A Cascaded HERIC based Multilevel Inverter for Reducing Leakage Current in the PV Applications

This paper presents a cascaded, highly efficient and reliable inverter configuration (HERIC) based multi-level inverter (MLI) to minimise the leakage current in the PV applications. The cascaded HERIC based nine-level MLI proposed in this paper requires less number of power semiconductor devices when compared with the conventional neutral point clamped (NPC), flying capacitor and cascaded H-bridge (CHB) MLI with same output voltage levels. Additionally, given MLI have lower switching and conduction losses. The pulse width modulation (PWM) technique given in this paper minimises voltage transitions in the terminal voltage. This minimises the magnitude of leakage current and maintains it below the permissible value of the leakage current as per the standards such as VDE 0126-1-1. Hence, the given MLI can be effectively utilised in the PV applications. The simulation and experimental results for the proposed cascaded HERIC based nine-level MLI with the given PWM technique is also presented in this paper.