| 引用本文: | 赵熙临,王成伟.计及电压控制的柔直系统参数解耦VSG频率支撑方法[J].电力系统保护与控制,2025,53(7):99-111.[点击复制] |
| ZHAO Xilin,WANG Chengwei.Decoupled VSG frequency support method considering voltage control in flexible HVDC systems[J].Power System Protection and Control,2025,53(7):99-111[点击复制] |
|
| 摘要: |
| 利用柔性直流输电系统潜在的调频能力，可实现对电网频率的有效支撑。但在传统调频过程中，由于虚拟惯量的增加降低了系统对参考功率的跟踪速度，同时带来电压控制稳定裕度的降低，弱化了系统的频率支撑能力。因此，提出一种计及电压的参数解耦虚拟同步发电机(virtual synchronous generator, VSG)策略。首先，对换流站辅助频率控制模型及常规VSG控制方式进行分析，引入直流母线电压，并采用带下垂的PI控制器对电压偏差进行调节。然后，对部分有功功率控制回路(active power loop, APL)进行改进，引入低通滤波器及前馈回路消除VSG固有的振荡极点，将APL的参考功率跟踪速度和VSG可提供的虚拟惯量支撑能力进行解耦。最后，利用Matlab/Simulink仿真对所提策略进行仿真验证。结果表明，所提策略能将虚拟惯量的调节和参考功率的跟踪由两参数独立控制，使控制方式更加灵活，并有效提高换流站的频率支撑能力，同时也保证了对电压的良好控制效果。 |
| 关键词: VSC辅助调频 虚拟同步发电机 解耦控制 电压闭环调节 |
| DOI：10.19783/j.cnki.pspc.240785 |
| 投稿时间：2024-06-24修订日期：2024-11-19 |
| 基金项目:湖北省自然科学基金联合基金项目资助(2023AFD186) |
|
| Decoupled VSG frequency support method considering voltage control in flexible HVDC systems |
| ZHAO Xilin,WANG Chengwei |
| (School of Electrical and Electronic Engineering, Hubei University of Technology, Wuhan 430068, China) |
| Abstract: |
| Utilizing the potential frequency regulation capability of flexible HVDC systems can effectively support grid frequency stability. However, conventional frequency regulation methods reduce the tracking speed of reference power changes because of increased virtual inertia, and decrease voltage control stability margins, thereby weakening the system’s frequency support capability. To address this issue, a parameter decoupled virtual synchronous generator (VSG) strategy based on voltage control is proposed. First, the auxiliary frequency control of the converter station and conventional VSG control method are analyzed. A DC bus voltage is introduced, and a droop-based PI controller is used to regulate voltage deviations. Then, an improved active power loop (APL) control is proposed. It incorporates a low-pass filter and a feedforward loop to eliminate the inherent oscillation poles of the VSG, thereby decoupling the reference power tracking speed of the APL from the virtual inertia support capability provided by the VSG. Finally, the proposed strategy is simulated and validated using Matlab/Simulink. The results show that the proposed strategy enables independent control of virtual inertia and reference power tracking through two separate parameters, rendering the control approach more flexible. Additionally, it effectively enhances the frequency support capability of the converter station while ensuring excellent voltage control performance. |
| Key words: VSC auxiliary frequency regulation VSG decoupling control voltage closed-loop regulation |
