In the series hybrid active power filter (SHAPF) based on fundamental magnetic flux compensation (FMFC), the harmonic voltage across the magnetising inductance of the series transformer will disturb the inverter output current and worsen the filtering effect of the SHAPF. However, this influence caused by harmonic voltage was ignored in the previous research. Therefore there is blindness and casualness in the parameter selection of the SHAPF based on FMFC. Taking a 10 kV, 1 MVA industrial application of the SHAPF in a manufacture factory in Guangdong Province as an example, this study establishes the accurate global mathematical model of the SHAPF. Furthermore, based on the proposed global mathematical model, the series transformer parameters are analysed in detail to show its influence on the filtering performance of the SHAPF. This mathematical model can be used as foundations of the parameter selection of the SHAPF. Finally, an engineering prototype is manufactured and applied. The practical experimental results verify the theoretical analysis.

-In the series hybrid active power filter (SHAPF) with magnetic flux compensation (MFC), the system current oscillate in the experimental results when adding the same phase harmonic current command in current control block. This condition endangers the security of the SHAPF. Taking the digit period average arithmetic as example, this paper explains the inter-harmonics current oscillation in the experiment. The conclusion is that the SHAPF is unstable to the inter-harmonics current in theory. Limited by the capacity of the inverter, the system current and the inverter output current do not increase to infinite. At last, some methods are proposed to solve this problem. From the practical viewpoint, the voltage feed-forward control is easy to achieve. It can suppress the current oscillation problems, and also improve the filtering effect. The feasibility of the methods is validated by both the emulation and experiment results.