Giuseppe Raffaello Carrara

SLIDING MODE SPEED CONTROLLER FOR TRAPEZOIDAL BRUSHLESS MOTORS

ABSTRACT This paper describes the application of a variable structure speed controller for a non sinusoidal brushless permanent magnets motor drive. Our trapezoidal brushless motor model changes the working conditions for every phase commutation and moreover it allows to simulate the different structural motor configurations. Controller synthesis is carried out using sliding mode theory with a pole assignment technique. During the sliding motion the state point is forced to reach a prescribed surface due to an active change of the control action. The order of the system is therefore reduced and moreover the dynamic behaviour of the closed-loop system is imposed. Results by digital computer simulation prove parametric variation insensitivity, disturbance rejection, fast transient responses, no overshoot and absence of speed ripples during phase commutations.

Field oriented adaptive controller using EKF for asynchronous drives

ABSTRACT This paper presents a high dynamic induction motor drive system utilizing a fully digital direct field oriented controller. The drive is characterized by a sliding mode controller and by a stochastic filtering technique, the latter obtained by an extended Kalman filter (EKF), in the feedback loop. The EKF, in addition to supplying a reliable estimation of state variables, is able to identify and to correct in real-time the values of rotor resistance and of rotor constant time, in effect, becoming an adaptive state observer. The system can work both with or without a speed sensor. Some computer simulations are reported.