Research On Control System Of Doubly-fed Wind Turbine

Since entering the 21st century,the exhaustion of traditional energy and the environmental problems caused by it have become the focus of human attention,but the human demand for energy is increasing.Under this background,new energy such as wind energy and solar energy has gradually entered our lives.Wind energy has become the focus of domestic and foreign experts and scholars because of its huge energy and easy to scale development,and now the development technology is relatively mature.In this paper,doubly-fed induction machine(DFIG)is taken as the research object,and the main focus is on the research of DFIG control system.Firstly,the model and operation status of DFIG are analyzed,and then the control schemes of grid-side and motor-side power converters of DFIG are designed respectively.In the traditional network side control system,the grid voltage is collected by the voltage sensor,and then the vector control is carried out.In this paper,an improved virtual flux technology is proposed to replace the grid voltage sensor in the original topology.The three-phase grid voltage is imagined as a three-phase synchronous motor,and then the phase angle is calculated by flux linkage calculation.Finally,the calculated current component is brought into the control loop.In the traditional side control system,the speed is obtained by the speed sensor and then brought into the control loop.The stator flux orientation method is used to realize the side control.In the original control principle,PI adaptive control strategy is proposed and adopted to realize sensorless operation of the control system,and the estimated value of speed is brought into the control loop.On the basis of theoretical analysis,the control algorithm is tested on MATLAB simulation software,and the system converter models of grid side and motor side of doubly fed wind power generation are built respectively.In the simulation system of the grid-side converter system,it is concluded that the voltage on the DC bus is stable and the power factor is 1.In the simulation system of the motor side converter system,it is concluded that the speed is stable and the stator output current is stable.From the simulation results,it can be concluded that the strategy of the control methods of grid-side voltage Sensor-less Technology and motor-side Speed Sensor-less Technology is feasible.Finally,the experiment is carried out on the experimental platform with DSP as the controller.The wind speed is simulated by DC motor.The correctness of the control method is verified by observing the voltage on DC bus and the output current of stator.