一种柔性直流输电前馈解耦无功补偿控制系统设计

Design of Flexible HVDC Feedforward Decoupling Reactive Power Compensation Control System

针对传统解耦控制系统只能保证柔性直流输电系统传输有功和降低交流电流中的谐波信号,而不能对串联电路进行补偿的问题,文中提出了一种具有谐波与无功补偿能力的前馈解耦控制系统。该系统基于模块化多电平换流器的数学模型,将检测的无功电流反馈给前馈解耦的无功内环作为参考值实现无功补偿,把高通滤波器检测的谐波分量反馈给前馈解耦无功内环作为参考值实现谐波补偿。实验与测试结果表明,所提出的无功补偿系统能将测试系统的高压直流输电的相电流THD由18.92%降到7.22%,同时该系统不仅可以补偿供端与受端的谐波和无功,还具有传输有功与直流扩容的能力。。

In view of the problem that the traditional decoupling control system only ensures the flexible DC transmission system to transmit active power and reduce the harmonic signal in the AC current but not compensates the series circuit,a kind of feedforward decoupling control system with harmonic and reactive power compensation capability is proposed.The system is based on the mathematical model of modular multilevel converter,the detected reactive current is fed back to the feed-forward decoupled reactive inner loop as a reference value to achieve reactive power compensation and the harmonic component detected by the high pass filter is fed back to the feedforward decoupling reactive inner loop as reference value to achieve harmonic compensation.The simulation and test results show that the proposed reactive power compensation system can reduce the phase current of the THD of high-voltage DC transmission of the test system from 18.92%to 7.22%and,at the same time,it can not only compensate for the harmonics and reactive power for the supplier and receiver,but also has ability to transmit active power and DC expansion.