Harmonic elimination PWM technique for multilevel inverter

Abstract EN

The multilevel voltage source inverters are recently applied in many applications such as ac power supplies and ac motor drives.

The concept of multilevel voltage source inverter is explained.

The concept of the harmonic elimination pulse-width-modulation (HEPWM) technique based on Walsh function is presented, By using HEPWM technique, specific low order harmonics can be eliminated, a total harmonic content is minimized and the output voltage THD can be improved.

A procedure to achieve the appropriate switching angles of HEPWM is proposed.

The harmonic amplitudes of the multilevel inverter output voltage can be expressed as functions of switching angles.

Thus, solving linear algebraic equations instead of solving nonlinear transcendental equations optimizes the switching angles.

The HEPWM technique is implemented on a multilevel inverter using cascaded-inverter with separated dc sources.

Simulation results are presented using ORCAD package version 9.1.