Research On Real-time Hardware-in-the-loop Simulation Of Double-fed Induction Generator Wind Power System

The research on interaction between renewable energy generation power system, such as wind power system, and grid power system, is normally conducting by low power rating dynamic simulation experiment. But because of the complex of renewable energy generation power system, especially wind power system, it would take a lot of time and resources to build and test the dynamic simulation system. Aiming at this problem, this thesis presented a experiment platform, which combines real-time simulation technology and inverter, with wind power system as subject. This experiment platform could produce the equivalent power of wind generator injection to power grid. Then in order to lay the root for real-time-in-the-loop simulation, this thesis studied control strategies and LVRT(low voltage ride through) of DFIG. Finally, this thesis built the experiment platform and tested it successfully. Only by changing the real time simulation model of wind power system, this experiment platform could adjust its parameters of electricity, machinery and wind farm to different situations, and becoming a whole new system immediately. Therefore this platform has great practical value. The following is the specific work of this thesis:Firstly, In order to study the DFIG system applied on this experiment platform, the mathematical model of DFIG was established. Simulations are done to verify the vector control technique, which are applied on the rotor-side converter and grid-side converter. In order to test the transient effect of the platform, this thesis studied the riding through the low grid voltage for DFIG wind power system. When the grid voltage dropped, a fast short circuit(Crowbar) protection circuit in the rotor side was adopted to achieve the low voltage ride through. Besides, the influence of series resistance value of Crowbar circuit on the protection effect was analyzed.Secondly, this thesis presented a experiment platform, which combines real-time simulation technology and inverter, with wind power system as subject. By combining Veristand and IPC, real-time simulation was established.Thirdly, this thesis designed the experimental platform of analog signal conditioning circuit, CAN signal processing circuit and so on. This thesis also designed the power driver circuit, with function of short circuit protection, temperature protection and the dc bus voltage monitoring. Then combining real-time in the loop simulation system and hardware units, this thesis constructed the experimental platform of DFIG.Finally, By using the designed experiment platform in this thesis, the DFIG's real-time hardware-in-the-loop experiments under the condition of normal operation mode and LVRT are carried out, the feasibility of this experiment platform are also tested.