A Novel Switching Method for All-speed Sensorless Control Strategy Based on Aviation Motor

All-speed sensorless control method on aviation motor has been investigated in recent years due to the strict operation request of More Electric Aircraft (MEA). Generally, I/F startup strategy and back-EMF based method are combined with a linear current reduction (LCR) switching method to realize all-speed sensorless control on PMSM. Nevertheless, conventional LCR method has bad transition performance under no-load and light-load conditions. Therefore, a linear angel reduction (LAR) switching method is proposed in this paper to smooth the transition process between I/F strategy and SMO algorism. The current in LAR method declines in a specific regulation which causes the angel to reduce in a constant rate. LAR method can be used in speed stationary and speed variation circumstance, furthermore it doesn't need to change parameters along with load variation. Compared to LCR method, LAR method eliminates the angel jumping problem in switching process. Consequently, it not only suppresses the current ripple but also reduces the speed oscillations significantly. Comparison simulation results of LCR method and LAR method are presented to verify the feasibility and effectiveness of the proposed switching method.