A novel virtual vector-based direct power control strategy to reduce common mode voltage in transformer-less two-level grid-connected VSI

The article introduces a novel virtual vector-based direct power control strategy designed to mitigate common mode voltage (CMV) in transformer-less two-level grid-connected voltage source inverters (VSIs). This strategy is particularly crucial for renewable photovoltaic (PV) energy systems, where high-frequency variations in CMV can induce undesirable leakage currents and safety issues. The proposed method leverages the virtual flux concept for grid voltage estimation, allowing for precise power control with reduced noise. By constructing virtual vectors that combine active vectors to achieve zero average CMV, the strategy effectively minimizes CMV variations and reduces leakage current. The article validates the effectiveness of the proposed DPC through numerical simulations and hardware implementation, demonstrating superior performance in CMV reduction and switching loss minimization compared to conventional DPC methods. This innovative approach offers significant advantages for compact PV systems, improved reliability, and compliance with safety standards, making it a standout solution in the field of power electronics and renewable energy systems.