A Review: Multilevel Hybrid Ultra-Boost Converter Topologies for PV Solar Applications

Multilevel hybrid transformer-less ultra-boost converters are playing a significant role in high power solar PV applications. Performance of multilevel hybrid ultra-boost converter is superior than the traditional DC to DC boost converter. Multilevel ultra-boost converter (MUBC) with the switched coupled inductors based on pulse width modulation (PWM) technique having high efficiency. It is basically DC to DC switched capacitors ultra-boost converters combinedly provide the desired balanced output voltage( Vout) using the one driven-switch(S), one switched-inductor(L) with [2(n)-1] diodes(D
₁
and D
₂
) and [2(n)-1] capacitors(C) for an (n)x MUBC. It is suggested to be used as a DC-link in the PV solar application with the multilevel inverters where controlled output voltage levels are mandatory with the unidirectional and the self-balancing current flow; each device stops one voltage level to achieve high voltages ultra-boost converters with low voltage device. In this paper the comprehensive analysis of multilevel hybrid transformer less ultra-boost converter topology has been done. This topology provides large duty ratio (D) without extreme duty cycle, continuous input current, high switching frequency, lower harmonics, higher efficiency, large output voltage and lower electro-magnetic interference, compact size.