| As the development and improvement of era, every field of human’s life andproductions could not regular work without electric energy, but the existing condition ofpower quality could not suit the one required. So the problem of reactive power andharmonic current became increasingly obvious and being in a situation urgent needed tosolve immediately. Direct at this severe challenge, in this article a new type of reactivepower compensation and harmonic treatment project was proposed, which wascurrent-source parallel active power filter.In this article, as a solution of the problem of reactive power compensation andharmonic treatment, the method of using current-source parallel APF was proposed,which can compensate the various times harmonics, while at the same time filter wascompensating harmonics in the load current, it can also compensate the reactive powerin the grid system. The major study contents of this paper include the following:This paper described the basic topology and working principle and the differentoperation modes of the current-source APF, then considering the electric character ofcurrent-source APF, established the mathematical model including the non-linear load,there were low frequency times space mathematical model of three-phase and the modelof high frequency and the model in frequency space; then combining the modelsanalyzed the working mechanism of current-source active power filter, meanwhileconsidering the influence of grid parameters variation and delay caused by detection andcontrol.Then introduced the reactive power compensation theory foundation, andresearched the algorithm used to detecting the harmonic and reactive power current bycurrent-source APF, just be the ip-iq algorithm based on the instantaneous reactivepower theory. What is more, in order to offset the delay caused by detection and control,enhance compensation precision of system, based on the ip-iq algorithm, drew into thepredictive control algorithm.Researched on two methods of current tracking control of current-source APF,including the triangular carrier modulation control and the instantaneous currentcompare control, then compare the simulation results of both methods, analysis theadvantages and disadvantages. Because the direct inductance current needed to retainsteady, the control method of the direct inductance current should be studied. When the APF’s load current detected included capacitive load’s current, with the compensationcoefficient change, the system had potential risk of resonance, affecting the stability andthe harmonic compensation. Then, a new control method of current-source parallel APFwas proposed. The active power filter’s stability was high and its harmonicscompensation performance was excellent.Built the current-source parallel APF’s simulation model with Matlab/simulink,then studied on the simulation experiments of command current detection algorithm, thecurrent tracking control method, the control method of the direct inductance current andthe control method of resonance suppression. Based on the simulation studies,estiblished the operational platform of current-source APF, then test and verifycompensation performance of current-source APF and the control method of resonancesuppression When the APF’s load current detected included capacitive load currentcaused potential risk of resonance, which control method make the original unstablecompensation system to become stable while good harmonic suppression effect. |
