Research on ropeless elevator driven by PMLSM

The permanent magnet linear synchronous machine (PMLSM) with long primary is a suitable candidate for ropeless elevator due to high force density and low thrust ripple. For the PMLSM with multi-segment long primary, it is impractical to excite all primary segments. The ordinary method is only energizing the primary segments covered by the secondaries, that is to say, section power supply technology. The switch control technology of primary sections has great influence on system performance because the parameters of PMLSM change with the secondary position. Based on finite element analysis, this paper investigates the characteristics of the PMLSM applied in ropeless elevator, including dand q-axis inductances, PM flux linkage, thrust force, etc. The suitable switching method of primary sections is then proposed to lower the copper loss and thrust force ripple. The fast and steady velocity trajectory tracking is obtained, which is validated by simulation and experiment results.