Investigations on sensorless control of permanent magnet synchronous motor

Abstract

newlinePermanent magnet synchronous machines are used at large in industrial applications owing to their advantages. high performance field-oriented control is obtained by, accurate rotor position information measured by sensors, rotary encoders and resolvers. contrarily, use of these sensors increases the cost, size, weight, and wiring complexity, reducing mechanical robustness and the reliability of the overall pmsm drive systems. the pmsm system model is non-linear. the estimation of position and speed for such systems is the objective of this work. further, non-linear system control is a major concern of current research. as a matter of fact, the control system with parameter uncertainties and output disturbances are usually considered. sliding mode variable structure control has good robustness, which is not sensitive for parameters perturbation and external disturbance. further, the concept of sliding mode observers for non-linear system is used for estimation. existing sliding mode observers exhibit finite time convergence and non-singular characteristic. but restriction on the range of exponent of a power function exist. the work proposes a range extended non-singular terminal sliding mode observer (rentsmo) that overcomes the restriction. back emf is estimated and rotor position and speed are calculated using rentsmo, which is comparatively better with the existing sliding mode observers newline newline