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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Reduced-order Aggregate Model for Parallel-connected Grid-tied Three-phase Photovoltaic Inverters
摘要： Ratings of utility-scale grid-tied photovoltaic (PV) inverters are typically no more than 1 MVA. This implies that a large number of inverters are usually installed in utility-scale PV energy-conversion systems. Given the complexity of inverter dynamic models (typical models are high dimension and nonlinear), reduced-order models for inverters are critical for performance assessment and accurate representation of PV-system dynamics in the bulk power grid with limited computational burden. In this paper, we formulate a reduced-order model for parallel-connected grid-tied three-phase PV inverters that has the same structure and model order as a single inverter. We adopt a single-diode model for the PV modules, and each inverter is assumed to be a single-stage dc-ac voltage-source converter with an input dc-link capacitor and an LCL output filter. The control architecture includes a maximum power point tracking (MPPT) algorithm, a dc-link voltage controller, a reactive power controller, a current controller, and a phase-locked loop for grid synchronization. Numerical simulations demonstrate the computational benefits and accuracy of the reduced-order model.
关键词： photovoltaic inverter,Maximum power point tracking,three-phase inverter,model reduction
更新于2025-09-23 15:19:57
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A Modified High Voltage Gain Quasi-Impedance Source Coupled Inductor Multilevel Inverter for Photovoltaic Application
摘要： The quasi-impedance source inverters/quasi-Z source inverters (Q-ZSIs) have shown improvement to overwhelmed shortcomings of regular voltage-source inverters (VSIs) and current-source inverters (CSIs) in terms of efficiency and buck-boost type operations. The Q-ZSIs encapsulated several significant merits against conventional ZSIs, i.e., realized buck/boost, inversion and power conditioning in a single power stage with improved reliability. The conventional inverters have two major problems; voltage harmonics and boosting capability, which make it impossible to prefer for renewable generation and general-purpose applications such as drive acceleration. This work has proposed a Q-ZSI with five-level six switches coupled inverter. The proposed Q-ZSI has the merits of operation, reduced passive components, higher voltage boosting capability and high efficiency. The modified space vector pulse width modulation (PWM) developed to achieve the desired control on the impedance network and inverter switching states. The proposed PWM integrates the boosting and regular inverter switching state within one sampling period. The PWM has merits such as reduction of coupled inductor size, total harmonic reduction with enhancing of the fundamental voltage profile. In comparison with other multilevel inverters (MLI), it utilizes only half of the power switch and a lower modulation index to attain higher voltage gain. The proposed inverter dealt with photovoltaic (PV) system for the stand-alone load. The proposed boost inverter topology, operating performance and control algorithm is theoretically investigated and validated through MATLAB/Simulink software and experimental upshots. The proposed topology is an attractive solution for the stand-alone and grid-connected system.
关键词： impedance source,multilevel inverter,coupled inductors,space vector pulse PWM,photovoltaic connected inverter
更新于2025-09-23 15:19:57
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[IEEE 2019 8th International Conference on Renewable Energy Research and Applications (ICRERA) - Brasov, Romania (2019.11.3-2019.11.6)] 2019 8th International Conference on Renewable Energy Research and Applications (ICRERA) - The Closed Loop Controller Gain Characterization for Enhanced Current Quality in Solar Inverters Coupled with Weak Grid
摘要： Majority of solar installations are coming up in remote locations where the stiffness of the grid is very weak, enforces to connect solar inverters to weak grid. In weak grid scenario, solar inverter would inject harmonic current into the grid that affect the power quality of the system. The solar inverters are designed to operate with stiff grid in which the closed (feedback and feed forward) loop control is planned by considering absolute decoupling between the direct and quadrature grid injected current. With the conventional design speci?cations in weak grid scenario, the absolute decoupling between the direct and quadrature current cannot be achieved due to grid inductance. The improper decoupling would create the oscillations in the grid injected current that result in increased harmonic distortion. To compensate the current oscillations, the current controller feedback loop gain need to be designed by accessing the degree of coupling. Since the grid injected current sensed at the point of common coupling and transformed to DC quantities (direct current id and quadrature current iq) using synchronous angle, the same current oscillations appear in d-axis and q-axis current control loop. In this work, the d-axis and q-axis loop oscillations with respect to grid inductance are analyzed analytically. Based on the analysis the d-axis and q-axis PI controllers are designed independently unlike conventional PI controller to ensure not only faster dynamic response of the system but also improved power quality.
