Research Of Motor Control For AMT Shifting Based On SPWM

Automatic mechanical transmission (AMT) is developed based on the manual transmission (MT), it installed the automatic shift and electronic control unit on the MT.AMT has been developed for several decades, optimized by many researchers, so nowadays the technology is better and able to implement intelligent shift. AMT has many advantages, not only the low cost, high efficiency, easy maintenance features as the MT, but also easily and quickly shift, intelligent power features as the AT. Of course, there is also a longer shift time, and poorer shift quality compared with AT. AMT have been widely used at home and abroad, especially on heavy-duty commercial vehicles, but the application of the car is less, and it is increasing recent years. The AMT of foreign companies has excellent performance; and in the country, a number of automotive companies and research institutions already pay attention on it, they have produced prototypes, and some products have applied on vehicles. Compared with foreign countries, there is certain gap on the quality and speed of the shift, so the research of AMT has a strong practical significance.This paper designs the electric shifting institution based on the manual shift system of an heavy commercial vehicle. Use two brushless DC motors (BLDC) as the main driver, one for the shift selection system and the other for the gear shifting system and installed speed reducers on their torque outputs. The main transmission device is a screw. The overall structure is small and reliable. The dynamic of all parts of the gearshift institutions and BLDC motors according to the process of shift selection, pick and hung is analyzed.According to gearshift conditions, make the goals of control of the shifting system. Apply the two-two conduction and six-state as the motor drive mode. Apply the method of SPWM to the servo control of the motor, so that it can make accurate positioning. And compared with the conventional square wave drive, it can reduce the torque ripples effectively. According to the above, select the proper DSP controller.According to the control strategy of the gearshift motor, this paper make a simulation of the control system of the BLDC motor based on MATLAB mainly according to the process of shift pick and hung. The simulation results show that the gearshift control has accuracy positioning, and the shift time is short. It fulfills the initial target and shows that the control method is effective. Finally, designs the soft of the control system based on CCS2000, and gives the soft design flow charts.