| With the rapid development of power electronics technology,various types of switching converters have emerged in an endless stream,and the demand of many kinds of secondary DC power supplies is increasing as well.In order to obtain a high-quality and stable DC voltage,rectification technology has received growing attention.Although the traditional diode rectification is simple and cheap,the output voltage contains quantity of ripple and can’t be regulated.Even if the late-occurred thyristor rectification,it can only realize voltage regulation in a fixed range.In short,the two sorts of rectification technologies both could result in discontinuous current with lot of harmonics and low power factor,especially when there is heavy load.Thanks for PWM rectification which dealt with all this problems.However,there still be the unbalanced-grid state or generator fault-operation state,which make an increasingly serious unbalanced grid.Unfortunately,the unbalanced grid environment blocked the traditional rectification technologies.This paper focuses on the system’s energy to realize the control for three-phase PWM rectifier by passivity-based control principle,and obtained nice control performance eventually.Firstly,this paper establishes mathematic model of the three-phase voltage-source rectifier(three-phase VSR)when fed with a balanced and unbalanced source respectively.The error energy function is deduced thereafter to judge systems’ passivity.Secondly,here designs two regulators according to their corresponding control aim for each power-supply state.Then programs and designs two kinds of PI controller as the parallel group based on SVPWM principle.Finally,here models the three-phase PWM rectifier and its control system on the MATLAB/Simulink platform.Then obtains and compares the performance results of PI and passive-based controller on each state.For the balanced system,the control target is to track the DC voltage reference and keep unit power factor on AC side.For the unbalanced system,it’s hard to keep unit power factor on AC side without harmonics in DC voltage.To be of the application value,the aim in this paper is to suppress the harmonic in DC voltage.The simulation results indicate that the passive-based controller has small overshoot,responds quickly,and is anti-interference,making the system be of the better application and higher efficiency. |
