Denis Pelin

Flux Reflection Model of the Ferroresonant Circuit

The paper presents a linear model of ferroresonant circuit with flux reflection. The proposed model—flux reflection model—derives from observations of typical flux waveforms of nonlinear coil during ferroresonant steady states. Simulation results of the flux reflection model are compared with simulation results of the usual nonlinear model as well as with measurements carried out on the physical model of the ferroresonant circuit. The flux reflection model enables a novel comprehension of the ferroresonant circuit behavior and simplifies the modeling of the nonlinear coil in the ferroresonant circuit.

Identification of chaos in a ferroresonant circuit

A second-order ferroresonant circuit is analysed. For a fixed set of circuit parameters and varying the voltage source amplitude only, the circuit can be driven into chaos through a process of period-doublings. The results of simulations agree well with those obtained by measurements carried out on a physical model of the circuit.

Bifurcation diagrams of the buck converter

The steady-state responses of the buck converter are determined by means of computer simulation and presented in a form of one-parameter bifurcation diagrams and two-parameter bifurcation diagrams. It is shown that the analysed converter can be driven into chaos through a process of period doublings; for each of the three chosen bifurcation parameters: the input voltage, the load inductance and the period of the external sawtooth ramp voltage. The results of simulation agree well with those obtained by measurements carried out on a physical model of the circuit.

Steady-state responses of the boost converter

A boost converter controlled by naturally-sampled constant frequency pulse-width modulation in a discontinuous conduction mode of operation is analysed. Several steady-state responses are recognised by varying the dc input voltage only. The analysis of steady-state responses is carried out in the time- as well as in the frequency-domain. A reasonable accordance between results of computer simulation and experiments in both domains is obtained.

Bifurcation diagrams - insight into the modes of operation of a boost converter

The modes of operation of the boost converter controlled by naturally-sampled constant frequency pulse-width modulation in discontinuous conduction mode of operation are determined. Bifurcation diagrams as a principal tool for the qualitative evaluation of behaviour of non-linear dynamical systems are used. It is shown that the boost converter considered here can be driven into chaos through a process of period doubling by varying some parameters of the boost converter: the input voltage, the capacitance of the output condenser, the inductance of the input inductor, period of external sawtooth ramp voltage (period of operation) and the load resistance.

Hysteretic Bifurcation Model of the Boost Converter

Steady-state responses of the boost converter by change of input voltage are experimentally identified. In a part of parameter space hysteretic behaviour of steadystate responses by varying input voltage in different tendency of change is noticed. Procedure for studying steady-state responses of the boost converter is proposed by using one-parameter and two-parameter bifurcation diagrams as simulation result. It is shown that the initial condition of bifurcation parameters affects steady-state responses inside hysteretic region. There is a variety of combinations of initial inductor current and initial capacitor voltage which cause particular steady-state. Therefore, hysteretic bifurcation model of the boost converter is proposed and verified by simulations and measurement outside hysteretic region.

The Poincaré map features of the boost converter bifurcation behavior

The bifurcation behavior of experimentally realized boost converter is observed. Mathematical model of the converter is derived and simulation of the converter is derived. Simulated Poincaré maps correspond to the steady-states obtained by the measurement. It is shown that Poincaré maps are more convenient for steady-state identification than state variable waveforms and trajectories. Simulated Poincaré maps of different initial instant of sampling in chaotic steady-state are verified with the maps obtained by the measurement. It is shown that the shape of chaotic attractor is invariant of initial sampling instant.

Smart-fast emulation of the photovoltaic systems

The paper describes smart-fast emulation of one, selected photovoltaic system. This method of emulation reduces the emulation time multiple times. This facilitates the evaluation and comparison of electrical energy production of photovoltaic systems of different power and/or different photovoltaic (PV) module technologies, which enables the optimal selection of photovoltaic system modules to adjust to the climate of a region.

Impact of initial conditions on hysteretic behaviour of the boost converter

The different steady-state responses of a boost converter are observed during measurements carried out on the physical model of the chosen boost converter. It is shown that by varying the input voltage only, the boost converter exhibits hysteretic behavior. The various set of steady-state responses are recognized by increasing the dc input voltage regarding the set of steady state responses which are obtained by decreasing the dc input. Also, the steady-state responses of the boost converter are determined by means of computer simulation and presented in figure of bifurcation diagram. The results of computer simulation and results of experiment coincide very well for one trend of varying input voltage only. Therefore, impact of initial conditions of the state variables in the form of bifurcation diagram is studied.