Energy savings in elevators by using a particular permanent magnet motor drive

Abstract

This paper concerns the energy savings achieved by using a particular three-phase permanent magnet motor drive control strategy in an elevator application. The proposed control methodology, based on a particular variable amplitude variable frequency voltage control pattern of a permanent magnet motor, is compared to a standard induction motor elevator case. By the adopted changes in the amplitude and frequency of the motor supply voltage simultaneously, high speeds can be attained in conjunction with smooth starting and stopping actions involving reduced supply current during the respective movement of the elevator. In addition, it exhibits high power factor with good driving quality. This control technique achieves the levelling off the floor and the group movement of the system, using the programmable memory a speed pattern which is generated which is proportional to the position of the lift. To that respect, significant energy savings can be achieved which, depending on the type of the motor implemented, can be up to 30% compared to conventional techniques. These improvements can be attained by appropriate handling of the applied pulse width modulation techniques. Various simulated and experiment results are given, illustrating the respective energy savings achieved by the proposed methodology.