STATCOM Nonlinear Control Design Of Multi-machine Power System Considering Input Constraints

The socio-economic development is very rapid,which makes the current power system have changed a lot compared with the past,the power grid has become larger and larger,and the structure has become complicated.Among them,the static synchronous compensator is a parallel type electronic device applied in an alternating current transmission system.It plays an important role in improving the stability of the power system.Therefore,designing a nonlinear controller for a multi-machine power system with STATCOM has deep practical significance.In this thesis,the two-machine system is used to replace the two-area interconnected multi-machine power system.The transient stability problem of multi-machine power system with static synchronous compensator is studied,and considering the practical application of multi-machine power system,it is subject to various aspects.The influence of physical factors,the input is constrained.The backstepping nonlinear control method is adopted,and the adaptive control and sliding mode control are combined.The following are the main research results:(1)For the multi-machine power system with STATCOM,the input constraint problem is solved by adding an auxiliary system and Nussbaum gain function.Firstly,the backstepping method is used to design the input bounded STATCOM nonlinear controller.On the basis of the previous step,the backstepping method is improved.By adding a K-like function,the state of the system converges faster and the amplitude of the oscillation is smaller,thereby improving the transient response performance of the system.(2)In the multi-machine power system,considering the uncertainty of parameters,the traditional backstepping control method is improved,combined with immersion and invariant adaptive control.The design considers the input of a bounded STATCOM adaptive controller.Simulation experiments were performed with different damping parameters to verify the effectiveness of the secondary input bounded controller.(3)In order to further enhance the robustness of the system,sliding mode control is introduced,and the traditional backstepping method,adaptive and sliding mode control are combined to design the STATCOM adaptive sliding mode controller.Finally,the controller is verified by MATLAB software.