A Review on New Hybrid Active Neutral Point Clamped Flying Capacitor Multilevel Inverter

This paper presents the hybrid seven-level cascaded active neutral-point-clamped (ANPC)-based multilevel converter. The converter topology is the cascaded connection of a three-level ANPC converter and an H-bridge per phase. The proposed topology provides a tradeoff between different component counts to achieve a good loss distribution, avoid direct series connection of semiconductor devices, keep the balanced operation of dc-link capacitors while keeping the number of costly components such as capacitors and switches low. This topology has redundant switching states for generating different pole voltages. By selecting appropriate switching states, the capacitor voltages can be balanced instantaneously (as compared to the fundamen-tal) in any direction of the current, irrespective of the load power factor. The topology is operated under selective harmonic elimination pulse width modulation (SHE-PWM), maintaining the switching frequency of the converter to a minimum. The operating principles, voltage balancing methods, and limitations of the converter are analyzed together with extensive simulation results of the topology. Experimental results from a low-power laboratory prototype are presented that verify the operation of the hybrid converter under SHE-PWM.