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oe1(光电查) - 科学论文

213 条数据
?? 中文(中国)
  • Power Quality Improvement of Grid-Connected Photovoltaic Systems Using Trans-Z-Source Inverter Under Partial Shading Condition

    摘要: Voltage-source inverter has been used widely in traditional photovoltaic systems which have limitations. To overcome, Z-source inverter has been introduced. In spite of all the features introduced in Z-source inverter, its configuration has been improved over the years, like trans-Z-source inverter which has added advantages compared to traditional inverters, namely buck–boost feature, lesser passive elements, and higher voltage boost gain. In this paper, photovoltaic arrays are connected to the grid via the trans-Z-source inverter with the aim of improving its power quality. Moreover, the shoot-through duty ratio is kept constant in the switching control method to add features like lower voltage stress (higher reliability), lower total harmonic distortion (lower maintenance cost), and higher voltage boost ratio. To evaluate the precision of the proposed system, the photovoltaic system is simulated on a standard grid and under partial shading condition which brings about voltage sag, and hence, a dynamic voltage restorer is used to mitigate voltage sag. Simulation results are presented to verify the validation of the proposed photovoltaic system in terms of voltage and current THD reducing 78.2% and 19.7%, respectively.

    关键词: PV system,DVR,THD,Partial shading,Voltage sag,Trans-Z-source inverter

    更新于2025-09-23 15:19:57

  • [IEEE 2019 IEEE Conference on Energy Conversion (CENCON) - Yogyakarta, Indonesia (2019.10.16-2019.10.17)] 2019 IEEE Conference on Energy Conversion (CENCON) - The 9a??150 kHz Disturbance Characteristics of a Grid-connected Rooftop Photovoltaic system

    摘要: The usage of renewable energy is increasing in many countries, Indonesia included. This spike of interest is supported by its environmental-friendly nature and the fact that it is one of the most effective ways to combat global warming. Solar power plants are electricity generators with the ability to convert solar energy to electricity by using solar panels. However, solar power plants are indubitably dependent on solar energy, which can cause a fluctuation of output because solar energy is affected by weather and the cloud’s condition. Generally, solar power plants have a power electronics component called an inverter. Inverters are used to convert the output of solar panels, the direct current (DC), to alternating current (AC). The usage of power electronics such as inverters plus the fluctuation of the solar panel commonly cause disturbances .Inverters usually have a switching rate higher than 1 kHz, which can cause disturbance in the range of 9-150 kHz throughout the whole system .However, there is little to none standardization regarding how much emission it is allowed to radiate at the 9-150Khz. With the aforementioned concerns in mind, this writing discusses research regarding the characteristics of disturbance on the 9-150Khz frequency on the On-Grid solar power plants located at a gas station. Measurement is done on the output side of the solar inverter. The result of the research shows that the disturbance produced remains constant in correlation with changes in power, however the disturbance produced increases as the power output drops or rises during a short interval.

    关键词: photovoltaic,disturbance,9-150 kHz,inverter

    更新于2025-09-23 15:19:57

  • 3-Phase grid-connected building integrated photovoltaic system with reactive power control capability

    摘要: Recently, a tendency in the growing of grid-connected building integrated photovoltaic (BIPV) systems has been noticed in most countries. Hence, high penetration of PV power into the system network can be observed in many points in the network. This may cause severe problems on the distribution network due to the intermittent nature of PV systems. As a feasible solution, the reactive power capability of voltage source inverter in PV systems can be employed rather than approaching expensive grid infrastructures in the distribution network. The purpose of this study is to implement a 3-phase grid-connected (BIPV) system with reactive power control to regulate the system voltage and improve the system power factor. Subsequent to this, a specific system model has been designed and developed in MATLAB Simulink application. The selection of PV system specifications is based on practical system implementation. The inverter control system along with the reactive power control has been developed for the proper system operation at different system conditions to reduce the var compensation on the utility grid. Better system accuracy of the developed system model has been found by validating with real system data. The overall system performance has indicated that the effective utilization of reactive power control of a grid-connected PV system yields to a stable, reliable and cost-effective system network operation which reduces the heavy burden on the utility grid to control the PV system effects.

