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Enohnyaket, Mathias
Publications (10 of 14) Show all publications
Enohnyaket, M., Hyyppä, K. & Delsing, J. (2011). Parameter characterization of low frequency pulsating emissions from space vector PWM drives (ed.). In: (Ed.), (Ed.), Proceedings of 2010 IEEE Vehicle Power and Propulsion Conference, VPPC 2010: Lille; 1 September 2010 - 3 September 2010. Paper presented at IEEE Vehicle Power and Propulsion Conference : 01/09/2010 - 03/09/2010. Piscataway, NJ: IEEE Communications Society
Open this publication in new window or tab >>Parameter characterization of low frequency pulsating emissions from space vector PWM drives
2011 (English)In: Proceedings of 2010 IEEE Vehicle Power and Propulsion Conference, VPPC 2010: Lille; 1 September 2010 - 3 September 2010, Piscataway, NJ: IEEE Communications Society, 2011Conference paper, Published paper (Refereed)
Abstract [en]

Power converters in hybrid electric drives constitute a major source of electromagnetic disturbances. Recent studies have established that the space vector PWM scheme commonly employed in drive systems, generates low frequency pulsating (LFP) emissions, at a frequency of 6f0, where f0 is the fundamental frequency the phase voltages. The switching of voltage vectors generates common mode current (icm) spikes due to the presence of stray capacitances and inductances. Across sector boundaries, the icm spikes superpose forming spikes of double or tipple amplitude which constitute the LFP emissions. These pulsating emissions could pose EMC issues, and functionality issues like torque pulsations and speed fluctuations that could affect the reliability of the drive. This paper investigates the effects of drive speed, load, and converter slew rates, on the amplitude of the LFP emissions, using theoretical models.

Place, publisher, year, edition, pages
Piscataway, NJ: IEEE Communications Society, 2011
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Industrial Electronics
Identifiers
urn:nbn:se:ltu:diva-27169 (URN)10.1109/VPPC.2010.5729167 (DOI)2-s2.0-79953134766 (Scopus ID)081215fc-4f30-4378-ab0b-d1e3ba6d2f16 (Local ID)978-1-4244-8220-7 (ISBN)081215fc-4f30-4378-ab0b-d1e3ba6d2f16 (Archive number)081215fc-4f30-4378-ab0b-d1e3ba6d2f16 (OAI)
Conference
IEEE Vehicle Power and Propulsion Conference : 01/09/2010 - 03/09/2010
Note
Godkänd; 2011; Bibliografisk uppgift: Article number 5729167 ; 20110426 (andbra)Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2018-07-10Bibliographically approved
Ekman, J. & Enohnyaket, M. (2011). Project: A New Method for Combined Electric and Electromagnetic Modeling of Power Distribution Systems -High frequency models for reactors. Paper presented at .
Open this publication in new window or tab >>Project: A New Method for Combined Electric and Electromagnetic Modeling of Power Distribution Systems -High frequency models for reactors
2011 (English)Other (Other (popular science, discussion, etc.))
Abstract [en]

The project has the following main objectives.(i) Detail an systematic approach for the generation of equivalent circuit descriptionsfor power components in the high frequency range. Demonstration include time-and frequency- domain analysis of free space coils.(ii) Introduce, evaluate, and develop the PEEC method for combined electric andelectromagnetic (EM) modeling of power components.(iii) Transfer of knowledge from microelectronics- to power engineering- modeling and simulation.

National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Industrial Electronics
Identifiers
urn:nbn:se:ltu:diva-36286 (URN)dd865f67-4772-40af-aaf0-579e70751da3 (Local ID)dd865f67-4772-40af-aaf0-579e70751da3 (Archive number)dd865f67-4772-40af-aaf0-579e70751da3 (OAI)
Note

Publikationer: High frequency models for air-core reactors using 3D equivalent circuit theory; PEEC models for air-core reactors modeling skin and proximity effects; Three dimensional high frequency models for air-core reactors based on partial element equivalent circuit theory; Electromagnetic fields from air-core reactors using equivalent circuit theory; PEEC modeling and verification for broadband analysis of air-core reactors; Analysis of air-core reactors from DC to very high frequencies using PEEC models; Status: Ended; Period: 19/09/2005 → 19/12/2007; End date: 19/12/2007

Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2017-11-25Bibliographically approved
Enohnyaket, M. (2010). Electromagnetic characterization of power electronic systems (ed.). (Doctoral dissertation). Paper presented at . Luleå: Luleå tekniska universitet
Open this publication in new window or tab >>Electromagnetic characterization of power electronic systems
2010 (English)Doctoral thesis, comprehensive summary (Other academic)
Alternative title[sv]
Electromagentic characterization of power electronic systems
Abstract [en]

Propelled by increased global awareness and demand for clean energy systems, there is a growing trend in transportation, utility, industrial, and residential applications towards the utilisation of power electronic systems with enhanced power ow controllability and eciency. Examples of power electronics applications include terminal converters in high-voltage direct Current (HVDC) transmission; exible AC transmission systems (FACTS); and converters to interface alternative energy systems such as wind turbines to the grid, variable-speed motor drives in pump systems, vehicular propulsion systems, air-conditioners, and refrigerators.The basic functionality of power electronic components is achieved by switching high voltages and currents. Recent advancements in semiconductor technology have significantly improved the current and voltage handling capabilities and the switching frequencies of power electronic devices. However, this rapid switching of high currents and voltages in turn generates electromagnetic disturbances that could distort the functionality of the power electronic equipment and other devices in the vicinity. Electromagnetic compatibility (EMC) regulations and functionality requirements impose restrictions on the design of power electronic systems. To design robust power electronic systems, a thorough understanding of the related electromagnetic issues is required.This thesis focuses on the EMC characterisation of power electronic systems and contains two major phases.In the first phase, the high frequency characterisation of air-core reactors was considered. Air-core reactors are typically used in power systems for current limiting, ltering, shunting, and neutral grounding applications. It is of interest to understand the behaviour of air-core reactors in the presence of high frequency signals, especially from switching operations in the power electronic components. Using the partial element equivalent circuit (PEEC) approach, air-core reactor models, helpful in design and electromagnetic analysis, were created. The PEEC models were able to predict the current and voltage distributions and the eventual electromagnetic emissions at different frequencies. The second phase involved the characterisation of electromagnetic emissions from PWM drives using both modeling and measurement. A case study was performed on a prototype hybrid electric vehicle (HEV). Typically, emissions from PWM drives are expected at harmonics of the PWM switching frequency (fc) and harmonics of the fundamental frequency (f0) of the phase voltages. In this study, it was established that space vector PWM drives generate low-frequency pulsating (LFP) emissions at a frequency of 6f0. The switching of voltage vectors generates common mode current spikes because of the presence of stray capacitances and inductances. The spikes superpose across sector boundaries, forming spikes of double or triple amplitude that constitute the LFP emissions. The amplitudes of these ulsations were shown to be dependent on the drive parameters, such as the load, the speed, and the voltage slew rates. These common mode emissions enhance the emissions at harmonics of the switching frequency, create low-frequency emissions, and when injected into an electric motor, could cause torque pulsations and speed uctuations that may degrade drive functionality. Measurements from an HEV prototype show the LFP emissions, and theoretical models were developed to characterise them.

Place, publisher, year, edition, pages
Luleå: Luleå tekniska universitet, 2010. p. 198
Series
Doctoral thesis / Luleå University of Technology 1 jan 1997 → …, ISSN 1402-1544
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Industrial Electronics
Identifiers
urn:nbn:se:ltu:diva-17800 (URN)5485a410-b09e-11df-a707-000ea68e967b (Local ID)978-91-7439-130-5 (ISBN)5485a410-b09e-11df-a707-000ea68e967b (Archive number)5485a410-b09e-11df-a707-000ea68e967b (OAI)
Projects
EM Karaktärisering och Modellering av Elektriska Hybriddrivsystem
Note

Godkänd; 2010; 20100826 (mathen); DISPUTATION Ämnesområde: Industriell elektronik/Industrial Electronics Opponent: Professor Mats Alaküla, Lund University and Volvo Car AB Ordförande: Professor Jerker Delsing, Luleå tekniska universitet Tid: Torsdag den 30 september 2010, kl 09.30 Plats: A1514 Demostudion, Luleå tekniska universitet

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2017-12-20Bibliographically approved
Enohnyaket, M. & Ekman, J. (2009). Analysis of air-core reactors from DC to very high frequencies using PEEC models (ed.). Paper presented at . IEEE Transactions on Power Delivery, 24(2), 719-729
Open this publication in new window or tab >>Analysis of air-core reactors from DC to very high frequencies using PEEC models
2009 (English)In: IEEE Transactions on Power Delivery, ISSN 0885-8977, E-ISSN 1937-4208, Vol. 24, no 2, p. 719-729Article in journal (Refereed) Published
Abstract [en]

