Analysis and design of a Cascaded H-Bridge topology based on current-source inverters

This work deals with the use of single-phase converters based on current-source inverters connected in a cascaded array (CSI-CHB) in order to get the dual topology of the classic Cascaded H-Bridged based on voltage-source inverters (CHB). The proposed configuration has similar advantages as the classic voltage source CHB as the use of semiconductors with lower voltage rating with respect to the load voltage. Moreover the CSI-CHB load voltage has a smaller distortion than the classic CHB due to the first order capacitive filter used at the inverters AC side. Also, the use of modulation techniques as phased-shifted carrier sinusoidal pulse modulation (PSC-SPWM) allows both, reduce the capacitive filter size and reduce the commutation frequency of the inverter switches. A theoretical analysis of the proposed topology and design guidelines for the capacitive filter are presented, considering a desired Total Harmonic Distortion (THD) on the load voltage and the SPWM modulation technique. Simulation results confirm the topology features.