Research On The Controller Introduced VPI For Improved Three-phase Four-switch SAPF

Shunt active power filter is effectively one of the commonly used measures of harmonic suppression and compensation. In order to save costs and reduce the price of SAPF in the low voltage field, three phase four switch SAPF is put forward. At the same time, a large number of six switch SAPF control algorithm and the detection algorithm is trying to used in four switch topology. How to choose a more effective and inexpensive four switch control strategy become a focus in the study of SAPF.Firstly, we will make the mathematical model for TPFSSAPF,and through mathematical models we will find the difference of DC voltage control between four-switch and six-switch, and thus make improvements on the four-switch DC voltage control. Improved control strategiesThen, for lack of a traditional control scheme, the VPI controller is introduced to the improved control strategy for TPFSSAPF. The control strategy can ensure good compensation performance of SAPF when it only detects network-side current at the same time reducing the number of sensors. Further, by setting the appropriate VPI parameters can achieve selective compensation for harmonic. Thereby the capacity of SAPFwill be reduced and the cost can be save. In addition, detailed analysis and research for single-phase digital phase-locked loop is achieved,and the current modulation algorithms of SVPWM for TPFSSAPF is proposed.Finally, a simulation and experiment platform is built in the laboratory to validate the feasibility of the proposed control strategy,controller and modulation strategy.