Sensor-less vector control of the nine-phase concentrated wound interior permanent magnet motor drive using a unique third sequence high frequency injection into the stator windings

This paper presents a sensor-less vector control method which estimates the rotor angle and speed of a nine-phase, Interior Permanent Magnet (IPM) machine with concentrated stator winding, especially for use at starting, zero and low speed operations. The injection of unique high frequency voltage signals into a non-torque producing third sequence circuit of the machine provides current information for the estimation of the rotor angle and speed without generating any high frequency torque ripple. The fundamental voltage component impressed on the motor by the converter, with the estimated rotor angle and rotor speed are used for the speed control of the motor drive under minimum stator copper loss operation. In order to computer simulate the complete controlled drive, including both the fundamental and high frequency components a full order model of the motor is utilized. The control and estimation strategies proposed have been implemented on a 2 hp, 36 slots, 4-pole concentrated stator wound interior permanent magnet motor drive. Some simulation based on a full order coupled machine model and experimental results validate the proposed vector control scheme for operation at both low and high speed operations.