Total Harmonic Distortion Research Papers (original) (raw)

A new control strategy that combines the resonant controller and the repetitive-controller based on the disturbance-observer (RSCDO) for offgrid four-leg voltage source inverter (VSI) has been presented in this paper. The aim of the new... more

A new control strategy that combines the resonant controller and the repetitive-controller based on the disturbance-observer (RSCDO) for offgrid four-leg voltage source inverter (VSI) has been presented in this paper. The aim of the new controller is to regulate the inverter output voltage, reducing as much as possible the voltage total harmonic distortion (THDv) in every load condition. The resonant controller allows to adjust the voltage at the fundamental harmonic, while the repetitive observer is able to compensate the voltage distortions due to inverter nonlinearity. The proposed strategy has been at first validated by means of simulation results performed in MATLAB/Simulink environment. Then, the new control strategy has been implemented in field-programmable gate array (FPGA) using LabView environmental and experimental results are performed on the 40 kVA three-phase 4-leg VSI prototype.

The integration of distributed generation like solar and wind are increasing nowadays due to fossil fuel reduction and increased carbon emission. Many integration issues arise of connecting Solar PV to the grid out of which power quality... more

The integration of distributed generation like solar and wind are increasing nowadays due to fossil fuel reduction and increased carbon emission. Many integration issues arise of connecting Solar PV to the grid out of which power quality is the important factor. Higher PV injection causes undesirable technical impacts on the distribution networks which leads to power quality issues. This paper studies the impact of PV on the power quality of the utility grid with different levels of penetration of solar energy into the grid. The power quality of the grid is studied using the Total harmonic distortion (THD) by performing Fast Fourier Transform (FFT) analysis. This paper deals with the development of controllers for boost converter and grid tied inverters which minimizes the harmonics due to solar PV system and power converters in grid connected PV system. The Maximum Power Point Tracking (MPPT) for boost converter and Hysteresis current control (HCC) for inverter has been designed and implemented in grid connected PV system. The hysteresis current controller for the inverter has been specifically designed to reduce the THD of the system meeting IEEE519_1992 regulations. The simulation model of the grid connected PV system has been designed in MATLAB 2018b version. The comparison studies are carried out in the PV system with and without hysteresis current controller, after which it can be concluded that, after the incorporation of the hysteresis current controller, the performance of the system is better in terms of power quality.

This paper presents the design and analysis of a parallel connected inverter configuration of. The configuration consists of parallel connected three-phase dc/ac inverter. Series resistors added to the inverter output to maintain same... more

This paper presents the design and analysis of a parallel connected inverter configuration of. The configuration consists of parallel connected three-phase dc/ac inverter. Series resistors added to the inverter output to maintain same current in each inverter of the two parallel inverters, and to reduce the circulating current in the parallel inverters to the minimum. High frequency third harmonic injection PWM (THIPWM) employed to reduce the total harmonic distortion and to make maximum use of the voltage source. DSP was used to generate the THIPWM and the control algorithm for the converter. Selected experimental results have been shown to validate the proposed system.

Two robust CMOS rail-to-rail OpAmp input stages are presented for low voltage (= 3 V) applications. The robust input stages are implemented using two recently reported universal approaches to achieve constant transconductance.... more

Two robust CMOS rail-to-rail OpAmp input stages are presented for low voltage (= 3 V) applications. The robust input stages are implemented using two recently reported universal approaches to achieve constant transconductance. Transconductance control circuit is also introduced to compensate for Kp, Kn mismatch of PMOS and NMOS differential pairs in the input stage. The input stages are designed for

This paper is based on the improvement of power quality (PQ) using fuel cell and fuzzy based controller. By using the proposed controller, the quality of power in the grid system especially in micro grid connected with non-linear and... more

This paper is based on the improvement of power quality (PQ) using fuel cell and fuzzy based controller. By using the proposed controller, the quality of power in the grid system especially in micro grid connected with non-linear and unbalanced load is enhanced. The configuration of the system is combined with hybrid arrangement of photovoltaic ([PV) with wind energy conversion system (WECS), fuel cell (FC) including the compressed air energy storage system (CAES) where the power management is controlled by using the distributed power sharing technique. In this proposed system the distortions in voltage at point of common coupling (PCC) is decreased by using the FC which acts as compensator in hybrid system. Reference current is developed which depends on real and reactive power of the source connected to the compensator. Based on demand of power for nonlinear load, without using any external communication interfaces, the proposed control theory can change the modes of operation and can compensate the unbalance in the system which is caused due to single-phase micro sources and load changes. The complete productive design of the micro-sources and power electronic converters are presented in the paper. The operation and performance of the proposed controller used in microgrid is validated through simulation in MATLAB/Simulink environment.

