Power filtering method with controllable inductance for eliminating thyristor rectifier load harmonics

In this paper, we propose a Controlled Inductance Power Filter (CIPF) to solve power quality problems in industrial DC power supply systems. This method is based on the theory of magnetic potential equilibrium combined with active hybrid filter technology. Initially the system structure and filter wiring scheme are presented and the equivalent circuit is performed with the mathematical models of the filtering system. Then, a refined control strategy is designed to achieve better filtering performance.  Technical features such as the elimination of harmonics caused by nonlinear loads and the attenuation are illustrated by the analysis mechanism. Also, the stability of the system based on the NYQUIST criterion is discussed and finally the simulation model of the filtering system is implemented in the Simulink environment of MATLAB software. The simulation results confirm the theory of path analysis and show that the proposed method with proper control gain can effectively eliminate the harmonics passing through the transformer and improve the efficiency of the rectifier system.