直流无刷电机高精度电流采样系统设计

Research of High Precision Blushless DC Motor Current Sampling Method

为及时、准确地采样直流无刷电机(BLDCM)绕组中的电流值,以实现电流闭环控制,针对常用的直流无刷电机电流采样方法中电路复杂,分立元件温漂严重,调整困难,可靠性低等问题,提出了一种高集成度、高精度的电流采样方案。该方案以FPGA为控制芯片,电流检测调理和A/D转换电路均采用精度高、温度稳定性好的集成芯片实现,消除了分立元件温漂大、抗干扰能力弱的缺陷。采用PWM周期中点采样法,克服了功率管开关噪声对电流采样精度的影响。实验结果表明,整个电流采样系统线性度好、精度高、实时性好,为高品质电流环控制提供了可靠保证。

In order to measure winding’s current of blushless DC motor（BLDCM） real-time and accurately for current loop of the digital control system,a current sampling scheme for BLDCM of high integration and high accuracy is proposed based on the analysis of usual methods of current sampling.This scheme overcomes the effect of discrete component’s temperature drift and power transistor’s switching noise by using FPGA controller,integrated chips and PWM-midpoint sampling method.The experimental results show that the current sampling system has high linearity,high accuracy and real-time performance.