ias 2009 - universal input voltage self-oscillating
DESCRIPTION
bookTRANSCRIPT
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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
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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
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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
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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
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Self-Oscillating Electronic Ballast - SOEB
Nonlinear control system;
Resonant current feedback;
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Self-Oscillating Dimmable Electronic Ballast
Branch BD;
Magnetizing current;
Switching frequency dimming capability.
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Universal Electronic Ballast
Switching frequency x lamp power;
Resonant filter gain changes as the switching frequency changes.
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Resonant filter design;
Command circuit design;
Additional circuit design;
Stability test.
Design Steps
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Design Strategy
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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
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Command Circuit Design
Equivalent command circuit Circuit waveforms
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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
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Command Circuit Filter Design
Simplified block diagram
4.
.
Z
Z
VN
I
1( )G s
N
Describing function
Characteristic equation
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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
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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
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Lamp voltage and current (100V/div, 500mA/div, 10s)
Experimental Results
Input voltage 100 VRMS
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Lamp voltage and current (100V/div, 500mA/div, 10s)
Experimental Results
Input voltage 220 VRMS
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Compact circuit;
Command circuit simplicity;
Lamp power is independent of the input voltage;
Easy installation.
Conclusions
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FiltroEMI
Capacitor+
Filtro
CorreoFator
Potncia
Inversor FiltroRessonante
110/220V60Hz
Lmpada(s)
www.ufsm.br/gedre