2012 IEEE International Power Engineering and Optimization Conference (PEOCO2012), Melaka, Malaysia: 6-7 June 2012
The Reduction of Total Harmonic Distortion and Electromagnetic Interference in High Pressure Sodium Street Lighting using Single Stage Electronic Ballast M.H.Omar, H.Abdul Rahman, M.S.Majid, M.Y. Hassan, N.Rosmin
However, EMI increases with frequency. EMI is a disturbance due to electromagnetic radiation that emitted from external source. One of the solutions to remove the noise is by adding a passive EMI filter [3]. The function of passive electronic devices is to suppress conducted interference found in a signal. EMI is another problem that needs to be considered, since EMI will cause the circuit to become unstable and short lifetime. The effect of EMI to the electrical system can be overcome by using EMI filter. A step to remove this EMI is placed the universal EMI filter and the comparison between circuit without EMI and with EMI filter is presented. Power quality is the relative frequency and severity of deviations in the incoming power supplied to electrical equipment from the customer at steady sinusoidal waveforms of voltage and current. To allow power system drives their loads, the power quality level must be satisfied and follow the required standard. This is because, with poor power quality, both electrical device and the load may experience failure, damage, data crashes, error or malfunction. The problem of power quality is generally caused by several factors, such as surge, spike, sag, noise and outage [4]. Harmonic analysis is performed to determine if harmonics voltage and current are at acceptable level. The aims are to avoid damage due to excessive harmonic current in circuit, to ensure sensitive electronic equipment will not malfunction due to excessive harmonic voltage and satisfies the utility’s voltage and current harmonic distortion requirements. According to the standard ANSI C82.11, electronic ballast should have the rated value of THD of 20 %, 15 %, 10 % or less than 10 % compared to the magnetic ballast (rated THD of 20% -28 %) [5]. The paper is organized in the following manner. The description of the adopted electronic ballast for 250W high pressure sodium lamp is presented in chapter II. In chapter II also describe the flow process for manufacture of electronic ballast. An analysis of designing that includes the electromagnetic interference, power factor correction and inverter and ignition stage in section III. The simulation results for performance (i) with and without EMI filter, (ii) the half bridge and (iii) the full bridge in section IV and followed by conclusion in section V.
Abstract –This paper presents the design of single stage electronic ballast for a conventional 250W High Pressure Sodium (HPS) street lighting. Historically the HPS street lighting operating hours is from sunset to dawn which is 12 hours in full brightness. The existing conventional street lighting HPS are powered by magnetic ballasts. The magnetic ballast is a device which consists of coil and core. It is an uncontrolled device, not energy efficient and generate flicker before it can give steady light. The use of electronic ballast provides a rapid start and energy efficient but will create electromagnetic interference and harmonic. This will reduce the circuit performance. To overcome the problems, the single stage design electronic ballast is used for the HPS lamp. The effect of the electromagnetic interference (EMI) and harmonic to the designed system is assessed. This is performed in three different stages; (i) with and without EMI filter, (ii) the half-bridge and (iii) the full-bridge inverter. For stage (ii) and (iii), the comparison of harmonic produced in electronic ballast was evaluated. The operating frequency for electronic ballast is 68 kHz. The findings show that the Total Harmonic Distortion current (THDi) of 5.55% for full bridge inverter compared to the half bridge inverter with THDi of 8.73%. A reduction of 36% of THD is obtained when full bridge inverter is applied. The current waveform result indicates a reduction of 25% without EMI filter from the original waveform. The reduction of both EMI and THDi can give benefit to street lighting system and energy efficiency. Index Terms – Electronic ballast, harmonic, HPS lamp, electromagnetic interference
I.
INTRODUCTION
T
he high-pressure sodium (HPS) lamp was developed since the last decades to be able to supply in high frequency (HF) condition. The development of technology in electronic ballast using HPS lamp in HF is to improve its lifetime, power efficiency, color and to reduce the ballast weight and size. However, at high frequency operation, some problem might be occurred such as electromagnetic interference and power quality issue. The power quality of the installed street lighting system needs to be maintained at the highest quality level. This can be assured when the THDi of the lighting system is at the minimum level. The high frequency electronic ballast consists of EMI filter, power factor corrector, high-frequency DC/AC inverter, and control circuit. Electronic ballast is able to control the power output and has higher efficiency since it uses the power semiconductor devices with better switching method. The normal frequency applied for a conventional street lighting is either 50 Hz or 60 Hz, while for the electronic ballast, it is operated at a frequency greater than 20kHz [1], [2].
