The stable operation of conventional power systems greatly depends on coherent impedances of the bulk power networks’ elements. However, penetration of inverter interfaced distributed generation (IIDG) units put the stability of modern power systems into a risk due the vague and arbitrary output impedance of IIDG units. Besides, the impedance specification of IIDGs can only be established by means of a virtual impedance loop, which needs extra control efforts also imposes voltage drops. Especially, the virtual impedance depends on the output current and cannot be thus freely adjusted. To this end, an optimal voltage regulator (OVR) is proposed for controlling IIDG units to achieve a free/wide range of impedance shaping. The OVR facilitates the optimal impedance shaping based on the control requirement and grid's impedance characteristics, which makes the IIDG units consistent with the power network thus contributing to stabilizing modern power systems. The OVR's control system is based on the state feedback control and the impedance shaping is achieved through an appropriate feedback gain adjustment process. Simulation results prove the effectiveness of the method to achieve the desired impedance shaping.

中文翻译：

---

逆变器接口分布式发电机组的最佳稳压器第І部分：控制系统

常规电力系统的稳定运行在很大程度上取决于大电网网络元件的相干阻抗。然而，由于IIDG装置的模糊和任意输出阻抗，变频器接口分布式发电（IIDG）装置的渗透使现代电力系统的稳定性受到威胁。此外，只能通过虚拟阻抗环路来建立IIDG的阻抗规格，这需要额外的控制工作，而且还会施加电压降。特别是，虚拟阻抗取决于输出电流，因此无法自由调节。为此，提出了一种最佳电压调节器（OVR），用于控制IIDG单元以实现自由/宽范围的阻抗整形。OVR可根据控制要求和电网的阻抗特性促进最佳阻抗整形，这使IIDG装置与电网保持一致，从而有助于稳定现代电力系统。OVR的控制系统基于状态反馈控制，并且通过适当的反馈增益调整过程可实现阻抗整形。仿真结果证明了该方法实现所需阻抗整形的有效性。