动态电压恢复器的复合数字多变量状态空间反馈控制

在三相三线制系统中，动态电压恢复器面临的主要控制问题是不平衡暂降下对系统三相不平衡的补偿问题。通过正负序分量分解并在正负序坐标下进行建模和控制的方法虽能较好地抑制三相不平衡，但由于正负序分解带来的延迟具有较慢的动态响应速度。为此，文中提出了一种复合数字多变量状态空间反馈控制的方法。在检测到暂降发生并在之后的一段时间内采用单数字多变量状态空间反馈法进行控制，进入稳态时通过控制量的分解无缝地切换到双数字多变量状态空间反馈法，检测到暂降结束时再无缝地切换到单数字多变量状态空间反馈法。该方法同时实现了较快的动态响应速度和较高的稳态精度。实验结果证明了该控制方法的有效性和可行性。

Hybrid Digital Multi-variable State Feedback Control of Dynamic Voltage Restorer

In the three-phase three-wire power system, the main control difficulty of the dynamic voltage restorer is the compensation of unbalanced voltage sag. Although the controller designed both in the positive and negative synchronous rotating frame can well compensate the unbalanced voltage sag, it has slow response because of the time delay in the state variable decomposition. To solve the problem, a hybrid digital multivariable state feedback controller is designed. When a sag is detected, a single digital multivariable state feedback controller designed both in the positive synchronous rotating frame is acted immediately to insure fast response. When the system has entered into steady state, the controller is switched to a double digital multivariable state feedback controller designed both in the positive and negative synchronous rotating frame seamlessly. When the sag die out is detected, the controller is switched back again. This control strategy ensures fast response and high steady accuracy as well. The feasibility of the proposed controller is verified through experiment results.