Asymmetrical Hybrid Multilevel Inverter with SHE Modulated NPC Cascaded by MPC Controlled CHB with Si/SiC Switches

Main issues with the implementation of multilevel converters in high-power applications are high power quality and minimum switching frequency. A combination of NPC and CHB with new schemes is proposed to find the middle ground in medium voltage applications. NPC is modulated with SHE to provide active power and eliminate selected harmonics. On the other hand, CHB with floating capacitor is utilized as reactive power compensator. Floating capacitor eliminates the need for real DC source, hence, the volume of the auxiliary circuit can be smaller and less costly. MPC is deployed for CHB, which can compensate the higher order harmonics left by the main stage, stabilize the capacitor voltage and provide better dynamic response simultaneously. Experimental results validate the effectiveness of the proposed topology.