As a contribution to previous studies in this thesis the SVM technique to control NPC and ANPC inverters has been implemented in Matlab/Simulink environment. In addition, the obtained simulation models have been utilized to investigate the distribution of both switching and conduction losses between the components of the inverters. The analysis also includes the calculation of total loss dissipations and efficiencies for both NPC and ANPC inverters.
During the implementation of ANPC modelling an unequal distribution of power losses of three-level NPC inverter has been overcome. The improved ANPC inverter model has been simulated, and, as a result obtained waveforms of output voltages and currents show the quality performance of the inverter. Thus, harmonic content of output signals correspond to IEC 61000-4-7 international EMC energy supply quality standard and THD does not exceed the accepted values. However, a simple model of grid filter can be implemented in order to improve the model or make it more realistic, as real power converters are usually include a certain filters in order to protect both the grid from the converter and vice versa.
The methods of calculations has been utilized in simulations are commonly used in practise, however the assumptions which were accepted during the simulations may essentially affect the obtained results. In general, obtained results correspond to the theoretical issues discussed in background theories of the thesis and the similar results can be found in and (FLORICAU et al 2009). Thus, the most stressed devices of NPC application have been revealed. Then, extended topology of ANPC has been simulated, in order to achieve more even distribution between semiconductors, so the losses distribution and total loss dissipation for the both topologies can be compared. However, it should be kept in mind that without relevant thermal behaviour model of the inverters the simulations could be incomplete.
Thus, the conduction and switching losses have been calculated for each component of NPC and ANPC structures. Then, the relations and distribution between conduction and switching losses among the semiconductors have been also investigated. Also, it has been shown that the total losses are the same for both structures.
In general, designed models can be characterized as base ones and not flexible enough, which can be used for different simulations by adding desired modules into them. For instance, more complex analysis with varying PF values and sophisticated control strategies can be provided, for instance SHE PWM. Moreover, the increased share of wind power in total energy production demands more realistic modelling, including fully controlled AC-DC-AC high power converter models, so not only the inverter model, but rectifier one can be simulated further.
REFERENCES
(AARNIOVUORI et al 2012) Aarniovuori, L. Laurila, L.I.E. Niemelä, M. Pyrhönen, J.J.
2012. Measurements and Simulations of DTC Voltage Source Converter and Induction Motor Losses. IEEE Transactions in Industrial Electronics, vol.59, no.5. Pages 2277-2287.
(APELDOORN et al 2005) Apeldoorn, O. Odegard, B. Steimer, P. Bernet, S. 2005. A 16 MVA ANPC-PEBB with 6 kA IGCTs. Industry Applications Conference, 2005. Fourtieth IAS Annual Meeting. Vol.2, pages 818- 824.
(BAROUDI et al 2005) Baroudi, J.A. Dinavahi, V. Knight, A.M. 2005. A review of power converter topologies for wind generators. 2005 IEEE International Conference on Electric Machines and Drives. Pages 458-465.
(BIERHOFF et al 2004) Bierhoff, M.H. Fuchs, F.W. 2004. Semiconductor losses in voltage source and current source IGBT converters based on analytical derivation. IEEE 35th Annual Power Electronics Specialists Conference, 2004. PESC 04, vol.4, Pages 2836- 2842.
(BIERK et al 2008) Bierk, H. Benaifa, N. Abdel-Latif, K.M. Nowicki, E. 2008.
Elimination of low-order harmonics in high power medium voltage inverter applications using a modified SHE-PWM technique. Power Symposium, 2008. NAPS '08. 40th North American. Pages 1-4.
(BRUCKNER 2005) Bruckner, T. 2005. The Active NPC Converter for Medium-Voltage Drives. Doctoral Thesis, Dresden
University of Technology. 197 pages. ISBN-10: 3-8322-5270-3.
(BRUCKNER et al 2005) Bruckner, T. Bernet, S. Guldner, H. 2005. The Active NPC converter and its loss balancing control. IEEE Transactions on Industrial Electronics, vol.52, no.3. Pages 855-868.
(DECC 2011) Department of Energy and Climate Change, 2011. DECC Fossil Fuel Price Projections: Summary. [online]
http://www.decc.gov.uk/assets/decc/11/about- us/economics-social-research/2933-fossil-fuel-price-projections-summary.pdf [suggested 12.10.2011]
(FEIX et al 2009) Feix, G. Dieckerhoff, S. Allmeling, J. Schonberger, J.
2009. Simple methods to calculate IGBT and diode conduction and switching losses. 13th European Conference on Power Electronics and Applications, 2009.
EPE '09. Pages 1-8.
(FLORICAU et al 2009) Floricau, D. Popescu, C.-L. Popescu, M.-O. Floricau, E.
Spataru, L. 2009. A comparison of efficiency for three-level NPC and Active NPC voltage source converters.
