Resonant Control Techniques for Grid-Connected Power Converters

Resonant control techniques for grid-connected power converters have emerged as a cornerstone for meeting stringent power quality requirements in renewable energy integration, electric vehicle charging infrastructure and distributed generation. By embedding resonant elements within the control loop, these methods achieve infinite steady-state gain at selected frequencies, enabling selective harmonic mitigation and precise tracking of fundamental currents. Proportional–resonant and multi-resonant controllers offer targeted attenuation of grid disturbances, such as voltage imbalance and frequency variation, without compromising dynamic response. Self-tuning resonant approaches adapt controller parameters to changing grid conditions, ensuring stability under weak-grid scenarios and distorted voltage. The implementation of resonant control in converters with LCL filters enhances damping of grid-side oscillations and complies with evolving grid connection standards worldwide. Collectively, these techniques underpin the reliable operation of photovoltaic inverters, wind turbine converters and micro-grid power electronics, advancing global decarbonisation efforts.

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Resonant Control Techniques for Grid-Connected Power Converters publication trend

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

Technical terms

Proportional–Resonant controller: A control algorithm combining a proportional term with a resonant term to provide high gain at a specified frequency, enabling precise tracking and rejection of sinusoidal signals.

Multi-Resonant current control: Extension of PR control that incorporates multiple resonant terms tuned to several harmonic frequencies for selective harmonic compensation.

LCL filter: A three-stage passive filter topology, comprising two inductors and a capacitor, used at the converter output to attenuate switching harmonics before injection into the grid.

Voltage Source Converter (VSC): A power electronic device that converts DC to AC voltage with controllable magnitude and frequency for grid integration.

Phase-Locked Loop (PLL): A control system that synchronises the phase of the converter’s internal reference with the grid voltage, providing accurate frequency and phase information.

Synchronous Reference Frame: A rotating coordinate system aligned with the grid voltage vector, allowing conversion of AC quantities to DC for simplified control.

Total Harmonic Distortion (THD): A metric quantifying the degree of harmonic content in an AC waveform relative to its fundamental component, expressed as a percentage.

References

1. Second-Order Harmonic Reduction Technique for Photovoltaic Power Conditioning Systems Using a Proportional-Resonant Controller. Energies (2013).
2. A Simplified Design Strategy for Multi-Resonant Current Control of a Grid-Connected Voltage Source Inverter with an LCL Filter. Energies (2018).
3. A Simple Self-Tuning Resonant Control Approach for Power Converters Connected to Micro-Grids With Distorted Voltage Conditions. IEEE Access (2020).