A new low cost single phase ac-ac power line conditioner

The paper presents a comparative study of three topologies of recently developed voltage-fed z-source inverter (ZSI) such as simple ZSI, quasi-ZSI and trans-ZSI. Different control techniques, proposed earlier for simple ZSI such as simple boost control, maximum boost control and constant boost control, have been applied here for all type of ZSI topologies. The detailed comparative evaluation of all topologies under different PWM techniques is done as power line conditioner. For the common boost factor and modulation index, the output voltage, line harmonics profile of all ZSIs powered by same source and load are evaluated. The operating principles are analysed and the boost factor, voltage gain, duty ratio and voltage stress across the switches are derived. Also the relationships among them are compared even under variable circuit parameters and switch frequency. The results would help to select suitable topology and PWM switching method for power line conditioner application.