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A
Comparison
of
LCC and LC Filters for its Application in Electronic Ballast for Metal-
Halide Lamps
J. Correa, M. Ponce,
A.
Lopez, J. Arau
Centro Nacional de Investigacion y Desarrollo Tecnologico-CENIDET
Departamento de Electronica
Cuernavaca, Mexico
E-mail: jcorrea@cenidet.edu.mx
P.O. BOX 5-164, C.P. 62050
FAX:
+52 (73) 12-24-34,
Abstract-
A
complete LC and LCC Resonant Tanks analysis for its
application in the starting and stabilization
of
Metal-Halide Lamps is
presented in this paper. The operation with a single frequency for the
starting and steady-state phases, the maximum gain voltage during pre-
starting phase, the possibility to achieve soft switching in the switches
during the starting and steady-state lamp operation and the resonant
tank design limitations for these conditions are considered in the
analysis. Experimental prototypes were built to verify the analysis and
the results are included.
1.
INTRODUCTION
For many years High Intensity Discharge (HID) Lamps have been
used for industrial and external lighting applications. Nowadays,
HID lamps are an attractive light source due to their high efficacy
and their high electric power per discharge length unit, which allows
to have high luminous
flux
light sources with a reduced size [l].
Metal Halide Lamps supplied using a high frequency electronic
ballast have become an attractive light source thanks to their
compactness, good color rendering and high efficacy. However,
compared to fluorescent lamps, the Metal Halide lamps require a
higher ignition voltage for the gas ionization during the starting
phase (1.5 to 5kV for cold starting); besides, an appropriate lamp
current for the transition from the glow discharge to the full high
pressure arc [2] must be supplied.
Similarly to fluorescent lamps, HID lamps could be ignited and
stabilized through a high frequency inverter plus a resonant tank.
There are many resonant tank topologies applied to electronic ballast
for fluorescent lamps and some of them have been analyzed in [3-51
and widely studied in the literature. The LC and LCC resonant
tanks, shown in figure
1,
are the simplest and most used topologies
for the ignition and stabilization of discharge lamps. The unique
difference between both tanks
is
the Cs capacitor in series with the
inductor
Lr.
This capacitor has been used to filtering the dc
component in the class D amplifiers, but if this capacitor
is
considered in the design, it represents additional advantages in the
lamp management.
Most
of
the analysis reported [l-51 only consider
if
the resonant
tank
is
capable to ignite and stabilize the discharge current in the
lamp. In this paper not only these basic issues are considered, but
three other aspects that are also examined:
1. Starting and steady-state frequencies are the same.
2. Maximum gain voltage during the pre-starting phase.
3. Turn-on and turn-off transitions in the switches with zero
current switching (ZCS).
LR
CRS
a)
b)
Fig.
1.
(a)
LC
Resonant
Tank;
(b)
LCC
Resonant Tank
0-7803-7067-8/01/$10.00
02001
IEEE
J.M. Alonso
Area de Tecnologia Electronica
Universidad de Oviedo
Campus de Viesques sln
Gijon, 33204.
SPAIN.
FAX:
+34-98-5 182 138
The first point considers that it is possible to ignite and stabilize
the lamp with the same frequency in both operation phases. In most
cases, two frequencies are considered: the first one is for the lamp
ignition and the second one for the lamp stabilization. However, it
is possible to use the same frequency in order to satisfy both
conditions. The use of a unique switching frequency simplifies the
control circuit and diminishes the resonant inverter cost.
If the switching frequency is equal to the natural resonant tank
frequency during the pre-starting phase, the tank will be in
resonance and a very high voltage will be obtained in the Crp
terminals. This means that the maximum voltage that the tank is
capable to produce will be applied to the lamp.
The third point establishes the switching frequency is the same to
the natural resonant tank frequency in the steady state, which means
that the resonant tank will be operating in resonance during the
steady state. In these conditions the resonant tank is not able to limit
the lamp current. In the conventional electronic ballast, the natural
tank frequency is lower than the switching frequency and the
resonant tank presents an inductive behavior and lets to limit the
lamp current. However, in an inductive behavior the inverter power
factor is lower than the unity, the
rms
current in the switches
increases and the conduction losses also grow higher. The current
and voltage waveforms in the switches for this operation conditions
are shown in Fig. 2a.
