EKF-based Hybrid Controller for Permanent Magnet Brushless Motors Combining Hall Sensors and a Flux-Observer-based Sensorless Technique

Accurate rotor position data is an essential requirement for permanent magnet brushless AC motors. An EKF-based hybrid controller which uses a combination of low-cost linear Hall sensors for low speed operation and a flux-observer-based sensorless technique for high speed operation of a Halbach magnetized permanent magnet brushless motor is proposed. The controller eliminates inaccuracies in the estimated rotor position and velocity during the changeover between the two operational modes. Its effectiveness is demonstrated experimentally, and its advantages over conventional hybrid controllers are highlighted