SELECTIVE HARMONIC ELIMINATION FOR SINGLE PHASE INVERTER USING PATTERN SEARCH METHOD

Author’s Name : M Narayanan | R Vidhya | S Siva

Volume 01 Issue 02  Year 2014  ISSN No:  2349-2503  Page no: 7-11

Abstract -As saving of electrical energy is the main target of industrial consumer and also utility, the use of energy efficient equipment increases rapidly. The modern industrial system utilize variable speed drives through thyristor converters as the control becomes simple, more efficient, accurate and widely available. However, it gives rise to a varied harmonic spectrum on the ac power systems and pollutes the system. Therefore some technique is needed to eliminate the dominant harmonics present in the system. Hence Selective Harmonic Elimination (SHE) or programmed harmonic elimination for an single phase inverter fed induction motor drive is considered in this paper. The main objective of selective harmonic elimination is to produce the fundamental while not generating specifically chosen harmonics. The output voltage waveform of an inverter is given by Fourier series expansion which contains both the fundamental and the harmonics. Suitable technique has to be used to solve the transcendental equation. 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. So in this research work, Pattern Search (PS) method has been employed to eliminate the harmonics. The complete solutions for 3-level unipolar switching patterns to eliminate the 5th, 7th and 11th harmonics are given.

Keywords –Selective Harmonic Elimination, Unipolar Pulse Width Modulation, Pattern Search Method, Total Harmonic Distortion