Improved Droop Control Strategy for Parallel Operation of Cascaded Power Electronic Transformers

被引：0

作者：

Wei X. ^{[1
]}

Zhu X. ^{[1
]}

Ge J. ^{[1
]}

Zhou Q. ^{[1
]}

Zhang Z. ^{[1
]}

Li Z. ^{[1
]}

机构：

[1] NR Electric Co., Ltd., Nanjing

来源：

Gaodianya Jishu/High Voltage Engineering | 2021年 / 47卷 / 04期

关键词：

Common DC bus voltage feedback; Current feedforward; Droop control; Parallel operation; Power electronic transformer; Voltage compensation;

D O I：

10.13336/j.1003-6520.hve.20201512

中图分类号：

学科分类号：

摘要：

In order to improve the static and dynamic performance of cascaded power electronic transformers(PETs) in parallel op-eration, an improved droop control strategy is proposed on the basis of the traditional droop control. Firstly, the equivalent circuit of the traditional droop control for parallel system is established, and the reasons for the problems such as large voltage control deviation, low current sharing control accuracy and poor dynamic characteristics are studied. Then, the closed-loop control realizes the compensation of the output voltage control deviation, and the Taylor-expansion of the function of the load current and the phase shift angle is derived and linearized to use as the current feedforward coefficient, thus the accuracy of voltage control and the balance of current control in static performance, as well as the rapid adjustment ability in dynamic performance, can be improved. Finally, the common DC bus voltage is used to replace the output voltage of each PET as the control feedback, which reduces the influence of the line impedance on the current sharing. The experimental results of a set of 3 PETs in a parallel system show that the improved droop control strategy can reduce the power dispersion of the parallel system to 0.18% and the DC voltage control deviation to 0.2 V, which verifies the ef-fectiveness, feasibility and practicability of the engineering application. © 2021, High Voltage Engineering Editorial Department of CEPRI. All right reserved.

引用

页码：1274 / 1282

页数：8

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