II.
The electronic ballast circuit for HPS lamp is divided into four parts as shown in Fig. 1. It consists of EMI filter, a full-bridge rectifier, a full-bridge inverter and resonant load.
Supply
The authors wish to acknowledge the Ministry of Higher Education (MOHE) under Research Universiti Grant, Universiti Teknologi Malaysia, Vote No: Q.J130000.7123.00J60 for the financial funding of this project M.H.Omar, H.Abdul Rahman, M.S.Majid, M.Y. Hassan, N.Rosmin are with Centre of Electrical Energy Systems (CEES), Faculty of Electrical Engineering, Universiti Teknologi Malaysia, Johor Bahru, Malaysia. (e-mail:
[email protected],
[email protected],
[email protected],
[email protected] and
[email protected].
978-1-4673-0662-1/12/$31.00 ©2012 IEEE
THE STRUCTURE OF ELECTRONIC BALLAST
EMI Filter
Resonant Load
Inverter Lamp
Figure 1: Flow of electronic ballast
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Rectifier and Power Factor
2012 IEEE International Power Engineering and Optimization Conference (PEOCO2012), Melaka, Malaysia: 6-7 June 2012
The power supply has to be connected to universal EMI filter that consist inductance and capacitance devices. Major sources of EMI and RFI are basically those works that involve using microprocessors, switching power supplies, AC motors, and electric power cords. The effects of EMI occur are from two main factors, namely, natural or manmade, which will results in degradation or malfunction of electronic or electrical equipment. Third stage is the conversion of AC supply to DC Supply by using rectifier which combined with power factor correction. In an electric power system, a load with a low PF produces more current than a load with a high power factor for the same amount of power transferred. The higher currents increase the energy lost in the distribution system, and require larger wires.
(2)
(3)
√
(
)
(4)
(
The calculation of CF is as shown in Equation (1).
III.
)
(5)
THE ELECTRONIC BALLAST DESIGN
(1) (
A. Electromagnetic Inference
)
In the fast growing electronic technology, the used of variety of the embedded system leads to the potential problem to environment, one of them is electromagnetic interference. EMI occurs in devices that transmit and distribute process, or use any form of electrical energy in any ways to generate operations or radiate the signals such as radio. This would cause deterioration of the equipment performance. Studied by [6], [7], [8] adopted filter to reduce EMI in electronic circuits, whereas [9], [10] did not implementing any filter design to overcome the EMI. Radio Frequency Interference (RFI) occurs in the specific transmitted range of radio frequency. The power supply has to be connected nearer to the device to avoid EMI or RFI. Besides, the used of an inductor (L) and capacitor (C) in Z-parameter the undesired conducted electromagnetic interference will be removed.
The next step is the conversion system from DC to AC. An Inverter used is the metal–oxide–semiconductor field-effect transistor (MOSFET) which is controlled by PWM circuit. The resonant load which is a filter is applied before input to the lamp. Equation (2) is used to calculate the value of resistance in HPS lamp for 250W and the two parameters that include in resonant load are a series inductor and parallel capacitor. Equation (3) is applied to determine the computation of Q, quality factor which will be used to calculate inductor, LS. Meanwhile, (4) and (5) were used to calculate the values of inductor, LS and capacitor, CP in resonant load circuit respectively.
Figure 3: The design of the electronic ballast
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2012 IEEE International Power Engineering and Optimization Conference (PEOCO2012), Melaka, Malaysia: 6-7 June 2012
Fig. 2 shows the universal EMI filter which will be used in the electronic ballast design. Due to this electromagnetic interference, the effective performance of this circuit will be also reduced. In the design of a low pass filter, the EMI filter is the combination of shunting capacitors and series inductors. This is to restrict or blocked the flow of high frequency signals. It is done by connecting to ground. The function of the EMI is to reduce and attenuate the unnecessary signal strength, and having minimal effect on other components or devices.
Figure 4: Parallel LC filter Other type of inverters studied is the full bridge and the half bridge. The authors [8], [9], [10], [13] studied the full bridge inverter in the design of electronic ballast to convert DC to AC power. Meanwhile, [6], [14] used the half bridge in electronic ballast design. The authors do not taking into consideration the problems of harmonic even in full bridge or half bridge inverter The comparison between the two inverters will determined the value harmonic in electronic ballast circuit. The full bridge inverter applied in the circuit design is to reduce total harmonic distortion level. The criteria to be considered for HPS lamp is the voltage rated and it is specify in the manufacturer datasheet. For example, a 250W HPS lamp, the voltage rated is 100VRMS with the rated power of 250W. Assuming if the resistance is presence, it can be calculated using (2).
