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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of Electrical Engineering and Technology
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Journal DOI :
The Korean Institute of Electrical Engineers
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Volume & Issues
Volume 7, Issue 6 - Nov 2012
Volume 7, Issue 5 - Sep 2012
Volume 7, Issue 4 - Jul 2012
Volume 7, Issue 3 - May 2012
Volume 7, Issue 2 - Mar 2012
Volume 7, Issue 1 - Jan 2012
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Repeated Clustering to Improve the Discrimination of Typical Daily Load Profile
Kim, Young-Il ; Ko, Jong-Min ; Song, Jae-Ju ; Choi, Hoon ;
Journal of Electrical Engineering and Technology, volume 7, issue 3, 2012, Pages 281~287
DOI : 10.5370/JEET.2012.7.3.281
The customer load profile clustering method is used to make the TDLP (Typical Daily Load Profile) to estimate the quarter hourly load profile of non-AMR (Automatic Meter Reading) customers. This study examines how the repeated clustering method improves the ability to discriminate among the TDLPs of each cluster. The k-means algorithm is a well-known clustering technology in data mining. Repeated clustering groups the cluster into sub-clusters with the k-means algorithm and chooses the sub-cluster that has the maximum average error and repeats clustering until the final cluster count is satisfied.
Classifier System and Co-evolutionary Hybrid Approach to Restoration Service of Electric Power Distribution Networks
Filipiak, Sylwester ;
Journal of Electrical Engineering and Technology, volume 7, issue 3, 2012, Pages 288~296
DOI : 10.5370/JEET.2012.7.3.288
The method proposed by the author is intended for assistance in decision-making (concerning changes of connections) by operators of complex distribution systems during states of malfunction (particularly in the events of malfunctions, for which the consequences encompass extended parts of the network), through designation of connection action scenarios (creating substitute configurations). It is the use by the classifying system working with the co-evolution algorithm that enables the effective creation of substitute scenarios for the Medium Voltage electric power distribution network. The author also completed works concerning the possibility of using cooperation of the evolutionary algorithm and the co-evolutionary algorithm with local search algorithms. The method drawn up may be used in current systems managing the work of distribution networks to assist network operators in taking decisions concerning connection actions in supervised electric power systems.
Analysis of Transient Overvoltages within a 345kV Korean Thermal Plant
Yeo, Sang-Min ; Kim, Chul-Hwan ;
Journal of Electrical Engineering and Technology, volume 7, issue 3, 2012, Pages 297~303
DOI : 10.5370/JEET.2012.7.3.297
This paper presents the simulation results for the analysis of a lightning surge, switching transients and very fast transients within a thermal plant. The modeling of gas insulated substations (GIS) makes use of electrical equivalent circuits that are composed of lumped elements and distributed parameter lines. The system model also includes some generators, transformers, and low voltage circuits such as 24V DC rectifiers and control circuits. This paper shows the simulation results, via EMTP (Electro-Magnetic Transients Program), for three overvoltage types, such as transient overvoltages, switching transients, very fast transients and a lightning surge.
Kalman-Filter Based Static Load Modeling of Real Power System Using K-EMS Data
Lee, Soo-Hyoung ; Son, Seo-Eun ; Lee, Sung-Moo ; Cho, Jong-Man ; Song, Kyung-Bin ; Park, Jung-Wook ;
Journal of Electrical Engineering and Technology, volume 7, issue 3, 2012, Pages 304~311
DOI : 10.5370/JEET.2012.7.3.304
So far, the importance for an accurate load model has been constantly raised and its necessity would be further more emphasized. Currently used load model for analysis of power system in Korea was developed 10 years ago, which is aggregated by applying the statistically estimated load compositions to load models based on individual appliances. As modern appliances have diversified and rapidly changed, the existing load model is no longer compatible with current loads in the Korean power system. Therefore, a measurement based load model is more suitable for modern power system analysis because it can accurately include the load characteristics by directly measuring target load. This paper proposes a ZIP model employing a Kalman-filter as the estimation algorithm for the model parameters. The Kamlan-filter based parameter identification offers an advantage of fast parameter determination by removing iterative calculation. To verify the proposed load model, the four-second-interval real data from the Korea Energy Management System (K-EMS) is used.