关键词： closed loop control,weak grid,PI controllers,current THD,Grid connected solar inverter,single stage transformer less grid connected inverter,Power quality
更新于2025-09-23 15:19:57
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Improvement of energy harvesting capability in grid-connected photovoltaic micro-inverters
摘要： In this paper, a multi-stage micro-inverter system depending on a dual neutral point clamped (D-NPC) inverter is developed for low power photovoltaic (PV) applications. The primary objectives of this study are determined as improving the performance of the proposed D-NPC inverter-based micro-inverter and its controller to ensure better system reliability and promote the overall efficiency. In comparison with conventional systems, the designed system provides many advantages: (1) utilization of lower rating switching components, (2) reduced switching frequency and voltage stress, (3) reduced the size of filter components, (4) higher efficiency, and (5) lower total harmonic distortion (THD). The weighted efficiency of the system is remarkably increased by the value of 2.15% compared to the conventional micro-inverter and reached 93.73%. Furthermore, the THD value of the output current is measured below 3% for the proposed system with the small size of passive filtering elements. Further, dynamic grid support and anti-islanding detection capabilities are provided through the utilized controller structure to fulfill grid codes. Consequently, obtained results demonstrate that the improved system can be a considerable candidate for photovoltaic micro-inverter applications in terms of weighted efficiency, output current THD, and reasonable cost.
关键词： efficiency,PV systems,D-NPC Inverter,dynamic grid support,micro-inverter
更新于2025-09-23 15:19:57
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[IEEE 2020 IEEE International Conference on Power Electronics, Smart Grid and Renewable Energy (PESGRE) - Cochin, India (2020.1.2-2020.1.4)] 2020 IEEE International Conference on Power Electronics, Smart Grid and Renewable Energy (PESGRE2020) - Maximum Power Point Tracking for Photovoltaic-Fed Multi-Source Switched Capacitor Based Multilevel Inverter
摘要： In this paper, a shifting carrier based maximum power point tracking (MPPT) algorithm for multisource converters is proposed. This MPPT algorithm is explained for both low frequency (constant carrier) and high frequency (triangular) carrier signals. The proposed algorithm is applied for a single stage multisource switched capacitor based multilevel inverter for grid connected and stand-alone photovoltaic applications. This converter features high gain, less component count, self capacitor charge balancing, better dispersed value of sources and increased source utilization. The importance of selecting an appropriate pulse width modulation technique for switched capacitor based inverters in order to maintain the capacitor charging time is explained. The proposed technique is able to track the maximum power under varying irradiance levels. The experimental results of the proposed algorithm is presented. The MPPT technique is analyzed and veri?ed in simulation for stand-alone and grid connected applications using MATLAB/Simulink platform.
关键词： multilevel inverter,Switched capacitor based converter,maximum power point tracking
更新于2025-09-23 15:19:57
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ICM based ANFIS MPPT controller for grid connected photovoltaic system
摘要： In this paper, grid-connected photovoltaic (PV) system is presented. PV system consists of a photovoltaic module, a boost converter, and voltage source inverter. ANFIS based ICM (Incremental Conductance Method) MPPT (Maximum Power Point Tracking) controller is utilized to produce gate signal for DC-DC boost converter. This controller is used for optimizing the total performance of the Photovoltaic system in turn the errors were reduced in Voltage Source Inverter (VSI). The grid-connected PV system performance is evaluated and harmonics occurred in the system are decreased. The proposed methodology is implemented in MATLAB/Simulink.
关键词： Photovoltaic (PV),Boost Converter,Incremental Conductance Method (ICM),ANFIS Controller,Voltage Source Inverter (VSI)
更新于2025-09-23 15:19:57
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Closed Loop Control of a Series Class-E Voltage-Clamped Resonant Converter for LED Supply with Dimming Capability
摘要： In this work, a new closed-loop control system is applied to a class-E resonant DC–DC converter with voltage clamp used for light-emitting diode (LED) supply. The proposed power topology was first described by Ribas et al. in a recent work. In the present paper, the LED current is sensed and used to implement a feedback control loop instead of the simplified feedforward scheme used in this previous reference. To design the control, a novel, simplified small-signal model is presented. This model is used to analyze the converter behavior as a function of the output power. The proposed approximation is significantly simpler than the multifrequency averaging technique normally used to analyze resonant converters. The feedback control loop is designed to reduce the LED low frequency current ripple while providing dimming control. Both the model and the control are verified by simulation and laboratory experimentation and the results obtained are in good accordance with the expected values.
