Research On Generalized Active Power Filter

There is a great demand to utilize the Generatlized Active Power Filter (GAPF) to reduce the harmonic of the power system and improve the power quality in China. Therefore it is worthy of research how to correctly choose the control arithmetic of GAPF to improve its performance at the time of reducing its cost.Firstly, the paper introduced the theory, structure and classification of the GAPF. The d-q-0 method of harmonics detection based on generalized instantaneous reactive power theory is studied. Detecting theory of the instructing current on d-q-0 is deeply researched in the many schemes for GAPF. Simulation results also validated the probability of applying this theory in three-phase four-wire system.Secondly, in order to remedy the disadvantage that does not accomplish the high compensation precision and rapid response speed for compensation current by the method of traditionary hysteresis current control, the control method of Three Dimensional Space Vector Pulse Width Modulation (3D-SVPWM) is applied in the controlled part of compensation current. In this paper, there is not only in-depth analysis that the control method of voltage space vectors PWM applied in based on the midpoint of the capacitor in three-phase four-wire system but also put forward achieve the experimental steps. The method has the high compensation precision and rapid response speed. The control method can be accomplished conveniently with algorithm because it does not need to simulate control circuit.Finally, a model of GAPF was built. With the load of three-phase diode rectifier and three-phase asymmetry load, simulation results of this model proved that the GAPF can work well suppressing harmonic. Compared with traditional hysteresis current control strategy, The 3D-SVPWM technique solves the problem of the neutral line current by this influence and realizes the compensation for the imbalance, harmonic and neutral currents. The simulation results show that the 3D-SVPWM technique is valid, and obtains better compensation effect and consequently improves power quality. The studies in this paper have some guidance on the exploitation of the Generalized active power filter experimental system.