LCL并网逆变器存在谐振问题,通常采用有源阻尼法对其进行抑制,但其数字控制过程中引入的控制延时,会影响有源阻尼控制的动态响应性能。针对上述问题,在原有的基于电容电压反馈的有源阻尼控制方案基础上,引入过采样的调制策略,通过一个开关周期内多次采样多次装载调制信号,有效减小控制延时,改善有源阻尼控制的动态响应性能。实验研究证明所提出控制方案的正确性和有效性。
The resonant problem is essential for grid-connected inverters with LCL filters, then active damping methods are usually adopted. But the delay caused by digital control affects the active damping control dynamic response performance. In view of the above difficulties, on the basis of the active damping control scheme which based on capacitor voltage feedforward, oversampling is introduced. In a switching period, data is sampled and modulation signal is updated multi times. The control delay is reduced greatly. The scheme can improve active damping control dynamic response performance. Experiment results show that the proposed control scheme is correct and effective