Z源逆变器驱动的无位置传感器无刷直流电机反电势过零点检测方法

Zero-Crossing Point Detection of Back EMF for Z-source Inverter Fed Sensorless Brushless DC Motor

基于Z源逆变器,该文提出了一种无位置传感器无刷直流电机的反电势过零点检测方法。使用单通道电压比较器,该方法在直通矢量作用下对虚拟中性点电压和中点电压进行比较。由于有效矢量和零矢量被专用于调速,提出的方法具有较宽的工作范围。文中分析了各矢量作用下的虚拟中性点电压,优选了中点电压作为参考电平,从而减小了由功率器件导通压降带来的检测误差。直通矢量作用下,虚拟中性点电压和中点电压均不含电源电压参量,避免了分压衰减导致的信噪比降低。Z源逆变器还提高了电源电压利用率,并提高了电机系统的安全性和可靠性。实验结果验证了理论的正确性和方法的可行性。

Based on the Z-source inverter, this paper ＇proposed a novel zero-crossing point （ZCP） detection approach of back EMF for Z-source inverter fed sensorless brushless DC motor. By the single channel voltage comparator, the proposed approach compares virtual neutral point voltage with input neutral point voltage during the shoot-through vectors. The proposed approach dedicates zero-vectors and active-vectors to speed regulation, thus gets a wide operation range. The virtual neutral point voltages were analyzed, and the input neutral point voltage was preferred as the reference level of the comparator to reduce errors caused by voltage drops of the power devices. During the shoot-through vectors, both the virtual neutral point voltage and input neutral point voltage do not contain the component of DC supply voltage, so the signal-noise ratio of the detection will not be affected by the voltage attenuation. Moreover, the DC voltage utilization can be improved by the Z-source inverter, and the safety of the drive system can also be improved. The experimental results verify the correctness of the theories and the effectiveness of the proposed approach.