"The general trends in the past decade of increasing solar cell efficiency, decreasing PV system costs, increasing government incentive programs, and several other factors have all combined synergistically to reduce the barriers of entry... more

"The general trends in the past decade of increasing solar cell efficiency, decreasing PV system costs, increasing government incentive programs, and several other factors have all combined synergistically to reduce the barriers of entry for PV systems to enter the market and expand their contribution to the global energy portfolio. The shortcomings of current inverter functions which link PV systems to the utility network are becoming transparent as PV penetration levels continue to increase. In this paper an analysis of solar system connected with the grid has been done. The system is subjected with two types of perturbations, i.e. variable load and the variable irradiance level which changes the output of the solar system. The design, modeling, and analysis of a grid-tied PV system are performed in the MATLAB software simulation environment. Solar cell works on the principle of photo voltaic effect, which has nonlinear voltage and current characteristics. These characteristics are improved with the help of maximum power point tracking (MPPT) controller. MPPT controller helps to feed the inverter with maximum power from the solar system. Results indicate that in the presence of grid disturbances the inverter can react dynamically to help restore the power system back to its normal state. A harmonic analysis was also performed indicating the inverter under study met the applicable power quality standards for distributed energy resources Anjali | Gourav Sharma""Power Quality Improvement in Grid Connected PV System"" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-1 | Issue-4 , June 2017, URL: http://www.ijtsrd.com/papers/ijtsrd2196.pdf
Article URL: http://www.ijtsrd.com/engineering/electrical-engineering/2196/power-quality-improvement-in-grid-connected-pv-system/anjali"

Durante muchos años, músicos y personas afines a la música han expresado su preferencia con respecto a preamplificadores realizados con válvulas termoiónicas, argumentando “calidad de sonido” en desmedro de los equipos basados en... more

Durante muchos años, músicos y personas afines a la música han expresado su preferencia con respecto a preamplificadores realizados con válvulas termoiónicas, argumentando “calidad de sonido” en desmedro de los equipos basados en tecnología de estado sólido. En el presente trabajo se realiza un análisis teórico y una simulación que permita explicar esta predilección. Se elabora una comparación centrada en el comportamiento de los dispositivos semiconductores BJT y las válvulas triodo en un circuito preamplificador clase A, analizando la distorsión armónica presente en la señal de salida y su efecto en el oyente. Finalmente se diseña y simula en un entorno de laboratorio virtual una etapa preamplificadora basada en cada dispositivo y se analizan los resultados según lo expuesto.

One of the most crucial problems in distribution networks (DNs) is islanding detection. This paper presents a new Gibbs phenomenon-based hybrid method for islanding detection in low voltage (LV) DNs, which is essentially based on a... more

One of the most crucial problems in distribution networks (DNs) is islanding detection. This paper presents a new Gibbs phenomenon-based hybrid method for islanding detection in low voltage (LV) DNs, which is essentially based on a combination of active and passive methods of frequency rate of change at a given moment and measurement of constant total harmonic distortion (THD). The proposed method exploits Gibbs phenomenon occurring at the interpolation of sinusoidal functions. Beside identification of Gibbs phenomenon, root mean square (RMS) of the voltage is tracked in parallel with THDU for firm islanding detection. Finally, to prove the effectiveness of the proposed islanding detection strategy, offline digital time-domain simulation studies have been performed on a test microgrid including voltage-sourced converter (VSC)-based renewable/ distributed energy resources (RERs/DERs) in MATLAB/Simulink environment for different configurations and load conditions and the results have been verified by comparing with previously-reported methods. The results indicate that the proposed method performs fast and precise islanding detection in both low-power and high-power LV microgrids with reasonable impact on power quality (PQ) according to EN 50160 standard. By combining these fields as active and passive techniques, the proposed hybrid method gives non detection zones (NDZs) and detection time (DT) much smaller compared with frequency-and harmonic-based individual islanding detection methods. Index Terms-Distributed energy resources, frequency rate of change, islanding detection, power quality, total harmonic distortion. NOMENCLATURE X(t) New interpolated function, A Signal amplitude having frequency f1, B Signal amplitude having frequency f2, f1 frequency of DG that is 52 Hz, f2 frequency of DN that is 50 Hz RMSU Root mean square value of voltage signal, D. Mlakić is with the Department of Measurement and Network Management in Electrical Energy Systems, Distribution Area, Centar", JP Elektroprivreda HZ HB" d.d,

