Measurement and Estimation of Electric FieldEmission of a Vacuum CleanerAmmar Ahmed Alkahtani, Farah Hani Nordin and Z.A.M Sharrif

Center of Signal Processing and Control System (SPaCS), College of Engineering, Universiti Tenaga Nasional,Putrajaya Campus, Jalan IKRAM-UNITEN, 43000 Kajang, Selangor, Malaysia

ammar@uniten.edu.myfarah@uniten.edu.myzainul@uniten.edu.my

Abstract—Electric field emission of electrical appliances hasbecome an important problem, especially when testing for safetyand compliance with regulations of electromagnetic compatibility(EMC). To confirm the safety and compliance of an electricalappliance, it is important to measure the levels of the emittedelectric and magnetic fields from this appliance and comparethem to the exposure limit values set by the internationalstandards. Moreover, modeling these emitted fields can aidunderstanding their characteristics and ease investigating howdifferent systems react to such emission. However, a goodmodel depends mainly on the accuracy and robustness of themeasurement methodology. Hence, the aim of this paper is topresent a measurement methodology and a frequency domainmodel for the emitted electric field of vacuum cleaners usingsystem identification tools. The proposed model is a data-drivenmodel where the recorded signal is used to construct the modelusing polynomial model estimation methods. Measurement setup,related work and the model equation are presented accordingly.

Index Terms—Electric field emission estimation, Electric fieldmeasurement, Vacuum cleaner, System identification.

I. INTRODUCTION

The rapid increase of the use of electrical appliances ineveryone’s house has posed an important question regardingthe effects that could be caused to human being as wellas with regard to the electromagnetic compatibility (EMC)issues [1]–[5]. It is important for sensitive system designers,manufactures and consumers to study the signals emitted fromthese appliances and model them for further considerationbefore the design stage. However, in order to build a reliablemodel of the electric field emission for a certain electricalappliance, it is essential to perform an accurate measurementand ensure capturing the right signal from the correspondingappliance.

A reliable measurement is a key step to study and investi-gate the characteristics of electric field emission of electricalappliances. Generally, electric field emission is capturedusing amplitude-only measurement which is performed in thefrequency domain. In frequency domain, the signal receivedby an antenna is a measure of the amplitude variation andis basically phaseless. With an accurate measurement, it iseasy to create an efficient model that predicts the electric fieldemission and help build a strong understanding of its behaviorsand mitigate it.

Modeling the electric field emission can be done in asimilar way of modeling the electromagnetic interference(EMI) and other electromagnetic fields. The model can aidunderstanding and studying the characteristics of the radiatedfields. Moreover, modeling eases investigating the immunityand susceptibility of the electrical systems with respect toelectric field emission resulted from different sources. Manyapproaches have been introduced for modeling phaseless data.Markus Johansson et al. [6] proposes a source modelingusing phaseless data which presents a good model for phaseretrieval using angle gradient functional. Song Zhenfei et al.[7] presents an identification method for the emission sourceusing Independent Component Analysis (ICA). This approachmakes use of electric field strength calculations, modulationtechniques and simulation methods to identify different noisesources. Other approximation models are proposed based onmathematical approaches such as those explained in [8], [9]and [10].

This paper presents an estimation model for the electricfield emitted from different types of vacuum cleaners whichare used in the daily life of many people. The model isconstructed based on the measured frequency domain data thatare collected from vacuum cleaner appliances.

The paper is arranged as follows: Section II presentsthe methodology and measurement setup. The results anddiscussion are presented in Section III. Finally, Section IVconcludes the paper.

II. METHODOLOGY

The following section presents the measurement setup andthe steps followed to model the electric field emission fromthe device under test (DUT).