As
can be seen the current is delayed to the
voltage and the turn off switching will be in a "hard mode".
The advantage
of
operating the resonant tank in resonance during
the steady state
is
that it will behave like a resistance, and the power
factor will be equal to the unity. Under these conditions, the stress
in the switches is lower and the conductions losses will be also
lower. The switches wave forms for the current and the voltage are
shown in fig. 2b. As can be seen, the voltage and current are in
phase and the switching losses are the lowest.
Fig.
2.
Voltage
and
Current
waveforms
in the switches,
(a)
fr(sFfs,
(b)
fr(s)=fs.
The stabilization problem, established by the third point, requires
an extra stage in order to stabilize the lamp current. This function
can be implemented with the first stage used as a power factor
corrector in a traditional electronic ballast scheme, like in Fig 3.
This stage not only will be used as a power factor corrector, but it
can also be used to stabilize the lamp current if the control is
appropriate [6].
In this paper the LC and LCC resonant tank analysis is presented
in order to fulfill the three conditions mentioned before. In this
analysis (a phasor-based analysis)
is
considered that the quality
factor is high enough to obtain a sinusoidal waveform in the
114
resonant tank current. This paper is organized as follows: The
LCC
and
LC
analysis are presented in sections
I1
and
111
respectively
taking into account the three issues established in the introduction.
Section IV presents a comparison between both resonant tanks based
on the results of sections
I1
and
111.
Section
V
describes a design
method for the LC and LCC tanks and some simulation results are
also presented. Finally, experimental results and conclusions are
presented in section
VI
and
VI1
respectively.
11.
LCC
RESONANT
TANK
ANALYSlS
The scheme of traditional electronic ballast with power factor
correction is shown in Fig.
3.
In this scheme the first stage
is
used
as power factor corrector in order to fulfill the standards about
power factor and total harmonic distortion and to obtain a regulated
DC bus voltage. The second one is a high frequency inverter plus a
resonant tank for lamp starting and stabilization during steady-state
operation.
In
this case the second stage is composed by
a
half-
bridge inverter plus a LCC resonant tank.
1
HIDLAMP
T
AC
*Ti
STAGE
pFc
LINE
-I--
I
I
Fig
3.
Half-Bridge Inverter
as
an
Electronic Ballast for HID Lamps.
The analysis is based on the use of the fundamental
approximation technique
[7]
and considering that the HID lamp may
be modeled as a large resistance before ionization and small
resistance (RL) after ionization. If the lamp power is maintained
constant the resistance value remains constant during steady state
operation. The simplified circuit is shown in Fig.
4,
in which the
inverter is represented by the fundamental voltage (Va) applied to
the LC tank, the HID lamp
is
RL
and Rp represents all parasitic
inverter resistances. Xce and Req are series impedances and are
RI,
’
Xc
R,.Xc2
R,’
+
Xc’
R,’
+Xc’
given by
Xce
=
and Req
=
respectively.
For the analysis, all variables express the maximum value
of
the
waveform that each one represents.
XL
XCS
Va
f--YqqRL
vaf--+T2
J
a)
b)
XL
XCS
XCE
C)
Fig
4.
a). LCC Filter,
b).
Pre-Ignition Stage,
c).
Steady-Sate Stage
11.1.
LCC
Resonant Tank Analysis
for
a Single Switching Frequency and
Maximum
Gain Voltage.
The equivalent circuits for pre-starting and steady state phases
are shown in Fig. 4. Before the lamp ignites, it may be modeled as a
large resistance (open circuit), after the ignition the lamp is modeled
as a nominal lamp resistance (RL). Before the ignition (Fig. 4b):
--
VOIOM=
XCP
Va
JRp’
+
(XL
-
Xcs
-
Xcp)’
From
(1)
the gain voltage will reach their maximum value only if
the next condition is satisfied:
XL
-
xcs
-
xcp
=
0
It means that the circuit operates in resonance during the pre-
starting stage in order to obtain a maximum gain voltage.
