Modification of separated DC source for cascade h-bridge multilevel inverter in solar power plant

Abstract

Application of 3 phasa inverter is used in Solar Power Plant (SPP) as a converter to convert DC voltage to AC. The 3 phase inverter has many advantages : need only 6 transistors for its operation and has simple switching techniques. But the disadvantage is the quality of output voltage inverter 3 phase is still not good. With the rapid development of power converter technology, the use of 3 phase inverter should be replaced with multilevel inverter. Multilevel inverter topologies have been widely discussed, including multilevel inverter cascaded h-bridge, multilevel inverter clamped diode, and multilevel inverter flyer capacitor. Among the topologies, cascaded H-Bridge multilevel inverter (CHB-MLI) has the simplest and easiest switching and construction techniques. But for the operation required separated DC source (SDCS) that have the same value. This balancing technique is the problem of implementing CHB-MLI in SPP. In this study designed SPP capacity of 100 kW connected to the distribution system 20 kV through CHB-MLI. The provision of DC sources is obtained from a centralized SPP separated by a multiwinding transformer to be rectified using a rectifier. The system is equipped with a Maximum Power Point Tracker (MPPT) to generate maximum power at different radiation and temperature values. The simulation results show CHB-MLI able to transfer power from PV to grid of 95,5 kW with tracking efficiency is 93,6%. CHB-MLI has a harmonic voltage content of 0.046%.