Analysis of stability and bifurcations of limit cycles in Chua's circuit through the harmonic balance approach

IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS: PART

An ECG-on-Chip with QRS Detection & Lossless Compression for Low Power Wireless Sensors

IEEE Transactions on Circuits and Systems II: Express BriefsPP991-

Soft-Decision Low-Complexity Chase Decoders for the RS(255,239) Code

[EN] In this work, we present a new architecture for soft-decision Reed-Solomon (RS) Low-Complexity Chase (LCC) decoding. The proposed architecture is scalable and can be used for a high number of test vectors. We propose a novel Multiplicity Assignment stage that sorts and stores only the location of the errors inside the symbols and the powers of a that identify the positions of the symbols in the frame. Novel schematics for the Syndrome Update and Symbol Modification blocks that are adapted to the proposed sorting stage are also presented. We also propose novel solutions for the problems that arise when a high number of test vectors is processed. We implemented three decoders: a h = 4 LCC decoder and two decoders that only decode 31 and 60 test vectors of true h = 5 and h = 6 LCC decoders, respectively. For example, our h = 4 decoder requires 29% less look-up tables in Virtex-V Field Programmable Gate Array (FPGA) devices than the best soft-decision RS decoder published to date, while has a 0.07 dB coding gain over that decoder.This research was funded by the Spanish Ministerio de Economia y Competitividad and FEDER grant number TEC2015-70858-C2-2-RTorres Carot, V.; Valls Coquillat, J.; Canet Subiela, MJ.; García Herrero, FM. (2019). Soft-Decision Low-Complexity Chase Decoders for the RS(255,239) Code. Electronics. 8(1):1-13. https://doi.org/10.3390/electronics8010010S11381Cideciyan, R., Gustlin, M., Li, M., Wang, J., & Wang, Z. (2013). Next generation backplane and copper cable challenges. IEEE Communications Magazine, 51(12), 130-136. doi:10.1109/mcom.2013.6685768Koetter, R., & Vardy, A. (2003). Algebraic soft-decision decoding of reed-solomon codes. IEEE Transactions on Information Theory, 49(11), 2809-2825. doi:10.1109/tit.2003.819332Sudan, M. (1997). Decoding of Reed Solomon Codes beyond the Error-Correction Bound. Journal of Complexity, 13(1), 180-193. doi:10.1006/jcom.1997.0439Guruswami, V., & Sudan, M. (1999). Improved decoding of Reed-Solomon and algebraic-geometry codes. IEEE Transactions on Information Theory, 45(6), 1757-1767. doi:10.1109/18.782097Jiang, J., & Narayanan, K. R. (2008). Algebraic Soft-Decision Decoding of Reed–Solomon Codes Using Bit-Level Soft Information. IEEE Transactions on Information Theory, 54(9), 3907-3928. doi:10.1109/tit.2008.928238Jiangli Zhu, Xinmiao Zhang, & Zhongfeng Wang. (2009). Backward Interpolation Architecture for Algebraic Soft-Decision Reed–Solomon Decoding. IEEE Transactions on Very Large Scale Integration (VLSI) Systems, 17(11), 1602-1615. doi:10.1109/tvlsi.2008.2005575Jiangli Zhu, & Xinmiao Zhang. (2008). Efficient VLSI Architecture for Soft-Decision Decoding of Reed–Solomon Codes. IEEE Transactions on Circuits and Systems I: Regular Papers, 55(10), 3050-3062. doi:10.1109/tcsi.2008.923169Zhongfeng Wang, & Jun Ma. (2006). High-Speed Interpolation Architecture for Soft-Decision Decoding of Reed–Solomon Codes. IEEE Transactions on Very Large Scale Integration (VLSI) Systems, 14(9), 937-950. doi:10.1109/tvlsi.2006.884046Zhang, X. (2006). Reduced Complexity Interpolation Architecture for Soft-Decision Reed–Solomon Decoding. IEEE Transactions on Very Large Scale Integration (VLSI) Systems, 14(10), 1156-1161. doi:10.1109/tvlsi.2006.884177Xinmiao Zhang, & Parhi, K. K. (2005). Fast factorization architecture in soft-decision Reed-Solomon decoding. IEEE Transactions on Very Large Scale Integration (VLSI) Systems, 13(4), 413-426. doi:10.1109/tvlsi.2004.842914Bellorado, J., & Kavcic, A. (2010). Low-Complexity Soft-Decoding Algorithms for Reed–Solomon Codes—Part I: An Algebraic Soft-In Hard-Out Chase Decoder. IEEE Transactions on Information Theory, 56(3), 945-959. doi:10.1109/tit.2009.2039073García-Herrero, F., Valls, J., & Meher, P. K. (2011). High-Speed RS(255, 239) Decoder Based on LCC Decoding. Circuits, Systems, and Signal Processing, 30(6), 1643-1669. doi:10.1007/s00034-011-9327-4Zhang, W., Wang, H., & Pan, B. (2013). Reduced-Complexity LCC Reed–Solomon Decoder Based on Unified Syndrome Computation. IEEE Transactions on Very Large Scale Integration (VLSI) Systems, 21(5), 974-978. doi:10.1109/tvlsi.2012.2197030Peng, X., Zhang, W., Ji, W., Liang, Z., & Liu, Y. (2015). Reduced-Complexity Multiplicity Assignment Algorithm and Architecture for Low-Complexity Chase Decoder of Reed-Solomon Codes. IEEE Communications Letters, 19(11), 1865-1868. doi:10.1109/lcomm.2015.2477495Lin, Y.-M., Hsu, C.-H., Chang, H.-C., & Lee, C.-Y. (2014). A 2.56 Gb/s Soft RS (255, 239) Decoder Chip for Optical Communication Systems. IEEE Transactions on Circuits and Systems I: Regular Papers, 61(7), 2110-2118. doi:10.1109/tcsi.2014.2298282Wu, Y. (2015). New Scalable Decoder Architectures for Reed–Solomon Codes. IEEE Transactions on Communications, 63(8), 2741-2761. doi:10.1109/tcomm.2015.2445759Garcia-Herrero, F., Canet, M. J., Valls, J., & Meher, P. K. (2012). High-Throughput Interpolator Architecture for Low-Complexity Chase Decoding of RS Codes. IEEE Transactions on Very Large Scale Integration (VLSI) Systems, 20(3), 568-573. doi:10.1109/tvlsi.2010.210396