For the steady state operation (Fig. 4.c) the HID lamp behaves as
a resistance. Assuming a
100%
efficiency and considering that all
reactive elements do not dissipate energy and the Rp effect
is
negligible, all energy
is
dissipated in Req. From power definition:
P,
=-
VX’
(3)
2Req
From Fig. 4.c, we obtain:
Va
Re
4
,/Re
qz
+
(XL
-
Xcs
-
Xce)’
vx
=
Replacing (4) in (3):
Vu
’
2p,.
(XL
-
Xcs
-
Xce)’
=
-Re
q
-
Re
q2
Replacing the maximum gain voltage condition
(2)
in
(5):
(Xcp
-
Xce)’
=
-Re
Vu
’
q
-
Re
q’
2PL
(4)
Replacing Req and Xce expressions in
(6)
and solving for Xcp,
we obtain:
(7)
where:
V, is the maximum value of the fundamental voltage applied to
the resonant tank.
VL
is the
rms
lamp voltage.
PL
is the lamp power.
From quality factor definition for the circuit in Fig 4c:
XL
=
Q
Re
q
;
and the Xcs value is obtained from the maximum
gain voltage condition, it means:
Xcs
=
XL
-
Xcp
.
Due
to Xcs value must be higher than zero implies
that
(Xes
=
XL
-
Xcp
>
0)
.
Replacing
(7)
and the quality factor
definition in the maximum gain voltage condition
(2)
we obtain:
2VL2
+v,’
JZVLVO
(8)
This expression determines the minimum value necessary to
satisfy Xcs>O and must also be satisfied in order to maintain a LCC
resonant tank configuration for maximum gain voltage operation.
For design purposes, the filter quality factor value must be high
enough to obtain sinusoidal current.
Replacing
(2)
and
(7)
in
(1)
gives the maximum gain voltage
expression for the pre-starting stage:
(9)
The maximum starting voltage applied to the lamp is specified by
the next expression:
115
II.2
LCC
Resonant Tank Analysis for Turn On and Turn OfSat Zero Current
Switching.
The objective of the analysis for turn on and
turn
off at zero
current switching is to achieve the current and voltage applied to the
LCC resonant tank are in phase during steady state stage. The pre-
starting stage analysis (Fig. 4b) is exactly the same as the analysis
for maximum gain voltage, due to this, the gain voltage during pre-
starting stage is determined by
(1).
Similarly to case of maximum gain voltage, the
HID
lamp
behavior is a resistance for the analysis in steady state operation
(Fig. 4c). Assuming a
100%
efficiency and considering that all
reactive elements do not dissipate energy and the Rp effect is not
significant, all energy is dissipated in Req. From power definition
(3)
and obtaining Vx fi-om Fig. 4c, expression
(4)
is again obtained.
In order to achieve turn-on and turn-off at zero current switching
during steady state operation, next condition must be satisfied:
XL
-
Xcs
-
Xce
=
0
(1 1)
It means that the circuit should be operated in resonance during
steady state. Replacing
(1
1)
in (4) we obtain:
Vx
=
Vu
(12)
Replacing
(12)
in
(3)
we obtain:
1
Re
q
=
-
Vu
2PL
Replacing Req expression in
(13)
and solving for Xcp, w,e obtain:
Va
V,
'
xcp
=
(14)
P,
Jm
Xcp will be a real value only if next condition is satisfied:
vu
<Jz
V,
(15)
It means that the fundamental voltage applied to the tank must be
lower than the lamp peak voltage.
