A Model Predictive Power Factor Control Scheme With Active Damping Function for Current Source Rectifiers

A model predictive power factor control (MPPFC) scheme is proposed for high-power medium-voltage (MV) current source rectifiers (CSRs). Facing two major issues on input power factor (PF) and LC resonance, the proposed MPPFC uses a novel line reactive power reference estimator to achieve unitary input PF or maximum achievable input PF for a CSR at various operating states, and involves active damping function into itself to mitigate LC resonance at line side. An online capacitance estimation method is associated with the proposed line reactive power reference estimator to guarantee more accurate input PF control, and a novel damping current calculation method, which avoids the use of band-stop filter, is also designed for active damping purpose. In comparison with traditional linear control, the proposed MPPFC not only realizes input PF regulation, but also achieves better steady-state performance on meeting the grid code requirements. In contrast to traditional model predictive control (MPC) for a CSR, the proposed MPPFC achieve more accurate reactive power control. Moreover, it overcomes the challenge on the realization of active damping based on MPC, which extends the application of MPC into high-power MV CSR. Simulation on a high-power CSR (1MVA/4160V/139A) and experiments on a low-power prototype (5kVA/208V/13.9A) are both conducted to verify the effectiveness of MPPFC.