A Rapid Sensorless Startup Method with Instantaneous Control Mode Switching for High-Speed Vane-Motor Based on Hybrid Speed-Position-Current Tracking Controller

The aim of this research is to shorten the startup time for high-speed vane-motor. This is considered as a challenging task because during startup, the signal-to-noise ratio (SNR) of the motor back electromotive-force (EMF) is too low to implement closed-loop control. Herein, a unique control strategy with a hybrid speed-position-current tracking controller (HSPCTC) is proposed to achieve rapid sensorless startup and an instantaneous control mode switching into closed-loop. The HSPCTC forms an equivalent semi-closed-loop that allows the uncertainty of back-EMF error to be distributed to multiple states, i.e., not only the estimated position but also the estimated speed and current. Consequently, the controller actively adjusts the corresponding state estimation values to better tolerate the low SNR, which is the key feature to achieve a high acceleration rate before closed-loop control can be activated. As the motor speed builds up, the estimated states will converge to their actual values, and this will trigger an instantaneous control mode switching directly from startup stage into normal sensorless closed-loop control. This method has been validated by both simulation and experiment. Without pre-alignment, the vanemotor can repetitively achieve 0-106,000r/min startup within a time window of 0.11sec for HSPCTC plus 0.27sec for speed acceleration.