Design And Study Of A Three-phase Voltage-type APFC Rectifier With Step-up And Step-down Voltage

In order to solve the problem that the devices such as diode uncontrolled rectifier and thyristor phase controlled rectifier inject a lot of harmonics into the power network and the low energy utilization(low power factor)of the rectifier itself,various power quality control devices and technologies have been developed,among which the typical active power factor filter(APF),static reactive power generator(SVG),active power factor correction(APFC).Compared with APF and SVG,APFC technology has become a research hotspot for researchers at home and abroad due to its lower cost and higher efficiency.Based on the analysis of the current three-phase APFC rectifier topology and the structure of three-phase APFC rectifier based on active third-harmonic injection network,a new rectifier topology is proposed in this paper.The rectifier consists of a front three-phase uncontrolled rectifier,a rear positive and negative DC bus double-tube buck-boost circuit,a third-harmonic injection circuit and an input LC filter.The performance of the three-phase uncontrolled rectifier is analyzed in this paper.Voltage pulsation generated by the DC side of the three-phase uncontrolled rectifier is injected into the AC side through the third-harmonic injection loop to improve the power factor of the input side.By controlling the buck-boost circuit of the rear positive and negative bus,the rectifier can operate in boost mode,buck mode and buck-boost mode,which can adjust the output voltage in a large range.The working modes of the rectifier in each mode are analyzed,the mathematical model of the rectifier is established,and the control strategy of the rectifier is designed.Finally,the topology parameters and control parameters of the rectifier are designed,and the simulation is completed in the MATLAB/sumlink environment.The simulation results show that the rectifier can adjust the output voltage of the DC side in a wide range on the basis of high power factor operation on the network side.