Research and application on the resonance suppression for parallel T-type three-level PCS based on capacitor voltage active dampling

摘要

In order to improve the power level and efficiency, combined with the advantages of T-type three-level converter, a parallel T-type three-level PCS topology is proposed. In order to solve the resonance problem, the system impedance model of LCL filter is established and the mathematical expression is set up. Then, the infulence of the current oscillation is analyzed from the excitation. The relationship between the number of parallel stations and the number and frequency of the resonace points is obtained with the spectrum charts simulated by Matlab. A coordinated control strategy of parallel T-type three-leve PCS based on capacitor voltage active dampling is proposed to suppress the resonace of the system. Finally, a 500 kW PCS prototype is developed. The Matlab simulation comparison and the experimental results show the correctness of the theoretical analysis, and the effectiveness of the proposed control scheme.