Single-Phase Multilevel Inverter with Simpler Basic Unit Cells for Photovoltaic Power Generation

Author(s):  
M. S. Chye ◽  
J. A. Soo ◽  
Y. C. Tan ◽  
M. Aizuddin ◽  
S. Lee ◽  
...  

This paper presents a single-phase multilevel inverter (MLI) with simpler basic unit cells. The proposed MLI is able to operate in two modes, i.e. charge mode to charge the batteries, and inverter mode to supply AC power to load, and therefore, it is inherently suitable for photovoltaic (PV) power generation applications. The proposed MLI requires lower number of power MOSFETs and gate driver units, which will translate into higher cost saving and better system reliability. The power MOSFETs in the basic unit cells and H-bridge module are switched at near fundamental frequency, i.e. 100 Hz and 50 Hz, respectively, resulting in lower switching losses. For low total harmonic distortion (THD) operation, a deep scanning method is employed to calculate the switching angles of the MLI. The lowest THD obtained is 8.91% at modulation index of 0.82. The performance of the proposed MLI (9-level) has been simulated and evaluated experimentally. The simulation and experimental results are in good agreement and this confirms that the proposed MLI is able to produce an AC output voltage with low THD.

2019 ◽  
Vol 28 (06) ◽  
pp. 1950089 ◽  
Author(s):  
V. Thiyagarajan ◽  
P. Somasundaram ◽  
K. Ramash Kumar

Multilevel inverter (MLI) has become more popular in high power, high voltage industries owing to its high quality output voltage waveform. This paper proposes a novel single phase extendable type MLI topology. The term ‘extendable’ is included since the presented topology can be extended with maximum number of dc voltage sources to synthesize larger output levels. This topology can be operated in both symmetrical and asymmetrical conditions. The major advantages of the proposed inverter topology include minimum switching components, reduced gate driver circuits, less harmonic distortion and reduced switching losses. The comparative analysis based on the number of switches, dc voltage sources and conduction switches between the proposed topology and other existing topologies is presented in this paper. The comparison results show that the proposed inverter topology requires fewer components. The performance of the proposed MLI topology has been analyzed in both symmetrical and asymmetrical conditions. The simulation model is developed using MATLAB/SIMULINK software to verify the performance of the proposed inverter topology and also the feasibility of the presented topology during the symmetrical condition has been validated experimentally.


2018 ◽  
Vol 7 (2.24) ◽  
pp. 55
Author(s):  
Anuja Prashant Diwan ◽  
N Booma Nagarajan ◽  
T Murugan ◽  
S Ashrafudeen ◽  
G J. Jenito Paul

In this paper, single phase nine level cascaded multilevel inverter using trinary voltage source is described. Normally for getting nine level MLI output, four H-Bridges are required. But in proposed method, nine level output is achieved by using two H-Bridges only. Performance of Multilevel inverter is improved by using modular switching pattern. This method reduces the number of switches to the half and thus reduces switching losses. Since the number of levels at the output voltage is increased, Total Harmonic Distortion (THD) gets reduced significantly. This presents simple configuration is simple and can be controlled easily. MATLAB-SIMULINK is used to validate the results of proposed technic, simulation is carried out using. The proposed method has been exhaustively compared with classical cascaded H-Bridge topology. 


Author(s):  
Wail Ali Ali Saleh ◽  
Nurul Ain Mohd Said ◽  
Wahidah Abd Halim

Multilevel inverters are gaining special interest among researchers and in the industry due to their widespread applications and numerous merits. Obtaining high quality, more reliable output while using a reduced number of electronic components is the main purpose of most of the research conducted in this area of study. The purpose of this study is to apply the nearest level control (NLC) method to a 13-level transistor-clamped H-bridge (TCHB) inverter with unequal DC voltage supplies. The NLC method operates at the fundamental frequency, thus reducing switching losses, and can reduce the harmonic content significantly. The adopted multilevel inverter consists of two TCHB cells supplied with two asymmetrical DC input sources with a voltage ratio of 1:2. This structure reduces the number of electronic components, and the asymmetry in the DC input voltages results in a higher number of levels. The adopted topology and its proposed control method were simulated in Matlab/Simulink, and the simulation results were verified through experiments using an Altera field-programmable gate array (FPGA) board. The results showed that the topology and its control method are efficient in obtaining a high-quality output with an improved total harmonic distortion (THD).


