The goal of this work was to design and implement a control scheme for a 3-phase qZSI in order to enable it to operate in a grid-forming role. The qZSI was analyzed in great detail and compared to a conventional boost converter that is commonly used in grid connected inverters. Literature was presented to demonstrate the need for current programed mode control for the dc side of the qZSI, and the control scheme was compared to a common control scheme used for boost converters. Then, recent literature was used to support why the universal droop control scheme was chosen for the ac-side control for this work. After contextualizing the design of the overall qZSI control scheme, the final control scheme was presented. An analytical approach was taken for design of the components and gain parameters. The goal was to design a qZSI system with similar properties to a conventional boost-cascaded VSI system. Thus, the performance of the qZSI system in a grid-forming role could be benchmarked against a conventional device, demonstrating whether the qZSI could operate as a fundamental grid-forming device.
Through PLECS simulations, the qZSI system presented in this work not only demonstrated its ability to operate in a grid-forming role, but also that it may potentially have superior performance to conventional VSI systems operating in the same role. While a much more optimized design approach is needed for both the qZSI and VSI to truly compare the two systems, this work demonstrated that the qZSI is more than capable of operating in a grid-forming role. It handled large step changes in load and input voltage with quick rise times and good damping, and
inverter systems, with the goal of analytically explaining the dynamic performance differences between the two systems.
Bibliography
[1] F. Z. Peng, “Z-source inverter,” IEEE Trans. Ind. Appl., vol. 39, no. 2, pp. 504–510, 2003, doi: 10.1109/TIA.2003.808920.
[2] “Power Electronics and Control in Grid-Connected PV Systems Grid-Connected PV System,” University of Colorado, 2012. [Online]. Available: http://ecee.colorado.edu/~ecen2060/materials/lecture_notes/GridPVsystem.pdf.
[3] J. Liu, J. Hu, and L. Xu, “Dynamic modeling and analysis of Z source converter - Derivation of AC small signal model and design-oriented analysis,” IEEE Trans. Power Electron., vol. 22, no. 5, pp. 1786–1796, 2007, doi: 10.1109/TPEL.2007.904219.
[4] Y. P. Siwakoti, F. Z. Peng, F. Blaabjerg, P. C. Loh, G. E. Town, and S. Yang, “Impedance- Source Networks for Electric Power Conversion Part II: Review of Control and Modulation Techniques,” IEEE Trans. Power Electron., vol. 30, no. 4, pp. 1887–1906, 2015, doi: 10.1109/TPEL.2014.2329859.
[5] Y. Liu, B. Ge, F. J. T. E. Ferreira, A. T. De Almeida, and H. Abu-Rub, “Modeling and SVPWM control of quasi-Z-source inverter,” Proceeding Int. Conf. Electr. Power Qual. Util. EPQU, no. 09, pp. 95–101, 2011, doi: 10.1109/EPQU.2011.6128914.
[6] Y. Liu, H. Abu-Rub, B. Ge, F. Blaabjerg, O. Ellabban, and P. C. Loh, “Voltage‐Fed Z‐ Source/ Quasi‐Z‐Source Inverters,” in Impedance Source Power Electronics Converters, John Wiley & Sons, Ltd., 2016, pp. 20–34.
[7] Y. P. Siwakoti, F. Z. Peng, F. Blaabjerg, P. C. Loh, and G. E. Town, “Impedance-Source Networks for Electric Power Conversion Part I: A Topological Review,” IEEE Trans. Power Electron., vol. 30, no. 2, pp. 699–716, 2015, doi: 10.1109/TPEL.2014.2313746. [8] Y. Liu, B. Ge, H. Abu-Rub, A. Iqbal, and F. Peng, “Modeling and controller design of quasi-
Z-Source inverter with battery based photovoltaic power system,” 2012 IEEE Energy Convers. Congr. Expo. ECCE 2012, no. 09, pp. 3119–3124, 2012, doi: 10.1109/ECCE.2012.6342353.
[9] J. G. Cintron-Rivera, Y. Li, S. Jiang, and F. Z. Peng, “Quasi-Z-Source inverter with energy storage for Photovoltaic power generation systems,” Conf. Proc. - IEEE Appl. Power Electron. Conf. Expo. - APEC, pp. 401–406, 2011, doi: 10.1109/APEC.2011.5744628. [10] B. Siefeddine, K. Djallel, B. Noureddine, H. Ammar, and B. Abdelhak, “Quasi Z Source
[11] D. Shuai, Z. Qianfan, Z. Weipan, Z. Chaowei, and N. Tuopu, “A Compound control strategy for improving the dynamic characteristics of the dc-link voltage for the pmsm drive system based on the quasi-z-source inverter,” IEEE Access, vol. 7, pp. 151929–151938, 2019, doi: 10.1109/ACCESS.2019.2948189.
[12] N. Sabeur, S. Mekhilef, M. Nakaoka, and A. Masaoud, “A simple modulation based maximum boost control strategy for three-phase quasi Z-source inverter,” 2016 IEEE 8th Int. Power Electron. Motion Control Conf. IPEMC-ECCE Asia 2016, pp. 570–574, 2016, doi: 10.1109/IPEMC.2016.7512349.
[13] A. Abdelhakim, F. Blaabjerg, and P. Mattavelli, “An improved discontinuous space vector modulation scheme for the three-phase impedance source inverters,” Conf. Proc. - IEEE Appl. Power Electron. Conf. Expo. - APEC, vol. 2018-March, pp. 3307–3313, 2018, doi: 10.1109/APEC.2018.8341577.
