Space vector pulse width modulation and control technique for single phase three level rectifier in d-q coordinate system

In order to reduce the coupling influence between high-speed electric multiple units (EMU) and the voltage of traction power gird, the operation principle of single-phase three-level neutral point clamped (NPC) rectifier in electrical traction converter was analyzed firstly, and the mathematic modeling in d-q reference frame was described. Then an active and reactive current decoupled control scheme in d-q synchronous frame was presented. On the basis of this, a single-phase three-level space voltage pulse width modulation (SVPWM) was proposed. Compared with the traditional sine pulse width modulation (SPWM), the adopted SVPWM method can not only reduce the requirement of insulation grade and voltage jump impulse durability for the traction transformer, but also balance neutral point voltage effectively. Finally, the validity and feasibility of the control and modulation scheme are verified by computer simulation and a low power prototype experiment.