Performance improvement of three-level five-phase inverter fed DTC controlled five-phase induction motor during low-speed operation

In this paper, the Direct Torque Control (DTC) for three-level five-phase inverter fed five-phase induction motor is proposed to improve the low speed performance. The classic DTC method initiates flux demagnetization effect when the five-phase induction motor runs at low speed, especially below 5Hz. This classic DTC scheme is modified in order to minimize the demagnetization effect during low speed operation. According to modification, the voltage vector space plane is divided into twenty sectors, each of width 18°. For odd number of sectors, ±36° displaced intermediate voltage vectors and for even number of sectors, ±36° displaced main voltage vectors are selected instead of ±72° displaced voltage vectors. Simulation results are presented in order to validate the proposed DTC scheme.