TY - GEN

T1 - An improved two-motor three-phase drive using FCS-MPC based flux and torque control with voltage constraint consideration

AU - Lim, Chee Shen

AU - Levi, Emil

AU - Jones, Martin

AU - Rahim, Nasrudin Abd

AU - Hew, Wooi Ping

PY - 2013

Y1 - 2013

N2 - This paper presents a flux and torque control scheme, based on finite-control-set model predictive control (FCS-MPC), for two three-phase induction motors supplied by a five-leg two-level inverter. The reduced-switch-count topology with leg sharing inherently imposes an additional constraint on the voltages in the system. In the best available PWM-based control scheme for this topology, the constraint means that, in simple terms, the sum of speeds of two machines cannot exceed the rated speed of one machine, in order to avoid over-modulation and large torque oscillations. In essence, no provision exists to account for the additional voltage limit of the topology. It will be shown here that the FCS-MPC can consider the voltage constraint dynamically in the control loop, and hence, apart from preserving the independent control of the two machines, it can significantly widen the speed operating range. Three different cost functions, corresponding to three operating modes, are considered. The unique way in which the MPC handles tracking errors allows the motors to operate dynamically in the base speed region with field weakening, without requiring any external change of the flux references. Simulation and preliminary experimental results verify the theory.

AB - This paper presents a flux and torque control scheme, based on finite-control-set model predictive control (FCS-MPC), for two three-phase induction motors supplied by a five-leg two-level inverter. The reduced-switch-count topology with leg sharing inherently imposes an additional constraint on the voltages in the system. In the best available PWM-based control scheme for this topology, the constraint means that, in simple terms, the sum of speeds of two machines cannot exceed the rated speed of one machine, in order to avoid over-modulation and large torque oscillations. In essence, no provision exists to account for the additional voltage limit of the topology. It will be shown here that the FCS-MPC can consider the voltage constraint dynamically in the control loop, and hence, apart from preserving the independent control of the two machines, it can significantly widen the speed operating range. Three different cost functions, corresponding to three operating modes, are considered. The unique way in which the MPC handles tracking errors allows the motors to operate dynamically in the base speed region with field weakening, without requiring any external change of the flux references. Simulation and preliminary experimental results verify the theory.

KW - Two-motor drive

KW - field weakening

KW - flux control

KW - model predictive control

KW - torque control

UR - http://www.scopus.com/inward/record.url?scp=84881619471&partnerID=8YFLogxK

U2 - 10.1109/IEMDC.2013.6556252

DO - 10.1109/IEMDC.2013.6556252

M3 - Conference Proceeding

AN - SCOPUS:84881619471

SN - 9781467349758

T3 - Proceedings of the 2013 IEEE International Electric Machines and Drives Conference, IEMDC 2013

SP - 188

EP - 195

BT - Proceedings of the 2013 IEEE International Electric Machines and Drives Conference, IEMDC 2013

T2 - 2013 IEEE International Electric Machines and Drives Conference, IEMDC 2013

Y2 - 12 May 2013 through 15 May 2013

ER -