Estimation of optimal single phase inverter´s switching angles using Pattern Search Method

Programmed PWM technique requires solution of set of non-linear transcendental equations in order to obtain the switching angles as well as for controlling the fundamental component of inverter output voltage. This paper presents a new method to determine the optimum switching angles for Selective Harmonic Eliminated PWM (SHEPWM) inverter. The complete solutions for unipolar SHEPWM switching pattern which produce the fundamental while not generating specifically chosen harmonics are investigated. The estimated angles are applied to an inverter circuit in order to verify its validity through output waveforms, THD and FFT. Since the THD is high due to low number of harmonic orders are eliminated, a low pass filter is also designed in order to filter the unwanted harmonics.