From quality factor definition for the circuit in fig 4c:
XL
=
Q
Re
q
;
the Xcs value is obtained from replacing the quality
factor definition in the zero current switching condition
(1
l), it
means:
Xcs
=
Q
Re
q
-
Xce
and:
Due to Xcs value must be higher than zero, this implies that
J~v,'
-
vu2
vu
This expression determines the minimum value necessary in order
to satisfy Xcs
>
0
and must be satisfied in order to maintain an LCC
resonant tank configuration for a turn on and turn
off
at zero current
switching operation. For design purposes, the filter quality factor
must be high enough to obtain a sinusoidal current.
In order to achieve turn on and turn off at zero current switching
and starting the lamp with a unique switching frequency
is
necessary
to satisfy both conditions: maximum gain voltage
(2)
and
turn
on
and turn
off
at
ZCS
(1 1).
In order to fulfill these conditions, it is
necessary that
Xcp
=
Xce
.
It means
Xcp
=
0
and it is not a
solution, since it is not possible to achieve turn on and turn off at
ZCS
and starting the lamp with the same switching frequency. The
circuit requires
two
frequencies: the first one for the lamp starting
and the second one for the steady-state operation. Starting
frequency is determined by:
7
Fstarting
=
Fs
-
dz
where
Fstarting is lamp ignition frequency,
Fs
is the steady sate operation frequency.
111
LC
RESONANT
TANK ANALYSIS: A PARTICULAR CASE OF LCC FILTER
LC resonant tank is a particular case of the LCC filter and it is
obtained when Xcs
=
0.
The LC filter diagram and the equivalent
circuits for the pre-starting and steady-state stages are shown in Fig.
5.
In this case the Req and Xce expressions are exactly the same as
those in the LCC resonant tank.
Va
BRL
vaf.,
a)
b)
XL
XCE
Va
r-T2
4-J
C)
Fig
5.
a).
LC Filter,
b).
Pre-ignition
Stage,
c). Steady
Sate Stage
III.I
LC
Resonant Tank Anal-vsis for a Single Switching Frequency and
Maximum
Gain Voltage.
When Xcs
=
0
from (1) the expression for the maximum gain
voltage for the LC resonant tank is obtained:
(19)
--
VO-M=
XCP
Vu
JRp2 +(XL-xcp)*
The gain voltage will reach their maximum value only if the next
condition is satisfied:
XL
-xcp
=
0
(20)
It
means that the circuit operates in resonance during the steady
state in order to obtain a maximum gain voltage.
The analysis in steady sate is exactly the same as that performed
for the LCC filter. From
(5)
and considering that Xcs=O for the LC
resonant tank, we obtain:
Vu
(XL
-
Xce)'
=
-Re
q
-
Re
q2
24
Replacing the maximum gain voltage condition
(20)
for the LC
filter in
(21)
we obtain again
(6),
for this reason the Xcp expression
is exactly the same for LCC and LC resonant tanks.
From quality factor definition for the circuit in fig 5c:
XL
=
Q
Re
q
;
and replacing it in the maximum gain voltage
condition for the LC filter, we obtain:
Expression
(22)
means that in a LC filter the quality factor is
determined by the fundamental voltage applied to the tank and by
116
the rms lamp voltage. Q is a fixed value and it can not change once
the rms voltage applied to the tank and the rms lamp voltage are
established.
The expressions for the maximum gain voltage and the maximum
starting voltage are exactly the same than expressions
(9)
and (10)
respectively. It must be noted that there is a quantitative difference
due to the parasitic resistance of the Cs in the LCC filter, but the
qualitative expressions are exactly the same. If we consider that the
Cs resistance parasitic effect is negligible, then the maximum gain
voltage and the maximum starting voltage applied to the lamp are
the same for both resonant tanks.
III.2
LC
Resonant Tank AnaLvsis for Turn On and Turn OjJat Zero Current
Switching.
Like in the LCC resonant tank case, the objective in the analysis
for
turn
on
and
turn
off at zero current switching is to achieve that
the current and voltage applied to the LCC resonant tank are in
phase during steady-state stage. Considering the LCC analysis and
taking into account that Xcs
=
0,
from (4) we obtain:
vu
Re
4
vx
=
,/Req2
+(XC-Xce)’
For the LC resonant tank, the
turn
on
and
turn
off at ZCS
condition for the steady state is:
XL-Xce=O
(24)
Replacing this condition in (23) we obtain the same results as
those in the LCC resonant tank, this is, the fundamental voltage
applied to the tank must be lower than the rms lamp voltage.
