Research On Active Power Filter

The nonlinear power electronic devices are widely used, lots of harmonic which do great harm to people's production and life generate in the power grid. So it is essential to take measures to compensate the harmonic. Active power filter is recognized as one of the effective methods to govern the harmonic, so its study has very important practical significance. This paper presents the comprehensive research on active power filter, and the main contents are as follows.Firstly, the development status, system structure and compensation principle of active power filter have been studied in this paper, shunt active power filter has been studied in detail particularly; also its mathematical model has been established, the main circuit parameters are derived, which provide a theoretical basis for the design of shunt active power filter.Secondly, harmonic current detection part is the crux of the entire design; d-q harmonic current detection method which is basis on instantaneous reactive power theory has been studied. Comparing to the other harmonic current detection methods, it can detect random harmonic current.Thirdly, another core part of active power filter is the control strategy including compensatory current control and DC voltage control. Compensatory current control adopts instantaneous value comparison method, and DC control adopts fuzzy PI control, which has an advantage in choosing initial parameters comparing to PI control.Finally, the shunt active power filter is simulated by MATLAB software, the results show that the active power filter has good compensation performance, and it also verify that the harmonic current detection and control strategy are correct.