Study On Separate-Excited Power Supply In Active Tuned Hybrid Power Filter

Recently, with the rapid development of the power electronic technology, the problems of harmonics are paid more focus and attention. Therefore, harmonic suppression becomes an important problem we should face. Passive filter has two functions : harmonic suppression and reactive compensation, but can only compensate the fixed harmonic and resonate with grid easily. Active filter can compensate dynamically, and have a performance of filtering, and can filter multiple harmonics synchronously. However, because of its high cost and large capacity,its application is only in low-voltage system. Active tuned hybrid power filter, which combines each advantage of passive filter and active filter, can not only reduce the capacity of active filter but also realize multi-tuning, and have a wide application prospects.DC-link voltage of APF is required to reach a certain value and maintain constant, in order to make ATHPF work and compensate well. In this paper, dc-link voltage of separate-excited ATHPF is provided by separate-excited power supply, which can not only keep dc-link voltage stable, but also suppress the DC voltage fluctuation of the APF in the dynamic harmonic compensation. Stable voltage and dynamic adjustment mechanism of separate-excited power supply is analyzed, and the selection methods of dc-link voltage and capacity and design of main circuit parameters of separate-excited power supply are given, which gives a reference basis for the design of separate-excited power supply; meanwhile, double closed loop control is used to keep the dc-link voltage stable, which makes separate-excited ATHPF a better effect of filtering.The Simulink simulation and RT-LAB of active turned filter is built. Meanwhile, the Simulink simulation and RT-LAB results on different operation conditions are analyzed.Finally, the correctness of the method of the dc-link voltage and capacity selection, and the control strategy of separate-excited power supply is verified with Simulink simulation and RT-LAB results.