This paper investigates a bandwidth extension technique for servo system current loops based on Σ-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 1.5 ms to 0.5 ms,significantly improves the sinusoidal tracking of the current,and effectively enhances the dynamic performance and steady-state accuracy of the servo system current loop.
关键词
Σ-ΔADC/电流环带宽延拓/电流同步采样/PI分离控制/伺服系统
Key words
Σ-Δ ADC/extension of current loop bandwidth/synchronous current sampling/PI separation control/servo system
维普
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