation results that the proposed power control scheme is effective to stabilize the active power from the three OWFs sent to the two power grids under a severe disturbance condition using the proposed HVDC system. [ABSTRACT FROM PUBLISHER]

This paper examined a method of using eigenvalues and eigenvectors of the state matrices to control power system oscillation using HVDC supplementary controller. HVDC devices eliminate line loses, increases transmission ability through damping of power oscillators and improves real power in an ac systems. Using eigenvalues and residue method the damping controllers are designed to solve a inter-area oscillation of two area four machine systems. The results ascertained the success of this method [ABSTRACT FROM PUBLISHER]

Low frequency inter-area oscillations are known stability issue of large interconnected electrical grids. It was demonstrated that additional control loop can be applied for static power sources, like FACTS, HVDC or modern Wind Power Plants, to modulate their power output and successfully attenuate these oscillations. Variety of control design methods were proposed for this service. In this paper focus is given to the most popular technique based on residues. Authors demonstrate on a small 4-machine 12-bus grid that residues may not provide sufficient information for effective damping control design. Hence, it is proposed to give more attention to additional indices like transfer function zero location and interactions between mode of interest and other system dynamics. Consequently, additional rules are proposed for residue based damping control design. [ABSTRACT FROM PUBLISHER]

In this paper, an approach for the efficient handling of mathematically stiff models in the case of a real-time simulation is shown. Here, the dynamic characteristics of models created in the simulation environment "Dymola" are analysed and the sources of the model stiffness are identified. Based on the gained information and according to the constraints of the real-time simulation, the model is adjusted automatically. In a first step, based on the eigenvalue distribution in the region of stability the model is partitioned into several sub-models. Each of these submodels is homogeneous and not stiff. If one or more models violate the real-time constraints and still threaten the stability of the simulation, an automatic optimisation of the model parameters will be performed in a second step. This affects the model's time constants and therefore the dynamic behaviour of the system. Based on this methodology stiff models are automatically adjusted and optimised in terms of real-time simulation. Thus, long analysis phases and the high number of iterations to identify and to eliminate the model stiffness can be reduced. Therefore, the transition from modelling (MIL) to real-time simulation (HIL, SIL) becomes more efficient. [ABSTRACT FROM PUBLISHER]

This paper presents an eigenvalues analysis method for an induction machine model based on phase variables a, b, c. This approach is validated by comparison with a d, q approach and applied to a variable speed pump-turbine unit using a simplified model of the converters. The proposed approach permits the study and analysis of the interaction between mechanical, electric and regulation parts of the system. [ABSTRACT FROM PUBLISHER]

This paper has two main objectives: to explain the dynamic characterization of wind farms as part of their integration in power systems using modal analysis and to present a qualitative development for understanding the main factors that impact on the damping of the oscillation modes by incorporating wind farms based on variable speed wind turbines. Moreover, such developments are validated by performing simulations on a 2017 peak scenario for the Uruguayan electrical system, showing a strong interaction between the hydroelectrics power plants located on the Río Negro and future wind farms Palmatir and Agua Leguas. [ABSTRACT FROM PUBLISHER]