Figure 2: Circuit of EMI filter
The specification of components EMI filter shown in Table 1. Table 1: Parameter of universal EMI components
Parameter
Value
C1 & C2
330 nF
C3 & C4
2200 nF
L1 & L2
The ratio between the switching frequency and the resonance frequency is 3. The value of resonant load is calculated, based on the lamp ignition. In the conventional ballast a typical ignition peak voltage (VCP) is 4kV, meanwhile for electronic ballast, the ignition peak voltage is 7kV [15]. Equation 3 is used to calculate the value of quality factor, Q. It is used to determine the value of inductor, L as in (4). The frequency used in this circuit is 68 kHz.
1µH
(
B. Rectifier and Power Factor Correction The second part of electronic ballast design is the rectifier that converts the AC power to DC power [11]. The uncontrolled diode was used in the rectifier conversion stage. It also consist the passive power factor corrector stage where the value of calculated capacitor CF will will increase the power factor (70% - 80%). Based on (1), the value of capacitor in passive power factor, where, f=50 Hz Ripple=0.0321R=40 Ω.
(
)
(
)
Equation (5) states the relation between the switching frequency and inductor over the capacitor CP. Frequency in CP three times bigger than switching frequency.
)
( C.
)
Inverter and Ignition Stage
Fig. 3 shows the complete circuit design of electronic ballast, whereas Fig. 4 shows the circuit for parallel LC load. There are three types of filter used to smooth (reduce) the fluctuating waveform to become sinusoidal waveform at the fundamental frequency by filtering out the higher harmonic frequency. The filters are series LC, series parallel LCC and parallel LC. The parallel LC filter which is a low pass filter is used in this study due to this filter easy incorporating with ballast to ignite the lamp. This parallel LC is suitable choice to use in resonant tank [12].
D. Total Harmonic Distortion Another factor that discussed in this work is electrical system is harmonic distortion. To discuss the harmonics distortion issues, it is common to refer to the THDi term. Lower value of THDi meant that more accurate production in the power system operation. THDi is defined as the ratio of sum of powers of the entire
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2012 IEEE International Power Engineering and Optimization Conference (PEOCO2012), Melaka, Malaysia: 6-7 June 2012
harmonic to the power of the fundamental frequency. The effect of THDi can be calculated by using (6a). However, in power system, THDi calculation is mostly expressed as in (6b). (6a) ∑
IV.
(6b)
SIMULATION RESULTS
The first result shows the comparison of circuit with and without EMI filter, while the second result is when the system contains half bridge and full bridge inverter. The result for voltage, V and current, I using conventional and electronic ballast was presented. The design of electronic ballast with PWM controller has been accomplished and the circuit configuration of the simulation system is based on circuit in Fig. 3. The parameters and the component specifications for simulation are indicated in part III. EMI circuit was placed between supply and rectifier. Fig. 5(a) and Fig. 5(b) show the current waveform of the input inverter with and without EMI filter respectively to the proposed lighting system. The current flows out from EMI filter for electronic ballast is smoother (refer Fig. 5(a)) compared to without EMI filter (refer Fig. 5(b)). Waveform with EMI filter has the perfect sinusoidal waveform. In contrast to the circuit without EMI filter, the circuit performance is lowered due to the noises and disturbances in the electronic ballast. It can be observed that the losses approximately 25% from the original value occurred during the conduction.
Figure 5(b): Current waveform without EMI filter
The results of the THD for the half-bridge and full-bridge inverter circuits are shown in Fig. 6 and 7. Based on (6) and Figure 6 indicates that the half-bridge inverter produces 8.73% of total harmonic distortion. The lowest level of a harmonic series is 50Hz which is the fundamental frequency for voltage supply.
Fig.7: THD for Half bridge inverter Fig. 6 also shows that the magnitude of fundamental frequency is higher than the magnitude for full bridge inverter in Fig. 7. This will cause higher harmonics in the system poor circuit performance. Fig.7 shows the result of THDi when the full-bridge inverter circuit is used. The THDi value for the full-bridge circuit shows significant improvement when compared to the half-bridge circuit where the THDi value dropped to 5.55%. Compared with the results [16], an experiment of 150W HPS lamp (connected to their corresponding ballast and controller, the value of THDi that produce is 5.1-6.5% at full load and another paper stated for the line voltage 220V; the THDi is 7.1% for 70W HID lamp [17]. In this paper, for the 250W HPS lamp and 220V line voltage, the result show and THDi are 5.55%, respectively. Table 2 tabulates the comparison of THDi for this paper and two references.
