Commutation Auto-Correction Method for Position Sensorless BLDCM With the Anti-Interference Ability Against Current Variation

Precise commutation is crucial to improve the sensorless brushless dc motor efficiency. In order to achieve the high-precision commutation, this article develops a commutation auto-correction method. Three challenges of the conventional correction method based on signal integral have been addressed. First, the line voltage difference of adjacent phases is integrated to construct the feedback quantity, which avoids the interference from the phase current variation. Second, the integration interval compression strategy is proposed, which avoids the impact of commutation freewheeling current. Third, a novel averaging circuit is designed, which realizes the high-precision acquisition of the integral. At last, by using the integral as the feedback quantity, a proportional integral controller is introduced to implement the commutation auto-correction. In contrast to the conventional method, the above three approaches ensure the accurate commutation in cases of the phase current variation and high motor speed. The effectiveness of the auto-correction method is verified by the experimental results on a magnetically suspended turbo molecular pump.

Automated summary

This article develops a commutation auto-correction method to achieve high-precision commutation in sensorless brushless dc motors. Three challenges of the conventional correction method have been addressed, ensuring accurate commutation in various conditions. Experimental results on a magnetically suspended turbo molecular pump confirm the effectiveness of the auto-correction method.