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Design and implementation
of a high-voltage high-frequency pulse
power generation system for plasma applications
M. T. Tsai
C. W. Ke
Department of Electrical Engineering
Southern Taiwan University
Tainan, TAIWAN. R.O.C. 710
I-Introduction
IV Experimental result
Arc discharge: this is a high power thermal discharge of very high
temperature ~10,000 K. It can be generated using various power supplies. It is
commonly used in metallurgical processes.
Corona discharge: this is a non-thermal discharge generated by the
application of high voltage to sharp electrode tips. It is commonly used in
ozone generators and particle precipitators.
Dielectric barrier discharge (DBD): this is a non-thermal discharge
generated by the application of high voltages ( a range of about 20-100 kHz,
0-2.4 kV peak) across small gaps wherein a non-conducting coating prevents
the transition of the plasma discharge into an arc. It is often mislabeled
'Corona' discharge in industry and has similar application to corona
discharges. It is also widely used in the web treatment of fabrics.
Capacitive discharge: this is a non-thermal discharge generated by the
application of RF power (e.g., 13.56 MHz) to one powered electrode, with a
grounded electrode held at a small separation distance on the order of 1 cm.
Such discharges are commonly stabilized using a noble gas such as Helium or
Argon.
L
ig
Iin
D
(400V/div)
V AB
iR
VAB
iR
(10A/div)
(400V/div)
iR
(10A/div)
(10A/div)
Vs
(5kV/div)
(10uS/div)
(400V/div)
VAB
Vs
Vs
(5kV/div)
II-System configuration
(10uS/div)
(5kV/div)
(10us/div)
(b)
(a)
(c)
Fig. 5. The experimental results of PWM control at 40 kHz switching
frequency.
PIC OUT
iL
3895 PWM
DQA
+
Vin
_
AC
CH1-20A CH2-200V M-5ms/div
Fig. 4. The source voltage and current
Vg
Q
CO
RL
+
Vdc
DQC
QC
CQA
QA
PDM
CQC
NP : NS
+
VAB
Vdc
LR
QB
+
Lm
VP
-
DQB
CQB
QD
Period
Ton
Period
C
PIC OUT
g
+
Vs
-
VZ
CH1
3895 PWM
VDS
C
DQD
PDM
d
CQD
Period
Ton
2
IR2110
Driver
Period
Toff
T
PIC OUT
CH2
1
K
Toff
T
iR
-
VGS
1
RS
3895 PWM
IR2110
Driver
PDM
Fig. 6. ZVS switching case for the inverter
PDM/PWM
Select logic
UC3895
PWM controller
PIC16F877
controller
Fig. 1(b). Inverter stage control structure.
III-Control circuit
PDM control signals
PIC 輸出信號
CK
UCC 3895
Fig. 1(a). PFC stage control structure.
QA
Q
D
PIC Out Signal
OUTA 輸出信號
A組 Q
A
B
C
D
D
The inverter has five stages, determined by the power switching elements of
the two legs. The stages in which two diagonally opposite power switches are
conducting are called active. On the contrary, the stages in which two
switches on the same site of power switches are conducting are called passive.
The switching of the leg can moves the inverter from active stage to passive
stage is called the leading leg (QC，QD). The other leg which switches only
from passive stage to active is called the trailing leg (QAQB).
QB
Q
QC
CK
B組 Q
Q A 驅動信號
Q D驅動信號
QD
PDM implementation
VAB
VAB ( 400V/ div)
( 400V/ div)
iR
Vab
CQA
CQC
QC
+
VIN
A
NP : NS
+
Vs
(5kV/ div)
VZ
-
DQD
CQB QD
Cd
CQD
QA
QB
( 100us/div)
(400V/div)
QD
t0
t1 t 2
t3 t 4
t5
t
Fig.2. The switching relationship of the power elements and the corresponding
inverter output voltage and current.
The PAM controls the inverter input voltage by controlling the PFC
stage output voltage to achieve the adjusting inverter output power.
The PWM controls the pulse width of the inverter output voltage by
shifting the phase difference of the control phase with respect to the
standard phase to adjust the output power.
The PFM controls the frequency of the inverter output voltage to
achieve the adjustable output power.
The PDM controls the output power by controlling the number of
inverter output voltage pulses.
(a)
(b)
(c)
Fig. 3. PSIM based simulation for plasma reactor characteristic, (a) plasma
reactor input voltage and gas discharger, (b) gas discharge voltage verse
charger, (c) plasma reactor input voltage verse charger.
VAB
iR
(10A/div)
( 100 us/ div)
(400V/div)
(10A/div)
Vs
(5kV/div)

(5 kV/ div)
iR
Vs

Vs
VAB
Power control strategies

(10 A/ div)
(b)
(a)
Fig. 7. The corresponding waveforms for PDM control
QC

iR
iR
Cg
VP
DQB
QB
(10A/ div)
Vab
iR
LR
V AB
B
iR
DQC
DQA
QA
(10us/div)
Fig. 8. PFM control for 50 kHz
switching frequency.
V- Conclusion
(5kV/div)
(10us/div)
Fig. 9. PFM control for 40 kHz
switching frequency.
As the experimental results, some conclusions can be made as follows:
The only PAM control is not encouraged as it needs a complicated front
stage to achieve voltage regulation function, and is hardly used to less that
half of the full range due to the required gas breakdown voltage level
The PWM control can fulfill the full load range conditions. However, a
small pulse width tends to a discontinuous load current or leading load current,
which is adverse to the switching loss, thus it is disapproved for a low pulse
width control.
The only PFM control is also not encouraged as it should be large than the
load resonant frequency to realize zero voltage switching. Thus, one can see
that the inverter power fact should decline in low power range, and it is
difficult to adjust the discharge power to less than half of the full power as the
electrodes voltage would be lower than the gas discharge breakdown voltage.
The PDM can work well over a range of pulse densities from 3/30 to 1,
however, the environment temperature fluctuations should disturb the stability
of the inverter output power. To compensate this influence, a hybrid control
such as PDM plus PFM or PDM plus PWM is suggested.