Blowers of Vacuum Cleaners Utilizing Coreless and Sensorless Axial-Flux Motors with Edge-Wire Coils

Axial-flux motors (AFM) generally have higher torque and power densities, smaller volume and weight, larger diameter to length ratio, and compact construction for the same power level than radial-flux motors (RFM). Hence, AFM are attractive alternative to conventional RFM for applying in low torque and speed servo control systems. Additionally, magnetic Hall-effect sensors and commutation circuits are unsuitable for environment with high temperature and restricted space, so sensorless driving control method of AFM by detecting zero-crossing of back-EMF signals has been achieved. Furthermore, coreless design can reduce motor total weight, normal attractive force and torque pulsation and can increase efficiency of machines as compared with conventional design with cores. Thus, this study focuses on sensorless AFM design applying for blowers in vacuum cleaners to follow the concepts of axial-flux, edge-wire with high space-utilization factors, and stators without ferromagnetic cores. The closed-loop velocity controller designs by adopting proportional-integral-derivative (PID) and fuzzy logic control (FLC) algorithms have been demonstrated effectively for the design sensorless AFM of blowers in vacuum cleaners. As a result, the settling time of velocity closed-loop control methods can be converged within 1.0 second; i.e. the vacuum cleaners can switch and operate in various speeds with different operational environment rapidly. Therefore, the system characteristics and lifetime of the designed sensorless AFM have been enhanced and satisfied the demands of blowers to employ in vacuum cleaners.