A Study on the Hot Spot Temperature in 154kV Power Transformers
Kweon, Dong-Jin ; Koo, Kyo-Sun ; Woo, Jung-Wook ; Kwak, Joo-Sik ;
Journal of Electrical Engineering and Technology, volume 7, issue 3, 2012, Pages 312~319
DOI : 10.5370/JEET.2012.7.3.312
The life of a power transformer is dependent on the life of the cellulose paper, which influenced by the hot spot temperature. Thus, the determination of the cellulose paper's life requires identifying the hot spot temperature of the transformer. Currently, however, the power transformer uses a heat run test is used in the factory test to measure top liquid temperature rise and average winding temperature rise, which is specified in its specification. The hot spot temperature is calculated by the winding resistance detected during the heat run test. This paper measures the hot spot temperature in the single-phase, 154kV, 15/20MVA power transformer by the optical fiber sensors and compares the value with the hot spot temperature calculated by the conventional heat run test in the factory test. To measure the hot spot temperature, ten optical fiber sensors were installed on both the high and low voltage winding; and the temperature distribution during the heat run test, three thermocouples were installed. The hot spot temperature shown in the heat run test was
on the low voltage winding. However, the hot spot temperature as measured by the optical fiber sensor appeared between turn 2 and turn 3 on the upper side of the low voltage winding, recording
. The hot spot temperature of the low voltage winding as measured by the optical fiber sensor was
higher than the hot spot temperature calculated by the heat run test. Therefore, the hot spot factor (H) in IEC 60076-2 appeared to be 2.0.
The Coordinate Control Method of LTC Transformer and Capacitor Banks at Distribution Substation
Choi, Joon-Ho ; Ahn, Seon-Ju ; Nam, Hae-Kon ; Kim, Jae-Chul ; Moon, Seung-Il ; Jung, Won-Wook ; Song, Il-Keun ;
Journal of Electrical Engineering and Technology, volume 7, issue 3, 2012, Pages 320~329
DOI : 10.5370/JEET.2012.7.3.320
The Load Tap Changing (LTC) transformer and Shunt Capacitor (SC) bank are major devices for voltage and reactive power control in a distribution substation. Thus, the coordination operation of a LTC transformer and a SC bank is required to achieve better voltage and reactive power compensation at a distribution substation in the same time. This paper proposes coordinate control method of LTC transformer and SC bank to achieve better voltage and reactive power compensation and operation times of these two devices in the same time. The mathematical formulations of the proposed coordinate control method are introduced. Sample case studies are shown to verify the effectiveness of the proposed coordinate control method.
Shape Optimization of a Thomson Coil Actuator for Fast Response Using Topology Modification
Li, Wei ; Koh, Chang-Seop ;
Journal of Electrical Engineering and Technology, volume 7, issue 3, 2012, Pages 330~335
DOI : 10.5370/JEET.2012.7.3.330
The shape optimization of a Thomson coil actuator used in an arc eliminator is done for fast response by adopting topology modification method. The displacement of the plate in a fixed calculation time is taken as the objective function. The objective function and contribution factor are calculated by using an adaptive equivalent circuit method which has been proved accurate and efficient. Both shape optimization and performance analysis are accomplished based on the segmentation of plate. Through the refinement of the sensitive segments a precise optimal plate shape can be obtained. The effectiveness of the proposed method is proved by the comparison of results before and after the shape optimization.
Contribution of Maxwell Stress in Air on the Deformations of Induction Machines
Fonteyn, K.A. ; Belahcen, A. ; Rasilo, P. ; Kouhia, R. ; Arkkio, A. ;
Journal of Electrical Engineering and Technology, volume 7, issue 3, 2012, Pages 336~341
DOI : 10.5370/JEET.2012.7.3.336
Deformations in a cage-induction machine are investigated with simulations. The contribution of the Maxwell stress in the air gap and coil regions of the machine on the deformation is studied by comparing results obtained with and without inclusion of the stress into the calculation. The work attests the acceptability of an energy-based magneto-mechanical model for a 2D mesh of two different rotating electrical machines.
