An Advanced Modulation Technique for Transformer-less Grid-Connected Inverter Circuits Used in Solar Photovoltaic Systems

This paper presents a new current peak point tracking third harmonic injected bus clamping pulse width modulation (CPPTTHBCPWM) technique for effective active and reactive power control in a transformer-less H5 solar photovoltaic (PV) inverter. The proposed technique reduces the switching loss compared to that of the traditional switching technique by using a new reference signal and eliminating unwanted gate pulses. The proposed CPPTTHBCPWM technique ensures better utilization of the dc bus voltage, lowers the total harmonic distortion (THD), and lowers the converter loss compared to the conventional modulation techniques. The proposed modulation technique also reduces the thermal stress in the switching devices and increases the power converter lifetime. The proposed modulation technique is simulated in MATLAB/Simulink environment and validated in the laboratory using a reduced-scale prototype test platform