海上风电场柔性直流输电变流器的无源性控制策略

摘要

As the converter model for wind farm power transmission has the characteristics of strong coupling and nonlinearity, a passivity-based control is proposed. The mathematical converter model in synchronous reference frame is expressed in the form of Lagrange equations and its strict passivity is proved. The smooth positive energy function is selected as Lyapunov function to meet the requirements of the controlled system for asymptotical stable at origin point. Damping injection is applied to accelerate the system energy dissipation and make the system quickly converge to the equilibrium point. Simulation model is created with Matlab and the control modes of constant DC voltage, constant active power and constant reactive power are analyzed respectively, which shows that the instantaneous active or reactive power can be independently controlled with better transient performance than PI controller.%由于海上风能并网直流输电变流器模型本身存在非线性强耦合特性,常规PI调节器控制方式需调节的参数较多,难以获得理想的动态特性.提出利用非线性系统无源性理论.将变流器两相同步旋转坐标系下的数学模型以拉格朗日方程形式表达,验证被控对象为严格无源系统,选取光滑可微的正定存储函数作为Lyapunov函数,满足控制系统在原点渐近稳定要求.同时,为使系统快速收敛到期望平衡点,在控制方程中加入阻尼相加快系统能量耗散.最后,利用Matlab建立的系统仿真模型,分析研究定直流电压、定有功功率、定无功功率等控制方式及其输出特性,结果表明上述方法能够独立控制瞬时有功功率、无功功率,暂态控制性能优于常规PI.