Research On Converter Control Technology Of Permanent Magnet Direct Drive Wind Power Generation System

As a green and pollution-free energy,wind energy has huge development and utilization value,and the research and development of wind power generation system is just a means to develop wind energy.As a rising star in the wind power generation system,the permanent magnet direct drive wind power generation system has become one of the mainstream systems in the field of wind power generation due to its advantages of simple structure and low cost.At present,one of the important research directions of wind power generation is the research of converter control technology to achieve maximum wind energy utilization and high-performance grid-connected power generation.This paper takes the converter of permanent magnet direct-drive wind power generation system as the research object,selects the topology of PWM rectification + PWM inversion,and conducts research around its control technology.The technology used by the generator-side converter is directly related to the running stability of the generator.In order to solve the problems of poor control accuracy and low efficiency of the PI regulator in the non-linear occasion of the vector control technology of the generator-side converter,an improved auto-rejection regulator is designed.The approximate estimation method of control parameters realizes the undifferentiated estimation of the desired state by adding new variables.Combining the designed auto disturbance rejection regulator with space voltage vector modulation technology,the vector control of the generator-side converter is realized.Simulation and experimental results prove that the designed auto disturbance rejection regulator has more stable control performance than PI regulator.Aiming at the problems of large calculation amount and complicated structure of the vector control technology,the direct torque control technology is applied to the generator-side converter.The basic principle of direct torque control is analyzed,the optimal voltage vector switch table of the generator-side converter based on direct torque control is constructed,and each module of the simulation model is analyzed.The simulation results show that the generator-side converter is used direct torque control not only simplifies the system structure,but also has good dynamic performance.The control technology of the grid-side converter has a great influence on the power transmission between the wind power generation system and the power grid.This paper studies two control technologies of the grid-side converter,which arevector control based on grid voltage orientation and direct power control technology.The basic principle of grid-side converter vector control is analyzed,and the structure of phase-locked loop is introduced,simulation and experiment prove that the system can run stably and reliably when the grid-side converter uses vector control.Aiming at the problem of too many PI regulators in vector control resulting in complex system structure,a six-sector direct power control technique is proposed,and a three-level hysteresis comparator is used to redesign the optimal voltage vector switch required by the converter table,simulation results prove the correctness and feasibility of six-sector direct power control.The direct drive wind power system experiment platform with the hardware-in-the-loop simulation controller YXSPACE as the core is introduced.The platform includes the hardware part and the software part.The hardware part is divided into intelligent power module,voltage and current conditioning module,encoder signal acquisition module,etc.,and introduces the development process of the control system software part.