Juliano de Pelegrini Lopes

Marcelo Freitas da Silva

Rafael Adaime Pinto

Ricardo Nederson do Prado

lysson Raniere Seidel

Universal Input Voltage Self-Oscillating

Electronic Ballast with Feedforward

Control

Mercury Low pressure discharge lamp with phosphor layers excited by UV radiation

Definition

Fluorescent Lamps

UV Radiation

Phosphor Hg Electrodes Electron

Light

High luminous efficiency 100 lm/W (TFLs)

High color rendering index (CRI) 60 90;

Long useful life;

Color temperature.

Fluorescent Lamps

Features of Fluorescent Lamps

Electronic Ballasts

High efficiency;

Lower weight and volume;

High useful life to the lamp;

Absence of flicker;

Absence of audible noise.

Features of Electronic Ballasts

The goal of this work is to show the possibility of implementing a universal input voltage self-oscillating electronic ballast supplying a

tubular fluorescent lamp T8/32 W.

Goal

Self-Oscillating Electronic Ballast - SOEB

Nonlinear control system;

Resonant current feedback;

Self-Oscillating Dimmable Electronic Ballast

Branch BD;

Magnetizing current;

Switching frequency dimming capability.

Universal Electronic Ballast

Switching frequency x lamp power;

Resonant filter gain changes as the switching frequency changes.

Resonant filter design;

Command circuit design;

Additional circuit design;

Stability test.

Design Steps

Design Strategy

Fluorescent lamp is represented by its

equivalent resistance;

Fundamental aproximation;

Design based on Impedance angle.

Z

a

b

Resonant Filter Design

Phase angle

Lam

p P

ow

er

Command Circuit Design

Equivalent command circuit Circuit waveforms

Command Circuit Filter Design

Circuit block diagram

Simplified block diagram Non linear elements can be

represent by the describing

function;

Describing function is used to determine the circuit command

equations.

Linear elements with low pass

caracteristics

(Resonant filter);

Circuit block diagram Circuit block diagram

Command Circuit Filter Design

Simplified block diagram

4.

.

Z

Z

VN

I

1( )G s

N

Describing function

Characteristic equation

G(j) must crosses the real axis (-1/N) in the clockwise during all the range of the input voltage to estimate stability.

Stability Test

Extended Nyquist stabiliy criterion

P1 P2

Z

Z

V

I

N 4

1

Additional Circuit Design

Ld is determined considering the maximal switching frequency (40 kHz) and the TSC equivalent resistance equals

to 0;

TSC must operates in linear region during all the range of the switching frequency.

Equivalent additional circuit

Lamp voltage and current (100V/div, 500mA/div, 10s)

Experimental Results

Input voltage 100 VRMS

Lamp voltage and current (100V/div, 500mA/div, 10s)

Experimental Results

Input voltage 220 VRMS

Compact circuit;

Command circuit simplicity;

Lamp power is independent of the input voltage;

Easy installation.

Conclusions

FiltroEMI

Capacitor+

Filtro

CorreoFator

Potncia

Inversor FiltroRessonante

110/220V60Hz

Lmpada(s)

www.ufsm.br/gedre