基于超螺旋二阶滑模控制静止无功发生器的研究

Study on Static Reactive Power Generator Based on Super-twisting Second-order Sliding Mode Control

静止无功发生器(static var generator,SVG)广泛用于电力系统中解决三相不平衡的问题。采用构造一个无延迟的旋转相量的方法,对静止无功发生器的电流检测部分进行了改进,以解决移相算子带来的延迟导致的误差,提升电流检测的实时性。控制部分的电流内环采用前馈解耦控制,以解决dq轴上直流变量的耦合问题;由于PI控制系统具有参数难以确定以及难以解决时变复杂系统的缺点,提出了在前馈解耦控制器中使用超螺旋二阶滑模控制的输出电压波形控制方案来代替PI控制。依托这种方法在Matlab中设计出静止无功发生器的模型,对动态三相不平衡负载进行仿真分析。由仿真结果可知,与传统的PI控制相比,此种方法控制效果更好。

Static var Generator(SVG)is used widely in power systems to solve the problem of three-phase imbalance.The adoption of the method of constructing a rotating phasor without delay to improve the current detection part of the static reactive power generator in order to solve the error due to the delay caused by the phase-shifting operator and improve the real-time performance of current detection.The feedforward decoupling control is adopted for the current inner loop of the control part to solve the coupling problem between DC variables on the dq axis.In view of such shortcomings of PI control system as difficulty in determining parameters and in solving the time varying complex system,it is proposed to use the scheme of output voltage waveform which is controlled by the super spirals second order sliding mode in the in the feedforward decoupling controller to replace the PI control.Based on this method,the static var generator model is designed in Matlab to simulate and analyze the dynamic three-phase unbalanced load.It is know by the simulation result that this kind of method,compared to the traditional PI control,has better control effect.