Low order harmonics mitigation in grid connected, parallel PV inverters

Abstract

This research is concerned with the problem of network power quality when grid connected systems are used to feed the network distribution grid. A parallel connection of photovoltaic (PV) system is the main interest of study for this research. This type of PV system uses power electronic components such as inverter and current controller that produce harmonics which adversely affect the power quality of the distribution network. Development and simulation of current controller using the proportional resonance (PR) scheme is considered to overcome the harmonic problems in single and parallel PV inverters. This scheme eliminates specific harmonic in the low order part. The control parameter randomisation technique is added to the scheme to produce a more efficient current controller system. Thus, the inverter harmonic performance (inverter output current) is improved. This concept is extended to parallel inverter based systems, where opportunities for harmonic cancellation improve the inverter harmonic performance further. Experimental hardware setup using TMS320F2812 is also developed to verify the promising simulation results.