Analogy Between Conventional Grid Control and Islanded Microgrid Control Based on a Global DC-Link Voltage Droop
Analogy Between Conventional Grid Control and Islanded Microgrid Control Based on a Global DC-Link Voltage Droop
复制标题
DOI：
10.1109/tpwrd.2012.2193904
复制
发表时间：
2012-05
影响因子：
4.4
通讯作者：
T. Vandoorn;B. Meersman;J. D. de Kooning;L. Vandevelde
中科院分区：
文献类型：
--
作者：
T. Vandoorn;B. Meersman;J. D. de Kooning;L. Vandevelde
对于孤岛微电网，通常采用基于下垂的控制方法来实现可靠的能源供应。然而，在电阻微电网的情况下，这些控制策略可能与传统电网控制所习惯的大不相同。因此，本文研究了同步发电机（SGs）控制与微电网变流器接口分布式发电（CIDG）控制之间的理论类比。传统的电网控制是基于频率作为全局参数，显示机械功率和交流功率之间的差异。SGs通过P/f下垂控制器控制频率变化，无需单元间通信。对于CIDG单元，直流侧功率和交流侧功率之间的差异在每个单元的直流链路电压中可见。与网格频率相反，这不是一个全局参数。因此，为了进行理论类比，需要对直流链路电压进行全局测量。提出了一种基于全局电压的控制策略，并研究了与传统电网控制的类比，强调了实现这种类比需要单元间通信。电阻微电网中已知的一种控制策略，称为基于电压的CIDG单元下垂控制，与这种类比非常接近，但避免了单元间的通信。因此，这种控制策略很容易实现，因为它接近于控制工程师所习惯的。同时，对于可再生能源并网也具有一定的优势。
For islanded microgrids, droop-based control methods are often used to achieve a reliable energy supply. However, in case of resistive microgrids, these control strategies can be rather different to what conventional grid control is accustomed to. Therefore, in this paper, the theoretical analogy between conventional grid control by means of synchronous generators (SGs) and the control of converter-interfaced distributed generation (CIDG) units in microgrids is studied. The conventional grid control is based on the frequency as a global parameter showing differences between mechanical power and ac power. The SGs act on changes of frequency through their P/f droop controller, without interunit communication. For CIDG units, a difference between dc-side power and ac-side power is visible in the dc-link voltage of each unit. Opposed to grid frequency, this is not a global parameter. Thus, in order to make a theoretical analogy, a global measure of the dc-link voltages is required. A control strategy based on this global voltage is presented and the analogy with the conventional grid control is studied, with the emphasis on the need for interunit communication to achieve this analogy. A known control strategy in resistive microgrids, called the voltage-based droop control for CIDG units, approximates this analogy closely, but avoids interunit communication. Therefore, this control strategy is straightforward for implementation since it is close to what control engineers are used to. Also, it has some specific advantages for the integration of renewables in the network.