Improvement of Velocity Control in the Permanent Magnet-HTS Hybrid Magnetically Levitated Conveyance System

The hybrid magnetically levitated conveyance system has been developed. In this system, pinning force of the HTS achieves stable levitation and guidance without control. Interaction between the permanent magnet and the air core copper coils (propulsion coils) generates propulsion force. As larger propulsion force is needed to improve propulsion characteristics, the pinned flux of the HTS for keeping the carrier levitation is also used. The propulsion coils under the influence of the HTSs are excited, and then propulsion force is added. To control the carrier velocity, improved excitation method for the propulsion coils is introduced. The hysteresis region around the target velocity is defined. By choosing the adequate hysteresis region, the exceeded acceleration and deceleration are suppressed. From the experimental results, the average velocity error decreases about 30% and rise time is improved by about 20%.