Flexible Dc Power Transmission System And No Network Side Of The Electromotive Force Sensor And Control Technology

With the rapid development of wind, solar and other renewable energy, the characteristic of inherent dispersion, small structure, far from the load centers and so on are constantly exposed. VSC-HVDC technology has small, efficient and flexible control characteristics and has significant economic and environmental value, reduces the transmission line voltage drop and flicker effectively, improves the power quality.The basis of the composition of the VSC-HVDC system structure and function are detailed described, and made an in-depth research on the core of the whole system-voltage sourced converter (VSC), focus on the principles and operational characteristics of modulation theory analysis and mathematical analysis, then concluded VSC-HVDC system Working principle. Established the precise mathematical model of VSC-HVDC under the dq rotating coordinate system, used feedforward decoupling control theory to decouple the dq axis coupling of the current inner loop controller, then successfully achieved the active and reactive power independently controlled, for outer power control loop could select the appropriate control strategy according to different requirements. Built a new type of VSC-HVDC system simulation platform using MATLAB 7.1 and made some relevant simulation research.The installation of the source voltage sensor in VSC-HVDC system will bring in some factors of instability, a new source voltage sensorlee control technology based on the VSC-HVDC system has been proposed in this paper. Based on voltage source converters current model, construct a new adjustable current model, using the model reference adaptive theory, regulated the current errors between the two model with PI regulator, then derived the rate of source voltage amplitude and phase angle respectively, thus identified the source voltage effectively. Simulation results show that the designed source voltage sensorless control technology has a good recognition rate, and high identification precision, a strong robustness.Compared to the successful application of VSC-HVDC transmission technology foreign projects, there is few application of VSC-HVDC in civil. The paper designed a small-capacity VSC-HVDC experimental system, the relevant experimental results show that the designed experimental system not only has good stability, anti-interference performance is also very superior, and has strong robustness to meet the basic requirements of engineering applications, made a well basis for the future engineering applications.