Ovidiu Pop

Using DSP technology for true sine PWM generators for power inverters

This paper presents theoretical and experimental aspects related to the implementation of a DSP-based fully digital single phase true sine PWM inverter. The proposed digitally-controlled PWM inverter employs a single chip DSP to realize a double-loop voltage and current mode control scheme. The Motorola DSP56F80/spl times/ family is well-suited for digital inverter control, combining the DSPs calculation ability with the microcontrollers function on a single chip and is a fully versatile part for a high performance, low cost, single chip PWM generator with many additional features not found in other solutions. The conclusions of the paper allow an objective evaluation of using DSP in the generation of sinusoidal PWM signals and in inverter control schemes.

Power factor correction circuit with a new modified SEPIC converter

This paper presents a new topology for a SEPIC converter used in power factor correction circuits. The conventional SEPIC converter was primarily designed to provide a nonpulsating input current, operating with both inductors in continuous current mode and only DC-DC conversion was considered. The modified SEPIC converter is designed to operate as an AC-DC converter and can be viewed as a cascade of a modified boost converter and a buck-boost converter. The boost converter operates in discontinuous current mode, while the buck-boost converter operates in continuous current mode. Since a high power factor is naturally achieved in this way, a simple feedback control technique is needed in order to regulate the output voltage. The paper also presents a calculus method for the power factor and total harmonic distortion factor for the proposed converter.

Analysis and simulation of power inverter with load variation for induction heating applications

All induction heating applied systems are developed using electromagnetic induction. Electromagnetic induction refers to the phenomenon by which electric current is generated in a closed circuit by the fluctuation of current in another circuit placed next to it. The basic principle of induction heating is that AC current flowing through a primarily circuit induces a current in the load (the secondary circuit) located near it and heating the load. The intent of this presentation is to present the details of half-bridge power inverter via a comprehensive analysis with operation equations of the circuit and their solving using specific sotware. An alternative to the use of circuit-oriented simulators for study of these circuits operating is to describe the circuit and the controller by means of differential and algebraic equations. We must develop the equations for all possible states in which the circuit may operate. These algebraic/differential equations can be solved by using of software packages specifically designed for this purpose that provide a choice of integration routines, graphical output, and so on.

New PSPICE model for power MOSFET devices

The common PSPICE model for the power MOSFET device is well known to CAD designers. This paper addresses the problem of how to correctly simulate a nonlinear device by modeling the nonlinear components of its PSPICE model: drain-to-source resistance vs. temperature, drain-to-source and gate-to-source capacitance vs. voltage. By comparing the simulation results of the common PSPICE MOSFET model with the manufacturers specifications, the drawbacks of the model are revealed. The paper explains the basic theory behind modeling linear and nonlinear capacitors and resistors and describes how to model nonlinear capacitors and resistors using the analog behavioral modeling (ABM) feature of PSPICE. Examples are provided that show the circuit diagrams for various nonlinear capacitors and resistors and PSPICE plots of the transient analysis results. Based on these principles, a new MOSFET model is generated and used in some examples.

Embedded system for remote monitoring of OBD bus

This paper aim is to present the implementation the monitoring system based on OBD reader, in order to read and compare the OBD CAN bus informations. The goal is to read the values of speed and other useful information during the cruise. This can be also helpful to improve the informations used in other applications. The goal of our work is to correlate these informations with the energy recovery and in future thus can leads to a considerable decrease of the energy consumption of cars. At the same time, is protecting the life expectancy of the electronics system of an automobile electric motor.

A Matlab tool for simulations of power resonant converters

The intend of this paper is to present a new tool for simulations of power resonant converters. The load of converters represents an oscillating resonant circuits and the major problem consist in obtaining the maximum power at resonant switching frequency, imposed by load. In order to simulate and implementing the resonant converters, we develop a Matlab tool based of the differential equations that define the converter topology. This tool returns the corresponding waveforms for converter operation and allows changing in every moment the circuit parameters.

Analysis and simulation of a half-bridge inverter

The intent of this presentation is to present the details of half-bridge power inverter via a comprehensive analysis with operation equations of the circuit and their solving using specific sotware. An alternative to the use of circuit-oriented simulators for study of these circuits operating is to describe the circuit and the controller by means of differential and algebraic equations. We must develop the equations for all possible states in which the circuit may operate. These algebraic/differential equations can be solved by using of software packages specifically designed for this purpose that provide a choice of integration routines, graphical output, and so on..

System for energy recovering with BLDC motor at deceleration momentum

This paper aim is to present the implementation of an energy recovery system based on DC motor deceleration momentum, in order to be used in propulsion systems. The energy which should be lost during deceleration is now recovered, stored and then used in other applications. The energy recovery and reutilization leads to a considerable decrease in total energy consumption necessary for such a system. At the same time, the super capacitors usage (in order to recover energy during the inertia momentum) is protecting the life expectancy of the battery, which normally supplies the propulsion system of an automobile electric motor.

Influence of power consumption over the input current harmonics pollution for a half-bridge power inverter

The intent of this presentation is to present the influence of power level delivered on a load over the total harmonic distorsion of input current for a power half-bridge inverter with resonant load. Half-bridge inverter is a configuration used for higher output power applications compared to single end quasi-resonant inverter. Even though it needs complicated control, half-bridge configuration has been winning popularity because it is relatively much more reliable and easier to build up higher power system.

Educational platform for modeling of zero-voltage switching quasi-resonant boost converters

This paper presents an educational platform for modeling of basic zero-voltage switching quasi-resonant boost converters using mathematical methods. In order to visualize the results of solving the equations that describe the converter operation, we used Matlab software modules. The advantages of this method of study are: (1) wider availability - it is possible to view the results over the Internet; (2) increased flexibility t is possible to modify any circuit component values, including parasitic components, and study their influence in converter operation, included the time periods affected; (3) it is possible to analyze both half-wave and full-wave operation mode; (4) it is possible to select which operating regimes are displayed, transient or steady-state. The conclusions of the paper allow an objective evaluation of the advantages described above vs. circuit-oriented simulators in the study of quasi-resonant switching mode power supplies. In addition, with an appropriate modeling of each circuit component, this platform allows analyses of component non-idealities (including package models) and their influence on circuit operation.