Boost Packed E-Cell: A Compact Multilevel Converter for Power Quality Ancillary Services

Beyond question, replacing conventional two-level power converters by their bidirectional multilevel rivals improves Flexible AC Transmission Systems (FACTS) and Active Power Filters (APF) in terms of efficiency, power quality and switching losses. Regarding the constructive impact of multilevel converters on the performance of FACTSs and APFs, this paper proposes Boost Packed E-Cell (BPEC) as an affordable and reliable compact multilevel converter for the power ancillary services. BPEC is able to generate a voltage waveform with either 9 or 11 levels using three dc capacitors and eight semiconductor switches. The boost operation empowers BPEC to dominate the grid voltage using low power dc-links. Horizontal expansion of the capacitors in BPEC reduces the dc voltage measurements and remarkably enhances the converter reliability. For the case study, BPEC is investigated in the form of a single-phase Compact Active Power Filter (CAPF) when reactive/nonlinear loads are connected to grid. Finite Control Set Model Predictive Control (FCSMPC) is also dedicated to assure the desired performance of BPEC in the CAPC application. The validation tests performed by dSPACE and MATLAB prove successful active damping of the load current harmonics at the point of common coupling.