Current Control Strategies in Power Electronic Converters

Current control is central to the performance and reliability of power electronic converters across applications such as grid‐tied inverters, motor drives and renewable energy interfaces. These converters employ an inner current loop to regulate the instantaneous flow of electrical charge, mitigating disturbances, ensuring stable operation and maintaining power quality. Traditional approaches rely on proportional–integral (PI) or proportional–resonant (PR) controllers implemented in synchronous reference frames, offering simplicity and ease of tuning. Advanced methods extend beyond linear control to include discrete‐time deadbeat algorithms, model predictive control and passivity‐based designs, each addressing limitations imposed by digital delays, switching harmonics and grid impedance variations. Hysteresis control delivers rapid dynamic response but can suffer variable switching frequency; multi‐band adaptations and unipolar modulation schemes have been proposed to constrain switching losses while retaining robustness. In parallel, active damping strategies and multi‐sampled pulsewidth modulation enhance stability by shaping converter admittance, extending passive frequency regions and suppressing resonances. Accurate small‐signal modelling of converter dynamics, encompassing sampling sidebands and modulation nonidealities, underpins robust controller synthesis and the prediction of high‐frequency interactions. Across these developments, there is a continuous trade-off between bandwidth, stability margin and implementation complexity. The global significance is underscored by the need to integrate increasing volumes of inverter‐based resources into power systems, drive efficiency gains in electric mobility, and maintain grid resilience in the face of variable renewable generation.

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Current Control Strategies in Power Electronic Converters publication trend

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Technical terms

Voltage‐Source Converter (VSC): A device that converts direct current (DC) into alternating current (AC) using semiconductor switches and control algorithms.

Admittance: The frequency-dependent measure of a system’s current response to a voltage perturbation, used to assess stability and resonance.

Nyquist frequency: Half the sampling rate of a digital control system, beyond which aliasing and nonpassive behaviour may arise.

Passivity: A property indicating that a system does not generate energy, employed to ensure robust interaction between converters and the grid.

Deadbeat current control: A discrete-time strategy that computes control actions to achieve predefined current trajectories with finite settling time and zero steady-state error.

Pulsewidth modulation (PWM): A technique for synthesising AC waveforms by varying the duration of fixed-frequency voltage pulses.

References

1. Low-Order Passivity-Based Robust Current Control Design for Grid-Tied VSCs. IEEE Transactions on Power Electronics (2021).
2. Passivation of Grid-Following VSCs: A Comparison Between Active Damping and Multi-Sampled PWM. IEEE Transactions on Power Electronics (2022).
3. Accurate High-Frequency Modeling of the Input Admittance of PWM Grid-Connected VSCs. IEEE Transactions on Power Electronics (2022).
4. Deadbeat Current Control in Grid-Connected Inverters: A Comprehensive Discussion. IEEE Access (2021).
5. A Digital Hysteresis Current Control for Half-Bridge Inverters with Constrained Switching Frequency. Energies (2017).