R
Due to Xcs
=
0,
from obtain
Q
=
L
or:
XCP
J2VLZ
-vu*
vu
Expression
(25)
means that the quality factor of the LC resonant
tank
is
a fixed value and it is determined by the fundamental voltage
and
by
the rms lamp voltage. Unlike the case of the LCC filter, Q is
a fixed value when the Va and VL values are given.
Alike the LCC filter case, in order to achieve
turn
on and
turn
off
at ZCS and to start the lamp with the same switching frequency, it is
necessary to satisfy both conditions: maximum gain voltage
(20)
and
turn
on and
turn
off
conditions (24). Due to this
Xcp
=
Xce
,
and
this condition
is
satisfied only when Xcp
=O.
It is not
a
solution and
is not possible to achieve
turn
on and
turn
off at ZCS and starting
the lamp with the same switching frequency. For these reason, like
in the LCC resonant filter, the circuit requires two frequencies: the
first one for the lamp starting and the second one for the steady state
operation. The expressions for the voltage gain, the starting voltage
applied to the lamp and the starting frequency are exactly the same
as those in the LCC resonant tank.
IV.
LC AND LCC FILTERS: A COMPARATIVE ANALYSIS.
LCC and LC filter expressions for maximum gain voltage
operation are resumed in Table
I.
The quality factor for both
resonant tanks depends only on the fundamental voltage applied to
the tank and by the rms lamp voltage. According to
(8)
and
(20)
the
maximum gain voltage and the maximum starting voltage applied to
the lamp (for both resonant tanks) do not depend on the filter quality
factor, but the filter parasitic resistance has a big influence on these
parameters. The maximum gain voltage and maximum starting-
voltage applied to the lamp expressions are exactly the same for
both resonant tanks; however, it must be noted that LCC filter has an
extra element (Cs) and, as a consequence, the parasitic elements in
the LCC filter are higher than the LC filter and then, the starting
voltage applied to the lamp is lower than LC filter depending de Cs
parasitic resistance.
When the LC and LCC filters are designed for
turn
on and
tum
off at ZCS for the steady state, the fundamental voltage value must
be lower than the peak lamp voltage. According to Table I1 the
quality factor for both filters depends only on the lamp voltage and
on the fundamental voltage applied to the tank. Alike the case of
maximum gain voltage, there is a minimum quality factor value for
the LCC filter determined by (1 7).
In the LC filter the quality factor is a fixed value and it can not be
selected arbitrarily because it is automatic determined when the
fundamental voltage and the lamp are selected. But in the LCC
filter case the quality factor must satisfy expression (17), but once it
is satisfied, it can be selected according to the designer criteria. It
is
possible due to the Cs presence and for instance, the LCC filter is a
more flexible structure than the LC resonant tank.
IV.1
Parasitic Resistance ERect
on
LC
and
LCC
Filters Performance
Quality factor, maximum gain voltage and maximum starting-
voltage lamp curves for the LCC filter are shown in the figures 6 to
8
for the Metal Halide Lamps CDM-T Family of 35, 70 and 150
Watts.
LCC filter curves can be applied to the LC filter, according to the
results of the previous sections, the LC filter is a particular case of
the LCC resonant tank. Only must be noted that all considerations
mentioned before (about quality factor and parasitic resistance)
should be keeping in mind in order to make a correct interpretation
of the characteristics.
V.
LCC RESONANT
TANK
DESING PROCEDURE
FOR
A SINGLE SWITCHING
FREQUENCY
AND
MAXIMUM
GAIN
VOLTAGE
The fundamental voltage (Va)
is
determined by the inverter
topology and by the supply voltage. For example, for a
full
bridge
inverter the fundamental voltage is
Vu
=
-
,
and for a half
bridge inverter is
Vu
=
-
.
