Abstract:With the merits of high efficiency, light weight, high torque density, long lifespan, and environmental friendly, the ironless-stator permanent magnet (PM) brushless DC (BLDC) motor has been widely used in attitude control systems of microsatellite in the aerospace industry. The ironless-stator PM BLDC motor is classified to radial-flux and axial-flux types according to the principle of magnet field formation. The main characteristics and key technologies of different ironless-stator PM BLDC motor topologies are discussed in detail, which contain the stator windings, rotors and PMs, magnetic bearing technologies, loss and vibration. The research progress of the ironless-stator PM BLDC motor is reported, and the efficiency and torque characteristics of the ironless-stator PM BLDC motor is summarized. Besides, the research direction and the development trend of the ironless-stator PM BLDC motor are discussed.