Sensorless Control of BLDCM Drive for a High-Speed Maglev Blower Using Low-Pass Filter

This paper develops the brushless dc motor sensorless control strategy for a high-speed maglev blower. The sensorless techniques are based on a phase voltage comparator and a nonlinear offline compensator. The nonlinear offline compensator is used to compensate for the phase delay of the back electromotive force due to a low-pass filter; the phase voltage comparator is used to compensate for variations of the phase due to changes in the load, calculation error, and unbalance of three-phase motor stator. The commutation mode based on the transition between "60 - phi," "120 - phi," and "180 - phi" by detecting the total delay angle, the process of start-up, and the antidisturbance capability is described in detail. Some experiments are implemented on a single-chip DSP controller to demonstrate the feasibility of the suggested sensorless and the good anti-interference property.