Compatibility and Power Electronics, 2009. CPE '09.
Pages 331-336.
(FRANQUELO et al 2008) Franquelo, L.G. Rodriguez, J. Leon, J.I. Kouro, S. Portillo, R. Prats, M.A.M. 2008. The Age of Multilevel Converters Arrives. IEEE Industrial Electronics Magazine, no.6. Pages 28-39.
(GRAOVAC et al 2009) Graovac, D. Purshel, M. 2009. IGBT Power Losses Calculation Using the Data-Sheet Parameters. Infineon, Application Note, V 1.1.
(HAITHAM et al 2010) Haitham, A. Holtz, J. Rodriguez, J. Baoming, G. 2010.
Medium-Voltage Multilevel Converters – State of the Art, Challenges, and Requirements in Industrial Applications.
IEEE Transactions in Industrial Electronics, vol.57, no.8.
Pages 2581-2593.
(HONSBERG et al 2009) Honsberg, M. Radke, T. 2009. 3-level IGBT modules with trench gate IGBT and their thermal analysis in UPS, PFC and PV operation modes. 13th European Conference on Power Electronics and Applications, 2009. EPE '09. Pages 1-7.
(IKONEN et al 2005) Ikonen, M. Laakkonen, O. Kettunen, M. 2005. Two-level and Three-level Converter Comparison in Wind Power Application. Lappeenranta University of Technology, Department of Electrical Engineering. [online]
http://www.elkraft.ntnu.no/smola2005/Topics/15.pdf
(JIA et al 2007) Jia, S. Wang, X. Tseng, K.J. 2007. Matrix converters for wind energy systems. IEEE Conference in Industrial Electronics. Pages 488–494.
(KIM et al 2010) Kim, H. Lu, D. 2010. Wind Energy Conversion System from Electrical Perspective—A Survey. Smart Grid and Renewable Energy, vol. 1, no. 3. Pages 119-131.
(KOCALMIS et al 2006) Kocalmis, A. Sunter, S. 2006. Simulation of a Space Vector PWM Controller For a Three-Level Voltage-Fed Inverter Motor Drive. 32nd Annual Conference on IEEE Industrial Electronics, IECON 2006. Pages 1915-1920.
(LAMPOLA 2000) Lampola, P. 2000. Directly Driven, Low Speed Permanent-Magnet Generators for Wind Power Applications. Acta
Polytechnica Scandinavica, Electrical Engineering Series, no.101. 62 pages. ISBN 951-666-539-X.
(MALINOWSKI et al 2010) alinowski, . Gopakumar, . Rodriguez, . P rez, . . 2010. A Survey on Cascaded Multilevel Inverters. IEEE Transactions on Industrial Electronics, vol. 57, no. 7. Pages 2197-2206.
(MELICIO et al 2010) Melicio, R. Mendes, V.M.F Catalao, J.P.S. 2010. Power converter topologies for wind energy conversion systems:
Integrated modeling, control strategy and performance simulation. Renewable Energy, vol. 35, no. 10. Pages 2165-2174. ISSN 0960-1481
(MOHAN et al 2003) Mohan, N. Robbins, W.P. Undeland T.M. Power Electronics: Converters, Applications and Design. . Third Edition. John Wiley & Sons, Inc. 802 pages. ISBN 0-471-42908-2
(MULJADI et al 1998) Muljadi, E. Pierce, K. Migliore, P. 1998. Control Strategy for Variable-Speed, Stall-Regulated Wind Turbines.
National Wind Technilogy Center, National Renewable
Energy Laboratory, USA. [online]
http://css.engineering.uiowa.edu/~me_048/fall2008/wind_t urbine_stall.pdf
(MUSIKKA 2010) Musikka, T. 2010. Thermal modelling of semiconductor switches in three-level neutral point clamped medium voltage DTC-inverter. Lappeenranta University of Technology, Department of Electrical Engineering. 97 pages.
(NALLAVAN et al 2011) Nallavan, G. Dhanasekaran, R. Vasudevan, M. 2011.
Power electronics in wind energy conversion systems — A survey across the globe. Electronics Computer Technology (ICECT), 2011 3rd International Conference, vol.1. Pages 416-419.
(PONTT et al 2003) Pontt, J.O.; Rodriguez, J.P.; Huerta, R.C.; Pavez, J.L.;
2003. Mitigation of no eliminated harmonics of SHEPWM three-level multipulse three-phase active front end converters with low switching frequency for meeting standard IEEE-519-92. Power Electronics Specialist Conference, 2003. 2003 IEEE 34th Annual, vol.2. Pages 531- 536.
(POTASHKO 2011) Potashko, N.S. 2011. Application of multilevel inverters to control induction motor with divided stator windings (in Russian). Bachelor’s Thesis, St. Petersburg Electrotechnical University. 82 pages.
