An Improved Quasi-z Source Inverter for Optical Grid-connected Systems

On the basis of the quasi-z source inverter, an improved quasi-z source inverter was proposed, which not only inherited all the advantages of the quasi-z source, but also had stronger voltage boost capacity and smaller capacitance voltage stress, and the conversion efficiency was also improved. The advantages of the improved quasi-z source inverter were as follows: In the case of the same duty cycle duty ratio, it had higher pressure boost; The modulation factor had a larger value space to improve the voltage quality of the inverter output; The capacitance voltage stress could be reduced effectively. The improved quasi-z source presented had higher voltage boost capacity and smaller capacitance voltage stress, the test results were consistent with the simulation results, and the theoretical analysis was verified. This design was more suitable for the photovoltaic grid-connected power generation system which needs higher voltage gain.