Compensation of Reactive Power and Unbalanced Power in Three-Phase Three-Wire Systems Connected to an Infinite Power Network

[EN] The compensation of an electrical system from passive compensators mainly focuses on linear systems where the consumption of charges does not vary significantly over time. In three-phase three-wire systems, when the network voltages are unbalanced, negative-sequence voltages and currents appear, which can significantly increase the total apparent power supplied by the network. This also increases the network losses. This paper presents a method for calculating the compensation of the positive-sequence reactive power and unbalanced powers caused by the negative-sequence line currents using reactive elements (coils and/or capacitors). The compensation is applied to three-phase three-wire linear systems with unbalanced voltages and loads, which are connected to an infinite power network. The method is independent of the load characteristics, where only the line-to-line voltages and line currents, at the point where compensation is desired, need to be known in advance. The solution obtained is optimal, and the system observed from the network behaves as one that only consumes the active power required by a load with a fully balanced current system. To understand the proposed method and demonstrate its validity, a case study of a three-phase three-wire linear system connected to an infinite power network with unbalanced voltages and currents is conducted.This work is supported by the Spanish Ministry of Science, Innovation and Universities (MICINN) and the European Regional Development Fund (ERDF) under Grant RTI2018-100732-B-C21.Blasco Espinosa, PA.; Montoya-Mira, R.; Diez-Aznar, J.; Montoya Villena, R.; Reig-Pérez, MJ. (2019). Compensation of Reactive Power and Unbalanced Power in Three-Phase Three-Wire Systems Connected to an Infinite Power Network. Applied Sciences. 10(1):1-17. https://doi.org/10.3390/app10010113S117101Emanuel, A. E. (1993). On the definition of power factor and apparent power in unbalanced polyphase circuits with sinusoidal voltage and currents. IEEE Transactions on Power Delivery, 8(3), 841-852. doi:10.1109/61.252612Willems, J. L. (2004). Reflections on Apparent Power and Power Factor in Nonsinusoidal and Polyphase Situations. IEEE Transactions on Power Delivery, 19(2), 835-840. doi:10.1109/tpwrd.2003.823182Emanuel, A. E. (1999). Apparent power definitions for three-phase systems. IEEE Transactions on Power Delivery, 14(3), 767-772. doi:10.1109/61.772313Czarnecki, L. S. (1994). Misinterpretations of some power properties of electric circuits. IEEE Transactions on Power Delivery, 9(4), 1760-1769. doi:10.1109/61.329509Kersting, W. H. (2001). Causes and effects of unbalanced voltages serving an induction motor. IEEE Transactions on Industry Applications, 37(1), 165-170. doi:10.1109/28.903142Pillay, P., & Manyage, M. (2006). Loss of Life in Induction Machines Operating With Unbalanced Supplies. IEEE Transactions on Energy Conversion, 21(4), 813-822. doi:10.1109/tec.2005.853724Poblador, M. L. A., & Lopez, G. A. R. (2013). Power calculations in nonlinear and unbalanced conditions according to IEEE Std 1459-2010. 