Research On H-bridge Cascaded Active Power Filter

With the power electronic devices widely, harmonic pollution caused bynon-linear loads is a growing problem, causing serious harm to the grid system.How to manage harmonics has become a hot topic of research at home and abroad.Active Power Filter (APF) is an important trend in the study of harmonic control. Inthe high-voltage and high-power applications, the operating voltage of the powerswitching devices and their switching frequency requirements are often conflicting.The carrier phase shift SPWM (CPS-SPWM) and the H-bridge cascaded multi-levelconverter can solve this problem. Namely, in a relatively low switching frequencythe system has high equivalent switching frequency and is used in high pressuresituations by low-voltage devices. This article do some research about cascadedH-bridge multi-level converter based on CPS-SPWM and its application in APF.This article describes the basic principles of CPS-SPWM, and analyzes thecharacteristics of the output voltage waveform, transmission width and multiplier.Cascaded H-bridge multi-level converter has many advantages such as the sameH-bridge unit to perform availably the modularized design, the least componentamount, achieving high output voltage by low-voltage devices. CPS-SPWM isapplied to the H-bridge cascade multi-level converter, because it has a perfectprospect in APF and power converter.Cascaded H-bridge multi-level converter based on CPS-SPWM is the maincircuit of the shunt APF. A single-phase detecting circuit of harmonic and reactivecurrent based on instantaneous reactive power theory is analyzed. Current trackingstrategy and the PI regulator parameters setting are analyzed to introduce thevoltage feed-forward compensation method and are verified in MATLAB bycreating a simulation model.A platform of APF with cascaded H-bridge multilevel converter based onCPS-SPWM is designed. The design process of main parameters is supplied.Experiment results show the good compensation performance of the experimentaldevice can be achieved.