Power Quality Improvement in Speed Control of Induction

A new harmonic elimination pulse width modulation method with genetic algorithm for single phase inverter is presented. The problem is to find the switching angles that produce desired output voltage while not generating specifically chosen harmonics for a speed control of an induction motor. The resolution method procedure of the nonlinear equation systems in order to achieve the best switching angles is explained with the dual objectives of harmonic elimination and output voltage regulation.

By Control Engineering Staff March 1, 2005

A new harmonic elimination pulse width modulation method with genetic algorithm for single phase inverter is presented. The problem is to find the switching angles that produce desired output voltage while not generating specifically chosen harmonics for a speed control of an induction motor. The resolution method procedure of the nonlinear equation systems in order to achieve the best switching angles is explained with the dual objectives of harmonic elimination and output voltage regulation. Optimum switching angles are calculated offline and then subsequently stored them into look up tables to eliminate the specified harmonics. A genetic algorithm (GA) optimization technique is applied to a single phase inverter to determine optimum switching angles for eliminating third, fifth, seventh, and ninth harmonics while maintaining the required fundamental voltage. For performance comparison of GAs, Newton-Raphson (NR) method is also applied to the present problem. The theoretical predictions of these angles are used in an experimental setup to validate the results. An outline to obtain the switching angles is presented. The theoretical findings are verified through experimental results. The main advantages of the technique are its low-cost, simplicity and efficient realization using a microcontroller.

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