Figure 5(a): Current waveform with EMI filter
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2012 IEEE International Power Engineering and Optimization Conference (PEOCO2012), Melaka, Malaysia: 6-7 June 2012
results prior to the harmonic assessment in both half bridge and full bridge inverter indicate that using the full bridge inverter reduces the total harmonic distortion to 39.5% compare with half bridge inverter. Circuit without EMI filter distorts the waveform 25% from the original value occurred during the conduction. The current waveform with EMI filters more stable. Hence, single stage electronic ballast with a full bridge inverter and EMI circuit is recommended in the design. For future work, the hardware will implements and the comparison between software and hardware will be evaluated. VI.
The authors wish to acknowledge the Ministry of Higher Education (MOHE) under Research Universiti Grant, Universiti Teknologi Malaysia, Vote No: Q.J130000.7123.00J60 for the financial funding of this project
Fig.7: THD for full bridge inverter TABLE 2 COMPARISON OF THDI Line Voltage
Lamp
THDi
Single Stage of Electronic Ballast
220V
250W
5.55%
Reference 1 [15]
220V
150W
5.1-6.5%
Reference2 [16]
220V
70W
7.1%
VII. [1]
REFERENCES
Emanuel, A.E.; Peretto, L. "The response of fluorescent lamp with magnetic ballast to voltage distortion," Power Delivery, IEEE Transactions on , vol.12, no.1, pp.289-295, Jan 1997doi: 10.1109/61.568252 [2] Chung, H.S.-H.; Ngai-Man Ho; Wei Yan; PokWai Tam; Hui, S.Y.; , "Comparison of Dimmable Electromagnetic and Electronic Ballast Systems— An Assessment on Energy Efficiency and Lifetime," Industrial Electronics, IEEE Transactions on , vol.54, no.6, pp.3145-3154, Dec. 2007 [3] Jiang, Yan; Lee, Fred C.; Wyk, J. D. van; Wyk, J. D. van; Liang, Yan; Liu, Wenduo; , "An Integrated Electronic Ballast for High Intensity Discharge (HID) Lamps," Integrated Power Systems (CIPS), 2008 5th International Conference on , vol., no., pp.1-6, 11-13 March 2008 [4] http://www.aps.com/main/_files/services/BusWaysToSave/ Power .pdf [5] Cassel, J. “Total Harmonic Distortion (THD): A Lesson for Lighting System”. Senior Specification Engineer [6] Hankui Liu, Yijie Wang, Xiangjun Zhang, DianguoXuM, LiliGuo "Dimmable Electronic Ballast for 250W HPS Lamp in Street Lighting with Analog Dimming Interface Circuit" 2007 IEEE, page:259-262 [7] Bor-Ren Lin; Yuen-Chou Hsieh; , "Dimming control of metal halide lamp with high power factor," Industrial Electronics, 1999. ISIE '99. Proceedings of the IEEE International Symposium on , vol.2, no., pp.590-595 vol.2, 1999 [8] Wakabayashi, F.T.; Canesin, C.A.; , "Electronic ballast for multiple fluorescent lamp systems," Electric Power Applications, IET , vol.1, no.1, pp.49-58, January 2007 [9] Huang, Y.-T.; Chen, S.-T.; Lee, C.-R.; Li, H.-J.; Lee, L.-L, "Designs and Implementation of the Dimmable Electronic Ballast for Metal-Halide Lamps," Industrial Electronics Society, 2007. IECON 2007. 33rd Annual Conference of the IEEE , vol., no., pp.1352-1356, 5-8 Nov. 2007 [10] Ichirou Terayama, Yoshihisa UMEZAWA, Tomokazu OOSATO and Yoshitaka ENMOTSU: “Dimmable Electronic Ballast for High Wattage Halide Lamp”, J. Light & Vis. Env., Vol. 34, No. 1, pp.42-46 (2010) [11] R. A. Gupta, RohitAgarwal, Hanuman Soni and Mahankali Ajay “Design And Simulation of Single stage High PF Electronic ballast with boost topology for multiple Fluorescent lamps” International Journal of Recent Trends in Engineering, Vol 2, No. 5, November 2009 [12] Shen, Eric Bertrand (1997) “Alternative topological approaches to the electronic lamp ballast” Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science [13] Miao sen Shen; Zhaoming Qian; Fang Zheng Peng; , "Design of a two-stage low-frequency square-wave electronic ballast for HID lamps," Industry Applications, IEEE Transactions on , vol.39, no.2, pp. 424- 430, Mar/Apr 2003 [14] Labo Chhun; Maussion, P.; Bhosle, S.; Zissis, G. "Characterization of Acoustic Resonance in a High-Pressure Sodium Lamp," Industry Applications, IEEE Transactions on , vol.47, no.2, pp.1071-1076, MarchApril 