Multilevel PWM waveforms can be decomposed into several multilevel PWM components. Phase-shifted carrier (PSC) is an efficient decomposition technique. In this paper, we have first demonstrated the equality of PSC and alternative Phase opposition Disposition techniques. Second, we have modified PSC to accommodate other Disposition techniques. Third, we have investigated the effects of using asymmetrical carriers on the spectrum of the resulting PWM waveform. Fourth, we have proposed a logical algorithm for decomposing all types of multilevel PWM waveforms.

This paper presents the performance of multi-Phase voltage source inverter (VSI) with simple PWM switching techniques, namely the harmonic injection and offset injection method. The technique discussed in this paper is easy to implement and avoid complicated controlling algorithm adapted in SVPWM technique. The generalized switching techniques are proposed in this paper. A generalized algorithm suitable for odd number of Phases is developed in Matlab/Simulink environment and discussed in detail for both the switching methods. The performance of the 5, 7 and 9-Phase VSI is studied with the above-said switching methods. The results of the simulation are presented for different modulation indices and a comparison in terms of fundamental voltage and THD identifies the better scheme suitable for multi-Phase inverter fed drives.

A new type of single-Phase stand-alone induction generator using a three-Phase induction machine and a single-Phase voltage-source PWM inverter is introduced. The generator scheme is capable of producing constant load frequency with a very well regulated output voltage. A small lead acid battery and a single-Phase full diode-bridge rectifier are used to feed the inverter. The inverter feeds one of the stator Phases. During the generator voltage build up, the inverter supplies the battery first and after a while a diode-bridge rectifier, which is fed by the generator, replaces if. The system steady state and dynamic equations are derived and are solved to obtain the performance characteristics of the generator scheme. A digital simulation study is carried out for a 2.2 KW three Phase induction machine. The simulated results obtained confirm that this generator can achieve an output power of about 0.6 pu..

A novel pulse width modulation (PWM) switching strategy is developed through carrier modification, which eliminates the restriction in the fundamental component of a conventional switching scheme in the linear region. The proposed strategy is suitable for single-Phase full-bridge inverter. The performance evaluation and comparison are based on the fundamental component, the total harmonic distortion (THD) and number of pulses per cycle. The aim of the novel method is to achieve overmodulated fundamental voltage values with modulation depths in the linear range, while improving THD and further reducing lower order harmonics dominancy. A significant enhancement in performance is validated by simulation and numerical commutations. In addition, a performance comparison of proposed method with harmonic injection PWM methods is also provided.

This paper presents the comparative study of three Phase twenty five level diode clamped and cascaded H-bridge multilevel inverters. The comparison is made in respect of requirement of devices, quality of output voltage and reduction of total harmonic distortion at the multilevel inverter terminals. In this work multicarrier sinusoidal pulse modulation control methods of Phase Disposition (PD-PWM), Phase opposition Disposition (PODPWM) and Alternative Phase Opposition Disposition (APOD-PWM) pulse width modulation control strategies are applied for both diode clamped and cascaded H-bridge multilevel inverters and compared its total harmonic distortion. The performance of both diode and cascaded H-bridge multilevel inverters is investigated and compared. Based on simulation results it is observed that the output voltage of the cascaded H-bridge multilevel inverters is better as compared to the diode clamped multilevel inverter. The proposed multilevel inverters are simulated using MATLAB/Simulink software.

This paper presents an innovative Asymmetrical Single-Phase Nine Level Inverter (ASRNLI) that stands out among various available configurations. The design achieves a staircase-like voltage pattern with the highest number of levels while utilizing a reduced number of components. Compared to conventional systems, asymmetric multilevel inverters require fewer components yet manage to create a cascade structure with multiple output levels. The ASRNLI configuration consists of two independent DC sources and 10 switches, allowing it to generate any desired level. This setup offers several advantages, including improved output voltage quality attributed to the switches' low blocking voltage. It proves particularly valuable in scenarios where asymmetric DC voltage sources are accessible, such as in modern electric vehicles and AC mini-grids powered by renewable energy sources. To generate gate pulses, the ASRNLI employs the level-shifted pulse width modulation approach. Validation of the suggested ASRNLI configuration was carried out through both MATLAB simulations and the construction of a prototype. The output waveform demonstrated a Total Harmonic Distortion (THD) of 13.50% at the highest fundamental voltage of 400V. Throughout this article, the effectiveness of the ASRNLI configuration is supported by findings from simulations and experimental tests, showcasing its potential as a promising solution for practical applications.

In this paper, a 7-level Diode Clamped Multilevel Inverter (DCMLI) is simulated with three different carrier PWM techniques. Here, Carrier based Sinusoidal Pulse Width Modulation (SPWM), Third Harmonic Injected Pulse Width Modulation (THIPWM) and Modified Carrier-Based Space Vector Pulse Width Modulation (SVPWM) are used as modulation strategies. These modulation strategies include Phase Disposition technique (PD), Phase Opposition Disposition technique (POD), and Alternate Phase Opposition Disposition technique (APOD). In all the modulation strategies, triangular carrier and trapezoidal triangular carrier signals are compared with reference signal, then control pulses are generated. The detailed analysis of the results has been presented and compared with experimental results in terms of fundamental component of output voltage and percent of THD.

Analysis and practical implementation of the regular symmetric sampled three-Phase PWM inverter waveform has been presented in this paper. It is digitally implemented on a Xilinx field programmable gate array FPGA, and the essential considerations involved in the feasibility of using a Xilinx XC4008E software-based to generate PWM has been discussed. All the necessary Xilinx hardware/software techniques and programs required to implement and generate three-Phase Pulse Width Modulation (PWM) are developed in detail, and demonstrated using practical results from an experimental Xilinx board. The techniques developed and presented in this paper are readily applicable to other currently available Xilinx chips. Simulation and experimental results of grid-connected inverter are presented. From the simulation and experimental results it is confirmed that the harmonic distortion of the output current waveform of the inverter fed to the grid is within the stipulated limits laid down by the utility companies