Stability analysis of a transformer free hybrid active power filter

The hybrid active power filter, which combines active power filter and passive filter, is the current development trend. It can make full use of the advantages of the two filters to compensate harmonics under high voltage and large capacity conditions. In this paper, the design principle of transformer free hybrid active power filter is studied, and the mathematical model is established; Under the feedback control strategy based on the harmonic current of the power grid, the influence of the inductance of the power grid side and the system delay time on the system stability is analyzed. Finally, the correctness of the analysis is verified by comparing the simulation results.