Design Of Elevator Door-Motor System Based On Direct Torque Control

The elevator door-motor is one of crucial components in elevator system, which works most frequently in the elevator and is directly used by passengers. Thus a stable and reliable door-motor controlling system is indispensable in modern elevator system. In door-motor controlling system designs, the characters of high precision, fast response, good robustness and simple algorithm are often used for evaluating the performance of the design. Recently, for the advantages of simple algorithm, low dependence of motor parameter, and good dynamic performance, Direct Torque Control (DTC) has become one of prevailing methods in asynchronous motor controlling. In this paper, DTC method is also applied for controlling elevator-door motor.The thesis introduces the basic principle of Direct Torque Control on asynchronous motor. In the beginning, stator flux and torque can be got through a typical mathematics model of asynchronous motor. Here, the mix model stator flux estimation is selected, which focuses on the current model of stator flux estimation in low speed as well as on the voltage model of stator flux estimation in high speed. For stator flux estimation is the key step in practical applications of motor controlling, it attracts many attentions in recent researches. Then, after the analysis of the state of inverter switches, the voltage space vector can be received. Finally, on basis of the relationship between voltage space vectors and torque or stator flux, hexagon or approximate round trace of stator flux can be got, and controlling of torque can also be achieved when two-value regulator is used to adjust flux and torque.The door-motor system utilizes Digital Signal Processor (DSP) and Intelligent Power Module (IPM) as key control parts. The DSP chosen here is TMS320LF2407A made by TI. It is specially designed for motor-controlling system, which composes many special modules and decreases the design of many peripheral instruments. The IPM is applied here as power instrument whose inner protect circuit raises the reliability of the system. In this experimental platform, the hardware system can be regarded as a universal one, which can be applied in any kind of asynchronous motor control system when configuring with corresponding software. And in the design of software system, Assemble Language is selected for the advantages of simple syntax, high efficiency and strong reliability.In practical applications, it is necessary for elevator door-motor controlling system obtains various working modes. And the speed curves during opening or closing operationsare different under various working modes, which are depended on passengers' input parameters. According to these speed curves, the motor's working speeds on specific times can be determined by software, these speeds are used as set value in DTC, therefore the controlling of speeds in the elevator-door motor controlling system are achieved.At the end of this paper, the running curves of the elevator door-motor achieved from the experimental platform discussed above are given, and the performance of the whole system is analyzed briefly. The experiment result shows that, the proposed method can fit the application of elevator door-motor system, and the experimental platform obtains good performance of high precision, strong reliability, and fast response, which can be broadly applied in industrial field.