| VSC-HVDC(voltage source converter based high voltage direct current transmission)technology is a new type of high voltage direct current transmission technology,which has the advantages of power supply to passive power network,independent power control and good power transmission quality.In recent years,with the rapid improvement of the performance of the power electronic devices,the manufacturing price and maintenance cost of the voltage source converter are relatively reduced,and VSC-HVDC technology is widely used in the field of power distribution and transmission.At the same time,the research on VSC-HVDC converter systems control is also concerned by many scholars and researchers in the world.However,the voltage source converters system is a complex high-order system with strong coupling characteristics,which makes the design of high performance controller more difficult,thus the design of high-performance controller for VSC-HVDC converter systems is a complex and difficult problem.It is very important to study a reasonable and effective control strategy to achieve high performance control for VSC-HVDC converter systems,which is also a challenge in the field of VSC-HVDC converter control.According to the above analysis,a high performance controller is designed by utilizing the backstepping control method,dynamic surface control technology and finite time control technology to realize the power regulation control of VSC-HVDC grid side converter.The main research results of this paper are as follows:1.This paper constructs a scientific and effective controller with the combination of backstepping and dynamic surface control technology based on VSC-HVDC grid side converter systems.In view of the complexity and high order characteristics of the VSC-HVDC converter systems,the controller of the converter systems is designed by using the backstepping method.Considering that the backstepping control method will produce the computational complexity problem in the process of designing the control laws,the dynamic surface technology is introduced to overcome the computational complexity problem.Compared with the backstepping controller,the controller designed by the backstepping method based on the dynamic surface technology does not require the high order derivative information of the setting power value.Therefore,the dynamic surface backstepping control technology has the superior control effect and wide application range compared with backstepping control method.2.For VSC-HVDC grid side converter system,in order to further improve the convergence speed of active and reactive power regulation errors,this paper introduces the finite time control technology to design a controller with better control performance based on the dynamic surface backstepping control technology.The dynamic surface finite time control technology based on backstepping maintains the advantages of the dynamic surface backstepping control method,and realizes the finite time fast regulation control of the active / reactive power of VSC-HVDC converter systems.Compared with the traditional control technology,the control method in this paper does not need to measure the current value of the filter capacitor.Finally,according to the stability analysis of the whole system based on Lyapunov stability theory,it can be seen that under the control strategy designed in this paper,the control system is stable and all signals in the closed-loop system are bounded.3.The contrast simulation experiment is completed in the MATLAB / Simulink environment,and the simulation results of the backstepping control method and the dynamic surface backstepping control method are compared,which verifies that the improved backstepping control method by dynamic surface technology has superior power regulation performance.In addition,the contrast simulation experiments of dynamic surface backstepping control technology and dynamic surface finite time control technology based on backstepping are completed,which verified the superiority and effectiveness of finite time control technology in VSC-HVDC grid side converter power regulation and control process. |
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