Implementation of PWM scheme for Z-Source inverter using embedded target on SIMULINK

Abstract

The voltage source inverter (VSI) and current source inverter (CSI) have their own conceptual limitations. When operated as a dc-ac converter, the output voltage of a VSI is lesser compared to input dc voltage. On the other hand, when operated as a dc-ac converter the CSI can generate higher output voltage compared to input dc voltage. To overcome these limitations Z-source converter acts as a suitable alternative. The Z-source converter contains an impedance network connected at the dc link of the conventional 6-switch converter. This impedance network enables the Z-source inverter (ZSI) to overcome the traditional limitations in VSI and CSI. By controlling switching sequence and duty cycle through specific PWM schemes, the ZSI can produce desired output which can be above or below the input dc link voltage as per the requirement. As a result, the ZSI system provides operational capability during various practical conditions like input voltage fluctuation coupled with harmonic mitigation as well as power quality improvement capabilities. This paper dwells into the implementation of the control of ZSI on embedded target feature of MATLAB/SIMULINK for the ease of practical realization. The PWM scheme specific to ZSI requires it to use various hardware circuits for practical realization, the said problem has been addressed in this paper and hardware results of the implementation are also discussed.