The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
This paper deals with the time response computation of closed loop control systems with fractional order PI controllers using the frequency response data of the closed loop system. The time response of fractional order transfer functions from frequency response data was first obtained by the authors using Fourier Series Method(FSM) and Inverse Fourier Transform Method(IFTM). In this paper, these methods...
The features of using double Fourier series for calculation spectrum of pulse-width modulated (PWM) signals are described. Restriction of implementation double Fourier series for signal with other type of modulation are indicated and approach for signals with arbitrary modulation on basis double Fourier series are proposed. The example of spectrum calculation of pulse-frequency signal (PFM) is demonstrated...
Image features vary in size and thus feature analysis often requires a multi-scale approach. Typically, this is achieved using a bank of filters centred at discrete scales. We introduce a novel filter bank constructed from Fourier series basis functions in the logarithmic frequency domain. The filter bank responses can be used to obtain a continuous approximation of the response to another filter...
The paper deals with obtaining the time response of closed loop control system with fractional order PID controller using frequency response data. For this aim, a feedback control system with an integer order plant and a fractional order PID controller are studied. The real and imaginary parts of the closed loop transfer function are obtained which depend on the parameters Kp, Ki, Kd, λ and μ of fractional...
In this paper, Selective Harmonic Mitigation (SHM) and Selective Harmonic Elimination (SHE) modulation techniques are combined to generate the appropriated firing pulses for a 4-leg 3-Level Neutral Point Clamped (NPC) inverter. SHM modulation technique is applied to the phase legs in order to get a desired modulation index (ma) and to mitigate the lower order odd non-triplen harmonics (5th, 7th, …)...
We propose continuous-time system identification using discrete data and continuous curves of the data obtained by curve fitting. We describe a method for fitting a finite Fourier series to discrete data and show that the fitted curve can be created as the output from a bilinear neural network system. By using this method for fitting, we propose a method for determining the optimal values for coefficients...
Hybrid architectures inverters for photovoltaic (PV) systems are an alternative to increase energy production in PV systems under partial shading conditions. For such systems, non-shaded modules are arranged in series, whereas shaded modules are set in parallel. To match the voltage of both arrays, a high step-up active-clamp dc-dc converter is used to increase the voltage of the parallel array allowing...
This paper proposes analytical methods for generating acoustically bright and dark zones on the horizontal plane using circular loudspeaker arrays without and with a cylindrical rigid baffle. Both sound fields on the horizontal plane produced by continuous circular monopole source distributions without and with a rigid baffle are analytically calculated using 2.5D sound field representation derived...
The empirical analysis of building the time series model as a combination of a linear function of time, the partial sum of the Fourier series and specific procedures of the Fourier coefficients has been considered in the report. The experiments have been conducted with real data of different nature. It is noted that the consistent series expansion into the Fourier sine and cosine transformations and...
In this paper, the relationship between the blood flow velocity and Doppler power spectrum in stenosed vessel is investigated to determine the variation between the maximum velocities and their frequency locations at the spectra in the vessels with different degrees of stenosis, and then a new method is proposed to extract the maximum velocity of blood flow in narrowed vessels. Firstly, a geometric...
Recursive filtering with multimodal likelihoods and transition densities on periodic manifolds is, despite the compact domain, still an open problem. We propose a novel filter for the circular case that performs well compared to other state-of-the-art filters adopted from linear domains. The filter uses a limited number of Fourier coefficients of the square root of the density. This representation...
Natural balancing of the flying capacitor converter is activated when the converter is operating with phase shifted carrier PWM and the carriers are exactly interleaved. The mechanism is stable and has many benefits but the dynamic response can be slow. In this paper a novel active balancing approach, based on the application of an off-line optimized phase shift of the individual carriers during the...
A generic, Fourier-based method for the derivation of optimal, full-operating-range zero voltage switching (ZVS) modulation schemes for dual active bridge (DAB) converters is presented. Thereby, the AC-link voltages and currents, and the DAB's input current and power flow, are described using trigonometric Fourier series. Furthermore, the amount of charge that is available in the bridge currents to...
This paper presents a new method for analysis of the electromechanical interactions in induction motors due to internal faults. These faults generate often electromechanical torque with rather low pulsations causing speed ripples, which change to the Fourier spectra of phase currents. The MCSA method uses those spectra for diagnosis. It is important to predict the spectra precisely, both qualitatively...
Controller design for transverse flux machines is a substantial challenge due to their nonlinear dynamic behavior. This paper places particular emphasis on the phase current control loop since it directly affects the generated torque. A state space representation of phase current harmonics in transverse flux machines is introduced to expand applicable control structures. A speed dependent feedforward...
Generalized State Space Average Modeling (GSSAM), of switching converters, offers an opportunity to improve fidelity of a model by inclusion of different harmonic components. Yet, the inclusion of each frequency component contributes to an increase in the number of the state variables and matrices describing the system. In this paper, automated arbitrary order generation of the GSSAM models for switched...
The identification of the dynamic model of a robotic manipulator represents a fundamental step for designing high performance model-based controllers. Despite the huge number of works presented on this topic, the symbolic dynamic model reduction (i.e., the identification of the set of parameters observable through the measure of joint torques and positions) still remain a challenging task, characterized...
The ideas of Fourier series and transform play a central role in mathematical treatment of imaging phenomena and the design of image reconstruction algorithms. This chapter discusses several ideas related to Fourier transforms, which will be used when discussing propagation of light waves and analysis of imaging systems. It notes a peculiar phenomenon, namely the Gibbs phenomenon, which arises near...
Oscillating motion of Oldroyd-B flow in a capillary tube at a triangular sine and cosine pressure waveform is considered. An analytical solution of velocity field is obtained for an oscillating laminar flow, which can be used to determine the existence of trapezoidal waveform effect on the flow. When both triangular sine and cosine components are dominate, the oscillating flow can result in significant...
In recent years, non-circular journal bearings are widely used in industry on account of their better stability, simplicity, efficiency and low cost. In this paper, an elliptical bearing neglecting the journal eccentricity is investigated. The results show that the oil-film thickness can always be expanded into a Fourier series. And the basis function of the series is just related to the total amount...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.