2013 Workshop on Power Electronics and Power Quality Applications (PEPQA). doi:10.1109/pepqa.2013.6614957Langella, R., Testa, A., & Emanuel, A. E. (2012). Unbalance Definition for Electrical Power Systems in the Presence of Harmonics and Interharmonics. IEEE Transactions on Instrumentation and Measurement, 61(10), 2622-2631. doi:10.1109/tim.2012.2209909Kukačka, L., Zissis, G., Kolář, M., Dupuis, P., & Kraus, J. (2016). Review of AC power theories under stationary and non-stationary, clean and distorted conditions. IET Generation, Transmission & Distribution, 10(1), 221-231. doi:10.1049/iet-gtd.2015.0713Chicco, G., Postolache, P., & Toader, C. (2007). Analysis of Three-Phase Systems With Neutral Under Distorted and Unbalanced Conditions in the Symmetrical Component-Based Framework. IEEE Transactions on Power Delivery, 22(1), 674-683. doi:10.1109/tpwrd.2006.887095Paap, G. C. (2000). Symmetrical components in the time domain and their application to power network calculations. IEEE Transactions on Power Systems, 15(2), 522-528. doi:10.1109/59.867135Czarnecki, L. S. (1992). Minimisation of unbalanced and reactive currents in three-phase asymmetrical circuits with nonsinusoidal voltage. IEE Proceedings B Electric Power Applications, 139(4), 347. doi:10.1049/ip-b.1992.0041San-Yi Lee, & Chi-Jui Wu. (1993). On-line reactive power compensation schemes for unbalanced three phase four wire distribution feeders. IEEE Transactions on Power Delivery, 8(4), 1958-1965. doi:10.1109/61.248308Czarnecki, L. S. (1994). Supply and loading quality improvement in sinusoidal power systems with unbalanced loads supplied with asymmetrical voltage. Archiv für Elektrotechnik, 77(3), 169-177. doi:10.1007/bf01573892Sainz, L., Caro, M., & Caro, E. (2009). Analytical Study of the Series Resonance in Power Systems With the Steinmetz Circuit. IEEE Transactions on Power Delivery, 24(4), 2090-2098. doi:10.1109/tpwrd.2009.2028790Otto, R. A., Putman, T. H., & Gyugyi, L. (1978). Principles and Applications of Static, Thyristor-Controlled Shunt Compensators. IEEE Transactions on Power Apparatus and Systems, PAS-97(5), 1935-1945. doi:10.1109/tpas.1978.354690Czarnecki, L. S. (1989). Reactive and unbalanced currents compensation in three-phase asymmetrical circuits under nonsinusoidal conditions. IEEE Transactions on Instrumentation and Measurement, 38(3), 754-759. doi:10.1109/19.32187Czarnecki, L. S. (1988). Orthogonal decomposition of the currents in a 3-phase nonlinear asymmetrical circuit with a nonsinusoidal voltage source. IEEE Transactions on Instrumentation and Measurement, 37(1), 30-34. doi:10.1109/19.2658Willems, J. L. (2007). Current compensation in three-phase power systems. European Transactions on Electrical Power, 3(1), 61-66. doi:10.1002/etep.4450030110Origa de Oliveira, L. C., Barros Neto, M. C., & de Souza, J. B. (s. f.). Load compensation in four-wire electrical power systems. PowerCon 2000. 2000 International Conference on Power System Technology. Proceedings (Cat. No.00EX409). doi:10.1109/icpst.2000.898206Jeon, S.-J., & Willems, J. L. (2011). Reactive power compensation in a multi-line system under sinusoidal unbalanced conditions. International Journal of Circuit Theory and Applications, 39(3), 211-224. doi:10.1002/cta.629Leon-Martinez, V., & Montanana-Romeu, J. (2014). Representation of load imbalances through reactances. Application to working standards. 2014 16th International Conference on Harmonics and Quality of Power (ICHQP). doi:10.1109/ichqp.2014.6842894Czarnecki, L. S., & Haley, P. M. (2015). Unbalanced Power in Four-Wire Systems and Its Reactive Compensation. IEEE Transactions on Power Delivery, 30(1), 53-63. doi:10.1109/tpwrd.2014.231459

