Five-phase induction motor drives with DSP-based control system

This paper extensively introduces two kinds of control schemes that can be applied to the operation of a five-phase induction motor - vector control and direct torque control, as well as their fully digital implementations. Vector control of the five-phase induction motor generates the fundamental and third harmonic currents. In conjunction with the designed five-phase induction motor geometry, this current profile induces the nearly rectangular flux linkage in the air-gap resulting in higher power density and more output torque. The direct torque control method is advantageous when applied to the five-phase induction motor. The five-phase inverter provides 32 space voltage vectors in comparison to 8 space voltage vectors by the three-phase inverter. Therefore, a more elaborate flux and torque control algorithm for the five-phase induction motor can be employed. Direct torque control of the five-phase induction motor minimizes the ripples of the stator flux and the torque, and achieves a more precise flux and torque control. A 32-bit floating-point TMS320C32 Digital Signal Processor (DSP) enables these two sophisticated control techniques to be conveniently implemented with a high control precision. Experimental results show that an ideal control performance is obtained for both two control methods as applied to the five-phase induction motor, and further validate theoretical analysis and simulation results.