High-frequency link DC for power quality improvement of stand-alone PV system in cascaded multilevel inverter

Multilevel inverters are emerging as a new breed of power converter options for power system applications. Recent advances in power switching devices enabled the suitability of multilevel inverters for high voltage and high power applications because they are connecting several devices in series without the need of component matching. Usually, a transformerless battery energy storage system (BESS) based on a cascaded multilevel inverter, is used as a measure for voltage and frequency deviations. System can be reduced in size, weight, and cost of energy storage system. This paper presents a DC-DC type high-frequency link DC (HFLDC) stand-alone photovoltaic (PV) system in cascaded multilevel inverter. Each converter cell is implemented a control strategy for two H-bridge inverters that are controlled with the same multi-carrier pulse width modulation (PWM) technique. The proposed cascaded multilevel inverter generates lower voltage total harmonic distortion (THD) in comparison with conventional cascaded multilevel inverter. Digital simulations are carried out using PSCAD/EMTDC to validate the performance of the proposed cascaded multilevel inverter.