Quasi Cascaded H-Bridge Five-Level Boost Inverter
Abstract
Latterly, multilevel inverters have become more attractive for researchers due to low total harmonic distortion (THD) in the output voltage and low electromagnetic interference (EMI). This paper proposes a novel single-stage quasi-cascaded H-bridge five-level boost inverter (qCHB-FLBI). The proposed five-level inverter has the advantages over the cascaded H-bridge quasi-Z-source inverter (CHB-qZSI) in cutting down passive components. Consequently, size, cost, and weight of the proposed inverter are reduced. Additionally, the proposed qCHB-FLBI can work in the shoot-though state. A capacitor with low voltage rating is added to the proposed topology to remove an offset voltage of the output AC voltage when the input voltages of two modules are unbalanced. Besides, a simple PID controller is used to control the capacitor voltage of each module. This paper presents circuit analysis, the operating principles, and simulation results of the proposed qCHB-FLBI. A 1.2-kVA laboratory prototype was constructed based on a DSP TMS320F28335 to validate the operating principle of the proposed inverter.
EXISTING SYSTEM:
A CHB quasi-Z-source inverter (qZSI) with single-stage power conversion where a qZS network with two capacitors and two inductors is connected to each H-bridge circuit. In the CHB-qZSI, a shoot-through (ST) state is used to boost voltage without any damages in the power circuit. In one switching period, the number of the ST states in the single-phase qSBI is two. Therefore, the operating frequency of the inductors is twofold the switching frequency. In the CHB-qZSI, the input DC current is continuous with low ripple. Each module in the CHB qZSI can produce the same DC-link voltage by control the ST duty cycle. An effective control method, including system-level control and PWM for single-phase CHB-qZSI based grid-tie photovoltaic (PV) power system is presented. Three-phase CHB-qZSI’s control is proposed and demonstrated in for application to PV power systems. A qZS modular cascaded converter is addressed in for dc integration of high-power PV systems. Energy stored CHB-qZSI based PV power generation system is proposed in. Fault-tolerant CHB inverters using Z-sourced network are investigated in. A cascaded transformer-based multilevel inverter using single Z-source network is presented. An active-front-end (AFE) CHB multilevel inverter based on dual-boost/buck converter is proposed in. Like the CHB-qZSI, the AFE-CHB inverter also has the shoot-through immunity and buck/boost voltage. However, the CHB-qZSI in and the AFE-CHB inverter in use a large number of passive elements with raising the size, cost, and weight of the power cascaded system.
PROPOSED SYSTEM:
A quasi-switched boost (qSB) network in is used to replace the qZS network. In comparison to the qZS network, the qSB network uses one less capacitor, one less inductor, one more diode and one more switch in front of the main H-bridge circuit. An isolated high step-up DC-DC converter is proposed in [27] based on the qSB network. In this paper, a new single-stage quasi-cascaded H-bridge five-level boost inverter (qCHB-FLBI) is proposed. In the proposed qCHB-FLBI, the qSB network as presented in is used in each module. The main features of the proposed qCHB-FLBI are five-level output voltage with boost voltage ability, reduction in a number of passive components and shoot-through immunity. The configuration of the proposed single-stage qCHB-FLBI is illustrated. The proposed inverter consists of two separate DC sources, two quasi-boost inverter (qBI) modules and an inductor filter connected to the resistive load in series. Each qBI module contains one capacitor, one boost inductor, four switches and two diodes. The output voltage of the proposed qCHB-FLBI has five levels.
CONCLUSION
A new single-phase single-stage CHB five-level inverter with boost voltage ability has been proposed in this paper. The proposed inverter has the following main features as: five-level output voltage, reduction in number of passive components and shoot-through immunity. With the simple PID controller, a constant capacitor voltage can be achieved with an excellent transient performance which enhances the rejection of disturbance, including the input voltage and load current variations. Also, circuit analysis and PWM control strategy for the proposed system are shown. Simulation and experimental results are shown to verify the validity of the proposed qCHB-FLBI.
REFERENCES
[1] S. Kouro, M. Malinowski, K. Gopakumar, J. Pou, L. G. Franquelo, B. Wu, J. Rodriguez, M. A. Pérez, and J. I. Leon, “Recent advances and industrial applications of multilevel converters,” IEEE Trans. Ind. Electron., vol. 57, no. 8, pp. 2553– 2580, Aug. 2010.
[2] M. Malinowski, K. Gopakumar, J. Rodriguez, and M. A. Pérez, “A survey on cascaded multilevel inverters,” IEEE Trans. Ind. Electron., vol. 57, no. 7, pp. 2197– 2206, July 2010.
[3] G. Farivar, B. Hredzak, and V. G. Agelidis, “A DC-side sensorless cascaded H-bridge multilevel converter-based photovoltaic system,” IEEE Trans. Ind. Electron., vol. 63, no. 7, pp. 4233–4241, July 2016.
[4] J. Chavarría, D. Biel, F. Guinjoan, C. Meza, and J. J. Negroni, “Energy-balance control of PV cascaded multilevel grid-connected inverters under level-shifted and phase-shifted PWMs,” IEEE Trans. Ind. Electron., vol. 60, no. 1, pp. 98–111, Jan. 2013.
[5] M. Coppola, F. D. Napoli, P. Guerriero, D. Iannuzzi, S. Daliento, and A. D. Pizzo, “An FPGA-based advanced control strategy of a grid-tied PV CHB inverter,” IEEE Trans. Power Electron, vol. 31, no. 1, pp. 806–816, Jan. 2016.
[6] E. Villanueva, P. Correa, J. Rodríguez, and M. Pacas, “Control of a single-phase cascaded H-bridge multilevel inverter for grid-connected photovoltaic systems,” IEEE Trans. Ind. Electron., vol. 56, no. 11, pp. 4399–4406, Nov. 2009.
[7] G. Farivar, C. D. Townsend, B. Hredzak, J. Pou, and V. G. Agelidis, “Low-capacitance cascaded H-bridge multilevel StatCom,” IEEE Trans. Power Electron, vol. 32, no. 3, pp. 1744–1754, Mar. 2016.
[8] F. Khoucha, S. M. Lagoun, K. Marouani, A. Kheloui, and M. E. H. Benbouzid, “Hybrid cascaded H-bridge multilevel-inverter induction-motor-drive direct torque control for automotive applications,” IEEE Trans. Ind. Electron., vol. 57, no. 3, pp. 892– 899, Mar. 2010.
[9] S. Vazquez, J. I. Leon, J. M. Carrasco, L. G. Franquelo, E. Galvan, M. Reyes, J. A. Sanchez, and E. Dominguez, “Analysis of the power balance in the cells of a multilevel cascaded H-bridge converter,” IEEE Trans. Ind. Electron., vol. 57, no. 7, pp. 2287–2296, Jul. 2010.
[10] J. Napoles, A. J. Watson, J. J. Padilla, J. I. Leon, L. G. Franquelo, P. W. Wheeler, and M. A. Aguirre, “Selective harmonic mitigation technique for cascaded H-bridge converters with nonequal DC link voltages,” IEEE Trans. Ind. Electron., vol. 60, no. 5, pp. 1963–1971, May 2013.