动态电压恢复器数字矢量控制方法的性能分析及改进

动态电压调节器(dynamic voltage restorer，DVR)是解决暂态电能质量问题的有效手段。根据DVR在dq同步旋转坐标系下的状态空间模型，采用前向欧拉法和无差拍控制原理推导得出包含内环电流控制器和外环电压控制器的数字双矢量控制算法。利用闭环模型进行稳定性分析和频率响应分析，研究参数变化对数字控制系统的影响。为补偿数字控制系统的采样延迟和计算时间，采用状态观测器对输出电流进行预估，并反馈至内环矢量电流控制器。仿真结果表明算法具有良好的动态和静态性能。提出2种改进的双矢量控制算法，实现对不对称电压跌落的无差补偿，并通过仿真和实验进行初步验证。

Performance Analysis and Improvement of Digital Vector Control Algorithm for Dynamic Voltage Restorer

Dynamic voltage restorer(DVR) is an effective solution to transient power quality problems. The state space model of DVR in dq synchronous reference frame is established. Then the digital double vector control algorithm which incorporates both inner loop current controller and outer loop voltage controller is derived employing the forward Euler method and deadbeat control principle. The stability and frequency response analysis of the closed-loop model are performed to investigate the influence of the variations of system parameters on the controller performance. To compensate one sample delay due to analog to digital conversion and computer calculation time, Smith predictor based on state observer is used to predict the output current one sample ahead and feeds the predicted current back into the current controller. Simulation results show that controller possesses good dynamic and static performances and the load voltage can be compensated to the reference level. To improve the transient performance of the controller under unbalanced sags, two modified dual vector controllers are proposed and verified in principle by simulation and test results.