A New Moving-magnet Type Linear Actuator utilizing Flux Concentration Permanent Magnet Arrangement
Goto, Akira ; Okamoto, Takuya ; Ikariga, Atsushi ; Todaka, Takashi ; Enokizono, Masato ;
Journal of Electrical Engineering and Technology, volume 7, issue 3, 2012, Pages 342~348
DOI : 10.5370/JEET.2012.7.3.342
This paper presents a moving-magnet type linear actuator designed by using flux concentration type permanent magnet arrangement, which can generate higher magnetic flux density in air-gap. In this construction, detent force which is induced by both slot-effect and end-effect becomes larger due to strong attractive forces. To reduce cogging force we have employed a modular mover structure of two magnetic pole sections connected with a center yoke. The improved motor performance is demonstrated with the prototype machine.
Analysis and Application of a Hybrid Motor Structure Convenient to Modify the Magnet and Reluctance Torques on the Rotor
Beser, Esra Kandemir ; Camur, Sabri ; Arifoglu, Birol ; Beser, Ersoy ;
Journal of Electrical Engineering and Technology, volume 7, issue 3, 2012, Pages 349~357
DOI : 10.5370/JEET.2012.7.3.349
This paper presents a hybrid motor prototype convenient to modify the magnet and reluctance torques. The rotor of the prototype consists of magnet and reluctance parts, so the generated torque includes both magnet and reluctance torques. A considerable feature of the motor is that the ratio of the magnet and reluctance parts can be modified on the rotor and the rotor hybridization ratio can be varied. Another important point is the mechanical angle between the parts changed by means of the suitable construction of the parts on the rotor shaft. Finite element (FE) analysis was carried out for the proposed motor and static torque measurements were realized. The FE results were compared with the experimental results. Average torque and maximum torque values were obtained and three dimensional 3-D graphs were formed by using the experimental data. It is possible to make different combinations by changing the parts and the angle between the parts due to the proposed motor. So the magnet and reluctance torques are modified and different combinations give different torque behavior.
Third Harmonic Injection Circuit to Eliminate Electrolytic Capacitors in Light-Emitting Diode Drivers
Yoo, Jin-Wan ; Jung, Kwang-Hyun ; Jeon, In-Ung ; Park, Chong-Yeun ;
Journal of Electrical Engineering and Technology, volume 7, issue 3, 2012, Pages 358~365
DOI : 10.5370/JEET.2012.7.3.358
A new third harmonic injection circuit for light-emitting diode (LED) drivers is proposed to eliminate electrolytic capacitors and thereby extend the lifetime of LED drivers. When a third harmonic current is injected to the input current of the LED driver, the required capacitance of the driver can be reduced. The proposed circuit can control an injection ratio and has simple circuitry. The synchronous third harmonic is generated by a phase locked loop (PLL), a 1/3 counter, and op-amps and applied to a power factor correction circuit. Thus, the storage capacitor can install film capacitors instead of the electrolytic capacitor. The value of storage capacitance can be reduced to 78% compared to an input power factor of 100%. The proposed circuit is applied to the 80W prototype LED driver to experimentally verify the performances.
Design and Temporal Analysis of Hardware-in-the-loop Simulation for Testing Motor Control Unit
Choi, Chin-Chul ; Lee, Kang-Seok ; Lee, Woo-Taik ;
Journal of Electrical Engineering and Technology, volume 7, issue 3, 2012, Pages 366~375
DOI : 10.5370/JEET.2012.7.3.366
This paper describes a design and temporal analysis of a hardware-in-the-loop (HIL) simulation environment for testing a motor control unit (MCU). The design concepts and main characteristics including unavoidable time delays of each component module are described. From temporal analysis results according to the module integration method, an appropriate solution is proposed to fix and minimize time delays. In order to verify the effectiveness of the proposed solution, the HIL test results are compared with the results of experiments and an offline simulation.
