【目的】电流采样是实现电机高效稳定控制的关键环节，其精度直接决定系统性能。在无刷直流电机(BLDCM)控制系统中，传统多传感器方案不仅会增加硬件成本，还会因传感器参数漂移或特性差异导致闭环精度下降。针对空间矢量脉宽调制(SVPWM)下，单电流传感器在低调制比区和扇区边界存在电流重构盲区的问题，本文提出了一种脉宽调制(PWM)后半周期中点采样移相法。【方法】通过调整PWM脉冲相位，使相位补偿设定下降沿后的2倍最小采样时间为实际采样窗口，并在窗口中点实施电流采样操作，该方法既保证满足最小采样时间条件，又为开关噪声引起的信号畸变预留了足够的裕量，有效降低了采样时机的不确定性和电流瞬态波动。【结果】仿真与试验结果表明，本文所提方法有效减小了低调制比区与扇区边界的电流重构盲区。相比于无补偿移相法，在所提补偿方法下重构相电流精度显著提升，重构误差稳定在较低水平，最大误差从6.8 A降至1.38 A，降幅达79.71%；总谐波畸变率从26.38%降至3.37%，谐波抑制效果明显。【结论】本文所提方法有效解决了SVPWM驱动型BLDCM系统中单传感器电流重构的难题，同时降低了硬件成本，为电机的电流采样设计提供了可行性参考。

[Objective] Current sampling serves as a critical component to achieve efficient and stable operation of the motor, and its accuracy directly determines the motor control performance. In brushless direct current motor (BLDCM) control systems, conventional multi-sensor schemes not only increase the hardware costs, but also degrade the closed-loop control accuracy due to sensor parameter drift or characteristic differences. Aiming at the problem of current reconstruction blind zones of single current sensor in the low index modulation regions and sector boundary areas under space vector pulse width modulation (SVPWM), this paper proposes a midpoint sampling phase-shifting method in the second half cycle of pulse width modulation (PWM). [Methods] By adjusting the phase of the PWM pulse, the phase compensation set two times the minimum sampling time after the falling edge as the actual sampling window and implemented the current sampling operation at the midpoint of the window. This method not only ensured that the minimum sampling time requirement was met, but also reserved a sufficient margin for the signal aberration caused by the switching noise, which effectively reduced the uncertainty of sampling timing and current transient fluctuations. [Results] Simulation and experimental results demonstrated that the proposed method effectively reduced the current reconstruction blind zones in low index modulation regions and sector boundary areas. Compared with the uncompensated phase-shifting method, the accuracy of reconstructed phase current was significantly improved under the proposed compensation method, and the reconstruction error was stabilized at a lower level. The maximum error was reduced from 6.8 A to 1.38 A, which was a reduction of 79.71%, and the total harmonic distortion was reduced from 26.38% to 3.37%, which was a significant effect of harmonic suppression. [Conclusion] The method proposed in this paper effectively addresses the challenge of single-sensor current reconstruction in SVPWM-driven BLDCM systems, while reducing the hardware costs,and provides a feasible reference for the current sampling design of motors.

陕西省重点研发项目(2024GX-YBXM-059)