สวิตชิ่งเพาเวอรซัพพลายแรงดันสูง 2 kVdc กําลังไฟฟาต่าํ สําหรับแทงโอโซน
A LOW-POWER HIGH VOLTAGE 2 kVdc DC SWITCHING POWER SUPPLY
FOR OZONE TUBE
ศิศีโรตม เกตุแกว1
Siseerot Ketkaew1
1
Faculty of Engineering, Ramkhamhaeng University (RU), Bangkok 10240, Thailand.
E-mail : siseerot@eng.ru.ac.th, Fax: (662)310-8579
บทคัดยอ: บทความนี้นําเสนอสวิตชิ่งเพาเวอรซัพพลายแรงดันสูงความถี่สูงกําลังไฟฟาต่ํา สําหรับแทงผลิตกาซโอโซน
โดยใชหลักการของวงจรฟลายแบคคอนเวอรเตอรแบบเพิ่มระดับแรงดันไฟฟา โดยใชไอซี TL494 ควบคุมการทํางาน
ของอุปกรณสวิตชิ่ง โดยออกแบบวงจรฟลายแบคคอนเวอรเตอรใหทํางานที่ความถี่ 40 kHz ผานหมอแปลงฟลายแบคค
วามถี่สูง เพื่อใหไดไฟฟากระแสตรงแรงดันสูง 2 kVdc และประยุกตใชกับอิเล็กโตรดแบบไมสม่าํ เสมอสูงในเครื่องผลิต
โอโซน โดยออกแบบใหทํางาน 1 ชั่วโมง และสามารถผลิตโอโซนไดสูงสุด 30 mgO3/hr
Abstract: This paper presents a low-power high frequency high voltage DC switching
power supply for ozone tube. The high voltage generating circuit is based on a flyback
converter. The converter was designed to operate at 40 kHz switching frequency through a
high frequency flyback transformer, a rectifier and filter circuits. The circuit is capable of
producing up to 2 kVdc. By adapting the highly nonuniform electric field to the electrode
design of the ozone generator, one-hour operating yields the maximum ozone generating
capacity of 30 mgO3/hr.
Introduction : Nowadays, ozone gas is widely brought to use for living such as using
ozone to clean the vegetables instead of manganese to kill diseases and reduce a quantity of
chlorine in water. Bringing ozone to clean the air purely has some drawbacks. For
examples, if it is used too much concentrated, it can irritate to the body. It is useful to the
health if quantity is properly used and is applied for work suitably. Therefore, to control the
quantity of ozone gas should be matched with the work. This is the reason why to study and
generate ozone gas. This paper presents a study of the effect of high frequency high voltage
DC switching power supply to the ozone quantity. The high voltage high frequency is
constructed using a principle of switching DC power supply. A high voltage high frequency
is supplied to the load, which are two-layer ozone tube in series, for producing ozone gas.
The generating ozone gas is based on the principle of spreading molecules of oxygen. It
will produce ozone gas from the equation of O2 + O = O3. The ozone gas can withstand a
high voltage level. Also, the heat affects to the quantity of the occurring ozone gas.
Therefore, the quantity of voltage and the suitable frequency have to be controlled to
generate ozone gas.
Methodology: Design of converter, The following components were selected and designed
corresponding to load testing requirements. The system specifications are as follows:
Rated load voltage = 2 kVdc
Rated load frequency = 40 kHz
Rated dc link voltage = 155 V
AC mains supply
= 110 V, 50 Hz, 1 φ
Ripple of dc link voltage ⟨ 10 %
Efficiency ⟩ 70 %
High Frequency Switching Transformer : Specifications for design : Ein = Input voltage (V)
= 155 V, Eout = Output voltage (V) = 2 kVdc, f = Switching frequency (kHz) = 40 kHz,
τm / T = Maximum duty (%) = 40 %, (∆ Bmax )Changing width of magnetic flux density
=140 mT.
High Frequency High Voltage (HF-HV) DC switching power supply : The HF-HV DC
switching power supply is controlled by IC # TL494 [5] as shown in scheme 2. from IC #
TL494 , switching devices, IGBT #MGW14N140D, are used in the flyback converter
controlled by the PWM strategy from IC #TL494. The switching frequency is 40 kHz. The
energy from converter can transfer through a HF-HV transformer to produce DC HF-HV
supplying the ozone tube.
Scheme 1 Block diagram of ozone generator
Scheme 2 A high frequency and high voltage switching power supply
Results, Discussion, and Conclusion: From the experiment, the controlling circuit has
been adjusted the switching frequency at 40 kHz , Vout = 2 kVdc and the maximum ozone
generating capacity of 30 mgO3/hr as table I. From the experimenting of ozone generator
with high voltage high frequency power supply is able to help to generate the plenty of
ozone. The ozone gas quantity, which ozone gas generator produces, can be applied for
solving the environmental problems and used widely.
Table I : The relationship between the parameter electrical and ozone quantity
frequency
(kHz)
40
Vin(rms)
(V)
10
(a)
Iin(rms)
(A)
0.62
Pin
(W)
55.2
PF
0.81
Vout
(kVdc)
2
(b)
Ozone quantity
(mgO3 /hr)
30
(c)
Scheme 3 (a) Waveform of VGS , (b)Waveform of output voltage 2 kVdc and (c) Voltage
divider for high voltage measurment
(a)
(b)
Scheme 5 (a) Ozone tube and (b) The chemical element in testing and equipment set which
used in the testing
Acknowledgement: Thanks the Department of environment, faculty of engineering,
Ramkhamhaeng University for helping to advise and Department of power electrical
engineering, Mahanakorn University of Technology for giving convenience in using
equipments and instruments for the experiment.
References:
(1) Ned Mohan, Tore M. Undeland, and William P. Robbins, (1989) Power Electronics,
John Wiley & Sons. INC.
(2) kuff, E. and Zaengl W.S., (1984) High Voltage Engineering Fundamental. Pergamon
Press Oxford. 1st ed.
(3) ST.Louis, (1989) High Frequency Switching Power Supply. McGraw-Hill.
(4) T. Sutiworrapan et al, , (2004) A study design and construction of high frequency high
voltage inverter for electrode. Thesis in Department of Electrical Engineering, Faculty of
Engineering. Mahanakorn University of Technology. Thailand.
(5) TL 494 Data sheet, (2002) Pulse-width-modulation control circuits. Texas instruments.
1-10.
Keyword : switching, flyback converter, ozone tube, high voltage, high frequency