Development of a New Personal Magnetic Field Exposure Estimation Method for Use in Epidemiological EMF Surveys among Children under 17 Years of Age
Yang, Kwang-Ho ; Ju, Mun-No ; Myung, Sung-Ho ; Shin, Koo-Yong ; Hwang, Gi-Hyun ; Park, June-Ho ;
Journal of Electrical Engineering and Technology, volume 7, issue 3, 2012, Pages 376~383
DOI : 10.5370/JEET.2012.7.3.376
A number of scientific researches are currently being conducted on the potential health hazards of power frequency electric and magnetic field (EMF). There exists a non-objective and psychological belief that they are harmful, although no scientific and objective proof of such exists. This possible health risk from ELF magnetic field (MF) exposure, especially for children under 17 years of age, is currently one of Korea's most highly contested social issues. Therefore, to assess the magnetic field exposure levels of those children in their general living environments, the personal MF exposure levels of 436 subjects were measured for about 6 years using government funding. Using the measured database, estimation formulas were developed to predict personal MF exposure levels. These formulas can serve as valuable tools in estimating 24-hour personal MF exposure levels without directly measuring the exposure. Three types of estimation formulas were developed by applying evolutionary computation methods such as genetic algorithm (GA) and genetic programming (GP). After tuning the database, the final three formulas with the smallest estimation error were selected, where the target estimation error was approximately 0.03
. The seven parameters of each of these three formulas are gender (G), age (A), house type (H), house size (HS), distance between the subject's residence and a power line (RD), power line voltage class (KV), and the usage conditions of electric appliances (RULE).
Determination of the Ampacity of Buried Cable in Non-Homogenous Environmental Condition by 3D Computation
Vahidi, Behrooz ; Mahmoudi, Amin ;
Journal of Electrical Engineering and Technology, volume 7, issue 3, 2012, Pages 384~388
DOI : 10.5370/JEET.2012.7.3.384
Finite Volume Method (FVM) is chosen to calculate the heat transfer field and the heat generation with in the cable and heat dissipation in the surrounding soil of a three phase 145kV underground cable brunch that make it possible to analyze the ampacity of the cable. FLUENT as the proper software in this field is used to generate and solve the problem. Non-homogenous environment is considered for cable ampacity calculation and results are compare with homogenous environment condition.
Frequency Spectrum Analysis of Electromagnetic Waves Radiated by Electric Discharges
Park, Dae-Won ; Kil, Gyung-Suk ; Cheon, Sang-Gyu ; Kim, Sun-Jae ; Cha, Hyeon-Kyu ;
Journal of Electrical Engineering and Technology, volume 7, issue 3, 2012, Pages 389~395
DOI : 10.5370/JEET.2012.7.3.389
In this paper, we analyzed the frequency spectrum of the electromagnetic waves radiated by an electric discharge as a basic study to develop an on-line diagnostic technique for power equipment installed inside closed-switchboards. In order to simulate local and series arc discharges caused by an electric field concentration and poor connections, three types of electrode systems were fabricated, consisting of needle and plane electrodes and an arc generator meeting the specifications of UL 1699. The experiment was carried out in an electromagnetic anechoic chamber, and the measurement system consisted of a PD free transformer, a loop antenna with a frequency bandwidth of 150 kHz-30 MHz, an ultra log periodic antenna with a frequency bandwidth of 30 MHz-2 GHz, and an EMI test receiver with a frequency bandwidth of 3 Hz-3 GHz. According to the experimental results, the frequency spectra of the electrical discharges were widely distributed across a range of 150 kHz-400 MHz, depending on the defects, while commonly found between 150 kHz and 10 MHz. Therefore, considering the ambient noise and antenna characteristics, the best frequency bandwidth for a measurement system to monitor abnormal conditions by detecting electromagnetic waves in closedswitchboards is 150 kHz-10 MHz.
Fabrication of Metal Nanobridge Arrays using Sacrificial Silicon Nanowire
Lee, Kook-Nyung ; Lee, Kyoung-Gun ; Jung, Suk-Won ; Lee, Min-Ho ; Seong, Woo-Kyeong ;
Journal of Electrical Engineering and Technology, volume 7, issue 3, 2012, Pages 396~400
DOI : 10.5370/JEET.2012.7.3.396
Novel fabrication method of nanobridge array of various materials was proposed using suspended silicon nanowire array as a sacrificial template structure. Nanobridges of various materials can be simply fabricated by direct deposition with thermal evaporation on the top of prefabricated suspended silicon nanobridge arrays, which are used as a sacrificial structure. Since silicon nanowire can be easily removed by selective dry etching, nanobridge arrays of an intended material are finally obtained. In this paper, metal nanobridges of Ti/Au, around 50-200 nm in thickness and width, 5-20
in length were fabricated to prove the advantages of the proposed nanowire or nanobridge fabrication method. The nanobridges of Ti/Au after complete removal of sacrificial silicon nanowire template were well-established and bending of nanobridge caused by the tensile stress was observed after silicon removing. Up to 50 nm and 10
of silicon nanowire in diameter and length respectively was also very useful for nanowire templates.
