Research On Active Power Filter Based On Fundamental Magnetic Flux Compensation

In recent years, with the rapid development of HVDC and rail traffic, a lot of power electronic converter device and nonlinear loads have been widely used, so that the power system harmonic pollution problem becomes more serious. But at the same time, the ruquirements of intelligent electrical equipment for power quality become more stringent, in this context, to eliminate harmonics become the primary problem to be solved. Based on the fundamental magnetic flux compensation hybrid active power filter good to avoid the issues of detecting multi-frequency harmonics, making tracking and control are relatively easy. This paper mainly focus on research of current compensating working mechanism and related issues to large-capacity magnetic flux compensation filter.The main contents of research:(1)the performance of fundamental magnetic flux compensation hybrid active filter, depending on the transformer impedance effects to harmonic in system. By analyzing the working mechanism of compensation transformer, establishing its mathematical model, doing in-depth research based on the influence of various parameters on the system of the transformer to provide a theoretical basis for the engineering design.(2) Aim at the critical issue of compensating current harmonics effecting large capacity fundamental magnetic flux compensation filter, proposing the use of carrier phase shift current compensation method of multi-level topology, regarding the fundamental sine wave signal as CPS-SPWM modulated signal, by adjusting the magnitude of the voltage to achieve rapid tracking current indirectly, to achieve fundamental flux compensation condition.(3) According to the multi-level compensation current design needs, combined with DSP28335 digital signal processor to curry out hardware and software design, using RT-LAB Semi-physical simulator as the compensation transformer testing device. The simulation and experimental results show that, the high power quality, the low harmonic contents, proving the feasibility of applying the carrier phase shifting multi-level technology to fundamental magnetic flux compensation active filter.