Elissaveta Gadjeva

A nullor approach to computer-aided analogue circuit diagnosis

In this article, a nullor approach to analogue circuit diagnosis at subcircuit and at component levels is developed. The test voltages of the accessible nodes and the current through the voltage supply are selected as test quantities. A nullor diagnosis model of the circuit under test is constructed. The automated fault localization and identification of single and multiple faults is reduced to simulation of a nullor diagnosis model. The approach allows us to automatically carry out fault identification of soft (parametric) faults using standard circuit simulators. Based on the simulation of the diagnosis model of the faulty circuit, fault coverage investigation and optimal test node selection can be performed in order to increase the testability of the circuit. An example illustrating the proposed approach is presented.

Computer modelling and simulation of the PV–boost converter system working at MPPT mode of operation

A PV–Boost converter system working at hysteresis MPPT mode of operation is proposed in the present paper. A computer model of the system is developed and simulated. Behavioural parameterised PSpice macromodels are developed for the single photovoltaic element, for series connection of single cells and for PV panel. The PV model is used to simulate a concrete electrical circuit, which optimises the mode of operation of the Boost converter in order to achieve maximum transmitted power from the photovoltaic element (maximum power point tracking – MPPT). The computer models are realised in the Cadence Capture and Cadence PSpice environment.

Optimization Of Geometric Parameters Of Spiral Inductors Using Genetic Algorithms

An approach for optimal design of spiral inductors with the use of genetic algorithm is proposed. The approach is applied to optimal geometry design of planar spiral inductors for RF applications with respect to the quality factor Q. MATLAB methodology was implemented, based on the genetic algorithm toolbox

Computer-aided model parameter extraction of photovoltaic modules using SPICE

An approach is developed in the paper to model parameter extraction of photovoltaic (PV) modules based on manufacturers datasheet characteristics. The model parameters are obtained simultaneously for any environmental conditions (irradiance and temperature). The computer realization of the parameter extraction procedure is performed using the general-purpose circuit simulator PSpice and postprocessing in the graphical analyzer Probe to obtain the model parameters satisfying the defined requirements. The model accuracy is validated for different irradiance and temperature conditions. The implementation of the parameter extraction procedure of PV modules in standard circuit simulators such as PSpice allows its accessibility for the designers of PV systems.

Computer modeling of graphene nanoribbon interconnects

In this paper computer models are developed of graphene nanoribbon (GNR) interconnects. A multilayer GNR interconnect model is created, as well as an accurate computer interconnect model based on ABCD parameters. Investigation in the frequency and in the time domain is performed. Computer SPICE models are also created taking into account the frequency effects in GNR interconnects. The results are compared to measured data obtained from referenced sources and thus have been verified.

Parameterized SPICE models of carbon nanotube interconnects

Parameterized computer SPICE models of carbon nanotube (CNT) interconnects are developed in the paper. The nonlinear I-V characteristic of a CNT is described. RLC models of an isolated single-walled CNT (SWCNT), as well as of SWCNT bundle interconnect are created. Based on the SWCNT bundle model a parameterized computer RLC model is created in the form of hierarchical block. The parameterization of the block gives great freedom and possibilities for further indept investigation on the topic. Computer SPICE models of higher accuracy for SWCNT bundle interconnect are proposed based on two-port Y-parameter representation. Verification is performed to confirm the applicability of the developed computer models.

Bidirectional DAB DC-DC converter with hysteresis current mode control

A new modulation strategy with Hysteresis Current Mode Control for Bidirectional Dual Active Bridge (DAB) is proposed in the paper. A simulation model for Buck and Boost mode of operation is developed and implemented in the MATLAB/SIMULINK environment. The value of the calculated leakage inductance is verified using COMSOL program. The proposed Hysteresis Current Mode Control allows combining the advantages of Current Fed Bidirectional Converter and Bidirectional DAB.

Development of Temperature-Dependent SPICE Computer Models of Photovoltaic Cells

Parameterized computer models of photovoltaic (PV) cells and modules are proposed in the paper. Four-and five-parameter one-diode models, two-diode model, as well as behavioral models of the PV cell are considered. The temperature-dependence of the model parameters is taken into account. Parameter extraction approach is developed to determine the model parameters, based on nullor equivalent circuit and datasheet characteristics of the PV cells and modules. PSpice description of the developed PV model is given in the form of parameterized block. The accuracy of the computer PV models is investigated by comparison to the datasheet characteristics.

Application of standard circuit simulators for optimal design of electronic circuits

An approach is proposed in the paper to apply the general-purpose circuit analysis programs such as PSpice together with the graphical analyzer Probe as a tool for optimal computer-aided design of electronic circuits. The extended possibilities of the input language of the PSpice simulator for adequate computer modeling and the ability for multi-variant analysis of electronic circuits in different modes of operation allow obtaining the required circuit characteristics. Examples are presented to illustrate the proposed approach.

Generalized SPICE model of photovoltaic modules

In the present paper, a generalized SPICE simulation model of photovoltaic modules is developed, valid for operating conditions of solar irradiance and temperature different from nominal conditions. An extraction procedure for model parameter determination is proposed using datasheet characteristics of the modules. In order to improve the model accuracy, the values of the voltage Vmp and the current Imp corresponding to the maximum power point MPPT, are also used as input data. The computer realization is performed in the Cadence Capture and Cadence PSpice environment. The description of the computer model is presented. The verification of the developed SPICE simulation model of PV modules confirms its validity and accuracy.