AbstractsEngineering

Actuators are the key components of any industrial system and the electromechanical actuators are widely used in variety of applications particularly in engine gimbal control actuator in flight control mechanism of launch vehicle. Hydraulic and pneumatic systems were used previously for energy conversion in engine gimbal control of launch vehicle. In recent years with the advancement of power electronics switching devices and control newlinetechniques, the electrical motors are widely used in electromechanical system replacing the older hydraulic system. For a safety critical system such as aerospace application, reliability of the electrical motor is important and the conventional structured motors are unable to satisfy this requirement. In all electrical motors the probability of winding faults are high in proportion compared to other kinds of electrical machine faults. Advanced electrical motors such as redundant motors and fault tolerant motors are considered for reliability improvement. The electrical motor used in electromechanical actuator for spacecraft application must possess operational winding redundancy in order to increase the reliability of the system. The actuator in aerospace application requires a motor of high torque, high efficiency, long life, less weight and size. The conventional dc motors are not suitable for this high critical application due to the presence of commutator, brushes and electromagnetic interference. Replacing the electromagnets with permanent magnets and with the use of rotor position sensor and commutation electronics makes brushless dc motor (bldc) suitable for the space environment. The permanent magnet brushless dc motor is best suited for this electromechanical energy conversion application due to its superior performance and better controllability compared to other motors. newline%%%