An ADRC-based Model Predictive Direct Power Control to Alleviate Low-Frequency Oscillations of Traction Dual Rectifiers

Low-frequency oscillation (LFO) phenomenon of traction network often occurs in vehicle-grid coupling systems (VGCS), which may lead to traction blockade of the electric multiple units (EMUs). To improve the control of traction dual rectifiers (TDR) and suppress LFO, an auto-disturbance rejection control-based model predictive direct power control (ADRC-MPDPC) approach is developed. First, a voltage correction based on Newton interpolation is carried out to eliminate the error caused by the sampling process of the line-side voltage sensor. Besides, to improve the dynamic performance and robustness of the MPDPC, a voltage outer-loop control strategy based on first-order ADRC is designed. Finally, a simulation model of VGCS is constructed to test the control performance and the effectiveness of the proposed algorithm. The experimental results show that the proposed control can not only improve LFO of the dc-link voltage but also effectively alleviate the harmonic distortion of the current and suppress the power pulsation of MPDPC in the TDR.