Electrical Actuator Based On Direct Torque Control

The electric actuator system has become widely used for process control in modern chemical engineering, especially petroleum engineering. The new generation electric actuator requires higher levels of valve open speed and range and its remote control. The existence and the level of these functionalities directly determine the flux and pressure of liquid or gas in the pipelines within industrial process control system. Fatal accidents may occur if the flux and pressure in pipelines are not controlled properly. The currently used electric actuators within industrial process control have various problems and no longer fit contemporary control requirement. In this paper, a new high performance electric actuator will be proposed.This paper analyzes major technologies within position control, speed control and remote control of electric actuator and establishes fundamental conditions for new generation smart electric actuator. Main sections are outlined as follows,1.Based upon direct torque control principles and models for asynchronous motors and D-A inverters, asynchronous motors'magnetic torque can be calculated though hysteresis loop control after linkage observer's estimation of stator magnetic linkage.2.PID neural network is implemented into electric actuator valve location control. P, I, D parameters are set to fit valve actions and eventually enable accurate location control.3.Both hardware and software modules for communication system are designed on the basis of Modbus protocol. This will enable the electric actuator system to be controlled remotely.4.Hardware controlling circuits are developed to achieve direct torque control and bus communication functions for electric actuator system. dsPiIC30F4011 and PIC24FJ256GA106 from Microchip corporation are used as the core controlling units.Electric motor driving technologies, PID control and FCS control system are other significant theories referenced for the integrate development. Technical analysis is tested by the designed electric actuator software/hardware system and their experiment kits.