Elena Niculescu

Modelling the PWM Zeta converter in discontinuous conduction mode

A full-order dynamic model of the pulse-width modulation (PWM) DC-to-DC Zeta converter in discontinuous conduction mode (DCM) is presented in this paper. The derivation procedure is based on the small-signal PWM switch model in DCM used in conjunction with a PWM derived Zeta topology. The small-signal characteristics of the PWM Zeta converter in DCM obtained in a similar way as the small-signal properties of a linear amplifier are presented in a symbolic form. Such a model can be directly used in conjunction with a computational environment as Matlab, MathCAD and Mathematica to analyze the small-signal low-frequency dynamics of the PWM Zeta converter in DCM.

Application of fourier method in energetics, for root-mean-square value and phase shift measurement

Recorded information about transmission system faults or disturbances is essential for determining the performance of system components and to analyze the nature and cause of a disturbance in energetics. The systems for disturbance recording perform the monitoring and analysis of different events specific to energetic systems. The root-mean-square (RMS) values and phase shifts of voltages and currents are widely used in post-failure analysis and for monitoring the characteristic parameters of electric lines. This paper deals with the Fourier method adequate for measurement of RMS values and phase shifts in energetic systems. Experimental results obtained using a system for disturbance recording in power stations of energetic system are also presented.