Research On The Implement Of Inverters And The Method Of Measuring Characteristics Based On Virtual Synchronous Generator

The micro-grid will be an important networking mode under the background of smart grid in the future.The key to ensure the micro-grid safe,stable,and reliable is its operational control system.The network unit of micro-source interface has fast dynamic response and almost no inertia,when the disturbance occurs in distribution network or energy supply and demand imbalance,it can't use the kinetic energy stored in the rotor to suppress power or frequency fluctuations like the conventional synchronous generator.At the same time,the traditional way using DSP development system,designers not only develop control algorithms,but also spend a lot of time to master the DSP internal registers of settings and software compilation method.Moreover,the preparation of the code and debugging will spend a lot of time and effort.Therefore,this paper adopts a method based on RTW to realize the virtual synchronous generator of inverter,the main research contents are as follows:First of all,the main circuit topology of micro-source is described and modeled.Then the dual-loop control methods of micro-source are analyzed and researched,including the inner and outer loop control methods.Secondly,virtual synchronous generator is modeled.The rotor motion equation and the stator voltage equation of synchronous generator are introduced into the control of micro-source.The power frequency characteristics and excitation characteristics of synchronous generator in power system are analyzed.The power frequency controller and excitation controller of virtual synchronous generator are designed.By contrasting the simulations of droop control strategy and virtual synchronous generator control strategy,it can be seen that the moment of inertia and the damping have inhibition to frequency mutation.The key parameters of virtual synchronous generator control are simulated and analyzed,then the impacts of inertia and damping for the frequency of micro-grid system are obtained.Finally,the virtual synchronous generator inverter implemented based on real-time workshop(RTW)is proposed.The design cycle of VSG implemented based on RTW is shown.The Micro-source inverter platform is built,and the hardware circuits and software design are conducted a detailed introduction.The control characteristics of the control strategy of the virtual synchronous generator are verified by the comparison with the droop control strategy.