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Enhanced Active Power balancing capability of Grid connected Solar PV fed Cascaded H-bridge Converter
摘要： Cascaded H-bridge converter is a promising solution for next generation large scale PV system having both active and reactive power exchange capacity. However, one challenge with this converter is unbalanced power generation among the clusters or cells due to variation in radiation level, temperature, dusting on PV cells etc. In order to inject balanced power to the grid, in this paper, a controlled exchange of reactive power is proposed so that the converter can work with unbalanced power generation within the clusters. Magnitude of reactive power exchange is derived and necessary conditions discussed. Additionally, the magnitude of zero voltage is derived taking into account both active and reactive power exchange with the grid. By exchanging reactive power, the converter can also be used during low voltage ride through (LVRT) condition. This paper introduces a novel representation of unbalanced power generation using barycentric coordinate system which helps to identify regions in the power plane which require the exchange of reactive power. The proposed method is verified through computer simulation and in a laboratory prototype.
关键词： Maximum Power point tracking (MPPT),Active power,Zero sequence voltage,Reactive power,Solar Photovoltaic,Cascaded H-bridge multilevel converter(CHB)
更新于2025-09-23 15:23:52
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[IEEE 2019 International Conference on Intelligent Computing and Control Systems (ICCS) - Madurai, India (2019.5.15-2019.5.17)] 2019 International Conference on Intelligent Computing and Control Systems (ICCS) - Controlled PV Systems Power Quality Retention and Output Power Escalation
摘要： Due to the burden on fossil fuels the trend of generating power through renewable energy resources is gaining more importance day by day. In such systems there are issues related to efficiency and reliability. The paper focuses mainly on developing a model using MATLAB / SIMULINK software to overcome the above mentioned obstacles to the PV system and improve its overall performance by introducing appropriate control schemes. The aim of the PV system design is to escalate the output power under varying environmental conditions and also to retain the power quality of the PV system during faulty conditions. MPPT is applied to optimize through Incremental conductance thus ensuring the system is running at its maximum power point irrespective of the partial shading effect and temperature variations in the environment. With the employment of power quality compensation scheme that in turn uses a DVR, the system is capable of restoring the power quality thereby commuting the power quality issues. Significant fall in the THD levels is attained by usage of DVR control scheme along with a CHB multilevel DC/AC converter. The significance of developing MPPT algorithm is illustrated by examining the impact of partial shading condition and the temperature variations on its productivity. The demonstration of the power quality compensation capability of the PV system is achieved by the power quality compensation control scheme under faulty conditions.
关键词： Cascaded H-Bridge Multilevel Inverter (CHB),Incremental Conductance (IncCond),Total Harmonic Distortion (THD),Dynamic Voltage Restorer (DVR),Maximum Power Point Tracking (MPPT)
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE Industry Applications Society Annual Meeting - Baltimore, MD, USA (2019.9.29-2019.10.3)] 2019 IEEE Industry Applications Society Annual Meeting - Elimination of Phase Unbalance in Cascaded Multilevel Converters for Large-Scale Photovoltaic Grid Integration
摘要： Cascaded H-bridge converters (CHB) are ideal candidates for large-scale photovoltaic (PV) power plants because of their modular structure and the absence of bulky line frequency power transformer. To eliminate leakage current, isolated dc-dc converters are needed to connect the PV arrays to the H-bridges of CHB. These dc-dc converters extract maximum power from each PV array independently. Under partial shading conditions, the power generated in the three phases of CHB is different, leading to an unbalance in the grid currents. The existing methods to balance the grid currents require the converter to be overrated or operate at reduced PV power. So a new topology is proposed to distribute the power equally among the three phases of CHB without overrating the converter or reducing the PV power. This is achieved by using high-frequency transformers each having one primary and three secondaries. Simulation results are presented to validate the proposed topology.
关键词： grid integration,multilevel converter,phase unbalance,photovoltaic applications,Cascaded H-bridge (CHB) converter
更新于2025-09-16 10:30:52
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Direct measurement of electrostatic interactions between poly(methyl methacrylate) microspheres with optical laser tweezers
摘要： In this study, we measured the force of electrostatic interactions between poly(methyl methacrylate) (PMMA) particles dispersed in organic solvent mixtures of cyclohexyl bromide (CHB) and n-decane. Optical laser tweezers were employed to directly measure interactive forces between paired PMMA particles in a CHB medium that contained n-decane in various volume ratios. CHB, having a moderate dielectric constant, provided an environment with a high charge storage capacity. The addition of n-decane lowered the effective refractive index of the medium, which increased the optical trapping efficiency. We also fabricated microscope flow cells with a commonly used UV-curable adhesive and quantified the effects of dissolved adhesive compounds through interactive force measurements and nuclear magnetic resonance analysis. In addition, we studied the impact of CHB dissociation into H+ and Br? ions, which could screen electrostatic interactions.
关键词： UV-curable adhesive,NMR analysis,electrostatic interactions,optical laser tweezers,CHB,PMMA particles,n-decane
更新于2025-09-16 10:30:52
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Extended Reactive Power Exchange With Faulty cells in Grid tied Cascaded H-Bridge converter for Solar PhotoVoltaic Application
摘要： Fault tolerant operation is a key feature of grid tied PV fed Cascaded H-Bridge (CHB) converter, where the converter operates continuously with faulty bypassed cells. After bypassing the faulty cells, the number of healthy cells decreases, the available dc link voltage reduces and active power among the phases become unequal. As a result, the converter produces unbalanced and distorted grid currents. Moreover, the maximum reactive power exchanged with the grid gets reduced with the available DC link voltage. This paper injection proposes a novel zero sequence voltage technique for balancing the grid currents and preventing over modulation in each cell of the converter. The proposed technique extends the reactive power capability of the converter during post fault condition. Additionally, it also helps in equal active and reactive power flow in each phase of the converter. A new PWM clamping strategy is proposed in this paper to implement the zero sequence voltage addition in the converter. The proposed concept is verified through computer simulation and experimental results.
关键词： cascaded H-bridge (CHB) multilevel converters,PWM clamping strategy,solar PhotoVoltaic (PV),fault tolerance,reactive power,Ancillary services
更新于2025-09-11 14:15:04
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[IEEE 2018 International Conference on Smart Electric Drives and Power System (ICSEDPS) - Maharashtra State, India (2018.6.12-2018.6.13)] 2018 International Conference on Smart Electric Drives and Power System (ICSEDPS) - Cascaded H-Bridge Inverter based PV-STATCOM
摘要： The environmental effect and need of energy have been increasing rapidly, due to this demand for renewable resources increased. One of the renewable resources Solar Photovoltaic (PV) energy is presently most popular in the environment. An inverter is a necessary part of grid-connected PV systems. This paper presents a new approach of large-scale photovoltaic solar farm inverter as STATCOM, known as PV-STATCOM, for regulation of voltage at the point of common coupling which recovers the voltage stability of the transmission line. Over daytime, the solar PV farm generates active power, but stay in idleness at the night-time. In this paper, PV-STATCOM incorporating multilevel inverter is presented. The voltage at the PCC is regulated at different loading conditions using PV-STATCOM. The entire system modeling and study are performed using MATLAB/SIMULINK.
关键词： STATCOM,photovoltaic(PV),cascaded H-Bridge (CHB),flexible AC transmission system (FACTS),Pulse width modulation (PWM),neutral point clamped (NPC)
更新于2025-09-10 09:29:36