An Alternate Representation of the Vector of Apparent Power and Unbalanced Power in Three-Phase Electrical Systems

[EN] Low-voltage distribution systems are typically unbalanced. These ine¿ciencies cause unbalanced powers that can significantly increase the apparent power of the system. Analysing and measuring these ine¿cient powers appropriately allows us to compensate for them and obtain a more e¿cient system. Correcting the imbalance at some nodes can worsen the rest of the system; therefore, it is essential that all nodes are analysed such that action can be taken when necessary. In most studies, the unbalanced power is measured from the modulus. Other more recent studies have proposed phasor expressions of unbalanced powers; however, in both cases, these are not enough to address the compensation of unbalanced powers in systems with unbalanced voltages. In this work, a di¿erent representation of the vector expressions for analysis of the unbalanced powers and the apparent powers of the three-phase linear systems is proposed. Additionally, these vector expressions are extended to nonlinear systems to quantify the harmonic apparent powers. These expressions have been formulated from the power of Buchholz and are valid for systems with unbalanced voltages and currents. To help understand the use of the proposed formulation, a practical case of a three-phase four-wire system with unbalanced loads and voltages is demonstrated.This work is supported by the Spanish Ministry of Science, Innovation and Universities (MICINN) and the European Regional Development Fund (ERDF) under Grant RTI2018-100732-B-C21.Blasco Espinosa, PA.; Montoya-Mira, R.; Diez-Aznar, J.; Montoya Villena, R. (2020). An Alternate Representation of the Vector of Apparent Power and Unbalanced Power in Three-Phase Electrical Systems. Applied Sciences. 10(11):1-16. https://doi.org/10.3390/app10113756S1161011Emanuel, A. E. (1993). On the definition of power factor and apparent power in unbalanced polyphase circuits with sinusoidal voltage and currents. IEEE Transactions on Power Delivery, 8(3), 841-852. doi:10.1109/61.252612Willems, J. L. (2004). Reflections on Apparent Power and Power Factor in Nonsinusoidal and Polyphase Situations. IEEE Transactions on Power Delivery, 19(2), 835-840. doi:10.1109/tpwrd.2003.823182Emanuel, A. E. (1999). Apparent power definitions for three-phase systems. IEEE Transactions on Power Delivery, 14(3), 767-772. doi:10.1109/61.772313Czarnecki, L. S. (1994). Misinterpretations of some power properties of electric circuits. IEEE Transactions on Power Delivery, 9(4), 1760-1769. doi:10.1109/61.329509Kersting, W. H. (2001). Causes and effects of unbalanced voltages serving an induction motor. IEEE Transactions on Industry Applications, 37(1), 165-170. doi:10.1109/28.903142Pillay, P., & Manyage, M. (2006). Loss of Life in Induction Machines Operating With Unbalanced Supplies. IEEE Transactions on Energy Conversion, 21(4), 813-822. doi:10.1109/tec.2005.853724Poblador, M. L. A., & Lopez, G. A. R. (2013). Power calculations in nonlinear and unbalanced conditions according to IEEE Std 1459-2010. 