馈能式非线性负载模拟装置电流跟踪无差拍控制策略

A Current Tracking Deadbeat Control Scheme for Energy Feedback Nonlinear Load Simulator

为构建绿色、节能的电能质量装置测试平台,将2个电压源变换器(VSC)形成背靠背拓扑结构,搭建了一台馈能式非线性负载模拟装置。在采用数字信号处理器(DSP)进行控制时,控制延时会带来较大误差甚至使系统失稳。传统的无差拍控制忽略了延时,电流跟踪效果不理想。对传统无差拍控制进行改进,提出一种基于采样反馈电流预测的无差拍控制,通过将采样周期和载波周期的起始时刻错开一定时间,并在此时间内进行反馈电流预测,可以准确计算出下一拍所需的调制信号。最后,采用传统无差拍控制算法与改进后的无差拍控制算法,在样机上进行了实验,实验结果表明,基于采样反馈电流预测的无差拍控制算法有效提高了控制精度和时间利用率。

In order to construct a green and energy-efficient platform for testing power quality devices,an energy-feedback nonlinear load simulator is developed.The simulator includes a back-to-back structure of two voltage source converters（VSCs）.When the control system of VSC is based on digital signal processors（DSPs）,the time delay in control is likely to cause errors,or even makes the control system unstable.Traditional deadbeat control does not consider the time delay,thus the current tracking results are not satisfactory.Improvement to this approach is made in this paper by introducing feedback current prediction into the traditional deadbeat control method.In the improved deadbeat control algorithm,the starting points of a sampling period and a carrier period are staggered a certain period of time,during which the feedback current is predicted to accurately form the modulation signal for the next period control.Finally,the traditional and improved algorithms are verified and compared on an experimental prototype.Experimental results demonstrate that the deadbeat control based on the feedback current prediction effectively enhances control precision and utilization of time.