Design Of Shunt Active Power Filter Based On Quick-Detection Current Method

With the development of power electronics technology and the universal application of power electronic devices, the amount of non-linear loads in power system is increasing recently,therefore, the harmonic problem caused by non-linear load is becoming severe. To compensate the harmonic effectively with modern technology is of great emergency. Active power filter (APF) is a new-type power electronic device to restrain the harmonics and compensates the reactive power dynamically. It can overcome the disadvantage of traditional harmonics suppression methods such as LC filters, and is considered to be the most effective method to improve the power quality.During the project, the following tasks are carried out:Firstly, the harm of harmonic,harmonic suppression method,the schematic of APF and circuit topology are introduced briefly, then various harmonic current detection methods are represented in great detail. A new kind of quick detection method is proposed and tested by the simulation with the software Matlab and OrCAD. The simulation results show this method is of great rapidness and precision. It meets with the need of APF, and can be utilized as a quick detection method.Secondly, a harmonic detecting circuit based on analog devices is designed with power electronics technology as well as analog technology. Then an APF experiment device of small capacity based on this circuit is built. The experiment results show the detecting circuit can detect the harmonics component rapidly and precisely both in triangle waveform, square waveform and harmonic waveform caused by single-phase uncontrolled rectifier with resister and inductance load; the APF based on the method proposed in this thesis can restrain the harmonics in the power system effectively. Thus it can be considered as one of valid methods to improve the power quality. The rapidness and the precision verifications of the detection method mentioned above provide the theory foundation for the future research in APF of high-capacity.