Leakage Flux Distribution in the Simulated Environment
Kim, Chung-Hyeok ; Kim, Tag-Yong ; Oh, Yong-Cheul ;
Journal of Electrical Engineering and Technology, volume 7, issue 3, 2012, Pages 401~405
DOI : 10.5370/JEET.2012.7.3.401
Current research about voltage leakage involves investigation of the effects of leaked voltage and current on humans through simulated environments and dummies. Electrocution results from leaked current when electricity flows through the body as a result of potential difference. Research that analyzes actual electrocution is insufficient because of the danger from leaked voltage present in the leakage area. This thesis analyzes magnetic flux density from current around a leak to investigate the distribution of current. The authors used a simulated environment to investigate electrocution accidents that frequently occur during floods through leakage along metal surfaces, and evaluated the distribution of leaked magnetic flux.
The Field of Power/Ground Planes influenced by the HPEM Source, and its Damage Reduction
Kahng, Sung-Tek ; Kim, Hyeong-Seok ;
Journal of Electrical Engineering and Technology, volume 7, issue 3, 2012, Pages 406~410
DOI : 10.5370/JEET.2012.7.3.406
This paper looks into the field inside the wide rectangular box structure that is excited by the High Power Electromagnetic(HPEM) source as a potential threat to electric grid and communication networks causing malfunction or destruction. The rectangular box is assumed power/ground planes and its internal field is calculated by the cavity model with the lightning strike excitation as an HPEM pulse. The accuracy of the calculation method employed here is validated through a
parallel metallic plate case which is manufactured and tested, and is applied to the size of a building. With the help of the cavity model that takes into account loading, the level of the electric field is shown to decrease when a metal pillar is loaded between the power and ground planes.
Two-Faults Detection and Isolation Using Extended Parity Space Approach
Lee, Won-Hee ; Kim, Kwang-Hoon ; Park, Chan-Gook ; Lee, Jang-Gyu ;
Journal of Electrical Engineering and Technology, volume 7, issue 3, 2012, Pages 411~419
DOI : 10.5370/JEET.2012.7.3.411
This paper proposes a new FDI(Fault Detection and Isolation) method, which is called EPSA(Extended Parity Space Approach). This method is particularly suitable for fault detection and isolation of the system with one faulty sensor or two faulty sensors. In the system with two faulty sensors, the fault detection and isolation probability may be decreased when two faults are occurred between the sensors related to the large fault direction angle. Nonetheless, the previously suggested FDI methods to treat the two-faults problem do not consider the effect of the large fault direction angle. In order to solve this problem, this paper analyzes the effect of the large fault direction angle and proposes how to increase the fault detection and isolation probability. For the increase the detection probability, this paper additionally considers the fault type that is not detected because of the cancellation of the fault biases by the large fault direction angle. Also for the increase the isolation probability, this paper suggests the additional isolation procedure in case of two-faults. EPSA helps that the user can know the exact fault situation. The proposed FDI method is verified through Monte Carlo simulation.
Intelligent Digital Redesign for Nonlinear Interconnected Systems using Decentralized Fuzzy Control
Koo, Geun-Bum ; Park, Jin-Bae ; Joo, Young-Hoon ;
Journal of Electrical Engineering and Technology, volume 7, issue 3, 2012, Pages 420~428
DOI : 10.5370/JEET.2012.7.3.420
In this paper, a novel intelligent digital redesign (IDR) technique is proposed for the nonlinear interconnected systems which can be represented by a Takagi-Sugeno (T-S) fuzzy model. The IDR technique is to convert a pre-designed analog controller into an equivalent digital one. To develop this method, the discretized models of the analog and digital closed-loop system with the decentralized controller are presented, respectively. Using these discretized models, the digital decentralized control gain is obtained to minimize the norm between the state variables of the analog and digital closed-loop systems and stabilize the digital closed-loop system. Its sufficient conditions are derived in terms of linear matrix inequalities (LMIs). Finally, a numerical example is provided to verify the effectiveness of the proposed technique.
