Pulse-width modulation (PWM) grid-connected inverters are essential for incorporating renewable energy sources. But PWM creates harmonics that have the potential to cause grid instability. These harmonics are attenuated using passive filters, including L, LC, and LCL filters; LCL filters offer the highest attenuation. LCL filters are effective, but they can also cause resonance, necessitating damping methods. While active damping is effective but impacted by digital control delays, passive damping (PD) is dependable but results in power losses. There are six variants of passive damping techniques (PD-1 to PD-6), each with trade-offs. PD-1 and PD-5 have significant power outages. High resistance is required for PD-2 and PD-6, which limits harmonic attenuation. A balance between attenuation and damping is provided by PD-3. The best filtering is offered by PD-4, which has a resistor in parallel with the capacitor but suffers from large damping losses. Similar to notch filters, active damping can effectively minimise resonance; but, in order to suppress harmonics, it must maintain a high-quality factor “q”. Power loss and filtering performance are balanced by combining PD-4 with notch filters in a hybrid damping technique. While active components target specific frequencies to improve overall stability and efficiency in varying grid situations, passive components tackle broad-spectrum harmonics and power dissipation. By addressing both resonance and power loss, this hybrid approach maximises the performance of grid-connected inverters.
Improved Filtering with Hybrid Damping Suppression in Grid Connected Solar PV inverter
2024-07-31
680142 byte
Conference paper
Electronic Resource
English