Control Experiment Research On The Grid Side PWM Rectifier Of Double Fed Power Generation Excitation System

Growing shortage of conventional energy,and it brings seriou envirmental pollution in process of use. In this case, varieties of new energy have emerged, because it is relatively mature that the control technology of wind power, wind power is favored by countries. In the field of the wind power generation, VSCF doubly fed wind power generation has a variety of advantages to other methods of wind power, such as, it can realize the separate control of active power and reactive power, and wind machines can always run at the state of the most tip speed ratio to get the most wind energy. It is crucial to control the AC excitation in the VSCF doubly fed wind power generation system, and Dual PWM converter is a common method to realize AC excitation. PWM rectifier play an important role in energy transfer and DC voltage stability, it is one of the main problems in Double-fed Generator Excitation System, therefore, its study has some practical value.In this paper, the research status of PWM rectifier is described at first. Four quadrant work principle of voltage source PWM rectifer is analyzed in theory. In order to realize to control, on the basis of switching function, the mathematic mold of three phase stationary coordinate system and two phase rotating coordinate system are builted. Indirect current control methods and direct current control methods are introduced from control strategy, PWM rectifier current decoupling vector control strategy was researched on the basis of oriented of the grid voltage of the two-phase rotating coordinate system. A DC voltage as the outer loop and active current component as the inner loops' Dual-loop control system was constructed, PI parameters of outer voltage and inner current is derived. It laid the foundation in order to control experiments of voltage source PWM rectifier.Based on the experimental platform, voltage and current detection circuit are developed, Zero-crossing comparator is designed, and the external drive and protection circuit of IPM is analyzed. TMS320F2812 as a main control chip, main program and interrupt routines of PWM rectifier are designed, including system initialization, event management settings, software filter, A/D conversion, PI controller realization and so on. Focus on the working principle of SVPWM, software algorithms and software algorithm implementation steps on the TMS320F2812 is analyzed.Partial experiment of three-phase voltage-type PWM rectifier is executed. The output waveforms of the zero-crossing point comparator, AC side input line voltage waveform of IPM, current waveform changes of transition process during the Diode rectifier to IPM rectifier and a stable DC voltage waveforms when a stable DC voltage waveforms are picked. The experimental results show that power system voltage oriented is accuracy in the three-phase voltage-type PWM rectifier control system, and DC facet is stable voltage rectifier, Basically, to achieve unity power factor control. The experimental results indicate that control method is correct and valid.