An Approach for GPS Clock Jump Detection Using Carrier Phase Measurements in Real-Time
Heo, Youn-Jeong ; Cho, Jeong-Ho ; Heo, Moon-Beom ;
Journal of Electrical Engineering and Technology, volume 7, issue 3, 2012, Pages 429~435
DOI : 10.5370/JEET.2012.7.3.429
In this study, a real-time architecture for the detection of clock jumps in the GPS clock behavior is proposed. GPS satellite atomic clocks have characteristics of a second order polynomial in the long term showing sudden jumps occasionally. As satellite clock anomalies influence on GPS measurements which could deliver wrong position information to users as a result, it is required to develop a real time technique for the detection of the clock anomalies especially on the real-time GPS applications such as aviation. The proposed strategy is based on Teager Energy operator, which can be immediately detect any changes in the satellite clock bias estimated from GPS carrier phase measurements. The verification results under numerous cases in the presence of clock jumps are demonstrated.
Decentralized Load-Frequency Control of Large-Scale Nonlinear Power Systems: Fuzzy Overlapping Approach
Lee, Ho-Jae ; Kim, Do-Wan ;
Journal of Electrical Engineering and Technology, volume 7, issue 3, 2012, Pages 436~442
DOI : 10.5370/JEET.2012.7.3.436
This paper develops a design methodology of a decentralized fuzzy load-frequency controller for a large-scale nonlinear power system with valve position limits on governors. The concerned system is locally exactly modeled in Takagi-Sugeno's form. Sufficient design condition for uniform ultimate boundedness of the closed-loop system is derived based on the overlapping decomposition. Convergence of all incremental frequency deviations to zero is also investigated. A simulation result is provided to visualize the effectiveness of the proposed technique.
Optimized Security Algorithm for IEC 61850 based Power Utility System
Yang, Hyo-Sik ; Kim, Sang-Sig ; Jang, Hyuk-Soo ;
Journal of Electrical Engineering and Technology, volume 7, issue 3, 2012, Pages 443~450
DOI : 10.5370/JEET.2012.7.3.443
As power grids are integrated into one big umbrella (i.e., Smart Grid), communication network plays a key role in reliable and stable operation of power grids. For successful operation of smart grid, interoperability and security issues must be resolved. Security means providing network system integrity, authentication, and confidentiality service. For a cyber-attack to a power grid system, which may jeopardize the national security, vulnerability of communication infrastructure has a serious impact on the power grid network. While security aspects of power grid network have been studied much, security mechanisms are rarely adopted in power gird communication network. For security issues, strict timing requirements are defined in IEC 61850 for mission critical messages (i.e., GOOSE). In this paper, we apply security algorithms (i.e., MD-5, SHA-1, and RSA) and measure their processing time and transmission delay of secured mission critical messages. The results show the algorithms satisfying the timing requirements defined in IEC 61850 and we observer the algorithm that is optimal for secure communication of mission critical messages. Numerical analysis shows that SHA-1 is preferable for secure GOOSE message sending.
Stimulus Artifact Suppression Using the Stimulation Synchronous Adaptive Impulse Correlated Filter for Surface EMG Application
Yeom, Ho-Jun ; Park, Ho-Dong ; Chang, Young-Hui ; Park, Young-Chol ; Lee, Kyoung-Joung ;
Journal of Electrical Engineering and Technology, volume 7, issue 3, 2012, Pages 451~458
DOI : 10.5370/JEET.2012.7.3.451
The voluntary EMG (vEMG) signal from electrically stimulated muscle is very useful for feedback control in functional electrical stimulation. However, the recorded EMG signal from surface electrodes has unwanted stimulation artifact and M-wave as well as vEMG. Here, we propose an event-synchronous adaptive digital filter for the suppression of stimulation artifact and M-wave in this application. The proposed method requires a simple experimental setup that does not require extra hardware connections to obtain the reference signals of adaptive digital filter. For evaluating the efficiency of this proposed method, the filter was tested and compared with a least square (LS) algorithm using previously measured data. We conclude that the cancellation of both primary and residual stimulation artifacts is enhanced with an event-synchronous adaptive digital filter and shows promise for clinical application to rehabilitate paretic limbs. Moreover because this algorithm is far simpler than the LS algorithm, it is portable and ready for real-time application.