    关键词: Reactive power control,Voltage source inverter,Grid-connected PV system,Voltage regulation

    更新于2025-09-23 15:19:57

  • Methodology to Determine Photovoltaic Inverter Conversion Efficiency for the Equatorial Region

    摘要: Photovoltaic inverter conversion efficiency is closely related to the energy yield of a photovoltaic system. Usually, the peak efficiency (ηmax) value from the inverter data sheet is used, but it is inaccurate because the inverter rarely operates at the peak power. The weighted efficiency is a preferable alternative as it inherently considers the power conversion characteristics of the inverter when subjected to varying irradiance. However, since the weighted efficiency is influenced by irradiance, its value may not be appropriate for different climatic conditions. Based on this premise, this work investigates the non-suitability of the European weighted efficiency (ηEURO) for inverters installed in the Equatorial region. It utilizes a one year data from the Equatorial irradiance profile to recalculate the value of ηEURO. Furthermore, a new weighted efficiency formula for the Equatorial climate (ηEQUA) is proposed. Validation results showed that calculated energy yield with ηEQUA closely matched the real energy yield of 3 kW system with only 0.16% difference. It is envisaged that the usage of ηEQUA instead of ηmax or ηEURO will results in a more accurate energy yield and return of investment calculations for PV systems installed in Equatorial regions.

    关键词: equatorial climate,weighted efficiency,energy yield,PV inverter,conversion efficiency

    更新于2025-09-23 15:19:57

  • Performance analysis of the Single-Phase Grid-Connected Inverter of a photovoltaic system in water and wind applications

    摘要: Single-phase grid connected inverters are nowadays broadly developed and tested in various types of applications especially in photovoltaic systems. The main aim of the inverter control strategy is to extract the maximum energy from the PV system which corresponds to the maximum power at certain conditions. However, the MPPT methods are also important in other renewable energy conversion systems. This paper analyses the performance of a commercially available photovoltaic inverter in water and wind systems. Presented models are implemented in a laboratory test bench in the form of torque characteristics realised by an induction motor fed by the inverter with vector control. The parameters are scaled into relative variables to provide a proper performance comparison. Presented tests include step response to assess the performance of a system dynamic. The dynamic tests showed a fast response of the investigated systems. The MPPT tracking accuracy tested under realistic profiles is similar for both cases: 98% and 96% respectively for the wind and water systems. These results prove the satisfactory performance of the MPPT of the PV microinverter in these applications.

    关键词: Single-phase grid-connected inverter,wind turbine,water turbine,MPPT,photovoltaic system

    更新于2025-09-23 15:19:57

  • [IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Intermediate Band Challenge in InAs/GaAs Quantum Dot Solar Cell at Cryogenic Temperatures

    摘要: Medium voltage drives (MVDs) are commonly used in high-power applications and show significant impact on the overall system dynamics due to their large size and high power demand. Although detailed switching models for MVDs can be built using MATLAB/Simulink, such models cannot be used in large-scale simulation software for power system dynamic studies. To solve this problem, the dynamic load model for the medium voltage cascaded H-bridge multi-level inverter drive and induction motor systems, which is suitable for power system dynamic studies, is proposed in this paper. Analytical formula of the model is presented. The model includes the aggregated effect of an MVD, an induction motor, and their control system, and thus, it can accurately represent the dynamic responses of the motor drive system under disturbances. Both voltage and frequency dependence are considered in the model. The accuracy of the model is verified by a case study. A sensitivity study is conducted to evaluate the impact of the model parameter variation on dynamic response characteristics. The developed load model can be readily inserted in the large-scale power system simulation software for power system dynamic studies.

    关键词: power system dynamic studies,voltage dependence,load model,Cascaded H-bridge multi-level inverter,frequency dependence,medium voltage drives (MVDs)

    更新于2025-09-23 15:19:57

  • Computation of Power Extraction From Photovoltaic Arrays Under Various Fault Conditions

    摘要: Medium voltage drives (MVDs) are commonly used in high-power applications and show significant impact on the overall system dynamics due to their large size and high power demand. Although detailed switching models for MVDs can be built using MATLAB/Simulink, such models cannot be used in large-scale simulation software for power system dynamic studies. To solve this problem, the dynamic load model for the medium voltage cascaded H-bridge multi-level inverter drive and induction motor systems, which is suitable for power system dynamic studies, is proposed in this paper. Analytical formula of the model is presented. The model includes the aggregated effect of an MVD, an induction motor, and their control system, and thus, it can accurately represent the dynamic responses of the motor drive system under disturbances. Both voltage and frequency dependence are considered in the model. The accuracy of the model is verified by a case study. A sensitivity study is conducted to evaluate the impact of the model parameter variation on dynamic response characteristics. The developed load model can be readily inserted in the large-scale power system simulation software for power system dynamic studies.

