单相三电平并网逆变器的改进无差拍电流控制

传统无差拍电流控制策略的控制性能受滤波电感值变化的影响较大。在单相三电平并网逆变器中,首先引入易于DSP实现的双调制波三电平正弦脉宽调制(sine pulse widthmodulation,SPWM)方法,进而推导基于该方法的并网逆变器暂态数学模型。以此为基础,提出采用两次电流采样的在线电感辨识方法,结合数字低通滤波技术获得了实时电感辨识结果,并用于无差拍电流控制算法中,从而有效提高了并网电流控制性能。相应的实验结果证明了所提出方法的正确性和可行性。

Improved Deadbeat Current Control of Single-phase Three-level Grid-connected Inverters

The control performance of traditional deadbeat current control is easily affected by the variation of filtering inductor.In single-phase three-level grid-connected inverter,a dual reference waves three-level sine pulse width modulation(SPWM) method that suitable for implementation by DSP was introduced firstly,and then the dynamic mathematical model of the grid-connected inverter based on the aforementioned pulse width modulation(PWM) method was derived.On the basis,an online inductor identification method adopting two current samples was proposed.Combining with digital low-pass filter,real time inductor identification result was obtained.This result was applied into deadbeat current control algorithm,thus the grid-connected current control performance is increase efficiently.Corresponding experimental results verified the accuracy and feasibility of the proposed method.