非并联运行AC/DC系统中直流变流器的非线性附加控制器设计

针对交直流联合输电系统中直流线路与交流线路非并联运行的情况,本文为HVDC换流站设计了附加控制器以阻尼交流系统中区域间的功率振荡.文中将直流线路功率调节作用等效为一阶惯性环节,将交直流联合的多机系统等值为两机两区域系统,由此建立了综合考虑机电振荡的三阶模型;然后运用反馈线性化方法设计了交直流系统非线性稳定控制器.仿真结果证明了该文所提出的控制器能有效地阻尼区域间功率振荡,提高系统的暂态稳定性.但同时也引入了其它一些问题.需要进一步研究的内容在最后进行了讨论.

Design of nonlinear auxiliary power controller for HVDC converters in non-parallel operating AC/DC systems

A nonlinear auxiliary controller for HVDC converters in AC/DC power systems, where the AC and DC lines are not in parallel connection, was developed to damp inter-area oscillations. The method treats the dynamics of DC power regulation as a first-order inertia block and simplifies the AC/DC multi-machine system into a two-machine power system. Based on the third-order model obtained, state-feedback linearization and LQR approach are applied to design a nonlinear controller. Computer simulation results have shown that the controller can effectively damp inter-area oscillations and enhance transient stability. But the auxiliary control for HVDC converters also introduced some undesirable side effects. Possible problems and future work are discussed at last.