A. Measurement Setup

Fig. 1 shows the measurement setup which is carried outin the digital signal processing laboratory, Universiti TenagaNasional (UNITEN), Malaysia. The instrument used forcapturing the electric field emission in this measurement isa Spectran device (NF5035) as shown in Fig. 2. This deviceis a handheld Spectrum Analyzer and is supported with anintegrated antenna that can be used for electric and magneticfield measurements. The antenna has a frequency range of

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Emission Source

Spectran

PC

(DUT)

Fig. 1: Measurement setup

Fig. 2: Spectran device

1 Hz to 30 MHz which allows capturing the very smallelectric field emission from different sources. To prevent otherexternal disturbances from affecting the measurement results,the measurement is taken while no other devices or appliancesare on. The Spectran is placed 2 meters away from the DUTto capture the emitted electric field emission. The followingsteps are then followed in completing the measurement:

From the graphical user interface (GUI) of the Spectrandevice, the electric field sensor is activated. After the sensoris activated, the frequency range is selected, which is 1 Hz to30 MHz. This range is proved to cover the emitted electricfield from the DUT [2]. To adjust the clarity and sensitivity ofthe measured signal, the resolution bandwidth (RBW) is setto its optimum value (30 KHz). A high value of RBW willspeed up the sweep, however, the accuracy of the measurementwill decrease. On the contrary, decreasing the value of RBWwill improve the accuracy of the measurement, however, thesweep will slow down. Hence, it is essential to choose asuitable value that helps display and record an accurate andclear signal. In this measurement, a value of 30 KHz for theRBW is used.

On the other hand, the sample-time (Ts) is selected todetermine the time per sample. Unlike RBW, a highersample-time may give more accurate and better measurement,however, this will elongate the sweep time. Differently, if

the sample-time is set to a low value, the accuracy of themeasurement will decrease. Thus, choosing the right sample-time is crucial for better measurement results. The optimumvalue of the sample-time that gives an accurate measurement ischosen to be 1 second. After selecting the RBW and sample-time, the DUT is switched on first and then the sweep of theSpectran is started. For each measurement, the electric fieldemission is captured for 3 minutes. After signal is captured, itis transferred to a PC for further analysis. The measurement isrepeated for comparison purposes and to ensure that no othersignals, except those of the DUT, are captured.

B. Modeling

Modeling is representing a system with a mathematicaldescription to describe its characteristics. Generally, thepurpose of modeling the electric field emission is to investigatethe efficiency of certain devices and predict their behaviorwhen emitting or receiving interference signals from differentsources.

After data are transferred to the computer, a preprocessingstep is performed. The imported signal is a frequency domainsignal and is used to estimate the model of electric fieldemission from the DUT. In the System Identification Toolbox,frequency domain I/O data are created using iddata objects.The data object is used as an input to the GUI to estimate thefrequency domain model.

III. RESULTS AND DISCUSSION

Even though the methodology presented in this paper can beused for other electrical appliances, the results and discussionin this paper are limited to the electric field emission fromthe vacuum cleaner appliance only. The vacuum cleaner isa motorized device and is proved to emit signals with highmagnitudes as presented in [2]. In Fig. 3, Fig. 4 and Fig. 5,the measurements are taken from 3 different vacuum cleanerslabeled as vacuum cleaner 1, vacuum cleaner 2 and vacuumcleaner 3, respectively. The signal from vacuum cleaner 1 ismodeled and validated by the measured signals from vacuumcleaners 2, and vacuum cleaner 3.

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Fig. 3: Measured electric field from vacuum cleaner 1

Fig. 4: Measured electric field from vacuum cleaner 2

Fig. 5: Measured electric field from vacuum cleaner 3

A. Proposed Model Results

The model is selected with an order an of the value 10which is the optimum order that gives the best fit. Selectingthis order is obtained through testing and evaluating differentvalues until the best fit is achieved. Table I shows selectedmodels with their respective fit. The optimum fit is reachedwhen the order is 10 where the proposed model has a fit of83.98%. This fit indicates that the model is efficient, especiallyfor non-linear and non-stationary signals. The proposed modelis expressed as a discrete transfer function in digital signalprocessing (DSP) format and is presented in Eq. (1):

A(z) = 1 + 0.3554z−1 + 0.5884z−2 + 0.4624z−3

+0.09939z−4−0.07601z−5−0.102z−6−0.2072z−7

+ 0.01592z−8 − 0.1696z−9 − 0.02014z−10

(1)

This expression represents the frequency domain model ofthe electric field emission of the vacuum cleaner. It is worthnoting that different models can be obtained for the electricfield emission of other appliances using the same method ofmodeling.

