A DSP-based direct torque control of five-phase synchronous reluctance motor drive

Abstract

This paper develops the direct torque control (DTC) technique for five-phase synchronous reluctance motor (SynRel) using a digital signal processor (DSP). The mathematical model of the proposed five-phase SynRel motor is first given. The well-known winding function method is used to derive winding inductances in order to develop the dynamic equations of SynRel in natural frame of reference (a-b-c-d-e). The five-phase transformation from the stationary (a-b-c-d-e) reference system to a rotating (q-d-Q-D-n) reference system is used to remove the angular dependency of the inductances to obtain voltage equations for the five-phase SynRel motor in the synchronous rotating reference frame. The torque in terms of currents is then obtained using the magnetic co-energy method. Direct torque control is thus developed for the five-phase SynRel motor followed by simulation results in the Matlab/Simulink environment. The control block diagram of the proposed direct torque control is also given in the paper. The switching pattern is developed in order to maintain a sinusoidal flux waveform in the air gap. A five-phase SynRel motor plus the five phase current regulated IGBT based inverter were designed and fabricated in the laboratory. The control method is implemented on a TMS320C32 digital signal processor board.