Research On Three-phase Pwm Rectifier And Control Algorithm

As the power electrons being used avaidly, the problem of harmonic wave pollution is more and more serious in the electric network. It was a grave subject to erase harmonic wave and increase power factor. Scholars firstly pay attention to the rectifier which was the main pollution source. Through PWM rectifier, the current is realized sinusoid and the power factor is controlled, as the electric energy can be converted in two way and the dynamic control response of the rectifier system is faster and so on.The writer recognized the existing condition of the three phase high power PWM rectifier and the merits and flaws of various control strategies after consulted many literature cites both internal and abroad.Firstly, on the base of analyzing the use of PWM in the three phase rectifier, the thesis represented the physical working process and operating principle of PWM rectifier. The writer took emulation by MATLAB/SIMLINK according to establishing the mathematic model, the result proved that it was correct and feasible.Secondly, the writer designed a control system witch was a double closed loops. The current inner loop used space vector pulse width modulation, the writer represented a new method to dynamic dispense zero vector according to the power factor angular of the load. It reduced not only switching loss but also the biggest switching current of the device. The voltage external loop used conventional PI control.Lastly, the writer emulated by MATLAB6.5/SIMULINK and designed the digitited system of three phrase voltage source rectifier with DSP as it's core. The result proved that the theoretical analyse was correct and feasible.