Analysis of nonlinear oscillation of four-quadrant converter in high-speed trians based on discrete model

High-speed train is supplied by alternating current (AC) power and bases on single-phase four quadrant (4Q) converter as one necessary part of the `AC-DC-AC´ transform process. The discrete mathematical model for a single-phase 4Q converter is derived with small disturbance method and digital control delay effect is considered in 4Q converter modeling and analysis. Focusing on stability characteristics of the system, the effect of different circuit parameters and control parameters is analyzed with Hopf bifurcation theory of nonlinear systems. The Matlab simulation and small scale prototype hardware platform have been developed to confirm the theoretical analysis.