基于Σ-ΔADC的伺服系统电流环带宽延拓技术研究

A Study on Bandwidth Extension Technology of Servo SystemCurrent Loop Based on Σ-ΔADC

研究了基于Σ-ΔADC的伺服系统电流环带宽延拓技术,旨在提高电流采样精度和电流环带宽。设计了一种与PWM中心对齐的平均电流同步采样方法,以减少采样过程中的噪声和延迟。通过优化PWM更新时序并采用SINC3滤波器的同步策略,实现了电流采样时刻与PWM周期的精准对齐,从而降低了电流环中的谐波干扰。提出了PI分离控制策略,分别为比例控制器和积分控制器配置不同滤波器,以兼顾系统的动态响应和稳态精度。实验结果表明,所提方法使相电流中的谐波幅值降低了80%,转矩反馈波动降低了64%,电流过零点的延迟时间从1.5 ms缩短至0.5 ms,电流跟踪的正弦度显著提升,有效提高了伺服系统电流环的动态性能和稳态精度。

This paper investigates a bandwidth extension technique for servo system current loops based onΣ-ΔADC,aiming to enhance current sampling accuracy and current loop bandwidth.A center-aligned average current synchronous sampling method is proposed to reduce noise and delay during the sampling process.By optimizing the PWM update timing and adopting the synchronization strategy of the SINC3 filter,the precise alignment of current sampling moments with the PWM period is achieved,thereby reducing harmonic interference in the current loop.Additionally,a PI separation control strategy is proposed,configuring different filters for the proportional controller and the integral controller to balance the system’s dynamic response and steady-state accuracy.Experimental results show that the proposed method reduces the harmonic amplitude of the phase current by 80%,decreases torque feedback fluctuation by 64%,shortens the delay time at the current zero-crossing point from 1.5ms to 0.5ms,significantly improves the sinusoidal tracking of the current,and effectively enhances the dynamic performance and steady-state accuracy of the servo system current loop.