- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
[IEEE 2018 IEEE Power & Energy Society General Meeting (PESGM) - Portland, OR, USA (2018.8.5-2018.8.10)] 2018 IEEE Power & Energy Society General Meeting (PESGM) - A Study on Control Strategy of PV inverter for Harmonic Mitigation in A Microgrid
摘要： This paper presents a study of the control strategies of three-phase grid-connected photovoltaic inverter to mitigate its harmonic current output and improve the power quality of the grid. The operation principle and topology of the PV inverter is analyzed by establishing the state-space mathematical model based on the adaptation of proportional resonant (PR) and quasi-proportional resonant (QPR) controllers. According to the characteristics of the PR and QPR controllers, the theories for mitigating harmonic currents are reviewed. A three-phase ac microgrid with grid-connected inverter systems is then built on Matlab/Simulink and the performances of the inverter controllers for harmonic mitigations are verified by comparing the simulation results.
关键词： quasi-PR controller,Three-phase grid-connected PV system,harmonic compensation,inverter
更新于2025-09-23 15:22:29
-
Polarization, inner and outer field and surface charge compensation of a molecular crystal
摘要： The polarization of molecules embedded in crystals is of fundamental importance for understand and modeling of dielectric properties of these materials. Typically, the simulations concern ideal crystals, meaning infinite objects lacking of any defect and of any truncation. But in real life, crystals of finite sizes, and containing defects, are used. In this work, we focus on the calculation of the polarization of crystals of 4-iodo-4’-nitrobiphenyl (belonging to the polar class mm2), by mimicking several finite sizes and analyzing the effects of surfaces. This simulation implies calculation of the inner electric field, starting from the dipole of each molecule or, for a better accuracy, of each atom in the crystal. Using the atomic/molecular polarizabilities, calculations are repeated iteratively until a self-consistency is achieved. These simulations enable calculation of the polarization of several kinds of crystal shapes, up to ca. 80 nm scale range. Needle-like crystals slightly enhance (10%) the average dipole moment in polar direction of the constituting molecules, compared to their values in vacuo, whereas plate-like crystals severely reduce it (ca. 50%). In real systems, the effects of screening charges on the crystal surfaces cannot be neglected. A simple model enables to calculate that the dipole of needle-like crystals, under the effect of compensating charges, can be reduced close to extinction. On the other hand, the situation of plate-like crystals does not differ significantly under the influence of screening charges.
关键词： polar crystals,compensation,outer electric field,polarization,surface charge density,inner electric field
更新于2025-09-23 15:21:21
-
Streamlining volumetric multi-channel image cytometry using hue-saturation-brightness-based surface creation
摘要： Image cytometry is the process of converting image data to flow cytometry-style plots, and it usually requires computer-aided surface creation to extract out statistics for cells or structures. One way of dealing with structures stained with multiple markers in three-dimensional images, is carrying out multiple rounds of channel co-localization and image masking before surface creation, which is cumbersome and laborious. We propose the application of the hue-saturation-brightness color space to streamline this process, which produces complete surfaces, and allows the user to have a global view of the data before flexibly defining cell subsets. Spectral compensation can also be performed after surface creation to accurately resolve different signals. We demonstrate the utility of this workflow in static and dynamic imaging datasets of a needlestick injury on the mouse ear, and we believe this scalable and intuitive approach will improve the ease of performing histocytometry on biological samples.
关键词： spectral compensation,image cytometry,surface creation,hue-saturation-brightness,histocytometry
更新于2025-09-23 15:21:21
-
Model Predictive Voltage Control Based on Finite Control Set with Computation Time Delay Compensation for PV Systems
摘要： For the conservativeness and computational delay of the traditional finite control set model predictive control (FCS-MPC), a multi-step model predictive voltage control method based on finite control set (FCS-MMPVC) with delay compensation method is proposed in this paper, and the proposed method is validated on a three-level three-phase voltage source PV inverter. In each control cycle, the twenty-seven voltage vectors for inverters are evaluated on line based on predictive model to obtain the optimal and suboptimal switching state. The selected switching state is optimal in two control cycle with the proposed method. Considering that the time spent in the actual sampling and calculation process cannot be ignored, the delay compensation is added in FCS-MMPVC algorithm. The simulation and experimental results show that the proposed method has good stability and reliability. Compared with the traditional FCS-MPC algorithm, the proposed method can reduce the difference significantly between the output voltage and the reference under the unbalanced and non-linear load, and the output voltage quality of the inverter is improved.
关键词： Delay compensation,Multi-step model predictive voltage control,PV inverter,Finite control set
更新于2025-09-23 15:21:21
-
[IEEE 2018 28th International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV) - Greifswald, Germany (2018.9.23-2018.9.28)] 2018 28th International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV) - Research on Hybrid Reactive Power Compensation Switch Based on Vacuum Switch
摘要： In the field of low and medium voltage reactive power compensation, the switching of capacitor groups based on phase-controlled switching technology is a better way than others. However, the accuracy and reliability of contacts switching point are the key factors affecting the work efficiency. It is technically difficult to meet all the requirements. In recent years, ABB has proposed a phase-choosing model based on the hybrid device composed of semiconductor and mechanical switches, which has a certain effect on suppressing the transient effect of reactive power compensation. Based on the ABB model, this paper presents an optimization model of Y- connection hybrid switching system of vacuum switch and power electronic device, and studies the switching strategy of the model. The simulation and the tests show its effectiveness in suppressing transient problems. Compared with the traditional phase-controlled switch technology, the new scheme will help the switch work in a wide phase range for avoiding transient effect. It is demanded that the new method has more tolerance to the dispersion of the operating mechanism, and more benefit to the realization of the flexible phase -choosing technology.
