Two-phase active power filter direct current control with capacitor voltages estimation and balance

In this paper an active power filter is presented based on a multilevel converter. The active power filter is intended to be used in domestic applications where reactive power compensation in two-phase networks is required. An innovative technique to balance the DC bus voltages of the power converter capacitors is proposed and also an estimation algorithm for those voltages is developed, allowing for an operation of the power filter with reduced sensors number.