This paper presents direct torque control (DTC) methodology for a four-switch three-phase (FSTP) inverter-fed permanent magnet brushless ac (PM BLAC) machine, with reference to a conventional six-switch three-phase (SSTP) inverter. It has... more

This paper presents direct torque control (DTC) methodology for a four-switch three-phase (FSTP) inverter-fed permanent magnet brushless ac (PM BLAC) machine, with reference to a conventional six-switch three-phase (SSTP) inverter. It has been found that when derived from conventional voltage model flux estimation scheme, the predicted stator flux imbalance may be caused by unbalanced inverter voltage drop in the FSTP inverter, in which one phase winding is directly connected to dc-link midpoint. While this imbalanced problem does not adversely affect the performance of current-model-based DTC, it causes significantly nonsinusoidal current waveforms and considerably unbalanced current magnitudes in voltage-model-based DTC. A new compensation scheme taking into account the different forward voltage-drop values in the switching device and the freewheeling diode is proposed for the voltage-model-based DTC to correct for stator flux imbalance via the addition of corrective voltages to flux equations. The proposed scheme has significantly improved the shape of current waveforms with satisfactory balanced magnitudes, total harmonic distortion, and torque ripple factor, as verified by both simulation and experimental results. It has been shown that it is possible for an FSTP inverter to provide similar performance to an SSTP inverter when driving a PM BLAC machine.

This paper offers a two-stage boost converter for a single-phase inverter without transformer for PV systems. Each stage of the converter is separately controlled by a pulse width modulated signal. A Simulink model of the converter using... more

This paper offers a two-stage boost converter for a single-phase inverter without transformer for PV systems. Each stage of the converter is separately controlled by a pulse width modulated signal. A Simulink model of the converter using efficient voltage control topology is developed. The proposed circuit performance characteristics are explained and the obtained simulation results are confirmed through the applied experiments. Moreover, this paper has examined the control circuit of a single-phase inverter that delivers a pure sine wave with an output voltage that has the identical value and frequency as a grid voltage. A microcontroller supported an innovative technology is utilized to come up with a sine wave with fewer harmonics, much less price and an easier outline. A sinusoidal pulse width modulation (SPWM) technique is used by a microcontroller. The developed inverter integrated with the two-stage boost converter has improved the output waveform quality and controlled the dead time as it decreased to 63 µs compared to 180 µs in conventional methods. The system design is reproduced in Proteus and PSIM Software to analyze its operation principle that is confirmed practically. 1. INTRODUCTION The quality of load matching of Photovoltaic (PV) and AC load types has considered one of the urging problems. The key solution of such a problem has been characterized by the inverter configuration and its capability of supplying pure sine wave and controlled voltage limit for AC loads. The line frequency transformers (LFT) employed in the grid side of transformer-type PV inverters are large and heavyweight, therefore, such inverter systems are bulky and tough to install, while high-frequency transformers (HFT) utilized on the dc-dc stage are much smaller than the line frequency transformer. Nevertheless, they have many power stages that raise the system complexity and decrease both the overall efficiency and system reliability [1-5]. Now, the focus has become to get the extreme energy from the PV system and step up PV output voltage from 24 V to 100 V then to 312 V, because of the high cost of the photovoltaic modules. Hence, the 312 VDC is inverted to AC 220 V (RMS value) successfully by means of single-phase inverter. The requirement of the power rating inverter is increased to run the electrical and digital home equipment efficiently. The majority of the available commercially uninterruptible power. Supplies (UPSs) are quasi-sine wave inverters or square wave inverters. If an electronic device operated by these inverters, it will be damaged because of the contents of the harmonics [6, 7]. The generation of a pure wave is significance in