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Cascaded H-Bridge MLI and Three-Phase Cascaded VSI Topologies for Grid-Connected PV Systems with Distributed MPPT
摘要： Cascaded multilevel inverter topologies have received a great deal of attention for grid-connected PV systems. In this paper, three-cascaded multilevel inverter configurations are proposed for grid-connected PV applications. These are the three-phase cascaded H-bridge multilevel inverter topology, three-phase cascaded voltage-source inverter topology using inductors, and three-phase cascaded voltage-source inverter topology using coupled transformers. Distributed maximum power point tracking (MPPT) of PV modules using perturbation and observation algorithm is used for all presented topologies. In all presented configurations, each PV module is connected to one DC-DC isolated ?uk converter for best MPPT achievement. Simulation is achieved by using the SIMULINK environment. The simulation results show that the three proposed topologies function well in improving the grid’s power quality. The grid currents are kept in phase with the grid voltage to ensure unity power factor, and the THD of the grid currents are within the acceptable range. The proposed topologies are experimentally implemented in the lab, and the switching pulses are generated with the help of the MicroLabBox data acquisition system. Comparing the three topologies according to the number of switches, voltage, and current stresses on switches and THD of the generated voltages and grid currents and according to the efficiency has been achieved in this paper, both experimentally and by simulation. The simulation and experimental results and comparisons are presented to verify the proposed topologies’ effectiveness and reliability.
关键词： voltage-source inverter,power quality,distributed MPPT,cascaded multilevel inverter,grid-connected PV systems,H-bridge
更新于2025-09-23 15:22:29
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[IEEE 2019 IEEE PES Innovative Smart Grid Technologies Conference - Latin America (ISGT Latin America) - Gramado, Brazil (2019.9.15-2019.9.18)] 2019 IEEE PES Innovative Smart Grid Technologies Conference - Latin America (ISGT Latin America) - Control of Split-Source Cascaded Multilevel Inverter (SS-CMI) for Single-Phase Grid-Connected Photovoltaic Systems
摘要： The exponential growth of distributed generation has driven the development of new technologies for grid connection. Among them, the converters and control strategies are constantly improved in order to guarantee high efficiency, good dynamic performance and quality of output harmonic content. The Split-Source Inverter (SSI) was proposed as an alternative for the Impedance-Source Inverter (ZSI). Furthermore, several multilevel topologies have been originated from the ZSI including the Cascaded Multilevel Inverter (CMI), however, the CMI has not been investigated for the SSI. Therefore, this paper proposes a control strategy for the SS-CMI, due its interesting characteristics, such as low harmonic content and reduced voltage stress across the switches. The whole control system includes individual Maximum Power Point Tracking (MPPT) for each photovoltaic (PV) array and controllers for grid current and dc-bus voltages. Simulation results based on a five-level system are performed aiming to explore the response of the system to forced variations of irradiance, temperature and a grid voltage swell.
关键词： Photovoltaic Generation Systems,Split Source Inverter,Cascaded Multilevel Inverter
更新于2025-09-16 10:30:52
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[IEEE IECON 2019 - 45th Annual Conference of the IEEE Industrial Electronics Society - Lisbon, Portugal (2019.10.14-2019.10.17)] IECON 2019 - 45th Annual Conference of the IEEE Industrial Electronics Society - A Secondary Classification Fault Diagnosis Strategy Based on PCA-SVM for Cascaded Photovoltaic Grid-connected Inverter
摘要： The cascaded H-bridge multilevel inverter for grid-connected photovoltaic(PV) system has the advantages of high power quality and easy modularization, but as the levels of the inverter increase, the failure probability of the power switching devices will also increase. In the open-circuit faults of the power switching devices, there are two groups of similar faults that are difficult to distinguish. To solve this problem, a secondary classification fault diagnosis strategy based on PCA-SVM is proposed. The first classification is used to make a preliminary fault diagnosis between all types of faults, the second classification is to make a further diagnosis of the two groups of similar faults. Finally, compared with other fault diagnosis strategies, the proposed strategy improves the accuracy of fault diagnosis.
关键词： Fault Diagnosis,Photovoltaic System,Principal Components Analysis,Cascaded Multilevel Inverter,Support Vector Machine
更新于2025-09-16 10:30:52
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A Fault Diagnosis Strategy Based on Multilevel Classification for a Cascaded Photovoltaic Grid-Connected Inverter
摘要： In this paper, an effective strategy is presented to realize IGBT open-circuit fault diagnosis for closed-loop cascaded photovoltaic (PV) grid-connected inverters. The approach is based on the analysis of the inverter output voltage time waveforms in healthy and faulty conditions. It is mainly composed of two parts. The first part is to select the similar faults based on Euclidean distance and set the specific labels. The second part is the classification based on Principal Component Analysis and Support Vector Machine. The classification is done in two steps. In the first, similar faults are grouped to do the preliminary diagnosis of all fault types. In the second step the similar faults are discriminated. Compared with existing fault diagnosis strategies for several fundamental periods and under different external environments, the proposed strategy has better robustness and higher fault diagnosis accuracy. The effectiveness of the proposed fault diagnosis strategy is assessed through simulation results.
关键词： fault diagnosis,support vector machine,cascaded multilevel inverter,principal components analysis,closed-loop photovoltaic system
更新于2025-09-16 10:30:52
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Analysis for the Minimization of Leakage and Common Mode Currents in Cascaded Half-Bridge PV Fed Multilevel Inverter
摘要： This paper gives the detailed study and analysis of the terminal voltage and the common mode voltage (CMV) for the photovoltaic (PV) fed cascaded half-bridge (CHB) multilevel inverter (MLI). The expression for the terminal voltage and CMV are also derived using switching function. The analytical waveforms obtained using the expression of the terminal voltage and CMV clearly indicate that the terminal voltage and CMV are not constant simultaneously. Thus, two PWM schemes are proposed using redundant states concept for CHB nine-level MLI without the addition of any extra circuit element. The first PWM scheme reduces the high-frequency transitions in the terminal voltage and thus, minimises the leakage current. The other PWM scheme is designed to reduce the common mode current by maintaining CMV constant. Further, the proposed PWM schemes are compared with the conventional PWM schemes. And the effect of each PWM schemes on the terminal voltage and CMV are analyzed using the given switching function analysis. The given switching function analysis is also supported with the help of simulation and experimental results. The simulation and experimental results of the proposed PWM schemes are further compared with the conventional SPWM technique.
关键词： Cascaded multilevel inverter,leakage current,common mode current,common mode voltage,terminal voltage
更新于2025-09-04 15:30:14