Abstract: Multilevel inverters such as flying capacitor, diodeclamped,
and cascaded H-bridge inverters are very popular
particularly in medium and high power applications. This paper
focuses on a cascaded H-bridge module using a single direct current
(DC) source in order to generate an 11-level output voltage. The
noble approach reduces the number of switches and gate drivers, in
comparison with a conventional method. The anticipated topology
produces more accurate result with an isolation transformer at high
switching frequency. Different modulation techniques can be used for
the multilevel inverter, but this work features modulation techniques
known as selective harmonic elimination (SHE).This modulation
approach reduces the number of carriers with reduction in Switching
Losses, Total Harmonic Distortion (THD), and thereby increasing
Power Quality (PQ). Based on the simulation result obtained, it
appears SHE has the ability to eliminate selected harmonics by
chopping off the fundamental output component. The performance
evaluation of the proposed cascaded multilevel inverter is performed
using PSIM simulation package and THD of 0.94% is obtained.
Abstract: This paper present the harmonic elimination of hybrid
multilevel inverters (HMI) which could be increase the number of
output voltage level. Total Harmonic Distortion (THD) is one of the
most important requirements concerning performance indices.
Because of many numbers output levels of HMI, it had numerous
unknown variables of eliminate undesired individual harmonic and
THD nonlinear equations set. Optimized harmonic stepped waveform
(OHSW) is solving switching angles conventional method, but most
complicated for solving as added level. The artificial intelligent
techniques are deliberation to solve this problem. This paper presents
the Particle Swarm Optimization (PSO) technique for solving
switching angles to get minimum THD and eliminate undesired
individual harmonics of 15-levels hybrid multilevel inverters.
Consequently it had many variables and could eliminate numerous
harmonics. Both advantages including high level of inverter and
Particle Swarm Optimization (PSO) are used as powerful tools for
harmonics elimination.
Abstract: Selective harmonic elimination-pulse width modulation techniques offer a tight control of the harmonic spectrum of a given voltage waveform generated by a power electronic converter along with a low number of switching transitions. Traditional optimization methods suffer from various drawbacks, such as prolonged and tedious computational steps and convergence to local optima; thus, the more the number of harmonics to be eliminated, the larger the computational complexity and time. This paper presents a novel method for output voltage harmonic elimination and voltage control of PWM AC/AC voltage converters using the principle of hybrid Real-Coded Genetic Algorithm-Pattern Search (RGA-PS) method. RGA is the primary optimizer exploiting its global search capabilities, PS is then employed to fine tune the best solution provided by RGA in each evolution. The proposed method enables linear control of the fundamental component of the output voltage and complete elimination of its harmonic contents up to a specified order. Theoretical studies have been carried out to show the effectiveness and robustness of the proposed method of selective harmonic elimination. Theoretical results are validated through simulation studies using PSIM software package.