Multifrequency Averaging in Power Electronic Systems

Power electronic systems have been widely used in the electrical power processing for applications with power levels ranging from less than one watt in battery-operated portable devices to more than megawatts in the converters, inverters and rectifiers of the utility power systems. These systems typically involve the passive elements such as inductors, capacitors, and resistors, the switching electronic components such as IGBTs, MOSFETS, and diodes, and other electronic circuits. Multifrequency averaging is one of the widely used modeling and simulation techniques today for the analysis and design of power electronic systems. This technique is capable of providing the average behavior as well as the ripple behavior of power electronic systems. This work begins with the extension of multifrequency averaging to represent uniformly sampled PWM converters. A new multifrequency averaging method of solving an observed issue with model stability is proposed and validated. Multifrequency averaging can also be applied to study the instability phenomenon in power electronic systems. In particular, a reduced-order multifrequency averaging method, along with a genetic algorithm based procedure, is proposed in this work to estimate the regions of attraction of power electronic converters. The performance of this method is shown by comparing the accuracy and efficiency with the existing methods. Finally, a new continuous-time multifrequency averaging method of representing discrete-time systems is proposed. The proposed method is applied to model digitally controlled PWM converters. Simulation and hardware results show that the proposed method is capable of predicting the average behavior as well as the ripple behavior of the closed-loop systems. Future research in the area of multifrequency averaging is proposed

ОСОБЛИВОСТІ РОЗРАХУНКУ НАПІВПРОВІДНИКОВИХ ПЕРЕТВОРЮВАЧІВ ПОСТІЙНОЇ НАПРУГИ НА ОСНОВІ УСЕРЕДНЕННЯ В ПРОСТОРІ СТАНІВ

The application of state space averaging method using Lagrange theorems for calculating of semiconductor converters in a formalized matrix form is considered. Analytical expressions are obtained for calculating the average and pulsating components of variable states in two-interval processes in single-cycle converters. The matrix coefficients of model with averaged variables for buck converter in the continuous-current choke mode are determined for illustration. Advantages of considered method using Lagrange theorems are shown, which are characterized by at least of six times less computational complexity in comparison with traditional methods based on solving of differential equations (fitting method) and the possibility of pulsating components calculation in comparison with classical averaging methods. References 12, figures 2, tables 2

МОДЕЛЮВАННЯ ПРОЦЕСІВ НА ОСНОВІ УСЕРЕДНЕННЯ В ПРОСТОРІ СТАНІВ У ПІДВИЩУВАЛЬНОМУ ПЕРЕТВОРЮВАЧІ З МАГНІТОПОВ’ЯЗАНИМИ ЕЛЕМЕНТАМИ

The features of the state-space average method using Lagrange's theorems for calculation of processes in the boost converter with magnetically coupled elements (with autotransformer connection of inductors) in continuous currents mode are considered. A mathematical model of the converter based on relative variables has been developed, which makes it possible to calculate processes in a wide range of parameters taking into account the degree of magnetic cou-pling between inductive elements, including the definition of constant and pulsating components. It is shown that to obtain a complete system of the algebraic equations as a mathematical model of converters, which provides its single solution, it is advisable to additionally use the ratio according to energy balance in reactive elements in a steady state at the operation intervals of the converter during commutation period. The boundary dependences of boost converter parameters with magnetically coupled elements between the modes of discontinuous and continuous currents are calcu-lated. The relative characteristics of the converter have been studied, which demonstrate the influence of imperfection of the magnetic coupling in the regulation zone of the relative duration value of switching interval. References 21, fig-ures 6

Modeling, Analysis and Simulation of a DC Distributed Power Architecture for an Airborne Application

This paper describes a design and analysis method for a DC distributed power architecture design in Airborne Application, utilizing simulation. Typically the used system components are commercial off-the-shelf components (COTS) thus complicating the system level analysis and simulation. Within this paper, it is shown how these systems can be designed utilizing simulation results, based on behavioural models of dc/dc converters. Additionally, models for commercial EMI filters are developed. This enables system level simulations and important information from efficiency, transient response, failures and stability is obtained assisting the designer to reach an optimum power system solution with minimum time and effort. Complex systems in avionics require high reliability. Therefore, the system level simulation is an essential tool for reaching the feasible solution complying with all the requirement

Modeling, Control and Characterization of Aircraft Electric Power Systems

A study model of advanced aircraft electric power system (AAEPS) corresponding to B767 Aircraft is developed in the PSIM9 software environment. The performance characteristics of the system under consideration for large sharing of non-linear loads are studied. A comprehensive mathematical model describing system dynamics is derived where the GSSA technique is applied for reduced-order system approximation. The transient and steady-state performance of the hybrid PEM-FC/battery APU integrated to the aircraft electric network is analyzed while different loading scenarios are taken into account. In addition, dynamic bifurcation analysis is employed to characterize the systems stability performance under multi-parameters condition. Also, the power quality of the system is assessed under various loading configurations, and the effect of installing active/passive power filters (APF/PPF) on power quality of the system is investigated for a wide range of operating frequencies

Modeling and Simulation of a Distributed Power System for Avionic Application

This paper describes design and analysis method for a DC distributed power system for Avionic Application utilizing simulation. In order to obtain rapid time to market, the used system components are typically commercial off-the-shelf components (COTS). This complicates the system level analysis and simulation because traditional modeling methods are not applicable. Within this paper, it is shown how these systems can be designed utilizing simulation results based on behavioral models of commercial dc/dc converters. Additionally, models for commercial EMI filters are developed. From the system level simulations important information of the whole system behaviour, such as power consumption, and overall stability is obtained. This assists the designer to reach an optimum power system solution with minimum time and effort. Therefore, the system level simulation is an essential tool for reaching the feasible design solution complying with all the requirement

Determination of unified time constants of switching circuits in terms of averaged-nodal equations

Switching circuits have variable structural topologies. In every topology, they have different dynamics and time constants. Resistances of switching elements vary between a very small value and a very large value during conduction mode and disconnection mode. Therefore, equivalent circuit modelling of switching circuits requires averaging the on-state and off-state resistances of switching elements over one switching period. Determining averaged switch models allows to determine unified time constants of variable structural switching circuits. In this paper, analytically, it is shown how to calculate the equivalent average resistance and to derive unified time constants. The formulation method is based on nodal equations, very suitable for the analysis of switching circuits