scholarly journals Harmonic elimination by SPWM and THIPWM techniques applied in photovoltaic inverters

Author(s):  
Falil Fatima ◽  
Bénabadji Nourddine

With advances in solid-state power electronic devices, control techniques (PWM) have been devised to obtain high dynamics responses from a multilevel power conditioning converter-Photovoltaic. This work discusses the advantages and drawbacks of two different PWM techniques, the sinusoidal (SPWM) technique and the Third harmonic injection PWM (THIPWM) technique. These two methods are compared by discussing their ease of implementation and by analyzing the output harmonic spectra of various output voltage and their total harmonic distortion (THD). The focus of this paper is the simulation study of single-phase inverter, three phases, two levels and three levels inverter for application photovoltaic. Firstly, single phase is modeled with inductive load and their waveforms are observed. Secondly, a two levels inverter, and three levels inverter are leading to the high industrial performances of the drives synchronous, especially, if a high-power quality is requested.

2021 ◽  
Vol 19 ◽  
pp. 577-582
Author(s):  
E. Kaufhold ◽  
◽  
J. Meyer ◽  
P. Schegner

This study demonstrates the frequency coupling in pulse width modulated (PWM) single-phase converters and inverters. As current state of the art, the harmonic frequency range, e.g. from fundamental frequency up to 2 kHz, is typically assessed separately from the so-called supraharmonic frequency range, i.e. above 2 kHz up to 150 kHz. The frequency coupling between the harmonic and supraharmonic frequency range has not been thoroughly studied and is currently often neglected in the design process as well as for the analysis of the emission of power electronic devices. The aim of this study is to analyse the behaviour of the frequency coupling between the harmonic and the supraharmonic range. In addition, laboratory measurements of a commercially available single-phase inverter for photovoltaic applications are shown to verify the findings.


The single phase inverter provides continuous AC power supplies without any interrupt .The idea is to serve sinusoidal AC output whose voltage and frequency can be controlled by PWM pulse. The main theme of this concept is to present a new construction of an FPGA based control techniques for inverter. In this proposed system, a PI controller is used to the single phase PWM voltage source inverter. It minimizes periodic distraction resulted from linear load. Simulation provides the results, with reduced harmonics distortion of the output voltage .and innovative technique for including a fuzzy logic controller through a usual sampled pulse-width modulator is reported. The FLC is used to decrease the harmonic distortion and to offer better standard regulation. Simulations are carried out in ALTERA-Quartus II 8.0 software in addition by means of Matlab/Simulink and the results are presented for various control techniques. FPGA controller is preferred for the real time realization of the switching approach, for the most part owing to its larger computation speed which is able to guarantee the precision of the PWM pulse is developed. At the concluding stage the FPGA is used as a PWM generator in order to apply the appropriate signals for inverter switches


Electronics ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 154
Author(s):  
Wei Yao ◽  
Jiamin Cui ◽  
Wenxi Yao

This paper presents a novel digital control scheme for the regulation of single-phase voltage source pulse width modulation (PWM) inverters used in AC power sources. The proposed scheme adopts two deadbeat controllers to regulate the inner current loop and the outer voltage loop of the PWM inverter. For the overhead of digital processing, the change of duty of PWM lags one carrier period behind the sampling signal, which is modeled as a first-order lag unit in a discrete domain. Based on this precise modeling, the deadbeat controllers make the inverter get a fast dynamic response, so that the inverter’s output voltage is obtained with a very low total harmonic distortion (THD), even when the load is fluctuating. The parameter sensitivity of the deadbeat control was analyzed, which shows that the proposed deadbeat control system can operate stably when the LC filter’s parameters vary within the range allowed. The experimental results of a 2kW inverter prototype show that the THD of the output voltage is less than 3% under resistive and rectifier loads, which verifies the feasibility of the proposed scheme. An additional advantage of the proposed scheme is that the parameter design of the controller can be fully programmed without the experience of a designer.


Author(s):  
K.C. Chen ◽  
S. Salimin ◽  
S. A. Zulkifli ◽  
R. Aziz

<span>This paper presents the harmonic reduction performance of proportional resonant (PR) current controller in single phase inverter system connected to nonlinear load. In the study, proportional resonant current controller and low pass filter is discussed to eliminate low order harmonics injection in single phase inverter system. The potential of nonlinear load in producing harmonics is showed and identified by developing a nonlinear load model using a full bridge rectifier circuit. The modelling and simulation is done in MATLAB Simulink while harmonic spectrum results are obtained using Fast Fourier Transfor. End result show PR current controller capability to overcome the injection of current harmonic problems thus improved the overall total harmonic distortion (THD).</span>


Author(s):  
Taha Ahmed Hussein

<p>Selective harmonic elimination technique SHE is adopted in this work to reduce the harmonic contents in single phase cascaded multilevel inverter. The firing instants for the electronic switches MOSFETs in the inverter are calculated off line for five level to thirteen level inverter. An Arduino microcontroller is programmed to cope with different topologies of the multilevel inverter. The implemented multi-level (MLI) inverter results are compared with Simulink simulation program and are found very close to each other. SHE technique works at system frequency (50 Hz or 60 Hz) and the switching losses are very small. The sinusoidal pulse width modulation SPWM requires a carrier frequency not less 20 times the system frequency so SHE approach is found to be superior compared with SPWM. Also, SHE technique shows significant reduction in THD as the number of levels increased. Results for the output voltages and currents along with their frequency spectrum are shown and compared with traditional SPWM.</p>


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