关键词： small-signal dynamic model,light-emitting diode (LED) driver,high efficiency LEDs,resonant DC–DC converter,Class-E inverter,single-switch topology,closed-loop control,voltage clamp
更新于2025-09-23 15:19:57
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Inverter testing for verification of Hawaiian Electric Rule 14H
摘要： As utilities increasingly require inverters to perform grid-supportive functions, it is challenging to ensure that those functions are properly configured in the field. This paper presents details of inverter testing related to Hawaiian Electric’s latest rule 14H to validate that two commercial inverters from different manufacturers used in Hawaiian Electric territory were tested at the Energy System Integrations Facility (ESIF) at the National Renewable Energy Laboratory (NREL). The tests were conducted in conjunction with a field pilot project [7]. The inverters settings were configured using the same methods used by installers in the field, as prescribed by the inverter manufacturers. The inverter systems under test were connected to a PV emulator and to a grid simulator, as shown in Fig. 1.
关键词： Rule 14H,IEEE 1547-2018,UL 1741 SA,Hawaiian Electric,Inverter testing
更新于2025-09-23 15:19:57
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A strategy of PIa??+a??repetitive control for LCL-type photovoltaic inverters
摘要： Due to the traditional grid-connected current control method of single Proportional Integral (PI) and Repetitive Control (RC) strategies, the photovoltaic inverter output current will have a distortion problem, which can not only maintain the stability of the whole photovoltaic system, but also the current quality of the photovoltaic inverter grid-connected system is reduced in the case of high-order LCL photovoltaic inverter control system operation. So, a strategy of PI ? repetitive control in two-phase stationary frame is proposed. The introduction of the weighting coef?cient m of the PI controller branch can enhance the adjustment ability of the PI link and accelerate the responding speed to meet the dynamic characteristics of the entire operating system, while the other weighting coef?cient n on the repetitive controller branch can increase the correction capability and eliminate the steady-state error to meet system steady-state requirements. The scheme not only simpli?es the coordinate transformation and decoupling calculation process, but also improves the harmonics suppression ability of the photovoltaic inverter and reduces the total harmonic distortion rate of the grid-connected current. At the same time, with the load operation mode change, the system can also retain better stability and keep a fast dynamic response capability, and the grid current can be able to return to a stable state in one cycle. Finally, the effectiveness of theoretical analysis and the strategy is veri?ed by simulation.
关键词： Harmonics suppression,Repetitive controller,PI controller,PV inverter,Weighting coef?cient
更新于2025-09-23 15:19:57
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Performance investigation of grid integrated photovoltaic/wind energy systems using ANFIS based hybrid MPPT controller
摘要： The solar energy and wind energy are two natural, renewable energy resources for the mankind, for the energy supply without hassles that provided an avenue for its utilization. For the efficient of the resources, wind power generation is one of the options in association with a photovoltaic system for preserving solar energy. Hence the current system requires technology to be involved to control the operation to satisfy the major concern as initially a combinational hybrid system to keep track maximum power, DC voltage input and trade-off between renewable energy delivered for interconnections. The fluctuation in power for interconnection can be minimized by adaptive neuro fuzzy interference method (ANFIS) dependent maximum power point tracking (MPPT) system and microscopically trusted ANFIS based system. In this paper the hybrid MPPT controllers are compared that is with perturb-observe (P&O) and tip speed ratio (TSR) as one set of MPPT controller and another side incremental conductance method (ICM) and hill climb search (HCS) both the controllers are tested with the ANFIS. The proposed system to satisfy the defined objectives is modeled using MATLAB/SIMULINK software by connecting power grid system to inverter influenced by ANFIS controller.
关键词： PV system,PMSG,Hybrid system,MPPT,Voltage source inverter (VSI)
更新于2025-09-23 15:19:57