Faced with the challenges of increasing operational frequencies and switching rates of modern power electronics devices used in power systems, there is need for high frequency models (up to a few megahertz) for power components like reactors, capacitors banks and transformers. This paper presents the application of PEEC theory forthe creation of high frequency, electromagnetic models for air-core reactors. The electromagnetic field couplings are separated in mutual partial inductances and mutual coefficients of potential giving a correct solution from DC to a maximum frequency determined by the meshing. The PEEC models are validated by comparing simulation results, for both time and frequency domain analysis, against measurements and other established modeling methods, and show good agreement. The model created by PEEC theory, could be helpful in the design and diagnostics of air-core reactors and other power system components.

National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Industrial Electronics
Identifiers
urn:nbn:se:ltu:diva-15569 (URN)10.1109/TPWRD.2009.2014486 (DOI)000265093000028 ()2-s2.0-67349225022 (Scopus ID)f19e2bc0-afd6-11dd-b677-000ea68e967b (Local ID)f19e2bc0-afd6-11dd-b677-000ea68e967b (Archive number)f19e2bc0-afd6-11dd-b677-000ea68e967b (OAI)
Projects
A New Method for Combined Electric and Electromagnetic Modeling of Power Distribution Systems -High frequency models for reactors
Note
Validerad; 2009; 20081111 (mathen)Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-07-10Bibliographically approved
Enohnyaket, M. & Hyyppä, K. (2009). Characteristic signature of electromagnetic emissions from power converters (ed.). In: (Ed.), (Ed.), 2009 IEEE Vehicle Power and Propulsion Conference: VPPC 2009 ; Dearborn, Michigan, USA, 7 - 11 September 2009. Paper presented at IEEE Vehicle Power and Propulsion Conference : 07/09/2009 - 11/09/2009 (pp. 1036-1042). Piscataway, NJ: IEEE Communications Society
Open this publication in new window or tab >>Characteristic signature of electromagnetic emissions from power converters
2009 (English)In: 2009 IEEE Vehicle Power and Propulsion Conference: VPPC 2009 ; Dearborn, Michigan, USA, 7 - 11 September 2009, Piscataway, NJ: IEEE Communications Society, 2009, p. 1036-1042Conference paper, Published paper (Refereed)
Abstract [en]

Switching operations in power converters controlling electric machines in a hybrid drive train constitute a major source of electromagnetic related disturbances. The emissions from power converters seem to have a characteristic pattern or signature and can be picked up at different locations in the vehicle. This study aims at investigating the signature of emissions from power converters using an H-bridge driving a dc motor. PSpice model of the motor and drive circuit was made and current, voltage, and field measurements were performed on a constructed prototype. Current transients and oscillations generated during voltage transitions have been investigated using the PSpice model. A correlation between the common mode currents and the magnetic field emissions was observed.

Place, publisher, year, edition, pages
Piscataway, NJ: IEEE Communications Society, 2009
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Industrial Electronics
Identifiers
urn:nbn:se:ltu:diva-35270 (URN)10.1109/VPPC.2009.5289732 (DOI)72149090884 (Scopus ID)9bb15c10-3937-11de-9b53-000ea68e967b (Local ID)978-1-424-42600-3 (ISBN)9bb15c10-3937-11de-9b53-000ea68e967b (Archive number)9bb15c10-3937-11de-9b53-000ea68e967b (OAI)
Conference
IEEE Vehicle Power and Propulsion Conference : 07/09/2009 - 11/09/2009
Projects
EM Karaktärisering och Modellering av Elektriska Hybriddrivsystem
Note
Godkänd; 2009; 20090505 (mathen)Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2017-11-25Bibliographically approved
Enohnyaket, M. (2009). Generation of very low frequency beat waves from power converters (ed.). In: (Ed.), 2009 IEEE Vehicle Power and Propulsion Conference: VPPC 2009 ; Dearborn, Michigan, USA, 7 - 11 September 2009. Paper presented at IEEE Vehicle Power and Propulsion Conference : 07/09/2009 - 11/09/2009 (pp. 1025-1031). Piscataway, NJ: IEEE Communications Society
Open this publication in new window or tab >>Generation of very low frequency beat waves from power converters
2009 (English)In: 2009 IEEE Vehicle Power and Propulsion Conference: VPPC 2009 ; Dearborn, Michigan, USA, 7 - 11 September 2009, Piscataway, NJ: IEEE Communications Society, 2009, p. 1025-1031Conference paper, Published paper (Refereed)
Abstract [en]

