Active resonance damping and harmonics compensation in distributed generation based islanded microgrids

The development of distributed generation based microgrids with high penetration of electronically interfaced systems shows great interest in various applications. These systems commonly use LC-L filters with inherent resonance characteristics, which increases the risk of resonance amplification and propagation in microgrids. These resonances lead to current and voltage harmonics amplifications resulting in major power quality and stability issues. For this aim, an effective active resonance damping method is proposed to dampen out the undesired resonance amplifications. The proposed method uses a filter-based approach with inherent stability characteristics to reconstruct and compensate for the undesired resonance harmonics. This method uses an external control level that prevents control bandwidth limitation as it directly superposes the harmonic compensating signal to the control signal. This method offers simplicity of design and implementation without the need for additional measurements or prior knowledge of system parameters, which is of importance in scalable microgrid applications. Experimental results and discussions are provided to evaluate the effectiveness of the proposed strategy.