SHM‐PWM technique in a cascaded H‐bridge multilevel inverter with adjustable DC‐link for wide voltage range applications

Abstract

In this paper, a new method for achieving high-quality voltage in multilevel inverters is presented. The method is based on the selective harmonic mitigation pulse width modulation (SHM-PWM) technique applied on a cascaded Hbridge multilevel inverter (CHBMLI), which employs a variable DC-link voltage to reduce the amount of the total harmonic distortion (THD) in the output waveform. The variable DC sources in a CHBMLI can increase the modulation index to an acceptable range in the low output voltage values and also increase the number of harmonics to be eliminated in the SHM technique due to increasing the number of voltage levels. In the proposed method, the optimal switching angles are calculated by the particle swarm optimization (PSO) algorithm and the switching angles are stored in lookup tables (LUTs). Implementing the proposed method allows the CHB inverter to improve the performance in producing a high-quality voltage compared with conventional methods. As an applicable example, a single-phase CHBMLI, fed by two isolated DC sources, is examined in this paper. The analysis presented in this paper shows a significant improvement in the quality of the output voltage, especially for low output voltage conditions. The simulation and experimental results are presented to confirm the proposed approach.

African Vultures Optimization Algorithm-Based Selective Harmonic Elimination for Multi-level Inverter

“…  The F value given in Eq. (11) shows the saturation rate of vultures. iti represents the valid number of iterations, maxit represents the maximum number of iterations.…”

“…These optimization techniques aim to find optimum switching angles that satisfy the desired harmonic elimination conditions while minimizing the computational effort. Genetic Algorithms (GA) [10], Particle Swarm Optimization (PSO) [11], Differential Evolution (DE) [12], Artificial Bee Colony (ABC) [13], Red Deer Algorithm (RDA) [14], and other metaheuristic algorithms have been applied in SHE optimization. These algorithms explore the solution space to find the best solutions, considering factors such as convergence speed, computational efficiency, robustness, and the ability to handle different modulation indices.…”

Level vector pulse width modulation for multilevel inverters

“…Motor drives, power systems, renewable energy systems, and electric vehicles are among the applications of inverters. Generally, sinusoidal pulse width modulation (PWM), selective harmonics elimination modulation, nearest level modulation, and space vector pulse width modulation (SVPWM) are the most popular techniques for amplitude, frequency, and phase angle control of the output voltages of inverters 1–3 …”

“…Generally, sinusoidal pulse width modulation (PWM), selective harmonics elimination modulation, nearest level modulation, and space vector pulse width modulation (SVPWM) are the most popular techniques for amplitude, frequency, and phase angle control of the output voltages of inverters. [1][2][3] One of the most important issues in the implementation of modulation methods is the number of variables and computational burden, especially for multilevel inverters. In most of the existing modulation methods, the number of variables and the computational burden increase rapidly with the level number.…”

Analysis and suppression of switching‐frequency harmonics in variable‐output‐voltage inverters

“…In Panda et al, 9 a selective harmonic elimination (SHE) method has been presented for a multilevel inverter to enhance the output voltage harmonics. In literature, [10][11][12][13][14][15] also, the SHE/SHM method is used to cope with some loworder harmonics in CHB multilevel inverters. The SHE and selective harmonic mitigation (SHM) methods have been combined in Sharifzadeh et al 16 to reduce output voltage harmonics in three-level NPC inverters.…”