Study On Three-phase Three-wire Three-level Shunt Active Power Filter

Power electronic conversion devices are widely used in industry by the development of science and technology.Many serious harmonic pollution problems.are caused while it brings many conveniences.in production process.The emergence of a large number of harmonics in the power grid will affect the normal operation of other electrical equipments.Active power filter(APF)has become a hot research point in power electronics as the main power plant for harmonic control.This paper designed an APF system based on vector resonance(VR)control to make APF achieve accurate compensation for harmonic current.First of all,this paper introduced the types and hazards of harmonics and analyzed the existing harmonic control methods.This paper also introduced the research status and classification of active power filter.Secondly,some basic theories of three-level active power filters were analyzed and the mathematical model of three-phase threewire three-level shunt APF was analyzed in abc coordinate system and dq coordinate system in this paper.And then,this paper introduced the advantages and disadvantages of various harmonic detection methods.Finally,two harmonic current detection algorithms based on instantaneous reactive power theory were introduced respectively.The main content of this paper includes a kind of three-level simplified SVPWM algorithm modulation strategy.Firstly,traditional three-level SVPWM algorithm was introduced.And then,the simplified SVPWM algorithm was introduced based on traditional three-level SVPWM algorithm.Meanwhile,this paper analyzed the inherent neutral potential drift problem of the three-level converter in detail.After that,a reasonable solution was proposed based on the simplified SVPWM algorithm.This paper introduced the double closed-loop control system of three-level APF.This paper also introduced the PI design of voltage outer ring and analyzed the PR controller and VR controller theoretically.In order to remove the shortcomings of the PR controller,this paperr introduced and analyzed the vector resonance controller which can achieve an excellent effect of system control.After that,the design of discretized vector resonance controller was introduced combined with the practical application.Finally,in order to verify the effectiveness of the simplified SVPWM algorithm and the double closed-loop control system of three-level APF,this paper introduced a simulation model of three-phase three-wire parallel three-level active power filter in MATLAB and the simulation results were analyzed.Finally,this paper introduced the design process of the APF experimental system,including hardware,software syste and parameter selection etc.Based on that,this paper made a three-phase three-wire APF experimental prototype where TMS320F28335 severed as the core of control system.The steady and dynamic performances of the experimental device were respectively analyzed based on experimental results.It was verified that the proposed simplified SVPWM algorithm modulation strategy and vector resonant current control strategy were effective in the practical application of three-phase three-wire three-level shunt APF system.