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