    关键词: voltage dependence,power system dynamic studies,medium voltage drives (MVDs),frequency dependence,Cascaded H-bridge multi-level inverter,load model

    更新于2025-09-23 15:19:57

  • [IEEE 2018 4th IEEE International Conference on Emerging Electronics (ICEE) - Bengaluru, India (2018.12.17-2018.12.19)] 2018 4th IEEE International Conference on Emerging Electronics (ICEE) - Simulation Based Analysis of Grain Boundary in IBC Perovskite Solar Cells

    摘要: The active power filter (APF) that consists of a half-bridge leg and an ac capacitor is integrated in the single-phase quasi-Z-source inverter (qZSI) in this paper to avoid the second harmonic power flowing into the dc side. The capacitor of APF buffers the second harmonic power of the load, and the ac capacitor allows highly pulsating ac voltage, so that the capacitances of both dc and ac sides can be small. A model predictive direct power control (DPC) is further proposed to achieve the purpose of this new topology through predicting the capacitor voltage of APF at each sampling period and ensuring the APF power to track the second harmonic power of single-phase qZSI. Simulation and experimental results verify the model predictive DPC for the APF-integrated single-phase qZSI.

    关键词: Active power decoupling,second harmonic power,single-phase system,quasi-Z-source inverter,direct power control

    更新于2025-09-23 15:19:57

  • [IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Distribution Feeder Fault Comparison Utilizing a Real-Time Power Hardware-in-the-Loop Approach for Photovoltaic System Applications

    摘要: Power outages are a challenge that utility companies must face, with the potential to affect millions of customers and cost billions in damage. For this reason, there is a need for developing approaches that help understand the effects of fault conditions on the power grid. In distribution circuits with high renewable penetrations, the fault currents from DER equipment can impact coordinated protection scheme implementations so it is critical to accurately analyze fault contributions from DER systems. To do this, MATLAB/Simulink/RT-Labs was used to simulate the reduced-order distribution system and three different faults are applied at three different bus locations in the distribution system. The use of Real-Time (RT) Power Hardware-in-the-Loop (PHIL) simulations was also used to further improve the fidelity of the model. A comparison between OpenDSS simulation results and the Opal-RT experimental fault currents was conducted to determine the steady-state and dynamic accuracy of each method as well as the response of using simulated and hardware PV inverters. It was found that all methods were closely correlated in steady-state, but the transient response of the inverter was difficult to capture with a PV model and the physical device behavior could not be represented completely without incorporating it through PHIL.

    关键词: faults,photovoltaic inverter,short-circuit analysis,hardware-in-the-loop

    更新于2025-09-23 15:19:57

  • Grid-connected photovoltaic system employing a single-phase T-type cascaded H-bridge inverter

    摘要: This paper presents the control and application of a single-phase T-type nine-level cascaded H-Bridge (TCHB) multilevel inverter (MLI) topology. This paper focuses on the effectiveness of the TCHB and its control by presenting the inverter operation based on a PI current controller along with a Maximum Power Point Tracking (MPPT) scheme to realize a grid-tied photovoltaic (PV) system and a novel PWM method offering self-balancing at the DC-link capacitors. In order to attain gating signals for power transistors (IGBTs), the TCHB employs a PWM with one triangular carrier signal and eight reference signals. In addition, a mathematical modelling of the PWM method, along with a theoretical explanation of the self-balancing process has also been provided. To prove the effectiveness of the proposed TCHB topological design, it has been comparatively analysed against other fundamental MLI and symmetric CHB topologies. In addition, to corroborate the working of the control and the PV system application, levels ( ± 2Vdc, ± 2?Vdc, ± Vdc, ± ?Vdc, 0), simulation and hardware results have been presented.

    关键词: Nine-level inverter,Pulse Width-Modulation (PWM),Grid-connected,Photovoltaic (PV) system,T-type cascaded H-bridge

    更新于2025-09-23 15:19:57