[14] Y. Liu, B. Ge, H. Abu-Rub, and F. Z. Peng, “Control system design of battery-assisted quasi-z-source inverter for grid-tie photovoltaic power generation,” IEEE Trans. Sustain. Energy, vol. 4, no. 4, pp. 994–1001, 2013, doi: 10.1109/TSTE.2013.2263202.
[15] Q. C. Zhong, “Robust droop controller for accurate proportional load sharing among inverters operated in parallel,” IEEE Trans. Ind. Electron., vol. 60, no. 4, pp. 1281–1290, 2013, doi: 10.1109/TIE.2011.2146221.
[16] Q. C. Zhong and Y. Zeng, “Universal Droop Control of Inverters with Different Types of Output Impedance,” IEEE Access, vol. 4, pp. 702–712, 2016, doi: 10.1109/ACCESS.2016.2526616.
[17] Y. Li, S. Jiang, J. G. Cintron-Rivera, and F. Z. Peng, “Modeling and control of quasi-z- source inverter for distributed generation applications,” IEEE Trans. Ind. Electron., vol. 60, no. 4, pp. 1532–1541, 2013, doi: 10.1109/TIE.2012.2213551.
[18] A. Yazdani and R. Iravani, Voltage-Sourced Converters in Power Systems. John Wiley & Sons, Ltd., 2010.
[19] C. J. Gajanayake, D. M. Vilathgamuwa, and P. C. Loh, “Development of a comprehensive model and a multiloop controller for Z-source inverter DG systems,” IEEE Trans. Ind. Electron., vol. 54, no. 4, pp. 2352–2359, 2007, doi: 10.1109/TIE.2007.894772.
[20] R. W. Erickson and D. Maksimovic, Fundamentals of Power Electronics, 2nd ed. New York: Kluwer Academic/Plenum Publishers, 2004.
[21] Y. Liu, H. Abu-Rub, B. Ge, F. Blaabjerg, O. Ellabban, and P. C. Loh, “Design of Z‐Source and and Quasi-Z-Source Inverters,” in Impedance Source Power Electronics Converters, John Wiley & Sons, Ltd., 2016, pp. 226–243.
[23] Q. C. Zhong, W. L. Ming, and Y. Zeng, “Self-Synchronized Universal Droop Controller,” IEEE Access, vol. 4, pp. 7145–7153, 2016, doi: 10.1109/ACCESS.2016.2616115.
[24] J. M. Guerrero, L. G. De Vicuña, J. Matas, J. Miret, and M. Castilla, “Output impedance design of parallel-connected UPS inverters,” IEEE Int. Symp. Ind. Electron., vol. 2, no. 4, pp. 1123–1128, 2004, doi: 10.1109/ISIE.2004.1571971.
[25] Y. Jia and R. Wu, “Voltage source grid-connected PV inverters based on MPPT and droop control,” 2016 IEEE 2nd Annu. South. Power Electron. Conf. SPEC 2016, pp. 1–6, 2016, doi: 10.1109/SPEC.2016.7846033.
[26] Q. C. Zhong, P. L. Nguyen, Z. Ma, and W. Sheng, “Self-synchronized synchronverters: Inverters without a dedicated synchronization unit,” IEEE Trans. Power Electron., vol. 29, no. 2, pp. 617–630, 2014, doi: 10.1109/TPEL.2013.2258684.
[27] D. Dong, B. Wen, D. Boroyevich, P. Mattavelli, and Y. Xue, “Analysis of phase-locked loop low-frequency stability in three-phase grid-connected power converters considering impedance interactions,” IEEE Trans. Ind. Electron., vol. 62, no. 1, pp. 310–321, 2015, doi: 10.1109/TIE.2014.2334665.
[28] L. F. Chaparro, Signals and Systems Using Matlab, 2nd ed. San Diego, CA: Elsevier, 2015. [29] M. Rasheduzzaman, J. A. Mueller, and J. W. Kimball, “Reduced-order small-signal model of microgrid systems,” IEEE Trans. Sustain. Energy, vol. 6, no. 4, pp. 1292–1305, 2015, doi: 10.1109/TSTE.2015.2433177.
[30] P. Vorobev, P. H. Huang, M. Al Hosani, J. L. Kirtley, and K. Turitsyn, “A framework for development of universal rules for microgrids stability and control,” 2017 IEEE 56th Annu. Conf. Decis. Control. CDC 2017, vol. 2018-January, no. Cdc, pp. 5125–5130, 2018, doi: 10.1109/CDC.2017.8264418.
[31] M. Mao, Y. Ding, Y. Shen, and L. Chang, “Stability Enhancement Strategy for Islanding Microgrid with Multi-type Inverters Based on Hybrid Impedance Modelling,” 2018 Int. Power Electron. Conf. IPEC-Niigata - ECCE Asia 2018, pp. 815–821, 2018, doi: 10.23919/IPEC.2018.8507968.
[32] R. Middlebrook, “Input Filter Considerations in Design and Application of Switching Regulators,” IEEE IAS Annu. Meet., pp. 366–382, 1976.
[33] J. Sun, “Impedance-based stability criterion for grid-connected inverters,” IEEE Trans. Power Electron., vol. 26, no. 11, pp. 3075–3078, 2011, doi: 10.1109/TPEL.2011.2136439. [34] R. Burgos, D. Boroyevich, F. Wang, K. Karimi, and G. Francis, “On the Ac stability of high