Siemens Energy & Automation, Inc.

Siemens Industry, Inc.

Anthony C Schneider

Mukul Rastogi

Ralph Flaugher

Yusuke Fukuta

Ronald Gaillot

Michael R Amorino

Jr Ralph Flaugher

A method for controlling at least two series-cell based drives connected in parallel. The method comprises detecting a failed cell in one of the drives, inhibiting operation of the drive with the failed cell, determining a peak output voltage capability of the drive with the failed cell, communicating the peak output voltage capability to a master controller, and limiting a maximum voltage that each drive can apply to a motor. The method also comprises bypassing the failed cell and resuming operation of the drive with the failed cell after the motor voltage falls below the peak output voltage capability of the drive with the failed cell.

Method for parallel control of series-cell based drives

A method for controlling at least two variable frequency drives connected in parallel. The method comprises, for each variable frequency drive, communicating a magnetizing current component value to a master controller, and receiving a speed demand, a flux demand, and an average magnetizing current component value from the master controller. The method also comprises determining a motor speed and a motor flux based on measurements of a stator voltage and current of a motor coupled to the variable frequency drive, determining a speed reference based on a torque current component value, and determining a flux reference based on the magnetizing current component value and the average magnetizing current component value. The method further comprises adjusting a torque current component based on the speed reference and/or adjusting a magnetizing current component based on the flux reference.

System and method for parallel control of variable frequency drives

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Monroeville, PA, United States of America

Anthony C Schneider