Direct torque control of brushless doubly fed reluctance machines

A brushless doubly fed reluctance machine (BDFRM) allows the use of a partially rated inverter and as such is an attractive cost-effective candidate for applications with limited speed ranges. While the Direct Torque Control (DTC) method has been successfully applied to almost all conventional AC machines, it has not been considered so far as a potential mean for controlling doubly-excited systems. This paper attempts to fill in this gap, by exploring the principles and implementation aspects of Direct Torque Control (DTC) for the BDFRM. The presented results demonstrate good controller performance over the entire supply frequency range for the maximum, torque per inverter ampere control strategy.