Improved rotating carrier signal injection method for sensorless control of PM brushless AC motors, accounting for cross-saturation effect

摘要

In carrier signal injection-based sensorless control of permanent magnet brushless AC (BLAC) motors, although cross-saturation effect is advantageous to extend the sensorless safety operation range, it results in load-dependent error in the position estimation, and higher torque ripple as well. Considering the nonlinear behavior of estimated position error due to cross-saturation effect, an improved rotating carrier signal injection method is proposed in this paper, which pre-compensates the estimated position error resulting from cross-saturation effect by modifying the injected carrier voltage signal. Finally, experimental results show that a significant improvement in the position estimation can be achieved with the proposed method.