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[IEEE 2018 IEEE International Conference on Electrical Engineering and Photonics (EExPolytech) - Saint Petersburg, Russia (2018.10.22-2018.10.23)] 2018 IEEE International Conference on Electrical Engineering and Photonics (EExPolytech) - Signal Distortion Decreasing in Envelope Tracking Power Amplifiers
摘要： When amplifying signals with a high peak to average power ratio, the efficiency of linear radio frequency (RF) power amplifiers (PA) is reduced to about 30%. This flaw can be noticeably corrected by using envelope tracking technology. However, using switched mode PAs of envelope signal (ES) is accompanied by the emergence of nonlinear distortions, which can appear as undesirable components in the RF PA signal spectrum. One of the ways to reduce the negative influence of the switched mode is to use ES PA of multicell structure. The paper covers the issues of the ES PA number of cells influence on its efficiency and output signal distortion, as well as its influence on the efficiency and output signal distortion of the RF PA. It is shown that rational choice of the number of cells allows to increase the efficiency of ES PA from 94 through 98% and to reduce the level of intermodulation components in the envelope signal spectrum by 20 ... 25 dB.
关键词： envelope tracking,power amplifier,harmonic distortion,efficiency,multicell
更新于2025-09-23 15:23:52
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[IEEE 2018 VII. Lighting Conference of the Visegrad Countries (Lumen V4) - Trebic, Czech Republic (2018.9.18-2018.9.20)] 2018 VII. Lighting Conference of the Visegrad Countries (Lumen V4) - Electrical Parameters of Dimmable Luminaire
摘要： Lighting systems are currently one of the main uses of electricity. The most popular option for reducing of electricity consumption is the use of dimming. Dimming is a type of regulation in which we can regulate luminous flux of a lamps and luminaires. This system of regulation is used in the road lighting industry, but also in households. Dimming allows adaptation of the lighting system according to specific requirements and various ambient conditions such as traffic density, daylight, etc. The regulation of the luminous flux depending on the dimming system can affect the electrical parameters of the luminaires such as the power factor. The article deals with the electrical parameters of luminaires with various lamps at different types of dimming.
关键词： LED,total harmonic distortion,Power factor
更新于2025-09-23 15:21:21
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[IEEE 2019 7th International Renewable and Sustainable Energy Conference (IRSEC) - Agadir, Morocco (2019.11.27-2019.11.30)] 2019 7th International Renewable and Sustainable Energy Conference (IRSEC) - Power Quality Improvement of A Photovoltaic Active Power Filter using A Fuzzy Hysteresis Band Current Controller
摘要： This paper investigates a Fuzzy Hysteresis Band Current Control technique (Fuzzy-HBCC) for a Photovoltaic active power ?lter connected at PCC to the AC grid and a non-linear load. This connection offers good bene?ts of producing PV power as well as ensuring the power quality enhancement. In order to demonstrate the ef?ciency of the proposed system command using Fuzzy-HBCC, Fuzzy Vdc controller and Fuzzy-MPPT controller; several simulation cases have been carried out under an online solar variation, and a variable/?xed ignition angle of the nonlinear load. The proposed Fuzzy band current control technique (Fuzzy-HBCC) is developed and compared by simulation, in a Matlab/Simulink environment, with an adaptive Hysteresis controller (adaptive-HBCC) and a ?xed Hysteresis controller (?xed-HBCC) which require mathematical model determination. The results show the robustness of the proposed Photovotaic active power ?lter system with a better dynamic response and signi?cant reduction in Total harmonic distortion levels even under a sudden variation of the nonlinear load and of solar irradiance.
关键词： photovotaic active power ?lter,fuzzy band current control technique,dynamic response,total harmonic distortion
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE 2nd International Conference on Automation, Electronics and Electrical Engineering (AUTEEE) - Shenyang, China (2019.11.22-2019.11.24)] 2019 IEEE 2nd International Conference on Automation, Electronics and Electrical Engineering (AUTEEE) - Influence of Grid-connected Photovoltaic Systems on Power Quality
摘要： This paper reviews the power quality indicators and evaluation methods specified in the IEEE. Based on the experiments, the power quality problems caused by the switching of small-scale single-phase photovoltaic (PV) systems and large-scale three-phase PV power plants are analyzed. Meanwhile, under the state of PV systems input and cut-out, the influence of load switching of different properties on power quality is analyzed. Experiments show that the switching of PV systems will lead to voltage sags and impulsive transients, as well as current waveform distortion. However, the input of PV systems has a good restraint effect on voltage sags and impulsive transients caused by loads switching.
关键词： impulsive transients,voltage sags,photovoltaic systems,unbalanced,harmonic distortion,power quality
更新于2025-09-23 15:21:01
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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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The application of compound proportional resonant control strategy in multiple PV inverters system
摘要： In order to eliminate the effect on the grid current caused by the background harmonic voltage and the reference signal on the grid connected multi-inverter, this paper adopts the double closed-loop feed-forward control strategy. This strategy is based on the inductor voltage and the grid-connected current, and the integrated control strategy of quasi-proportional resonance loop parallel to a specific harmonic compensation loop. Based on the closed-loop model of multiple inverters, the change curves of the transfer function of the two control strategies are compared with the feed-forward control and the composite proportional resonance. The two corresponding control methods are used to analyze the current quality of the multi-inverter impact. Finally, the MATLAB/Simulink simulation model is set up to verify the proposed control strategies. The simulation results show that the proposed method can achieve better tracking of the sinusoidal command signal at the fundamental frequency, and enhance the anti-interference ability of the system at the 3rd, 5th, and 7th harmonic frequency.