Author(s):  
Sujitha N. ◽  
Partha Sarathi Subudhi ◽  
Krithiga S. ◽  
Angalaeswari S. ◽  
Deepa T. ◽  
...  

A grid tied photovoltaic system using modular multilevel inverter topology is proposed in this paper. Basic unit structure of modular multilevel inverter used in this system is capable of converting DC power from PV array to AC power for feeding power to the household loads or utility grid. The proposed modular multilevel inverter structure has lesser power electronic devices compared to the existing multilevel inverter topologies. The proposed system generates a nearly sinusoidal signal and achieves better output profile with low total harmonic distortion. Simulation of the proposed system is carried out in MATLAB/Simulink software and the results are presented.


2017 ◽  
Vol 7 (1.5) ◽  
pp. 209
Author(s):  
B.Vijaya Krishna ◽  
B. Venkata Prashanth ◽  
P. Sujatha

Multilevel Inverters (MLI) have very good features when compared to Inverters. But using more switches in the conventional configuration will reduce its application in a wider range. For that reason a modified 7-level MLI Topology is presented. This new topology consists of less number of switches that can be reduced to the maximum extent and a separate gate trigger circuit. This will reduce the switching losses, reduce the size of the multilevel inverter, and cost of installation. This new topology can be used in Electrical drives and renewable energy applications. Performance of the new MLI is tested via. Total harmonic distortion. This construction structure of this multilevel inverter topology can also be increased for 9-level, 11-level and so on and simulated by the use of MATLAB/SIMULINK. A separate Carrier Based PWM Technique is used for the pulse generation in this configuration.


Author(s):  
T. Porselvi ◽  
K. Deepa ◽  
R. Muthu

Harmonic elimination at the fundamental frequency is very much appropriate for high and medium range of power generation and applications. This paper considers a new technique for selective harmonic elimination (SHE), in which the total harmonic distortion (THD) is minimized when compared with that of the conventional one. With this technique, the harmonics at lower order are eliminated, which are more predominant than the higher ones.Cascaded H-Bridge inverter fed by a single DC is considered which is simulated with the switching angles generated by both the conventional method of SHE and the new method of SHE. The simulated results of the load voltage and the waveforms of the harmonic analysis are shown. The THD values are compared for the two techniques.  The experimental results are also shown for the new technique. The switching angles are generated with the help of field programmable gated array (FPGA) in the hardware. The value of experimental THD of voltage is compared with that of simulated THD and the comparison prove that the results are satisfactory.


2015 ◽  
Vol 793 ◽  
pp. 167-171
Author(s):  
Mohd Aizuddin Yusof ◽  
Yee Chyan Tan ◽  
M. Othman ◽  
S.S. Lee ◽  
M.A. Roslan ◽  
...  

Multilevel inverters are one of the preferred inverter choices for solar photovoltaic (PV) applications. While these inverters are capable of producing AC staircase output voltage waveform, the total harmonic distortion (THD) of the output voltage waveform can become worse if the switching angle of each voltage level is not carefully chosen. In this paper, four switching angle arrangement techniques are presented and the switching angles generated by these techniques are applied to a new single-phase boost multilevel (SPBM) inverter. The performance of 3-, 5-, 7-, 9-and 11-level SPBM inverter having four different sets of switching angles derived using the aforementioned techniques have been evaluated and compared using PSIM software. Simulation results show that one of the techniques is able to produce an output voltage waveform with the lowest THD, whilst the other generates an output voltage waveform with the highest fundamental voltage component.


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