In the course of investigation of the EMI emissions from DC/AC power converters controlling synchronous machines in a hybrid electric vehicle (HEV), very low frequency beat waves were picked up in the common mode currents on the AC link. The beat wave patterns have maxima which could be more than ten percent of the phase current amplitude and at frequencies several orders lower than the switching frequency of the converters. These high currents create strong low frequency magnetic fields in the vicinity. The beat waves could potentially perturb the rotor motion and eventually distort the smooth functionality of electric machines if undamped. PSpice models show that PWM switching of converter input voltage, generates common mode current spikes (transients) due to stray capacitances, and the spikes eventually beat up. This paper presents measurements on a HEV showing beat waves, and an experimental verification of the phenomenon using an H-bridge and a DC motor.

Place, publisher, year, edition, pages
Piscataway, NJ: IEEE Communications Society, 2009
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Industrial Electronics
Identifiers
urn:nbn:se:ltu:diva-32620 (URN)10.1109/VPPC.2009.5289734 (DOI)2-s2.0-72149090375 (Scopus ID)72becb50-3935-11de-9b53-000ea68e967b (Local ID)978-1-424-42600-3 (ISBN)72becb50-3935-11de-9b53-000ea68e967b (Archive number)72becb50-3935-11de-9b53-000ea68e967b (OAI)
Conference
IEEE Vehicle Power and Propulsion Conference : 07/09/2009 - 11/09/2009
Projects
EM Karaktärisering och Modellering av Elektriska Hybriddrivsystem
Note

Godkänd; 2009; 20090505 (mathen)

Available from: 2016-09-30 Created: 2016-09-30 Last updated: 2018-07-10Bibliographically approved
Enohnyaket, M. (2009). State of the art report on EMC characterization of hybrid drive systems (ed.). Paper presented at . Luleå tekniska universitet
Open this publication in new window or tab >>State of the art report on EMC characterization of hybrid drive systems
2009 (English)Report (Other academic)
Place, publisher, year, edition, pages
Luleå tekniska universitet, 2009
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Industrial Electronics
Identifiers
urn:nbn:se:ltu:diva-25349 (URN)ed263730-f6ae-11dd-a85e-000ea68e967b (Local ID)ed263730-f6ae-11dd-a85e-000ea68e967b (Archive number)ed263730-f6ae-11dd-a85e-000ea68e967b (OAI)
Projects
EM Karaktärisering och Modellering av Elektriska Hybriddrivsystem
Note

Godkänd; 2009; 20090209 (mathen)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-02-27Bibliographically approved
Enohnyaket, M. (2008). Evaluating the partial inductance routines in the LTU-PEEC solver (ed.). Paper presented at .
Open this publication in new window or tab >>Evaluating the partial inductance routines in the LTU-PEEC solver
2008 (English)Report (Other academic)
Abstract [en]

The accuracy of partial inductance calculations is a strong determining factor in PEEC simulations. Errors in partial inductance routines lead to non-physical solutions. The sign of partial inductances depends on the assumed current directions in the conductor segments. The current flow in the structure under analysis is represented by the connectivity matrix (Cm). The signs of the entries in the Cm matrix can be chosen such that the final results from the PEEC simulations are independent of the initial current assumptions. This approach has been tested on a simple geometry. The numerical integration routines have been looked and it was seen that the existing numerical integration routines are only good for flat surfaces. In fact, the errors in the self terms approach 100% for structures with some thickness.

Publisher
p. 13
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Industrial Electronics
Identifiers
urn:nbn:se:ltu:diva-24206 (URN)a162a480-d95b-11dc-8da8-000ea68e967b (Local ID)a162a480-d95b-11dc-8da8-000ea68e967b (Archive number)a162a480-d95b-11dc-8da8-000ea68e967b (OAI)
Note

