ABSTRACT
A number of important areas of research and development have arisen in the wake of the success of the Permanent magnets (PM) brushless drives in applications. The problems facing the second generation motor drives are common to all the ac motor drives. To overcome the unevenness in the flux density distribution, this distribution is measured or computed and accordingly the current is adjusted continuously to generate a constant torque. The motor parameters that are sensitive to variations in temperature are stator resistances and rotor magnets. The use of inner current loops overcomes the effect of stator resistance variations. The use of PM brushless motor drives in critical applications such as aerospace, medicine, and defense necessitates that a high amount of reliability be guaranteed for their operation under normal as well abnormal operating conditions such as faults in the machine, inverter, and controller.