The design parameters are: the
fundamental voltage (Va) applied to the tank, the
rms
lamp voltage
(VL), the lamp power
(PL),
the switching frequency (Fs), the lamp
equivalent resistance (RL) and the parasitic resistance (Rp). The
LCC resonant tank design procedure for the maximum gain voltage
condition
is:
4
vcc
x
2vcc
x
1
.-
Xcp value is determined by (6).
2.- Once Xcp is known, the minimum quality factor value is
obtained from expression
(8)
and it should be high enough to
have a sinusoidal filter current.
3.- XL and Xcs values are obtained from the quality factor
definition (Fig 4.c) and the maximum gain voltage condition
for the LCC tank respectively.
For the LC resonant tank, the procedure is exactly the same as that
for the LCC resonant tank case, but it must be noted that filter
quality factor
is
a fixed value and is determined by the rms voltage
lamp and the fundamental voltage applied to the resonant tank. LCC
resonant tank design procedure for
turn
on
and turn off at ZCS is
very similar but the correspondent expressions should be used.
As an example, for an electronic ballast for a CDM-R 70W lamp
(PL=~OW, VL=90V), with a LCC resonant tank and a full bridge
inverter supplied by 360 Vdc (Va=458.3V), a switching frequency
of 23 kHz and Rp=lO we obtain: Cp=16.7nF, Cs=163.5nF,
L1=3.16mH, M,,=41.38, V,%=18.967 V and Q=4.25.
117
TABLE
II
EXPRESSIONS FOR LCC
AND
LC FILTERS FOR TURN ON AND TURN OFF AT
ZCS
SWITCHING
LCC
FILTER
200
300
400
500
FUNDAh4l3TAL
VOLTAGE Va
Fundamental Voltage
vs
Quality
Factor
(Rp=lO)
Fig. 6. LCC Filter Quality
Factor
Curves.
LCC-FILWB
100
.
200
300
400
500
600
FUNDAMENTAL
VOLTAGE Va
Fundamental Voltage
vs
Gain Voltage (Rp=lO)
Fig.
7.
LCC Filter Gain Voltage Curves.
In the case of using a LC filter for the same lamp, with a full
bridge inverter supplied by 360 Vdc (Va=458.3 V), a switching
frequency of 22 kHz. and Rp=lO we obtain: Cp=17.48nF,
L1=2.99m, M,,,=41.38, V,,bg=14,896 V and Q=3.86.
60000
50000
9
40000
U
3
30000
U
20000
i
VI
10000
nt
7-
L.
.
..
..
.
.I..
..
,
.
..
.,I
200 300
400
500
600
FUNLlAMENTAL
VOLTAGE Va
Fundamental Voltage
vs
Srarting
Voltage
(Rp=lO)
Fig.
8.
LCC Filter Starting Voltage Curves
Starting lamp voltage for the LCC filter is shown in Fig
9
just
after the lamp ignites. The LCC resonant tank can generates almost
20
kV
for
the lamp ignition with Rp=lO.
As
mentioned before, the
starting voltage depends strongly of the filter parasitic elements.
Starting lamp voltage
for
the LC resonant tank is presented in Fig
10. The starting voltage like in the LCC filter case, is almost
20
kV
too. In both cases, the starting voltage is too high. However, in the
practice this voltage is not applied to the lamp due to high value.
The switching frequency is slightly greater than the resonant
frequency in order
to
avoid damage in the ballast components.
LCC
filter simulations
for
turn on and turn off at ZCS are shown
in Fig 1
1.
In this case, due to the circuit restrictions the fundamental
voltage applied to the tank must be lower than the lamp peak
voltage. For this reason the resonant tank only generates 1.4 KV for
the lamp ignition, and it
is
possible that this voltage is not high
enough to ignite the lamp.
Experimental results are presented in Fig 12. The LCC resonant
tank voltage and current lamp waveforms for steady state are shown
in Fig 12a. The Fig 12b shows the current and voltage waveforms
in the LC resonant tank, as can be seen they are very similar to the
LCC waveforms.
