Voltage switching tables for DTC controlled interior permanent magnet motor

This paper compares two voltage-vector switching tables for direct torque controlled (DTC) interior permanent magnet (IPM) motors. The conventional eight voltage-vector switching table which is normally used in the DTC of induction motors does not seem to regulate the torque and stator flux in an IPM motor well when the motor operates at low speed. Modelling and experimental studies have both revealed that a six voltage-vector switching table is more appropriate for an IPM motor drive at low speed. This paper reports the results of a modelling and experimental study of the two voltage switching tables for the DTC of the IPM motor, for operation at low and at high speeds.