Suppression of vibration for elevator system using dead-time compensation with current prediction

In this paper, a vibration suppression scheme is proposed for the riding comfort of elevator using dead-time compensation with an accurate current information. To obtain an accurate current information at switching instants, a current prediction is used. The prediction current at switching instant for dead-time compensation is calculated from the sampled current, which greatly reduces the polarity error of the current at switching instants and increases the compensation accuracy. Using the proposed dead-time compensation scheme, the torque ripple of 6 times harmonics and the corresponding elevator vibration are reduced. Experimental evaluation has been performed with an 11 kW induction machine and a medium-speed elevator system. The result obtained proves the feasibility of the proposed method.