2013 Workshop on Power Electronics and Power Quality Applications (PEPQA). doi:10.1109/pepqa.2013.6614957Langella, R., Testa, A., & Emanuel, A. E. (2012). Unbalance Definition for Electrical Power Systems in the Presence of Harmonics and Interharmonics. IEEE Transactions on Instrumentation and Measurement, 61(10), 2622-2631. doi:10.1109/tim.2012.2209909Kukačka, L., Kraus, J., Kolář, M., Dupuis, P., & Zissis, G. (2016). Review of AC power theories under stationary and non‐stationary, clean and distorted conditions. IET Generation, Transmission & Distribution, 10(1), 221-231. doi:10.1049/iet-gtd.2015.0713Chicco, G., Postolache, P., & Toader, C. (2007). Analysis of Three-Phase Systems With Neutral Under Distorted and Unbalanced Conditions in the Symmetrical Component-Based Framework. IEEE Transactions on Power Delivery, 22(1), 674-683. doi:10.1109/tpwrd.2006.887095Paap, G. C. (2000). Symmetrical components in the time domain and their application to power network calculations. IEEE Transactions on Power Systems, 15(2), 522-528. doi:10.1109/59.867135León-Martínez, V., & Montañana-Romeu, J. (2018). Formulations for the apparent and unbalanced power vectors in three-phase sinusoidal systems. Electric Power Systems Research, 160, 37-43. doi:10.1016/j.epsr.2018.01.028Castilla, M., Bravo, J. C., Ordonez, M., & Montano, J. C. (2008). Clifford Theory: A Geometrical Interpretation of Multivectorial Apparent Power. IEEE Transactions on Circuits and Systems I: Regular Papers, 55(10), 3358-3367. doi:10.1109/tcsi.2008.924885Diez, J. M., Blasco, P. A., & Montoya, R. (2016). Formulation of phasor unbalance power: application to sinusoidal power systems. IET Generation, Transmission & Distribution, 10(16), 4178-4186. doi:10.1049/iet-gtd.2016.0730Tongxin Zheng, Makram, E. B., & Girgis, A. A. (2003). Evaluating power system unbalance in the presence of harmonic distortion. IEEE Transactions on Power Delivery, 18(2), 393-397. doi:10.1109/tpwrd.2002.807460Mohamadian, S., & Shoulaie, A. (2011). Comprehensive Definitions for Evaluating Harmonic Distortion and Unbalanced Conditions in Three- and Four-Wire Three-Phase Systems Based on IEEE Standard 1459. IEEE Transactions on Power Delivery, 26(3), 1774-1782. doi:10.1109/tpwrd.2011.2126609Blasco, P. A., Montoya-Mira, R., Diez, J. M., Montoya, R., & Reig, M. J. (2019). Compensation of Reactive Power and Unbalanced Power in Three-Phase Three-Wire Systems Connected to an Infinite Power Network. Applied Sciences, 10(1), 113. doi:10.3390/app10010113Montoya-Mira, R., Blasco, P. A., Diez, J. M., Montoya, R., & Reig, M. J. (2020). Unbalanced and Reactive Currents Compensation in Three-Phase Four-Wire Sinusoidal Power Systems. Applied Sciences, 10(5), 1764. doi:10.3390/app10051764Salmerón, P., Vázquez, J. R., Herrera, R. S., & Litrán, S. P. (2007). Apparent power and power factor in unbalanced and distorted systems. Applications in three phase load compensations. Renewable Energy and Power Quality Journal, 1(05), 442-447. doi:10.24084/repqj05.31

Equivalent circuit and calculation of unbalanced power in three-wire three-phase linear networks

