Frequency Adaptive Multistage Harmonic Oscillator for Renewable Based Microgrid under Non-Ideal Grid Conditions

In this project, to mitigate the issues of weak grid integrated Hybrid Renewable Power Generation Based Microgrid (HRPGM) and to ensure reliable and effective operation, the frequency adaptive Multistage Harmonic Oscillator (MSHO) control is used. This control comprises of multistage filter with DC bias rejection loop and Frequency Locked Loop (FLL). 

The multistage filter is tuned to dominant lower order harmonic and allows the selective elimination of the harmonics. MSHO is used for assessing the fundamental constituent from harmonics and DC bias infected grid voltage. It also extracts the positive sequence constituent from distorted/unbalanced grid voltages while maintaining the balanced grid currents. It effectively overcomes the frequency perturbations, nonlinear load compensation and significantly increases the overall reliability and quality of power. 

A set of Back-to-Back (BTB) associated power converters provide flexible speed operation of the wind power generation system. Different functionality modes are incorporated in order to address, round the clock operation of the microgrid, enabling the reactive power compensation capability and mitigation of the harmonics demanded by the nonlinear load connected at the distribution side. The Maximum Power Operating Point (MPOP) for both wind and solar PV array is acquired by the individual implementation of perturb and observe technique. The performance investigation of the system is carried out on a developed simulation model.

Keywords: Frequency Adaptive Multistage Harmonic Oscillator, Hybrid Renewable Power Generation, Power Quality and Weak Grid.