Upravljanje asimetričnim inverterom ujednačenog koraka s 13 razina korištenjem optimizacije roja čestica

Harmonic Elimination Strategy (HES) has been a widely researched alternative to traditional PWM techniques. This paper presents the harmonic elimination strategy of a Uniform Step Asymmetrical Multilevel Inverter (USAMI) using Particle Swarm Optimization (PSO) which eliminates specified higher order harmonics while maintaining the required fundamental voltage. This method can be applied to USAMI with any number of levels. As an example, in this paper a 13-level USAMI is considered and the optimum switching angles are calculated to eliminate the 5th, 7th, 11th, 13th and 17th harmonics. The HES-PSO approach is compared to the well-known Sinusoidal Pulse-Width Modulation (SPWM) strategy. Simulation results demonstrate the better performances and technical advantages of the HES-PSO controller in feeding an asynchronous machine. Indeed, the harmonic distortions are efficiently cancelled providing thus an optimized control signal for the asynchronous machine. Moreover, the technique presented here substantially reduces the torque undulations.Strategija eliminacije harmonika je dobro istražena alternativa tradicionalnoj pulso-širinskoj modulaciji. U ovom radu opisana je strategija eliminacije harmonika asimetričnog višerazinskog invertera ujednačenog koraka uz korištenje optimizacije roja čestica čime se eliminiraju harmonici višeg reda uz zadržavanje fundamentalnog napona. Takva metoda može se primijeniti neovisno o broju razina invertera. Kao primjer korišten je inverter s 13 razina kod kojeg se eliminiraju peti, sedmi, jedanaesti, trinaesti i sedamnaesti harmonik. Predloženo rješenje uspoređeno je s dobro poznatom sinusnom pulsno-širinskom modulacijom. Simulacijski rezultati pokazuju prednosti predloženog rješenja. Harmonička distorzija je uspješno poništena te je upravljački signal za asinkroni stroj optimalan. Štoviše, predložena tehnika znatno smanjuje promjene momenta

Optimal SHE-PWM Technique for Three-Level Voltage Source Converter Control

Selective harmonic elimination pulse-width modulation (SHE-PWM) technique for three-level voltage source converter is presented in this paper. It is mathematically defined using Fourier-based equations to describe the output voltage waveform. An efficient minimization technique assisted with hybrid genetic algorithm is then applied to obtain the optimal switching angles. Different operating points including single- and three-phase systems are presented to demonstrate the effectiveness of the proposed method Selected simulation and experimentally validated results are reported to show the effectiveness of the proposed method Copyright (C) 2008 Praise Worthy Prize S.r.l. - All rights reserved

A Hybrid Genetic Algorithm for Selective Harmonic Elimination PWM AC/AC Converter Control

This paper presents an optimal solution for eliminating pre-specified orders of harmonics from the output waveform of AC/AC converter. The main challenge of solving the associated nonlinear equations, which are transcendental in nature and therefore have multiple solutions, is the convergence and therefore an initial point selected considerably close to the exact solution is required. The paper discusses an efficient hybrid real coded genetic algorithm (HRCGA) that reduces significantly the computational burden resulting in a fast convergence. An objective function describing a measure of effectiveness of eliminating selected orders of harmonics, while controlling the fundamental is derived and a comparison of different operating points is reported. It is observed that the modulation index can reach unity value. The theoretical findings are verified through simulation results using the PSIM software package