Design of Double Staggered Parallel Bearingless Motor Drive System

To make bearingless motors (BMs) more competitive, it is imperative to reduce the cost while ensuring high performance. In this article, the driving system of the BM is optimized from the perspectives of the inverter topology and the control strategy. A dual-hybrid vector control driving scheme of the BM based on the double staggered parallel topology is proposed for the control performance and cost. Meanwhile, the levitation/torque stagger phase shift is adopted to lower the root-mean-square value of the dc-link current. The proposed driving scheme is compared with the traditional vector scheme based on a full-bridge topology on a bearingless pump system. It turns out that the two driving schemes are similar in current, speed, and rotor radial displacement fluctuation. The proposed scheme shows the advantages of simpler system structure and lower cost, so it is deemed as an attractive driving scheme for the BM.