Modulation method for the three-level-output-stage matrix converter under balanced and unbalanced supply condition

In order to control motion and to improve efficiency of an electromechanical conversion chain, variable voltage and variable frequency AC drives have been widely used in commercial applications. The need for a bulky and limited lifetime energy storage electrolytic capacitor in the DC link is a major disadvantage for a traditional AC-DC-AC power converter so alternative topologies have been researched extensively. Matrix converter is a forced-commutated AC-AC power converter topology that directly converts energy from an AC source to an AC load without the use of an energy storage element. From this family, the three-level-output-stage matrix converter is a topology that can synthesise three-level voltage to improve the output performance in terms of reduced harmonic contents. This paper proposes a modulation scheme for this topology. Realistic simulation results prove the ability of this converter topology to produce better output voltages when compared to a conventional matrix converter and also to maintain a sinusoidal input current.