Research On Direct Power Control Of Three-phase Voltage-source PWM Rectifier

In modern industry, there is an increasing need of convertor device to be used in various circumstances, include frequency changer, high frequency switching power supply, reverse power and so on.Most of these devices use rectifier link to produce direct current.The conventional method is to take uncontrolled rectifier or phase controlled rectifier as rectifier link which inject harmonic currents and reactive power to the grid. Three phase pulse width modulation (PWM)rectifiers has grown rapidly over the past few years due to some of their advantages,such as the high power factor and near-sinusoidal input current waveforms.And this paper will present a atrategy of three phase pulse width modulation rectifier which has simple configuration and high control effect.Depended on the topological structure of three-phase voltage source rectifier,the paper described the operation principle and mathematical model in static three-phase coordinates. static two-phase coordinates and rotary two-phase coordinates.Then this paper produced the concept of instantaneous power and described calculation method of instantaneous power.After that the paper discussed the principle and structure of Direct Power Control (DPC) system. The traditional strategy take switching table as core which is called voltage oriented direct power control.The structure include voltage outer-loop and power inner-loop. The switch frequency of the conventional direct power control system using hysteresis comparator and switching table is not fixed.so the paper presented a DPC scheme based on the predictive control strategy. The proposed predictive DPC technique operates with constant switching frequency using space-vector modulation(SVM).Both voltage oriented DPC algorithms and predictive DPC algorithms of three phase PWM rectifier developed in this work have been simulated using MATLAB/Simulink,and the results shows that P-DPC is much better than DPC using switching table. At last experiment system was set up to verify the result.