2011 [15] F. Dos Reis, R. Tonkoski Jr., G. B. Maizonave, L. C. Lorenzoni, U. Sarmanho,G. B. Ceccon, F. B. Libano, V. Canalli and J. C. M. Lima “Full Bridge Single Stage Electronic Ballast for a 250 W High Pressure Sodium Lamp” [16] Manzano, E.R., Carlorosi, M., Tapia Garzon, M. “Performance and measurement of power quality due to harmonics from street lighting networks”: 2009 International Conference on Renewable Energies and Power Quality (ICREPQ’09). [17] Chien-Ming Huang; Tsorng-Juu Liang; Ray-Lee Lin; Jiann-Fuh Chen; , "A Novel Constant Power Control Circuit for HID Electronic Ballast," Power Electronics, IEEE Transactions on , vol.22, no.5, pp.1573-1582, Sept. 2007
The Fig. 8(a), 8(b) shows lamp voltage Vlamp and lamp current ilamp waveforms of 250W HPS lamp, respectively. Based on the 100% brightness of lamp, the output voltage is 150V and the output current is 4A under operating frequency 68 kHz.
Figure 8(a): Lamp voltage (Vlamp)
Figure 8(b): Lamp current (ilamp)
V.
ACKNOWLEDGEMENT
CONCLUSION
The design of electronic ballast for 250W high pressure sodium lamp is presented. The study of an EMI characteristic in this paper is to identify the appropriate current waveform to instability and cause short lifetime in circuit. The addition of an EMI filters circuit to prevent electromagnetic interference and thus can increase the efficiency of electronic ballast is also discussed. The
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2012 IEEE International Power Engineering and Optimization Conference (PEOCO2012), Melaka, Malaysia: 6-7 June 2012
VIII. BIOGRAPHIES M. H. Omar received his B.SC degree in electrical and electronic from Universiti Teknologi Malaysia in 2011. Currently, he is pursuing M.SC at Centre of Electrical Energy System (CEES), UTM. His research interest is in energy efficiency technology and micro-controller application.
H. Abdul Rahman received her B.Sc. in Electrical and Electronics Engineering from University of Aberdeen, UK in 1989, and M.Sc in Energy Studies from University of Wales College of Cardiff, UK in 1996. Currently she is a Senior Lecturer in the Faculty of Electrical Engineering; University Teknologi Malaysia. Her research interest includes renewable energy technology, energy efficiency, demand side management and its environmental impact. Her specialize area of research is on solar photovoltaic. She is a member of IEEE. M. S. Majid received his B.Sc degree in Electrical and Electronic Engineering from University of Strathclyde in 1980 and M.Sc. in Power System Analysis from University of Manchester Institute Science and Technology, United Kingdom in 1985. Currently he is an Associate Professor in the Faculty of Electrical Engineering, Universiti Teknologi Malaysia. His research interest include energy efficiency, demand side management and its environmental impact, application of control schemes to power system, renewable energy and power system economics. He is currently involves in building energy audit and as a consultant of energy auditing. He is also a member of IEEE. Mohammad Y. Hassan received his B.Eng. in Electrical and Electronics Engineering from Strathclyde University, UK in 1988, and M.E.E. from Universiti Teknologi Malaysia (UTM) in 1993 and PhD from Strathclyde University, UK in 2004. Dr. Mohammad Yusri is an Associate Professor and deputy director of centre of electrical energy system (CEES) in the Faculty of Electrical Engineering at UTM, Johor, Malaysia. His research interest is in power system economics, transmission pricing and energy management. He is currently appointed as faculty energy manager and as a consultant for energy auditing He is also a member of IEEE.
N. Rosmin is currently lecturer in the faculty of electrical engineering, Universiti Teknologi Malaysia and research associate at Centre of Electrical Energy System (CEES). Her research interest is in renewable energy such as wind, solar, tidal, biomass and etc. Currently, she is pursuing her PHD at Loughborough University.
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