Application Research Of United Harmonic And Reactive Compensation System Of IF Furnace Power

For solving the problems of active power filter without dynamic reactive power compensation, large capacity and phase shift of passive filter compensation, this paper proposed a unity compensation control system, which is a parallel hybrid power filter with thyristor controlled reactor(SHPF-TCR), the system can be applied to a furnace of the medium frequency power supply, improving power quality of the heating enterprise.This paper first proposes the new topology structure, SHPF, which includes small capacity active power filter of small capacity and fifth harmonic LC single tuned filter to compensate system harmonics. Reactor and TCR form a shunt passive filter to compensate reactive power of system, reduce current capacity of the active part, eliminate resonance of the passive filter when compensating the reactive power and harmonic. The parallel combination of active filter and single-tuned passive filter inductance significantly reduces the APF current.Then selecting suitable detection and simple control algorithm, tracking and locking the phase of power grids, using dq detection algorithm, accurately detecting the harmonic and reactive command values, PI decoupling controller is introduced to the whole control strategy of TCR-HAPF, which is used for the current tracking and voltage regulation, eliminating system steady-state error.The unity control of SHPF-TCR can effectively reduce the capacity of APF, eliminate the system resonance, possess good stability and fast dynamic response. The results of theoretical analysis, MATLAB simulation and prototype test prove that, the proposed structure contains engineering practice and effectiveness for improving power quality of the intermediate frequency furnace. The proposed structure and the control method are significantly suitable for harmonic and reactive power compensation. The study provides the theoretical basis for realizing the harmonic and reactive power compensation effectively, the study has certain practical value and important research signification of dynamic compensation of intermediate frequency harmonic governance and improving the quality of system.