Efficiency Optimization And Control Strategy Research Of Pmsm Traction System For Low Floor Tram

Modern low floor tram is essential developmental trend as the supplement and extension of metro transportation capacity. The low floor design of 300 mm from the ground makes the development of independent rotate wheel bogie and direct PM traction driver. For the reason that traction motor frequently runs out of the rating working point, the PM traction system has large margin for efficiency optimization. Existing optimal control strategy of PM traction system only can meet the requirement of single motor optimization in non-rail industry, how the optimal strategy of PM traction system combine the operation situations and the working traits(such as independent rotate wheel bogie, direct driving, the speed differential of left-right wheels, multi-motor joint control, etc.), based on above problem, this paper present the following research aspects:Study on the 15 T independent rotate wheel bogie of 100% low floor tram in SKODA corporation, this paper built the initiative orientation control model of speed differential feedforward coupling, and study PM traction motor vector control method, then built the PM traction control system that applied to low floor tram, the basic control method is MTPA below base speed and weakening flux above base speed, which is the control foundation for following efficiency optimal strategy.Aiming at the starting and acceleration stage of low floor tram, this paper built the iron loss mathematic model of PMSM, and using the minimum analytic solution to build lowest loss controller(LLC). Aiming at the constant speed stage of low floor tram, this paper present the input minimum power optimal strategy of traction inverter based on multi-layer fuzzy controller, which optimize global efficiency of one independent rotate wheel bogie system. Finally, combining the LLC controller and multi-layer fuzzy controller, this paper presents a integrated efficiency optimization strategy of PM Traction system that suitable for low floor tram.Simulation result shows that the LLC based on iron loss model and the multi-layer fuzzy controller based on SVPWM modulation depth signal effectively reduce the electrical loss, and the integrated efficiency optimization strategy could optimize the efficiency in the whole traction period with the advantages of small disturbance, well robustness and a high value of engineering practicability.