It is well known that there is the commutation interference pulse in zero-crossing points (ZCPs) of back electromotive force (EMF) for brushless direct current (BLdc) motors. Generally, the interference pulse is handled by a low-pass filter (LPF) with a low cutoff frequency. However, the phase delay caused by LPF will deteriorate the performance of BLdc motors. In this letter, a novel phase-delay-free commutation method based on terminal voltage is proposed. The ZCPs and commutation freewheeling signals are obtained according to terminal voltages. Then, the main part of commutation interference pulse is removed through detected freewheeling signals. Finally, the remaining part is eliminated through a fixed delay digital filter (FDF). Comparing with the conventional commutation methods, the faster starting and the phase-delay-free commutation are achieved reliably by the proposed method. The effectiveness of the proposed method is verified through an 80 W BLdc motor.

中文翻译：

---

基于端电压的无刷直流电动机无相换相新方法

众所周知，对于无刷直流（BLdc）电机，在反电动势（EMF）的零交叉点（ZCP）中存在换向干扰脉冲。通常，干扰脉冲由具有低截止频率的低通滤波器（LPF）处理。但是，由LPF引起的相位延迟将使BLdc电动机的性能下降。本文提出了一种新的基于端电压的无相位延迟换相方法。根据端电压获得ZCP和换向续流信号。然后，通过检测到的续流信号去除换向干扰脉冲的主要部分。最后，其余部分通过固定延迟数字滤波器（FDF）消除。与传统的换向方法相比，所提出的方法可靠地实现了更快的启动和无相位换相。通过80 W BLdc电机验证了该方法的有效性。