The output-current THD vs capacitor voltage ripple trade-off in the 2-cell single phase M2LC

The M2LC has many advantages such as a good output voltage, and current, spectrum. However, the large capacitor voltage ripple that results in a relatively large cell capacitance requirement is of concern. Some control methods had been proposed to counteract this ripple through active control of the cell voltages. This study investigates the interrelationship between the cell capacitor voltage ripple and the output current THD. It is shown that although it is possible to alter the voltage ripple this will incur a penalty in terms of THD.