This study proposes a new control method for a dual-motor drive system to share its output torque and extend its operating speed range. When the drive system is operated below the rated speed, the dual motors are operated in parallel to share the total output torque. By using the proposed parallel dual-motor, the efficiency of the whole drive system can be effectively increased. On the other hand, when the drive system is operated beyond the rated speed, one motor is operated at a standstill and its stator inductances are used as three-phase boost inductances. In addition, an interleave control algorithm is used for the boost converter to reduce the input current ripples. The other motor is used as a driving motor fed by the boost converter. As a result, an extended speed, reaching twice the rated speed range with a near constant torque, is obtained. Several experimental results are included to evaluate the theoretical analysis. This study proposes a new control method for the dual-motor drive system, which can be applied to the electric drive systems in the industrial applications.

This paper proposes a new control method for a multi-motor drive system to increase its output torque capability and extend its operating speed range. When the drive system is operated below rated speed, the motors are parallel operated to increase total output torque. By suitably distributing the stator currents based on an optimal efficiency algorithm, the output torque can be effectively increased. On the other hand, when the drive system is operated beyond rated speed, one motor is operated at a standstill and its stator inductances are used as three-phase inductances of an boost converter; moreover, an interleave control algorithm is used for the boost converter to reduce the input current ripples. The other motor is used as a driving motor. By using this method, an extended speed, which can reach twice the rated speed range with a near constant torque, is obtained. No field weakening is required. This paper proposes a new control method for a multi-motor drive system, which can be applied to electric vehicle drive systems. Keywords-multi-motor drive; wide-range speed; constant torque control I.978-1-4799-0224-8/13/$31.00 ©2013 IEEE