A capacitive-coupled transformerless active power filter with coupling current feedback control

This paper presents a low rating capacitive-coupled transformerless active power filter (APF) for reactive power, current harmonics and neutral current compensation in three-phase four-wire distribution power system. Besides the benefits of APF’s rating and initial cost reduction, it can lessen the switching loss and electromagnetic interference (EMI) problems, without significantly deteriorates the compensation capability. A novel control strategy is also proposed to strengthen the system damping and stability. Thus, the capacitive-coupled APF is characterized by low capacity, economical cost, stable and good filtering performance. Finally, simulation results are given to verify the viability and effectiveness of the APF and its control.