Study On Low-Speed And High-Torque Gearless Drive System

Nowadays, permanent magnetic synchronous motors (PMSM) are used very widely in many industry fields, especially in elevators and high precision servo systems, because of their advanced performances beyond other motors. What's more, permanent magnet material-rare earth is very rich in our nation;therefore, doing research on the control system for PMSM has great science significance and application value.This paper introduces a novel gearless drive system of low-speed and high-torque (LSHT) PMSM for elevator. It that supplied with spatial vector pulse width modifying (SVPWM) inverter can directly drive elevator without decelerator. This direct drive of elevator has not only simplified the construction of transmission mechanism which improved transmit power density and efficiency of the drive system, but also increased precision and reliability of the control system. In this system, rotor position observation is innovative point which avoids a lot of questions caused by mechanic sensor.On the theory, according to the mathematic model of PMSM, the paper presents and realizes i_d = 0 control strategy after analyzing the advantage and disadvantage of diversifiedcontrol strategies. Based on low-speed motor drive system, the design adopts a novel approach of rotor speed/position estimation based on adaptive control. Furthermore, it introduces SVPWM technology in order to reduce harmony of the system. This paper uses the simulation software MATLAB/Simulink to simulate the drive system of low speed and high torque PMSM and the results show that the system models are rightly built and control strategy is feasible. On the basis of hardware TMS320LF2407 of PMSM control system, the paper composes the complete control software using assembly language and realizes stator phrase current sampling, phrase voltage calculation, rotor speed/position observation and output of drive signal. Finally, the inverter-motor model drive system of 1 lkW PMSM is successfully designed and the data of experiment verifies that the proposed vector control scheme is valid, and the dynamic and static performances are quite well. Furthermore, the propose strategy has stronger robustness.