Z-source T-type inverter for renewable energy systems with proportional resonant controller

•A novel Z-source T-type inverter for grid connected renewable energy system is proposed.•Additional DC–DC converter or transformer requirement is removed through the Z-impedance network.•Total system efficiency is improved.•The PR current controller is introduced.•THD level is measured as 2.41% and it meets the international standards (<5%).

In this study, a novel z-source T-type inverter for grid connected renewable energy system is proposed. The proposed system has ability of boosting voltage level without any additional DC–DC converter or transformer through the z-impedance network. The size of the system is reduced by eliminating DC–DC converter or step-up transformer requirement. Furthermore, an additional improvement in system efficiency is obtained by using T-type inverter structure which is more efficient than the conventional two-level inverter or three-level neutral point clamped inverter. Inverter output currents are controlled by the proportional resonant controller. MATLAB/Simulink simulations show that, fast dynamic response is obtained and steady state error is eliminated. In addition, the inverter output currents are in sinusoidal waveforms and synchronous with the grid frequency and phase. Besides, total harmonic distortion values of the inverter currents are measured as 2.41% which meets the international standards such as IEC61727 and IEEE1547.