Design And Implementation Of Three-level Shuntactive Power Filter

The wide application of power electronics, it results in the distortion of grid current and voltage waveform. The harmonic current caused by these non-liner devices, decline in the quality of power supply, affect the safe of grid and threat the safety and service life of the devices. With the improvement of people’s living standards, and the increase of energy saving knowledge of electric industrial enterprises. So the quality of power quality is more and more attention, the greatest impact in the power quality is the content of the harmonic. Active power filter is a important method for controlling power harmonic, and it has become the research focus and development direction.At first, this paper introduces the definition of harmonic, the harmonic, the national standard of the harmonic, the harm of the harmonic content to the power network, and how to control the harmonic. Then the paper introduces the development of the active power filter at home and abroad. The basic principle and sort of active power filter are described in detail. Through the comprehensive comparison of the principle, performance, effect, price and so on. The paper finally chose the three-level parallel active power to study, and established mathematical model.About the harmonic current detection method. The harmonic current detection method is by digital filter to detect the harmonic current from grid. It can quickly and accurately detect the harmonic current. Finally, the validity and accuracy of the digital bandpass filter method are verified by simulation and experiment.In the aspects of compensatory current control technology. By comparing the performance of the current mainstream methods. The ultimate choice of this paper is triangular wave mode. In the DC bus capacitor side, we choose the commonly used PI control mode.The three-level shunt active power filter and the parameters of the main circuit are designed, and introduces the three-level shunt active power filter’s hardware and software design with the FPGA as the control chip.Finally, the system model of three-level shunt filter is built by using MATLAB, and the simulation results are analyzed. The oscilloscope and power quality analyzer are used to measurement and analysis the actual equipment. The simulation and real experiment results prove validity and effectiveness of this three-level shunt active power filter.