Active Damping Control for Grid-Connected Inverters

Grid-connected inverters are pivotal in integrating renewable energy sources into electrical networks. To mitigate switching harmonics and improve power quality, most inverters employ an inductance–capacitance–inductance (LCL) filter between the converter and the grid. However, the inherent resonance peak of the LCL network poses a stability challenge, especially under grid impedance variation and parallel inverter operation. While passive damping introduces additional losses, active damping control uses feedback strategies to suppress resonance without extra passive components. By embedding damping algorithms into current control loops—often combined with virtual impedance concepts, disturbance observers or predictive schemes—modern controllers achieve both high dynamic performance and robust stability. Advances in digital implementation have addressed computation delays and sensor requirements, leading to adaptive and robust solutions that maintain low total harmonic distortion and reliable operation under weak‐grid conditions. These developments underpin the deployment of photovoltaic arrays, energy storage systems and static compensators in microgrids and utility‐scale installations worldwide.

Research from Nature Portfolio

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Research from all publishers

Recent studies have demonstrated the following advances. A disturbance observer-based robust model predictive control scheme employs a full‐state estimator and lumped disturbance observer to achieve voltage sensorless operation and compensate for parameter mismatches and grid impedance variations. The controller, designed via linear matrix inequalities, ensures rapid convergence and minimal steady-state error while predicting system behaviour over a receding horizon. A novel super-twisting integral sliding mode controller applies a second-order sliding surface to a three-phase inverter, combining integral action with a super-twisting algorithm to eliminate chattering and maintain low total harmonic distortion under filter drift and grid harmonics. Experimental validation confirms enhanced disturbance rejection and robustness. An H∞ repetitive current control framework integrates capacitor-current-feedback active damping into an H∞ design to reject specific harmonic orders and stabilise the discrete‐time system despite computation and PWM delays. The derived stability criterion guides the selection of feedback gains, yielding efficient harmonic attenuation and resilience to grid-impedance changes.

Active Damping Control for Grid-Connected Inverters publication trend

The graph below shows the total number of articles in active damping control for grid-connected inverters across all publications each year (not limited to Nature Index journals).

Technical terms

LCL filter: A three-component network of inductor, capacitor and inductor used to attenuate switching harmonics in inverters.

Active damping control: A feedback-based method for suppressing filter resonance without adding passive resistors.

Disturbance observer: An estimator that infers unmeasured disturbances and parameter uncertainties for improved control robustness.

Model predictive control: An optimisation-based strategy that computes control actions by predicting future system states over a finite horizon.

Sliding mode control: A robust nonlinear technique that forces system trajectories onto a predefined sliding surface to handle uncertainties.

Total harmonic distortion (THD): A quantitative measure of waveform distortion caused by harmonic components relative to the fundamental frequency.

References

1. Disturbance Observer-Based Robust Model Predictive Control for a Voltage Sensorless Grid-Connected Inverter With an LCL Filter. IEEE Access (2021).
2. H∞ Repetitive Control Based on Active Damping with Reduced Computation Delay for LCL-Type Grid-Connected Inverters. Energies (2017).
3. A Robust Nonlinear Sliding Mode Controller for a Three-Phase Grid-Connected Inverter with an LCL Filter. Energies (2022).