基于电压源换流器的柔性直流输电系统非线性控制

Nonlinear Control of HVDC System Based on Voltage Source Converter

基于电压源换流器的柔性直流输电与传统直流输电相比,在运行的灵活性和可靠性方面具有明显优势。常规PI调节器为线性控制,使系统性能受到影响,对此,采用在电流环作为内环,功率环作为外环的双闭环传统控制方式基础上,内环采用输入-输出反馈线性化的方法对换流器的非线性耦合模型进行线性化和解偶,从而将复杂的非线性系统转化为线性系统控制问题。采用Matlab/Simulink软件进行了仿真,验证所设计控制方式的有效性。

VSC-HVDC（high-voltage direct current based on voltage source converter） has many advantages,such as flexible operating way and reliability,compared with conventional HVDC.First,VSC-HVDC continuous-time state equation was derived in the dq synchronous rotating coordinate system.However,the model was still nonlinear,strongly coupled and multivariable model.Conventional PI controller was a kind of linear control method which reduced system performance.For solving the above problem,the inside loop made use of input-output feedback linearization method to make the nonlinear coupled converter mathematical model be linearization and decoupled based on the conventional double closed-loop control structure（inside loop is current loop and outside loop is power loop）.It converted the complex nonlinear system into a linear system control problem.Finally,the Matlab/Simulink was used for validation of the designed control method.