Transformerless three-phase Z-source four-wire voltage source inverter-fed grid-connected PV system

Abstract

A transformerless three-phase Z-source four-wire Voltage Source Inverter (VSI)-fed grid-connected photovoltaic system is implemented and controlled using the 3D-Space Vector Modulation (3D-SVM) technique. Generally, the leakage current problem is the main disadvantage of the transformerless inverter system, which is controlled and reduced using the proposed 3D-SVM method. The cause for leakage in the current problem is common mode voltage, which leads to affect the performance inverter and increases the total harmonic distortion (THD) in the system. This proposed system obtains the dc input source from the photovoltaic system and maximum power is tracked using the maximum power point tracking (MPPT – P & O) method and the output of VSI inverter is connected with the grid-connected system through a coupled inductor. In the proposed transformerless Z-source inverter, the THD and leakage current of the system are minimised. The simulation and hardware results are verified using matlab/simulink and DSP processor, respectively.