Sensorless Control of Linear Motors

Sensorless linear motor control addresses the market need for cost effective and more reliable control of electric motors by removing the mechanical sensors from the feedback control system. The mechanical sensors are the weakest link in the controlsystem in terms of reliability and parts and maintenance costs, especially in demanding environments. For linear motors in particular, the position sensors are problematic since maintaining good resolution over long travel distances is both costly andphysically challenging. Previous work on sensorless control has focused on rotary motors yet still has not adequately addressed applications requiring wide speed range and repetitive transient operation. Little work has been done on linear motors whichpresent additional challenges due to nonlinear end effects. This program will mature sensorless controller technology to meet the operating demands of EMALS while developing enabling sensorless controller technology applicable to both rotary and linearmotor systems. Simulation and experimental techniques will be systematically applied to develop sensorless linear motor control that addresses transient performance, wide speed operating ranges, and changing external loads typical of an EMALS aircraftlaunch. Effective sensorless control technology for rotary and linear motors would benefit large volume markets such as automotive by reducing the cost of electric motors in vehicles and reducing maintenance costs. Demanding application evironments suchas those encountered in military or aviation industry would benefit by reducing system failure rates, thereby saving in costs and providing a competitive edge in performance.