Journal of Robotics, Networking and Artificial Life
Vol. 8(4); March (2022), pp. 269–272
DOI: https://doi.org/10.2991/jrnal.k.211108.008; ISSN 2405-9021; eISSN 2352-6386
https://www.atlantis-press.com/journals/jrnal

Research Article

Study on Evaluating the EMI Filter for Electronic
Communication Fans
Ching-Chun Chuang1,*, Chih-Chiang Hua2, Chung-Wen Hung2, Chun-Jen Yao3
Department of Computer Science and Information Engineering, National Formosa University, No. 63, Wunhua Rd.,
Huwei Township, Yunlin 632, Taiwan (R.O.C)
2
Department of Electrical Engineering, National Yunlin University of Science and Technology, No. 123, University Rd.,
Section 3, Douliu, Yunlin 64002, Taiwan (R.O.C)
3
Department of Electronics and Computer Engineering, National Taiwan University of Science and Technology, No. 43, Section 3,Keelung Rd., Taipei City 106, Taiwan (R.O.C)
1

ARTICLE INFOABSTRACT

Article History

An electronically commutated fan has a complex digital control mode compared to the conventional alternating current fans.
Since a serious electromagnetic compatibility situation occurs in the electronic commutation fan system, the filter circuit andmechanical design of a fan system are very important. A digital control strategy for a fan was designed to reduce the componentof the electromagnetic interference filter, therefore the suppression of conducted and radiated electromagnetic interference will
be achieved in the proposed fan system. Moreover, the proposed fan integrates the mechanical design to solve the problems ofradiated electromagnetic interference. A single-phase Brushless DC Electric Motor (BLDC) driver is designed and constructed.
Finally, the electromagnetic interference that occurred in the proposed fan is analyzed and the suppression strategy is provided.
The experiment verification for the electronically commutated fan is presented.

Received 30 October 2020
Accepted 14 September 2021
Keywords
Electronically commutated fanelectromagnetic compatibility
digital control strategy© 2021 The Authors. Published by Atlantis Press International B.V.
This is an open access article distributed under the CC BY-NC 4.0 license (http://creativecommons.org/licenses/by-nc/4.0/).

1. INTRODUCTION
The electronic communication fan combines the frequency conversion function, and the power transistors for frequency modulation toachieve speed control. Because of the higher speed, the motor output
efficiency is improved. The Single-Phase BLDC motor system isdriven by an AC power supply. A DC motor is used for this system,so the friction loss is reduced. The advantages of AC and DC fans are
combined to improve the efficiency and life of the electronic commutation fan. Figure 1 shows the circuit topology of a commercial
electronic commutation fan. Several switch devices were switched athigh speed, and the voltage and current are changed at the same time.
The result not only causes more serious electromagnetic interference
problems [1,2] but also affects the electromagnetic tolerance of theinternal controller. Therefore, the production design has to be considered for passing relevant electromagnetic compatibility certification.

2. EMI STANDARD FOR ELECTRONICCOMMUNICATION SYSTEM
Generally speaking, the tests of electromagnetic compatibility are
divided into two types: Electromagnetic Interference (EMI) andelectromagnetic susceptibility [3,4]. The EMI testing refers to measure of the intensity of conductive interference and radiant interference while the electronics device is normally operated during
the testing procedure. The purpose of electromagnetic interference
Corresponding author. Email: austincc@nfu.edu.tw*suppression design is to reduce the intensity of noise generated by
the electronics device under testing, and it was not to affect otherelectronic products in the test environment. On the contrary, thepurpose of electromagnetic tolerance is to prevent the device under
test (DUT) from being interfered with by other electronic productsin the environment during operations.
There are international standards for the electromagnetic interference law of electronic communication fans, which can refer to theEuropean regulations EN 55011, the United States FCC PART 18,
and the domestic CNS 13803. Among them, there are two different
limit values of class A and B according to the type of this product,
which is either commercial or residential households. However, theproduct analysis in this paper will be used in information products since Europe is the main market. So, the information products
for European standards will be adopted. Class B electromagnetic
interference standards in EN55022, EN55022, and EN55011 are thesame as for Class B electromagnetic interference test standards.

3. EMI SUPPRESSION AND ANALYSIS
OF ELECTRONIC COMMUNICATIONSYSTEM
3.1. Conduction EMI Measurement
To measure the noise values of the live wire (Line, L) andthe neutral wire (Neutral, N) after a connection of the270

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to add an EMI filter to the power line [5]. However, it can be seenthat a multi-stage filter with grounding is required to have a wider
suppression range from Figure 2. In this paper, the space of theDUT is limited, and there is no ground wire architecture. The input
EMI filter architecture of the electronic commutation fan systems isshow in Figure 6. The differential mode inductance is 100 µH, theX capacitor is 0.1 µF, and the common-mode inductance is 20 mH.
Figure 1 | Single-phase BLDC motor driver schematic diagram.

With the advantage of digital control, Spread Spectrum [6–9] isadded to suppress the interference problem caused by the main
operating frequency.
æ N ´ d ´ fc öAttenuation = 10 log ç÷fmèø
where N is the harmonic number
δ is spread spectrum
fc is switching frequency
fm is frequency modulation

Figure 2 | EMI testing of L phase conductivity.

