Design and control of a linear propulsion system for an elevator using linear switched reluctance motor drives

Linear switched reluctance motors (LSRMs) for the primary propulsion of a ship elevator is proposed and investigated for the first time in this paper. To achieve the stated objective, a new type of LSRM is proposed with twin stators and a translator between them with no back iron in the translator. The proposed configuration of the LSRM is designed, simulated, analyzed, compared with traditional LSRMs, and verified by experimental measurements. The number of LSRM propulsion subsystems required is studied with a view to minimize their weights and an optimization study for that purpose is developed. Unique placement of the LSRM propulsion systems on the elevator is presented. The propulsion force is generated using one phase or multiphase excitation. To reduce propulsion force pulsations, a major requirement in elevators, controlled multiphase excitation using one of the known force distribution functions (FDF) is an acceptable solution. In this paper, it is proved that the currently available FDFs are able to reduce the force pulsations but are not able to meet the peak force command for the system. Consequently, the velocity and position control do not meet even the elementary performance requirements any more. A new FDF is proposed in this paper and presented to overcome the problem caused by a conventional FDF. The control system with the proposed FDF is derived and integrated into velocity and position controllers. Extensive dynamic simulation and experimental verification of the proposed LSRM with the novel FDF is proved to give superior performance in this paper. Such high performance capable of meeting vertical elevator applications is demonstrated.

[1]  R. Krishnan,et al.  Design of a linear switched reluctance machine , 1999, Conference Record of the 1999 IEEE Industry Applications Conference. Thirty-Forth IAS Annual Meeting (Cat. No.99CH36370).

[2]  J.J. Cathey,et al.  A high force density linear switched reluctance machine , 1993, Conference Record of the 1993 IEEE Industry Applications Conference Twenty-Eighth IAS Annual Meeting.

[3]  R. Krishnan,et al.  Switched reluctance motor drives : modeling, simulation, analysis, design, and applications , 2001 .

[4]  Susumu Torii,et al.  The positioning control with velocity feed-forward for the rope-less elevator using linear synchronous motor , 1997, 1997 IEEE International Electric Machines and Drives Conference Record.

[5]  Michael G. Wing,et al.  Control of an elevator drive with a single-sided linear induction motor , 2002 .

[6]  Moon Hwan Kim,et al.  A study on the design of transverse flux linear motor with high power density , 2001, ISIE 2001. 2001 IEEE International Symposium on Industrial Electronics Proceedings (Cat. No.01TH8570).

[7]  R. Krishnan,et al.  Comparison of Linear Switched Reluctance Machines for Vertical Propulsion Application: Analysis, Design and Experimental Correlation , 2006, Conference Record of the 2006 IEEE Industry Applications Conference Forty-First IAS Annual Meeting.

[8]  Norbert C. Cheung,et al.  Position control of linear switched reluctance motors for high-precision applications , 2003 .

[9]  R. Krishnan,et al.  A study of current controllers and development of a novel current controller for high performance SRM drives , 1996, IAS '96. Conference Record of the 1996 IEEE Industry Applications Conference Thirty-First IAS Annual Meeting.

[10]  Byeong-Seok Lee,et al.  Linear switched reluctance machine drives with electromagnetic levitation and guidance systems , 2000 .

[11]  Cheng-Tsung Liu,et al.  Experimental investigation and 3-D modelling of linear variable-reluctance machine with magnetic-flux decoupled windings , 1994 .

[12]  R. Krishnan,et al.  A linear switched reluctance motor: converter and control , 1999, Conference Record of the 1999 IEEE Industry Applications Conference. Thirty-Forth IAS Annual Meeting (Cat. No.99CH36370).