Drive circuit-based torque-ripple suppression method for single-phase BLDC fan motors to reduce acoustic noise

This paper proposes a drive circuit for single-phase brushless direct current (BLDC) fan motors to reduce their acoustic noise. First, the torque ripple of a single-phase BLDC motor is analysed theoretically. Then, a drive circuit that is capable of regulating the DC-link voltage during commutation to weaken the negative effect of current lag is proposed to reduce the acoustic noise of single-phase BLDC fan motors. Furthermore, the characteristics of the proposed drive circuit are discussed theoretically using a deduced analytical model of the proposed drive circuit. Additionally, simulations based on the finite element method and experiments are performed. The torque ripple and acoustic noise generated by the conventional and proposed drive circuits are compared. The simulation results show that the torque ripple is reduced by 16.1% when the proposed drive circuit is used, and the experimental results illustrate that the acoustic noise generated by the second harmonic of the torque ripple is reduced by 7.3%. Ultimately, the effectiveness of the proposed drive circuit is verified.