Method for the Analysis of Three-Phase Networks Containing Nonlinear Circuit Elements in View of an Efficient Power Flow Computation

The present paper is devoted to applying the Hănțilă method for solving nonlinear three-phase circuits characterized by different reactance values on the three sequences (positive, negative and zero). Nonlinear elements, which are components of the circuit, are substituted by real voltage or current sources, whose values are an iteratively corrected function of the voltage across or the current through them, respectively. The analysis is carried out in the frequency domain and facilitates an easy evaluation of the power transfer on each harmonic. The paper presents numerical implementations of the method for two case studies. For validation, the results are compared against those obtained using the software LTspice in the time domain. Finally, the power flow on the harmonics and the overall power balance are analyzed.

The theoretical analysis and simulation of acoustic absorber for nonlinear shunted loudspeaker

In this paper, a nonlinear electroacoustic absorber based on a tunable loudspeaker is proposed to broaden its sound absorption bandwidth. The main mechanism is a nonlinear circuit is coupled at loudspeaker's terminal. A series of theoretical analysis and simulation work are carried out in this paper. The equivalent model is composed of a linear term describing the loudspeaker and a nonlinear term of a coupled Duffing-van Der Pol bistable circuit. The invariant manifold method is used to solve different time scales. The analysis and simulation results show that the nonlinear circuit can widen the frequency bandwidth of the structure.

Multiple Bifurcations and Complex Responses of Nonlinear Time-Delay Oscillators

In this paper, the dynamical properties of multiple van der Pol-Duffing oscillators with time delays are studied. The amplitude death and bifurcation curves in the parameter plane are determined by using the space decomposition method. Different patterns of bifurcated solutions are given on the basis of the symmetric bifurcation theory. The properties of bifurcated solutions are shown by using the norm forms on the center manifold. The interactions of bifurcations are discussed and their dynamical behaviors are shown. An electronic circuit platform is implemented by means of nonlinear circuit and time delay circuit. The revealed behaviors of the circuit reach an agreement with the obtained results. It is shown that the nonlinearity and time delays have great effects on the system performance and can induce interesting and abundant dynamic features.

Signal rectifying and detecting in the NI ELVIS complex

A half-wave diode rectifier is represented as a nonlinear circuit to study in a laboratory course of electrical engineering. The control and measurement complex NI ELVIS effectively displays the nonlinear circuit properties using oscillograms and spectrograms of signals. The coefficients of ripples and nonlinear distortions are calculated. They help to evaluate the influence of the circuit parameters on the quality of signal conversion when rectifying and detecting. The advantages of the NI ELVIS complex consist in, for instance, the real-time digital signal processing, the visualization of results, the ergonomic visualization tools. These advantages provide clarity and precision in the presentation of complex nonlinear processes in electrical engineering.