For
the turn on and turn
off
LCC resonant
tank
case we had problems during the lamp starting due to the starting
voltage was not high enough to ignite the lamp. The lamp was
VI. EXPERIMENTAL RESULTS
118
replaced by an equivalent resistance in order to verify the circuit
performance. The current and voltage waveforms applied to the
LCC resonant tank for turn on and turn off transitions for the steady
state are shown in 12c.
-*l-.x..xl”“Ix..-
__”.”^”
”,”,,
...^lll”-l.~”l,
_-,-,,
....
,...
Fig 9 LCC Resonant tank Starting Voltage
w-
-
.-
*h
*I
*-
x1
-_
-
?si.
ia
s
‘#(I
1
II
1,
Fig
IO
LC Resonant tank Starting Voltage
1
.”-
.-
Fig
I
I.
Staning voltage LCC resonant
tank
simulations for turn on and turn
off
at ZCS
VII. CONCLUSIONS
In this paper a comparative analysis for the LCC and LC resonant
tanks was performed. This analysis
shown
that it is possible to
operate the LCC and LC resonant tanks with a single switching
frequency in order to simplify the control circuit.
Also,
when the
LCC and LC resonant tanks are designed to operate in maximum
gain voltage conditions, the maximum gain voltage and the starting
voltage applied to the lamp are very similar for both resonant tanks
and the difference is caused by the parasitic resistance of Cs
capacitor. Particularly, the addition
of
Cs
allows to select the
quality factor in a LCC resonant tank, making this structure more
flexible for design purposes. Finally, it is possible to achieve turn
on and turn off at Zero Current Switching for the LCC and LC
resonant tanks. The operation conditions limit the filter capacity to
generate enough starting voltage to ignite the lamp; a first stage that
generates the appropriated input inverter voltage in order to satisfy
the
ZCS
operation conditions is also necessary. The maximum gain
voltage and the turn on and turn off design procedures were
experimentally validated in this paper.
REFERENCES
[I] J. Alonso, M. Rico et al.
“A Novel Low-Loss Clamped-Mode LCC Resonant
Inverter
for
HID
Lamp Supply”.
IEEE
APEC’95 Proceedings, pp. 736-742.
Tex
IQ
OMS/$
2627
Aql
t-e
t
i
MI
Mean
712mvv
c3
RMS
961mV
C4
RMS
744mV
c4
keg
22.883~~~
Unstable
hislogram
I
I
Ch3 500mVQ
BW
50QmVQ
Mathl
I
OOVV
loops
a) LCC remnant tank for maximum gam voltage
CH3 Lamp Current
0
5A/DiV, CH4 Lamp Voltage SOV/Div,
MIOOPS
U141
124V7sep2OQO
IO
00
59
Mathl CH3
*
CH4 100W/Div
t----l
r
4-
RkmS
OOMSls
221
Acqs
t
I
I
..
I
MI
man
720mVV
c3
RMS
97OmV
c4
RMS
747mv
c4
mq
~Z.IIESLHZ
Unstable
halognm
I
I
MI00111
Ch4f
I4OV 23(+~g2000
11
0447
Ch3 500mVQ Ch4
5OQmVQ
I
OOVV
10
0115
bl LC resonant tank
for
maximum
em
voltaee
CH3 Lamp Current OSADiv, CH4 Lamp’Voltage <OV/Div,
Mathl CH3
*
CH4 I00WDiv
m
c) Turn on and turn
off
LCC Filter at ZCS
CH3 Lamp Current
0
5A/DiV, CH4 Lamp Voltage SOViDiv,
Fig 12 Experimental Results
[2] C Moo,
C
Lee et al
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Nelms, T Jones and M Cosby
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Topologies for HPS Lamp Ballasts”
IAS’93 Meeting, Conference Records 1993,
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[4] A Bhat and C Weiqun “Analysis, Selection, and Design
of
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S
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M
,
A
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1
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119
