Sensorless guidance control with constant airgap in ropeless linear elevator

Ropeless linear elevator (RLE) is expected to be a new transport solution for skyscrapers and very deep underground applications in the near future. In our laboratory, an experimental model of RLE has been designed and manufactured using the theory of a controlled-PM linear synchronous motor (LSM) developed by one of the authors. We have succeeded in the fundamental elevator-motion control with contactless guidance by controlled-PM, including the stopping mode. But the gap sensor was necessary to measure a position of cage in the guidance direction. This paper presents a sensorless guidance control by detecting the difference in inductances of the series-connected guidance control coils in both sides of cage. It has been verified numerically by dynamics simulation of constant airgap sensorless guidance control.