Recently, different methods have been used for harmonic elimination in solar energy systems. Resilient Direct Unbalanced Control (RDUC) method is one of them. It is used to reduce harmonics in the integration of solar energy systems, especially in distributed generation systems (DGs).
During low power mode of PV inverter operation, current harmonics is dominant due to the fundamental current being lower than the non-fundamental current of PV inverter . The current harmonics in PV inverter is mainly dependent on its power ratio ( P o P R ), where P o is the output power and P R is the power rating of the PV inverter.
Harmonics is still a challenge for power generation in renewable energy technologies. Various state-of-the-art control techniques are available for harmonic elimination. Among all techniques available, virtual resistance based solar inverter control gives an outstanding performance about 30% of voltage harmonics can be reduced via this method.
As discussed above, In the PV system, the harmonics can be produced due to the use of inverter, converter, and other power electronic devices. In this context, the Photo voltaic power plants contain several power-electronic devices that produce distortion.
The harmonic amplification due to the effect of network resonance can limit the connectivity of solar PV in the distribution network. In general, the output power of PV inverter has the linear relationship with solar irradiance level in PV power system .
However, other power electronic equipment in wind farms is the main source of harmonics. Power converters play an important role in the integration of variable wind power into the grid . The most important features of power converters are that they allow variable speeds and power output at desired levels , .