Figure 4 | The vertical polarity test of radiation EMI.

Figure 3 | EMI testing of N phase conductivity.

line impedance stabilization network (LISN). The measured
results are shown in Figures 2 and 3. Observing the two figures, it
can be seen that the test value without any filter and other countermeasures far exceeds the standard limit value.

3.2. Radiation EMI Measurement
According to the above section, the noise measurement of the EUT
was received through the antenna under two different polarities, vertical and polar. The actual test diagrams are shown in Figures 4 and 5. It
can also be seen that the noise radiated through space is very serious.

Figure 5 | The horizontal polarity test of radiation EMI.

3.3. The Suppression Strategy for
Conduction EMI and Radiation EMI
3.3.1. A strategy of conduction EMI
Conducted EMI is mainly used to measure the noise transmitted by
the power line through LISN, so the main suppression method isFigure 6 | Input EMI filter structure.

(1)

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271

Figures 7 and 8 show the actual test patterns after adding the input
EMI filter and other countermeasures to the EUT internal circuit.

3.3.2. A strategy of radiation EMI
To solve the radiation problem between the circuit output and themotor, an output EMI filter design is required for the electroniccommutation fan systems. The common-mode inductance is 0.95 mH
and the X capacitor is 4700 pF. Both the useful safety certified components, as shown in Figure 9.
The proposed EUT has two types, namely plastic fan blades andmetal fan blades. Among them, the series of metal fan blades havethe most serious radiated EMI problem. The noise generated by thedrive motor will provide a path to the metal fan blade through themetal shaft, which results in a serious antenna effect. Therefore,
an insulating part will be added to the mechanism part, as shownin Figure 10, which not only saves the cost of motor manufacturing but also solves the problem of radiated EMI. Figures 11 and 12
show the actual test patterns after EUT suppression.

Figure 10 | A strategy for motor shaft and mechanism insulation design.

Figure 11 | The vertical polarity test of radiation EMI after the suppression.

Figure 7 | EMI testing of L phase conductivity after the suppression.

Figure 12 | The horizontal polarity test of radiation EMI after thesuppression.

4. CONCLUSION

Figure 8 | EMI testing of N phase conductivity after the suppression.

This paper has proposed an electronic commutation fan to perform the practical electromagnetic interference certification process for the EUT. The suppression of conductive EMI and radiate
EMI was discussed, and a digital control system was designed toreduce the EMI filter components in this research. Meanwhile,
the proposed system combines the proper mechanism to solve theproblem of serious radiated EMI caused by the system operating
without grounding. This method can not only be applied for thisproduct, but also other relative products producing a similar effect.
The saving of time and cost will be implemented after a successful
certification of the subsequent relative products.

CONFLICTS OF INTEREST
Figure 9 | Output EMI filter structure.

The authors declare they have no conflicts of interest.

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272

ACKNOWLEDGMENTS[4]

The research described in this paper was supported by the Ministryof Science and Technology, the Republic of China (Grant. No.
109-2221-E-150-041-MY3). The authors are indebted to the people
at Computer Science and Information Engineering, The National
Taiwan University of Science and Technology, for their help in providing the research data of the instrument equipment.

[5]
[6]

[7]

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AUTHORS INTRODUCTION
Asst. Prof. Ching-Chun Chuang
He received a PhD degree in Electronics
Engineering from the National Taiwan
University of Science and Technology, Taiwan,
in 2013. Since 2017, he has been an Associate
Professor at Computer Science and Information
Engineering, Formosa University, Taiwan. His
research interests include Power Electronics, Digital Control,
IoT Applications, and Robot Applications.

Prof. Chung-Wen HungHe received the PhD degree in ElectricalEngineering from National Taiwan Universityin 2006. Currently, he is a Professor in National
Yunlin University of Science & Technology.
His research interests include IoT, IIoT, PowerElectronics, Motor Control, and AI Application.

Dr. Chun-Jen Yao
Prof. Chih-Chiang Hua
He (S’91–M’92) received the B.S. degree inElectrical Engineering from National Cheng
Kung University, Tainan, Taiwan, in 1984,
and the M.S. and PhD degrees in ElectricalEngineering from the University of Missouri,Columbia, MO, USA, in 1990 and 1992,
respectively. Since 1992, he has been with the National Yunlin
University of Science and Technology, Douliou, Taiwan, where
he is currently a Professor at the Department of ElectricalEngineering. His research interests include Power Electronics
Converters, Uninterruptible Power Supplies, and Photovoltaic/
Wind Energy Systems. He is a member of the IEEE PowerElectronics and the IEEE Industrial Electronics Societies.

He (1980) received a PhD degree inElectronics Engineering from the National
Taiwan University of Science and Technology,
Taiwan, in 2010. Since 2017, he has been a
Postdoctoral Research Fellow at Electronics
Engineering, National Taiwan University ofScience and Technology, Taiwan. His research interests include
Electromagnetic Compatibility, Power Electronics and Digital
Control.