The Research Of Shunt Hybrid Power Filter With Time Delay Correction Function

Harmonic is an important factor affecting the quality of electric energy, current harmonics used mostly passive filter PF (power filter) and active power filter APF (active power filter), where PF is low in cost, but the filtering effect of general, can only eliminate fixed harmonic and easy system to produce resonance, not to reach the requirements in some occasions the filtering effect. The active power filter harmonic automatic tracking compensation can change, but by the switch capacity constraints. In order to reduce the capacity of APF, hybrid filter HAPF will be active and passive filter with a (Hybrid Active Power Filte) is the current direction of development.Control algorithm research of active power filter in topology and more advanced, but for the HAPF runtime to study its delay is rare. In fact, when the system is operating, because of the change of the load current, will inevitably lead to changes of system harmonics, so HAPF delay will make the harmonic compensation effect.This paper firstly introduces the basic concept of harmonics, harmonic generation and its harm, the domestic and foreign research present situation and research content, but also the development trend of the technology of active power filter are briefly analyzed. Focus on the analysis of the working principle, the hybrid active power filter classification and structure, and analyzes its time delay problem of active power filter and its influence on the filtering effect, and puts forward the improved harmonic current detection method to reduce the effect of time delay on the compensation. And discusses several harmonic detection method and control strategy, and analyzes the advantages and disadvantages, finally determined by adopting the control strategy of improved harmonic current detection method and triangular wave comparison method.On this basis, the selection principle of the main circuit of shunt hybrid active power filter and controller hardware circuit using DSP chip TMS320LF2407as hardware core. And the functions of hardware implementation is introduced in this paper, and gives the principle diagram, the hardware circuit includes:main circuit module design, the current collecting circuit, voltage conditioning circuit, signal sampling circuit. According to the hardware design of the control system, the software realization scheme, and gives the design flow chart.This paper adopts the design scheme, and in the MATLAB2012b/SIMULINK environment, the harmonic detection method and the control strategy mentioned in this paper, the parallel hybrid active power filter system modeling and simulation. From the simulation results, the shunt hybrid active power filter designed can effectively eliminate the harmonics generated by nonlinear loads, greatly reducing the harm of harmonics on the grid, which proves the feasibility of the design scheme and theoretical analysis.