—Renewable energy sources and technologies are increasingly gaining popularity in developing coun... more —Renewable energy sources and technologies are increasingly gaining popularity in developing countries as their increasing energy demand can be met by the unexplored potential of renewable energy. With help of decentralized system the power can be directly used at local load centers which will ease centralized grid. The Impedance Source Inverter (ZSI) has many unique advantages as compared to normal Voltage Source Inverter (VSI) and is suitable for both centralized and decentralized applications. This paper elaborates the distinguishing feature of ZSI which makes it suitable for isolated and grid integrated applications for a source whose nature is highly intermittent. Operating principle, steady state analysis, different carrier modulation techniques to control shoot-through (ST) states are described. ZSI is able to maintain the constant load bus voltage when connected to a highly intermittent PV panel with help of suitable control technique. Its superiority in decentralized photovoltaic (PV) application is verified with help of MATLAB/Simulink environment. An insight of inter-dependency of semiconductor device voltage stress, boosting factor (B) and modulation index (M) for sinusoidal pulsewidh modulation (SVPWM) control techniques is also presented.
— This paper presents method of selecting switching angles of a cascaded multilevel inverter so a... more — This paper presents method of selecting switching angles of a cascaded multilevel inverter so as to produce required fundamental voltage along with improved staircase waveform in terms of harmonics. Cascaded multilevel inverter uses number of DC sources, for k sources number of levels will be 2k+1 and leads to k number of non-linear equations to be solved. Many approaches can be made regarding the solution but this paper focuses on Specific Harmonic Elimination (SHE) technique for angle optimization. Newton-Raphson method is used and the difficulty with this method is a closed initial guess. Variation of angles with modulation index is observed and THD is calculated for selected modulation indexes and all attempts are made so as to get lowest THD. Results are simulated in MATLAB/Simulink environment.
—This paper presents the multi carrier pulse width modulation (MCPWM) and selective harmonic elim... more —This paper presents the multi carrier pulse width modulation (MCPWM) and selective harmonic elimination (SHE) technique for cascade multilevel inverter (CMI) to reduce the total harmonic distortion (THD) of the output voltage waveform. A comparison has been done between the SHE and MCPWM technique to show the advantage of SHE technique over the MCPWM technique. To find the accuracy of total harmonic distortion (THD) between the MCPWM and SHE technique is achieved by comparing the FFT based result for nine level cascade multilevel inverter.
—Cascade multilevel inverter is the best suitable topology among the other multilevel inverter to... more —Cascade multilevel inverter is the best suitable topology among the other multilevel inverter topologies in STATCOM application due to its distinguished featuring like modularity in structure and feasibility in control design in terms of less switching losses and better ac output waveform quality. DC voltage balancing and reactive power compensation at the point of common coupling are the challenging issues which may enhance the system superiority. In this paper special attention is dedicated to increase the reliability of the system by presenting the general control design for the system by which dc link voltage balancing and reactive power compensation can be carried out by using the nine-level cascade multilevel inverter as STATCOM. Computer based simulation result has been carried out to verify the superiority of the system at different load conditions and faulty condition.
—Renewable energy sources and technologies are increasingly gaining popularity in developing coun... more —Renewable energy sources and technologies are increasingly gaining popularity in developing countries as their increasing energy demand can be met by the unexplored potential of renewable energy. With help of decentralized system the power can be directly used at local load centers which will ease centralized grid. The Impedance Source Inverter (ZSI) has many unique advantages as compared to normal Voltage Source Inverter (VSI) and is suitable for both centralized and decentralized applications. This paper elaborates the distinguishing feature of ZSI which makes it suitable for isolated and grid integrated applications for a source whose nature is highly intermittent. Operating principle, steady state analysis, different carrier modulation techniques to control shoot-through (ST) states are described. ZSI is able to maintain the constant load bus voltage when connected to a highly intermittent PV panel with help of suitable control technique. Its superiority in decentralized photovoltaic (PV) application is verified with help of MATLAB/Simulink environment. An insight of inter-dependency of semiconductor device voltage stress, boosting factor (B) and modulation index (M) for sinusoidal pulsewidh modulation (SVPWM) control techniques is also presented.
— This paper presents method of selecting switching angles of a cascaded multilevel inverter so a... more — This paper presents method of selecting switching angles of a cascaded multilevel inverter so as to produce required fundamental voltage along with improved staircase waveform in terms of harmonics. Cascaded multilevel inverter uses number of DC sources, for k sources number of levels will be 2k+1 and leads to k number of non-linear equations to be solved. Many approaches can be made regarding the solution but this paper focuses on Specific Harmonic Elimination (SHE) technique for angle optimization. Newton-Raphson method is used and the difficulty with this method is a closed initial guess. Variation of angles with modulation index is observed and THD is calculated for selected modulation indexes and all attempts are made so as to get lowest THD. Results are simulated in MATLAB/Simulink environment.
—This paper presents the multi carrier pulse width modulation (MCPWM) and selective harmonic elim... more —This paper presents the multi carrier pulse width modulation (MCPWM) and selective harmonic elimination (SHE) technique for cascade multilevel inverter (CMI) to reduce the total harmonic distortion (THD) of the output voltage waveform. A comparison has been done between the SHE and MCPWM technique to show the advantage of SHE technique over the MCPWM technique. To find the accuracy of total harmonic distortion (THD) between the MCPWM and SHE technique is achieved by comparing the FFT based result for nine level cascade multilevel inverter.
—Cascade multilevel inverter is the best suitable topology among the other multilevel inverter to... more —Cascade multilevel inverter is the best suitable topology among the other multilevel inverter topologies in STATCOM application due to its distinguished featuring like modularity in structure and feasibility in control design in terms of less switching losses and better ac output waveform quality. DC voltage balancing and reactive power compensation at the point of common coupling are the challenging issues which may enhance the system superiority. In this paper special attention is dedicated to increase the reliability of the system by presenting the general control design for the system by which dc link voltage balancing and reactive power compensation can be carried out by using the nine-level cascade multilevel inverter as STATCOM. Computer based simulation result has been carried out to verify the superiority of the system at different load conditions and faulty condition.
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