High performance AC motors utilizing “written-pole” technology

A new type of AC motor has been developed which can achieve many of the performance goals of electronic drives. These motors do not use electronic devices in the power path. The elimination of power path electronics can significantly improve reliability, ruggedness and operating efficiency. This new motor technology utilizes a continuous layer of “permanent” magnetic material in the rotor and concentrated exciter pole in the stator. This construction provides the ability to “write” the proper number of magnetic poles in the rotor magnetic material while the machine is operating. Utilizing this design allows a synchronous motor to be built that has a very low per-unit direct line starting current, high operating efficiency, and very high inertial load starting capacity