[EN] For analysis of three-wire three-phase linear systems, the transformations wye-delta and delta-wye from theorem of Kennelly are used. These transformations can be applied to balanced systems but not to unbalanced systems. This is due to the fact that zero-sequence voltages or zero-sequence currents are present in these types of connections. This modifies the value of the unbalance power in the load with respect to the generator. These zero-sequence voltages and currents that appear in generators and loads are not transferred over the network. The zero-sequence voltage in a delta-connected load and the zero-sequence current that is obtained using theorem of Kennelly in a star-connected load, or vice versa, cause different imbalance effects. Here, the equivalent circuit for any point of the system is developed. The impedances of the equivalent circuit in any node are calculated using line-to-line voltages and line currents. This equivalent circuit incorporates all energetic phenomena, including the unbalance of all downstream loads. For its verification, the phasor unbalance power is used.Montoya-Mira, R.; Diez-Aznar, J.; Blasco Espinosa, PA.; Montoya Villena, R. (2018). Equivalent circuit and calculation of unbalanced power in three-wire three-phase linear networks. IET Generation Transmission & Distribution. 12(7):1466-1473. https://doi.org/10.1049/iet-gtd.2017.0670S14661473127Emanuel, A. E. (1993). On the definition of power factor and apparent power in unbalanced polyphase circuits with sinusoidal voltage and currents. IEEE Transactions on Power Delivery, 8(3), 841-852. doi:10.1109/61.252612Jeon, S.-J. (2005). Definitions of Apparent Power and Power Factor in a Power System Having Transmission Lines With Unequal Resistances. IEEE Transactions on Power Delivery, 20(3), 1806-1811. doi:10.1109/tpwrd.2005.848658Czarnecki, L. S. (1994). Misinterpretations of some power properties of electric circuits. IEEE Transactions on Power Delivery, 9(4), 1760-1769. doi:10.1109/61.329509Willems, J. L. (2004). Reflections on Apparent Power and Power Factor in Nonsinusoidal and Polyphase Situations. IEEE Transactions on Power Delivery, 19(2), 835-840. doi:10.1109/tpwrd.2003.823182Emanuel, A. E. (1999). Apparent power definitions for three-phase systems. IEEE Transactions on Power Delivery, 14(3), 767-772. doi:10.1109/61.772313Jayatunga, U., Ciufo, P., Perera, S., & Agalgaonkar, A. P. (2015). Deterministic methodologies for the quantification of voltage unbalance propagation in radial and interconnected networks. IET Generation, Transmission & Distribution, 9(11), 1069-1076. doi:10.1049/iet-gtd.2014.0661Von Jouanne, A., & Banerjee, B. (2001). Assessment of voltage unbalance. IEEE Transactions on Power Delivery, 16(4), 782-790. doi:10.1109/61.956770Viswanadha Raju, G. K., & Bijwe, P. R. (2008). Efficient reconfiguration of balanced and unbalanced distribution systems for loss minimisation. IET Generation, Transmission & Distribution, 2(1), 7. doi:10.1049/iet-gtd:20070216Kersting, W. H. (2001). Causes and effects of unbalanced voltages serving an induction motor. IEEE Transactions on Industry Applications, 37(1), 165-170. doi:10.1109/28.903142Pillay, P., & Manyage, M. (2006). Loss of Life in Induction Machines Operating With Unbalanced Supplies. IEEE Transactions on Energy Conversion, 21(4), 813-822. doi:10.1109/tec.2005.853724Emanuel, A. E. (1998). The Buchholz-Goodhue apparent power definition: the practical approach for nonsinusoidal and unbalanced systems. IEEE Transactions on Power Delivery, 13(2), 344-350. doi:10.1109/61.660900Leon-Martinez, V., Montanana-Romeu, J., & Palazon-Garcia, J. M. (2011). Unbalance Compensator for Three-Phase Industrial Installations. IEEE Latin America Transactions, 9(5), 808-814. doi:10.1109/tla.2011.6030993Reginatto, R., & Ramos, R. A. (2014). On electrical power evaluation in dq coordinates under sinusoidal unbalanced conditions. IET Generation, Transmission & Distribution, 8(5), 976-982. doi:10.1049/iet-gtd.2013.0532Diez, J. M., Blasco, P. A., & Montoya, R. (2016). Formulation of phasor unbalance power: application to sinusoidal power systems. IET Generation, Transmission & Distribution, 10(16), 4178-4186. doi:10.1049/iet-gtd.2016.0730Marzband, M., Moghaddam, M. M., Akorede, M. F., & Khomeyrani, G. (2016). Adaptive load shedding scheme for frequency stability enhancement in microgrids. Electric Power Systems Research, 140, 78-86. doi:10.1016/j.epsr.2016.06.03