A Study on Bandwidth Extension Technology of Servo System Current Loop Based on Σ-ΔADC
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.
Σ-Δ ADCextension of current loop bandwidthsynchronous current samplingPI separation controlservo system
万方数据
维普