(PULIKANTI et al 2011) Pulikanti, S.R. Dahidah, M.S.A. Agelidis, V.G. 2011.
Voltage Balancing Control of Three-Level Active NPC Converter Using SHE-PWM. IEEE Transactions on Power Delivery, vol.26, no.1. Pages 258-267.
(PYRHÖNEN 2010) Pyrhönen, J. 2010. Electrical Drives. Lecture Notes.
Lappeenranta University of technology, Department of Electrical Engineering. 400 pages.
(PYRHÖNEN 2011) Pyrhönen, O. 2011. Wind power from a Finnish perspective. The Nordic Wind Integration Research Network (NWIN). Seminar: Sweden 2011 [online].
http://srv128.bluerange.se/Documents/Market%20Design/
NWIN/SWE_7_LUT.pdf [suggested 14.12.2011]
(RAJAPAKSE et al 2005) Rajapakse, A.D. Gole, A.M. Wilson, P.L. 2005.
Approximate Loss Formulae for Estimation of IGBT Switching Losses through EMTP-type Simulations.
International Conference on Power Systems Transients, 2005 (IPST’05). Paper no. IPST05-184. Pages 1-6.
(RAMTHARAN et al 2007) Ramtharan, G. Jenkins, N. Anaya-Lara, O. Bossanyi E.
2007. Influence of rotor structural dynamics representations on the electrical transient performance of FSIG and DFIG wind turbines. Wind Energy, no.10. Pages 293-301
(RODRIGUEZ et al 2007) Rodriguez, J. Bernet, S. Bin Wu; Pontt, J.O. Kouro, S.
2007. Multilevel Voltage-Source-Converter Topologies for Industrial Medium-Voltage Drives. IEEE Transactions on Industrial Electronics, vol.54, no.6. Pages 2930-2945.
(RODRIGUEZ et al 2010) Rodriguez, J. Bernet, S. Steimer, P.K. Lizama, I.E. 2010.
A Survey on Neutral-Point-Clamped Inverters. IEEE Transactions on Industrial Electronics, vol.57, no.7. Pages 2219-2230.
(RUDERMAN et al 2009) Ruderman, A. Reznikov, B. 2009. Three-Level H-Bridge Flying Capacitor Converter Voltage Balance Dynamics Analysis, 13th European Conference on Power Electronics and Applications, Barcelona. Pages 1-10.
(SAYAGO et al 2008) Sayago, J.A. Bruckner, T. Bernet, S. 2008. How to Select the System Voltage of MV Drives—A Comparison of Semiconductor Expenses. IEEE Transactions on Industrial Electronics, vol.55, no.9. Pages 3381-3390.
(SUI 2007) Sui, Y. 2007. Development of high voltage P-channel DMOS-IGBTs in hydrogen-silicon carbide. Doctoral Dissertation, Purdue University, Department of Electrical and Computer Engineering. 162 pages.
(WIZELIUS 2006) Wizelius, T. 2006. Developing Wind Power Projects:
Theory and Practice by Tore Wizelius, Earthscan Publications, London. 296 pages. ISBN 1844072622.
(WHEELER et al 2002) Wheeler, P.W. Rodriguez, J. Clare, J.C. Empringham, L.
Weinstein A. 2002. Matrix converters: a technology review. Industrial Electronics, IEEE Transactions, vol. 49, no. 2. Pages 276–288.
(WWEA 2012) World Wind Energy Association. 2012. World Market recovers and sets a new record: 42 GW of new capacity in 2011, total at 239 GW [online].
http://www.wwindea.org/home/index.php?option=com_con tent&task=view&id=345&Itemid=43[suggested 7.2.2012]
(YAMANAKA et al 2002) Yamanaka, K. Hava, A.M. Kirino, H. Tanaka, Y. Koga, N.
Kume, T. 2002. A novel neutral point potential stabilization technique using the information of output current polarities and voltage vector. IEEE Transactions on Industry Applications, vol.38, no.6. Pages 1572- 1580.
blocks
12 Definition of angle and sector
m=0.866
Num_vectors
m2
al pha
routing
4
12
4
3
3
NPC and ANPC models
clc;
clear all;
% Switching states for one phase a...f=[s1 s2 s3 s4 s5 s6].
% States a and f give fully positive and negative voltages for one phase,
% respectively, and create paths for positive and negative currents,
% whereas states b,c,d and e create alternative paths for current flow
% in the middle point of ANPC topology.
a=[1 1 0 0 0 1];
% Parameters of the model and load
m=3; % number of phases
% Parameters of IGBTs and diodes used in calculation model Tail_time=0.0000002; % Rise time [s]
Fall_time=0.0000002; % Fall time [s]
RGin=0.42;
conducting Dx1 and Dx2 for NPC inverter.