A Novel Integrated LCL filter for High-order Harmonic Suppression in Locomotives

In order to suppress the harmonics of the traction network and improve the power quality of the traction network, a new harmonic suppression scheme is proposed in this paper, which a magnetic integrated LCL filter is configured at the front end of the traction four-quadrant rectifier. Firstly, the mathematical model of the four-quadrant rectifier with front-end access to the LCL filter is derived. Secondly, based on the problem of natural resonance peak of LCL filter, a method of resonant peak suppression is proposed based on the transient direct current control without capacitive current sensor. In order to reduce the space occupied by LCL filter, the traction winding port inductance is used as the first inductance, and the second inductance is integrated into the traction transformer. Finally, the traction drive system with the magnetic integrated LCL filter is simulated in Ansoft and Matlab. Simulation results show that the magnetic integrated LCL filter not only has good harmonic suppression effect, but also effectively overcomes the shortcomings of traditional LCL filter occupying a large space.