액티브 필터용 3레벨 인버터에 관한 연구

Abstract

In the past, utilities had the responsibility to provide a single-frequency voltage waveform, and for the most part, customers' loads had little effect on the voltage waveform.

Recently, however, increasing number of various power electronic device in power systems has caused many kinds of serious problem. Some negative effects of harmonics are as follows : Overheating of transformers and other distribution equipment, overheating of neutral conductors, high neutral-to-ground voltage, poor power factor, and power loss, etc.

Harmonic problem takes place when the magnitude of current harmonics caused mainly by nonlinear electronic elements exceeds the limit of equipment capacity for harmonics and now this kind of problem becomes serious due to growing of number of current harmonics generation sources.

In this paper, some solution of harmonic problem in power system is described. Also, an active power filter is designed. An active power filter is composed with the use of PWM(Pulse Width Modulation) voltage source inverter for the purpose of eliminating current harmonics in the power line caused by nonlinear load such as diode circuits. The performance of designed circuit is simulated using PSIM(Power Simulation) software. The simulated results show good current harmonics eliminating performance. Moreover, implementation of FPGA(Field Programable Gate Array) in control circuit of the active filter makes the system compact and simple.