Impedance stability analysis and impedance remodelling of matrix converter grid-connected system

Abstract

Matrix converter has become one of the research hotspots of power electronic converter due to its excellent input and output characteristics and adjustable power factor. To study the stability of the matrix converter grid-connected system, the harmonic linearisation method is adopted to model the positive and negative sequence output impedance models of the matrix converter grid-connected system. The stability of the system is analysed by judging whether the plot of the ratio of the input impedance to the positive and negative sequence output impedance satisfies the Nyquist stability criterion. Also, an impedance remodelling method based on the positive sequence impedance is proposed to improve the stability of the system. Finally, the simulation verification is carried out by MATLAB/Simulink. The simulation results prove the correctness of the theoretical analysis and the feasibility of the impedance remodelling method.

Keywords

• nyquist stability
• electric impedance
• power factor
• power grids
• power system stability
• matrix convertors
• power system simulation
• matlab-simulink
• nyquist stability criterion
• harmonic linearisation method
• adjustable power factor
• input characteristics
• negative sequence output impedance models
• positive sequence output impedance models
• output characteristics
• power electronic converter
• impedance stability analysis
• impedance remodelling method
• positive sequence impedance
• input impedance
• matrix converter grid-connected system