Research On Three-phase And Three-wire Parallel Active Power Filter

APF，as an advanced way of harmonic suppression, is attentioned and researchedextensively by scholar for the deterioration of the power environment. This paper aimsat the three-phase and three line active power filter,make a detail research on somekey techniques which are related with the filter.Analysis the basic principle of the filter and establish its mathematical model,then analyze the interaction among the key parameters of the main circuit; discussedthe value choice of the inductance and DC voltage based on space vector; analysis theenergy flow between the filter and the mains on the theory of instantaneous power,then give the method to gain the value of the energy storage capacitor; finally, provethe above methods combined with a circuit with a three-phase rectifier load, and thesimulation shows the effectiveness of these methods.Make a detailed theoretical and simulation analysis for sliding average filter andnotch filter which are used to improve low-pass filter in harmonic detection waysbased on instantaneous power theory, then, make a optimize the selected improvedmethod based on the subject.Harmonic detection is a key part which determining the compensation effect ofAPF. This project discuss the methods of pq and IpIq detailly under the conditions ofthree-phase grid voltage is ideal, distortion but symmetry, asymmetry in order toharmonic or full compensation; Then give a simplified algorithm to make a fullcompensation in the case of voltage asymmetry, and prove the simplicity bycalculation, the effective in full compensation by simulation.The control method of current tracking is another key factor which determine thecompensation performance. In this project, a method of repeat forecast dead-beatcontrol based on SVPWM is designed. This method get the prediction value of theinstrument current in the through repeat prediction, then turn the current to referencevoltage vector through dead-beat algorithm, and then combined with a simplifiedvoltage space vector modulation method, output the reference voltage vector rapidly,and get the compensation current which is needed. Theory analysis and simulation aswell as compared with some other methods, proved that the proposed method iseffectiveness.