Spectral modeling of switched-mode power converters

A new modeling approach for the spectral analysis of pulsewidth modulated (PWM) converters with independent inputs is developed. The key of this approach is to extend the Volterra functional series to nonlinear systems with multiple independent inputs. After formulating the state-space equations describing the dynamical behavior of PWM converters, the Volterra transfer function characterizing the output frequency response can be obtained, which is then symmetrized to form the spectral model. Since the model is developed in a closed form, it is suitable for computer analysis. The modeling approach has been applied to various PWM converters, and the results are verified. The spectral models of different power converters can readily be obtained by using this general approach.published_or_final_versio

Spectral modeling of switched-mode power converters in discontinuous conduction mode

Analytical spectral modeling of switched-mode PWM converters, operating in the discontinuous conduction mode, is presented. The modeling approach is to derive analytical expressions of the converter output response using the extended Volterra functional series. Nonlinear frequency responses, including additional DC offset as well as significant subharmonic and higher harmonic components, due to large-signal perturbations of both the duty ratio and source voltage, are investigated. Their vulnerability to switching frequencies are also described. This modeling approach has been applied to various PWM converters, boost, buck and buck-boost types, operating in the discontinuous conduction mode, and the results are verified.published_or_final_versio

Nonlinear identification of power electronic systems

This paper presents a new approach to modelling power electronic systems using nonlinear system identification. By employing the nonlinear autoregressive moving average with exogenous input (NARMAX) technique, the parametric model of power electronic systems can be derived from the time-domain data. This approach possesses some advantages over available circuit-oriented modelling approaches, such as no small-signal approximation, no circuit idealization and no detailed knowledge of system operation. Moreover, it is found that the inclusion of nonlinear terms in the model of power electronic systems is particularly necessary during the presence of large-signal perturbation.published_or_final_versio

An automotive thermoelectric-photovoltaic hybrid energy system

In recent years, there has been active research on exhaust gas waste heat energy recovery for automobiles. Meanwhile, the use of solar energy is also proposed to promote on-board renewable energy and hence to improve their fuel economy. In this paper, a new thermoelectric-photovoltaic hybrid energy system is proposed and implemented for automobiles. The key is to newly develop the power conditioning circuit using maximum power point tracking so that the output power of the proposed hybrid energy system can be maximized. An experimental system is prototyped and tested to verify the validity of the proposed system. © Copyright 2011 IEEE - All Rights Reserved.published_or_final_versionThe 2010 IEEE Vehicle Power and Propulsion Conference (VPPC), Lille, France, 1-3 September 2010. In Proceedings of VPPC, 2010, p. 1-

Nonlinear Dynamics of a Current Controlled D.C. Drive with PID Controller

ABSTRACT: This paper describes a closed loop model of a current controlled PMDC motor drive with PID Controller. The output speed of the PMDC motor is compared with a preset reference speed. The differences between these two signals are fed as an error signal to the PID controller of the system. The output of the speed controller is the actuating signal that controls the duty cycle of converter and hence controls the converter output. Through this controlled converter output, required voltage gets injected into the motor to bring it back to its desired speed. As a small change in the input voltage can cause a large change in the motor current and lead to a particular drive control feature. I. RELATED WORK PM motor drives have been a topic of interest for the last twenty years. Different authors have carried out modeling and simulation of such drives. The three most common speed control methods of a dc motor are field resistance control, armature voltage control, and armature resistance control II. INTRODUCTION Developments of high performance motor drives are very essential for industrial applications. A high performance motor drive system must have good dynamic speed command tracking and load regulating response. DC motors provide excellent control of speed for acceleration and deceleration and chopper fed permanent magnet PMDC motor allows precise voltage control, which is necessary for speed and torque control applications. DC drives, because of their simplicity, ease of application, reliability and favourable cost have long been a backbone of industrial applications. DC drives are less complex as compared to AC drives system. DC drives are normally less expensive for low horsepower ratings. DC motors have a long tradition of being used as adjustable speed machines and a wide range of options have evolved for this purpose. Cooling blowers and inlet air flanges provide cooling air for a wide speed range at constant torque. PMDC motors are conveniently portable and well fit to special applications, like industrial equipments and machineries that are not easily run from remote power sources. PMDC motor is considered a SISO (Single Input and Single Output) system having torque/speed characteristics compatible with most mechanical loads. This makes a PMDC motor controllable over a wide range of speeds by proper adjustment of the terminal voltage using various innovative design and control technique

Comparative Study between Conventional PID and Fuzzy Logic Controller for a Current Controlled D.C. Drive Using MATLAB/Simulink

ABSTRACT: This paper describes a closed loop model of a current controlled PMDC motor drive with two controller FUZZY & PID separately, then comparison of the effect on output parameters for this two different controller is established. The differences between the output speed of PMDC motor & a preset reference speed is fed as an error signal to the controller of the system. The output of the speed controller (actuating signal) controls the duty cycle of converter and hence controls the converter output. Through this controlled converter output, required voltage gets injected into the motor. A small change in the injected voltage can cause a large change in the motor current and hence leading to a particular drive control feature. In the past few years Fuzzy Logic became a very much popular choice of controller for feedback control of various industrial systems. Fuzzy logic control is much closer in spirit to human thinking and logical reasoning than conventional controller like PID or PI. Recent study shows that this type of controller (FUZZY) provides better settling time, low peak overshoot and less percent of steady state error in overall system output which leads to better stability of overall system. In this Paper, a performance analysis of the conventional PID controller and fuzzy logic controller has been done by the use of MATLAB. . Depending on the armature voltage control method simulink model of a current mode buck-type dc chopper-fed permanent-magnet (PM) dc motor drive with proportional controller in its feedback loop is realized [3][4] . But the importance of PID controllers in process industry cannot be overemphasized because although some modern controllers like FUZZY got popularity, the majority of the industrial controllers use PID or modified PID control schemes KEYWORDS