Smooth commutation of brushless DC motor by model‐free predictive current control without back‐EMF estimation

Abstract

Abstract This study presents a new predictive control approach for brushless DC (BLDC) motor to smooth its commutation process. The proposed predictive control method is applied to the BLDC motor's equivalent DC current. Therefore, this method utilises only one prediction equation, which means less calculation than the standard predictive control schemes. Here, the equivalent DC current equation is defined according to the model‐free control theory to remove the back‐EMF voltage estimation from the control system. In consequence, the proposed predictive DC current control (DC‐PCC) has a smooth commutation. Because of applying the model‐free theory, both commutation and non‐commutation periods of the BLDC motor have similar dynamic equations. Hence, one simple prediction equation can be utilised for both periods. Besides, the proposed method has less computational burden due to using only one prediction equation and removing the back‐EMF estimation process. To validate the proposed model‐free DC‐PCC, experimental tests are performed, and the results are discussed in this research.

Keywords

• brushless DC motors
• commutation
• electric drives
• predictive control