Backstepping Controller Design with Inherent Current Limitation for a Voltage-Controlled Grid-Side Converter

The control and optimization of gridforming converters remain crucial in power electronics research. A key challenge is limiting the converter’s output current during severe grid disturbances to protect equipment. Existing current-limiting strategies either indirectly modify the output voltage or directly control the current, the latter requiring an additional control loop that increases complexity and may introduce instability. To address these challenges, this paper proposes a backsteppingbased control strategy that ensures asymptotic stability while maintaining current limitation. A novel selection of control Lyapunov functions enables a continuous control law, ensuring seamless operation across normal and fault conditions without switching between control modes. This feature is particularly beneficial for stability analysis of power electronic-based grids under fault conditions, as it allows for a more straightforward and unified stability assessment. The proposed method is implemented on a two-level voltage source converter (2L-VSC) with an LCL filter. Preliminary simulations validate its effectiveness in ensuring stable operation under both nominal and fault conditions.