Godkänd; 2008; 20080212 (mathen)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-02-27Bibliographically approved
Enohnyaket, M., Wisten, Å. & Ekman, J. (2007). Electromagnetic fields from air-core reactors using equivalent circuit theory (ed.). In: (Ed.), Anders Karlsson; Gerhard Kristensson; Daniel Sjöberg (Ed.), EMB07 - the fourth Swedish conference on computational electromagnetics: methods and applications. Paper presented at Swedish Conference on Computational Electromagnetics : 18/10/2007 - 19/10/2007 (pp. 69-74).
Open this publication in new window or tab >>Electromagnetic fields from air-core reactors using equivalent circuit theory
2007 (English)In: EMB07 - the fourth Swedish conference on computational electromagnetics: methods and applications / [ed] Anders Karlsson; Gerhard Kristensson; Daniel Sjöberg, 2007, p. 69-74Conference paper, Published paper (Refereed)
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Industrial Electronics
Identifiers
urn:nbn:se:ltu:diva-37601 (URN)bac110d0-5fb0-11dc-807a-000ea68e967b (Local ID)bac110d0-5fb0-11dc-807a-000ea68e967b (Archive number)bac110d0-5fb0-11dc-807a-000ea68e967b (OAI)
Conference
Swedish Conference on Computational Electromagnetics : 18/10/2007 - 19/10/2007
Projects
A New Method for Combined Electric and Electromagnetic Modeling of Power Distribution Systems -High frequency models for reactors
Note
Godkänd; 2007; 20070910 (jekman)Available from: 2016-10-03 Created: 2016-10-03 Last updated: 2017-11-25Bibliographically approved
Enohnyaket, M. (2007). PEEC modeling and verification for broadband analysis of air-core reactors (ed.). (Licentiate dissertation). Paper presented at . Luleå: Luleå tekniska universitet
Open this publication in new window or tab >>PEEC modeling and verification for broadband analysis of air-core reactors
2007 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

There is an increasing utilization of modern Power Electronic (PE) devices in power systems, in for example, harmonic filters, reactive power compensation, and current limiting applications. The operational frequencies and switching rates of the PE devices now cover up to the megahertz range. As a consequence, an understanding of the functionality of static components like transformers, inductors (reactors), and capacitors in the presence of these high frequency signals are challenging issues. Present standards and legislation on EMC also put more constraints on the design of these power components. The focus of this work is the creation of high frequency electromagnetic models for power electronic components, with emphasis on air-core reactors. Attempts to model air-core reactors include lumped models, which typically consists of a series of mutually coupled lumped section, neglecting internal couplings within each section. This approach is limited to low frequencies where the voltage distribution along the turns in each section can be considered linear. For higher frequencies (several MHz), a more distributed model accounting for the electromagnetic couplings is inevitable. The Partial Element Equivalent Circuit (PEEC) modeling approach is suitable for mixed circuit and electromagnetic problems. It is based on the integral forms of Maxwell's equations upon which an equivalent circuit based model is developed. In this study, a broadband model for air-core reactors is created using the PEEC approach. Each reactor turn is represented by a finite number of interconnected bars or volume cells. From the volume cells equivalent circuit parameters, mainly the partial inductances, the coefficients of potential, and the resistances are evaluated using analytical routines. The electromagnetic coupling between the cells is represented by mutual partial inductances and the mutual coefficients of potential. The parameters are assembled into matrix equations, whose solution gives the current and voltage distribution in the model windings. The current distribution is post-processed to obtain the field distribution in the vicinity of the reactor. The PEEC reactor model was validated by comparing model results with measurements done on a laboratory air-core reactors and showed good agreement in both time and frequency domain. The time complexity for the PEEC simulation is greater compared to the corresponding lumped models, but the PEEC models give a better characterization at high frequencies. Using the frequency response from the PEEC model, smaller RLC resonance circuits replicating the same behaviour, can be synthesized. These reduced circuits can be easily included in system simulations as lumped components along side other power components. The PEEC model could also be helpful in design and diagnosis work for air-core reactors. Though the focus is on air-core reactors, the model could be enhanced to characterize other devices like power transformers.

Place, publisher, year, edition, pages
Luleå: Luleå tekniska universitet, 2007. p. 120
Series
Licentiate thesis / Luleå University of Technology, ISSN 1402-1757 ; 2007:51
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Industrial Electronics
Identifiers
urn:nbn:se:ltu:diva-17863 (URN)5909d2a0-8d23-11dc-a188-000ea68e967b (Local ID)5909d2a0-8d23-11dc-a188-000ea68e967b (Archive number)5909d2a0-8d23-11dc-a188-000ea68e967b (OAI)
Projects
A New Method for Combined Electric and Electromagnetic Modeling of Power Distribution Systems -High frequency models for reactors
Note

Godkänd; 2007; 20071107 (ysko)

Available from: 2016-09-29 Created: 2016-09-29 Last updated: 2018-02-27Bibliographically approved
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