Table I: MODEL FITS OF DIFFERENT SELECTED ORDERS

Polynomial order value Maximum fit %2 36.204 61.606 71.538 73.90

10 83.9812 81.30

B. Validation

As shown in Fig. 6 and Fig. 7, validation is performed bytesting the model with two new data sets from vacuum cleaner2 and vacuum cleaner 3, respectively. The fit percentage valuefor the test signal reached 81% for the data set from vacuumcleaner 2 and 79% for the data set from vacuum cleaner

Fig. 6: Validation using test data from vacuum cleaner 2

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Fig. 7: Validation using test data from vacuum cleaner 3

3. The validation results prove that the model is valid andis capable of reproducing the electric field emission of thevacuum cleaner in different conditions.

IV. CONCLUSION

Electric field emission measurements and modeling forvacuum cleaner have been presented and a frequency domainmodel has been proposed. The validation results of the modelare accepted since the accuracy is very satisfactory. In future,both magnetic field and electric field can be studied withregard to the exposure limits and for studying the condition ofthe electrical appliances. It is also recommended to conducttime-domain measurements and estimation of the radiatedfields of electrical appliances, which may improve the modelaccuracy and reliability.

ACKNOWLEDGMENT

The authors would like to express their gratitude to theMinistry of Higher Education (MOHE), Malaysia for fundingand supporting this project.

REFERENCES

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[2] A. A. Alkahtani, F. H. Nordin, Z. Sharrif, N. B. Bte, and A. Mustafa,“Analysis on rf emission of electrical appliances,” in IEEE InternationalConference on Control System, Computing and Engineering (ICCSCE).IEEE, 2012, pp. 539–543.

[3] E. Marthe, F. Rachidi, M. Ianoz, and P. Zweiacker, “Indoor radiatedemission associated with power line communication systems,” in IEEEInternational Symposium on Electromagnetic Compatibility, vol. 1.IEEE, 2001, pp. 517–520.

[4] Q. Qi-zhong, C. Yu, F. Ting-ting, D. Li, L. Jian-chao, and H. Ling-li, “Measurement and analysis of electromagnetic radiation of 110kvhigh-voltage lines in one urban location in chongqing pr china,” in 4thInternational Conference on Bioinformatics and Biomedical Engineering(iCBBE). IEEE, 2010, pp. 1–4.

[5] N. B. A. Mustafa, F. H. Nordin, F. A. A. Ismail, A. A. Alkahtani,N. Balasubramaniam, G. C. Hock, and Z. Shariff, “Electrical field ofelectrical appliances versus distance: A preliminary analysis,” in IOPConference Series: Earth and Environmental Science, vol. 16, no. 1.IOP Publishing, 2013, p. 012097.

[6] M. Johansson, H.-S. Lui, J.-C. Bolomey, and M. Persson, “Source mod-eling using phaseless low-frequency near-field measurements,” IEEETransactions on Electromagnetic Compatibility, vol. 54, no. 3, pp. 613–624, 2012.

[7] S. Zhenfei, S. Donglin, D. Fei, F. Duval, and A. Louis, “A novelelectromagnetic radiated emission source identification methodology,”in Asia-Pacific Symposium on Electromagnetic Compatibility (APEMC).IEEE, 2010, pp. 645–648.

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[9] W.-J. Zhao, B.-F. Wang, E.-X. Liu, H.-B. Park, H. H. Park, E. Song,and E.-P. Li, “An effective and efficient approach for radiated emissionprediction based on amplitude-only near-field measurements,” IEEETransactions on Electromagnetic Compatibility, vol. 54, no. 5, pp. 1186–1189, 2012.

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