关键词： semiconductor,hybrid switch,reactive power compensation,DSP
更新于2025-09-23 15:21:21
-
Fabry–Perot Cavity Sensing Probe with High Thermal Stability for an Acoustic Sensor by Structure Compensation
摘要： Fiber Fabry–Perot cavity sensing probes with high thermal stability for dynamic signal detection which are based on a new method of structure compensation by a proposed thermal expansion model, are presented here. The model reveals that the change of static cavity length with temperature only depends on the thermal expansion coefficient of the materials and the structure parameters. So, fiber Fabry–Perot cavity sensing probes with inherent temperature insensitivity can be obtained by structure compensation. To verify the method, detailed experiments were carried out. The experimental results reveal that the static cavity length of the fiber Fabry–Perot cavity sensing probe with structure compensation hardly changes in the temperature range of ?20 to 60 °C and that the method is highly reproducible. Such a method provides a simple approach that allows the as-fabricated fiber Fabry–Perot cavity acoustic sensor to be used for practical applications, exhibiting the great advantages of its simple architecture and high reliability.
关键词： high thermal stability,thermal expansion model,structure compensation,Fabry–Perot cavity,acoustic sensor
更新于2025-09-23 15:21:21
-
A New Approach to Guided Wave Ray Tomography for Temperature-Robust Damage Detection Using Piezoelectric Sensors
摘要： In this paper, a new approach to guided wave ray tomography for temperature-robust damage detection with time-of-flight (TOF) temperature compensation is developed. Based on the linear relationship between the TOF of a guided wave and temperature, analyses show that the TOF of the baseline signal can be compensated by the temperature measurement of the inspected materials without estimating the temperature compensation parameters. The inversion is based on the optimization of the TOF misfit function between the inspected and compensated baseline TOFs of the guided waves, and is applied by the elastic net penalty approach to perform thickness change mapping in a structural health monitoring (SHM) application. Experiments that are conducted in isotropic plates by piezoelectric sensors demonstrate the effectiveness of the proposed method. According to the results, our approach not only eliminates the artefacts that are caused by a temperature variation from 25 ?C to 70 ?C but also provides more accurate and clearer imaging of damage than conventional ray tomography methods.
关键词： TOF,ray tomography,piezoelectric sensors,guided wave,structural health monitoring,temperature compensation
更新于2025-09-23 15:21:21
-
LCO-FLL control for single-phase utility integrated single-stage solar PV system
摘要： This study presents a limit cycle oscillator-frequency locked loop (LCO-FLL) control for single-phase utility integrated single-stage photovoltaic (PV) system. The proposed topology increases the utility of the voltage-source converter (VSC), particularly in the absence of PV generation. It has the potential to load harmonics current mitigation. It estimates harmonic free load current accurately with low computational requirement due to the absence of cumbersome mathematical algorithm and transformation techniques. It provides reactive power compensation, both in the absence and the presence of PV generation, improves transient response during dynamics in load and varying irradiance conditions. The total harmonic distortions of utility current and utility voltage, compliance the limit of the IEEE-519 standard. The proportional–integral (PI) regulator regulates the DC-link voltage of VSC input to the reference DC-link voltage. The incremental conductance-based technique derives the reference DC-link voltage. The dynamic behaviour of the LCO-FLL-based control is improved using a feed-forward loop for the PV power sharing. It also reduces loading on the PI controller. Test results demonstrate satisfactory performance of LCO-FLL-based control.
关键词： single-stage solar PV system,LCO-FLL control,proportional–integral (PI) regulator,incremental conductance-based technique,feed-forward loop,reactive power compensation,voltage-source converter (VSC),IEEE-519 standard,single-phase utility
更新于2025-09-23 15:21:21
-
[IEEE 2019 IEEE 3rd Conference on Energy Internet and Energy System Integration (EI2) - Changsha, China (2019.11.8-2019.11.10)] 2019 IEEE 3rd Conference on Energy Internet and Energy System Integration (EI2) - Harmonic Current Detection and Reactive Power Compensation Method for Photovoltaic System Based on FBD Method
摘要： In order to improve the equipment utilization of distributed photovoltaic power generation system, the harmonic and reactive currents generated by grid-connected photovoltaic can be accurately detected and compensated. A phase-locked loop based on second-order generalized integrator (SOGI-PLL) is introduced into the traditional FBD current detection method to separate the positive and negative sequence components of unbalanced voltage and detect the phase and frequency of reference voltage more accurately. The simulation results show that the algorithm can reduce the computational complexity and increase the detection accuracy and steady-state performance.
关键词： harmonic current detection,reactive power compensation,improved FBD method,grid-connected PV system,SOGI-PLL
更新于2025-09-23 15:21:01
-
[IEEE 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - Sozopol, Bulgaria (2019.9.6-2019.9.8)] 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers (CAOL) - Using Artificial Neural Network for Compensation of Semiconductor Thermistor Nonlinearity
摘要： A method for correcting the transformation function of a semiconductor thermistor using a nonlinearity compensator based on a three-layer perceptron is proposed. Using of computer simulation, the operability of the proposed method has been investigated, a comparative analysis has been carried out with polynomial compensators of nonlinearity.
关键词： compensation of nonlinearity,learning,perceptron,artificial neural network
更新于2025-09-23 15:21:01