SelfDrive: fully integrated solution for DC PM motors

PM brushless motors with trapezoidal EMF are perhaps today the most used motors for low-cost applications. An increasing number of solutions is aimed to reduce control electronics in this kind of motor in order to reduce total size. The paper shows an application in which virtually all power and signal electronic components are placed in the same chassis as the motor. Particularly, Hall switches are placed inside motor slots, to provide adequate slot switching. The motor is thereby capable to be self commutated, just like an ideal DC machine. The reduced dimensions of the whole drive allows a suitable application of such a solution in a different field of application as robotics, automotive and so on. The placement of components inside the motor obviously poses some electrical, magnetic and thermal problems that are approached in the paper by means of finite element modelling and experimental tests.