Study On Control Technology Of Active Power Filter Based On Three Level Topology

With the continuous development of modern equipment manufacturing industryand the constant promotion of industrial technological level, power electronicstechnology as an important carrier of electricity technological attract widespreadattention. The join of nonlinear loads lead to the deterioration of electric energyquality and severe harmonic pollutions.Active power filter can effectively restrainharmonic, therefore become the research focus in the power electronic technology.First of all, this paper introduce the background and current situation of thedevelopment of harmonic suppression technology, the APF base on three-levelconverter is proposed, analyze the operating principle of three-level APF at the sametime. The harmonic current detection techniques based on instantaneous reactivetheory is conducted, the space vector pulse width modulation (SVPWM) technologyis adopted to achieve the current tracking control, in order to simplify the currenttracking control process, improve the traditional three-level SVPWM controltechnology, SVPWM control algorithm is proposed based on60°coordinate system.The midpoint voltage balance control strategy is proposed by analyzing the capacitormidpoint voltage fluctuation mechanism of diode clamp three level converter.Adopting Matlab/Simulink software simulation test system, set up three-levelAPF system simulation model of60°coordinate, and the harmonic suppressioncapability of the system is analyzed by simulation process, meanwhile carry on thesimulation of capacitance midpoint voltage balance control strategy. TheTMS320F2812DSP from TI is adopted to conduct the software design, and completethe system hardware circuit design. Establish the system experimental platform atlast. By the simulation and experiment result, this midpoint voltage balance controlstrategy can effectively restrain the capacitance midpoint voltage deviation,meanwhile three-level APF can realize the comprehensive treatment of harmonic,and then verify the feasibility of the system.