关键词： compound proportional resonant control,Grid-connected multi-inverter,background harmonics,total harmonic distortion (THD),feed-forward control
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE 26th International Symposium on the Physical and Failure Analysis of Integrated Circuits (IPFA) - Hangzhou, China (2019.7.2-2019.7.5)] 2019 IEEE 26th International Symposium on Physical and Failure Analysis of Integrated Circuits (IPFA) - Characterization of 1122nm Laser for Laser Based Fault Isolation Applications
摘要： This paper presents one of the first studies of the harmonic impact of a significantly large photovoltaic (PV) solar farm of 20 MW in a utility distribution system. This solar farm is a constituent of the 80-MW PV solar farm in Sarnia, Ontario, which is so far the largest solar farm in Canada. The utility network is modeled in detail using the commercial grade PSCAD/EMTDC software, which is validated through load flow studies conducted by CYME software and correlated with SCADA measurements. The validated network model is used for network resonance study and harmonics impact analysis of the solar farms under different network conditions. The harmonics data instrumented for several months were provided by the transmission utility at the two solar farm units and at the main feeder substation. These data were utilized for extensive harmonic impact studies with widely different short-circuit levels and network resonance conditions. This paper presents the detailed procedure adopted for performing such harmonic impact studies. It is concluded that this large solar farm may not cause any substantial voltage distortion on the distribution network during steady-state operating conditions. However, recommendations are made for utilities to perform such studies to ensure the safe operation of critical loads.
关键词： network resonance,total harmonic distortion,solar energy,harmonics,Distribution systems,total demand distortion,photovoltaic (PV) solar system,frequency scan
更新于2025-09-23 15:19:57
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Tracing harmonic distortion and voltage unbalance in secondary radial distribution networks with photovoltaic uncertainties by an iterative multiphase harmonic load flow
摘要： Secondary radial distribution networks (SRDNs) have been increasingly affected by the uncertainties of harmonic sources associated with photovoltaic (PV) systems. The quantitative assessment of uncertainty propagation causing harmonic distortion and voltage unbalance can be successively handled by probabilistic or affine formulations of harmonic load flows (HLFs). This study developed a general analytical technique (GAT) for solving iterative multiphase HLFs in SRDNs with PV uncertainties. This technique merges the point-estimate method (PEM) and complex affine arithmetic (AA), combined with Legendre series approximation (LGSA). It also models the input correlation. One advantage of this GAT is that the iterative harmonic penetration (IHP) method, modeled for HLF, accounts for the interaction of background harmonic voltage with the PV harmonic current. The first prerequisite was evidently an uncertainty model for PV harmonic current. This paper presents the results for a real unbalanced three-phase SRDN and compares them with those obtained with the Monte-Carlo simulation (MCS). These confirmed the accuracy of GAT as well as its lower computational cost. The numerical results obtained showed that the GAT outperformed the incomplete GAT (IGAT), which is solely based on PEM and Cornish-Fisher expansion, thanks to the ability of AA to bound the outputs used in the LGSA.
关键词： PV system,Unbalance,Complex affine arithmetic,Harmonic load flow,Harmonic distortion,Point estimate methods
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) - New designed electrode patterns on rear side of bifacial PERC solar cells
摘要： Present-day smartphones and tablets demand high audio fidelity (e.g., total harmonic distortion + noise, THD + N < 0.01%), and high noise immunity (e.g., power supply rejection ratio, PSRR > 80 dB) to allow high integration in an SoC. The design of conventional closed-loop pulse width modulation (PWM) Class-D amplifiers (CDAs) typically involves undesirable trade-offs between fidelity (qualified by THD + N), PSRR and switching frequency. In this paper, we propose a fully integrated CMOS CDA that embodies a novel input-modulated carrier generator and a novel phase-error-free PWM modulator, collectively allowing the employment of high loop-gain to achieve high PSRR, yet without compromising linearity/dynamic-range or resorting to high switching frequency. The prototype CDA, realized in 65 nm CMOS, achieves a THD + N of 0.0027% and a power efficiency of 94% when delivering 500 mW to an 8 ? load from VDD = 3.6 V. The PSRR of the prototype CDA is very high, –101 dB @217 Hz and 90 dB @1 kHz, arguably the highest to-date. Furthermore, the switching frequency of the prototype CDA varies from 320 to 420 kHz, potentially reducing the EMI due to spread-spectrum. In addition, the prototype CDA is versatile with a large operating-voltage range, with VDD ranging from rechargeable 1.2 V single battery to standard 3.6 V smart-device supply voltages.
关键词： Audio power amplifiers,power supply rejection ratio (PSRR),total harmonic distortion (THD),pulse width modulation (PWM),class D amplifiers
更新于2025-09-23 15:19:57
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Communication Compact CRLH Leaky-wave Antenna using TE20 Mode Substrate Integrated Waveguide for Broad Space Radiation Coverage
摘要： This paper introduces a combinational modulation method to be used in classic full-bridge single phase inverters. The proposed method eliminates even-order harmonics at the pulse width modulation (PWM) stage in the control section, unlike the conventional method of even order harmonic cancelation in the power stage, and offers a cost-effective design by switching one leg at high frequency. Using a low-cost digital signal controller platform, a regular sampling technique based on real-time calculation was employed to verify the feasibility of the proposed method on a 500-W single phase voltage source inverter. Performance characteristics, such as switching losses and harmonic distortions, are presented for the new approach and compared with a classic inverter modulation method.
关键词： switching frequency,Combinational logic circuits,inverters,pulse width modulation (PWM),silicon carbide,harmonic distortion
更新于2025-09-23 15:19:57