Research Of An Open-end Winding PMSM Based On Vector Control And Fault-tolerant Strategy

In this paper, an open-ending PMSM fed by a dual inverter in topology of single source is researched. For open-ending PMSM, its mathematical model and vector control system are built, at the same time SVPWM strategy in different modulation boundaries, dynamical restraint of zero-sequence current, two fault-tolerant control strategy for open-circuit and short-circuit fault in phase, system simulation and experiment verifying are discussed.Under ideal conditions, the motor mathematical model in three common coordinate systems for AC machines, including abc, αβ, dq with consideration of structure of open-ending PMSM. And combining vector control ideology, its vector control system could be obtained. Based on two-level convention, SVPWM concept in a dual inverter is extracted. This passage tells SVPWM procedure in middle hexagon in detail, including voltage space vector production and distribution, sector division, confirming of vector combination and calculation of effective time. In this situation, there won’t be zero-sequence current as a result of reasonable vector selection theoretically and it is equivalent to that in topology of double sources. To increase voltage utilization, the range is expanded to the largest and together an available access for modulation is put forward. What ’s more, to suppress zero-sequence current effectively, close-loop control strategy for zero-sequence current is come up with, which would adjust time distribution of zero vector and then improve SVPWM. Besides, open-circuit and short-circuit fault-tolerant topology are given and compared. The conclusion is that open-circuit topology has advantage over the other in the same condition. And introd uce two fault-tolerant control strategies accordingly. One is based on SVPWM and the other is SPWM.An open-end winding PMSM simulation model is built in Simulink,whose validity is proved by simulation result. Then, vector control and fault-tolerant control system model are established and strategies listed previously are tested. In the end,experiment results and phenomena on hardware platform with the core of TMS320F2812 DSP chip confirm the theories again.