Research On Approach Of Hybrid Active Power Filter In Low Voltage Harmonic

Power being treated as an invisible “commodity” is widely used in various fields,such as industrial and agricultural, people’s lives. For the “commodity”, our market requires it to achieve stringent standards, namely the power quality is qualified.However, with the widespread use of non-linear power electronic devices, there has been a lot of power system harmonics, it provoke voltage and current waveforms in the electrical distribution systems which are not sinusoidal. At the same time, power users increasingly demand power quality. Therefore, it is necessary to solve the harmonic problem which makes qualified “commodity”.Inverters acclaim in various production fields, especially transmission, such as fans, pumps, for its small size, light weight, low cost and high efficiency. Inverter is a typical non-linear power electronics load. Although it has excellent speed regulating performance and obvious energy saving effect, harmonic with generation can not be ignored.The measured system adopted AC-DC-AC inverter, the input side is a three-phase bridge rectifier circuit; in this circuit, the input current waveform is a rectangular wave. According to the Fourier series decomposition, the current contains( 6n ?1)harmonics. Therefore, we consider the three-phase bridge rectifier circuit as the harmonic source mode. Meanwhile, according to the inverters’ harmonic characteristics, analysis the topology of the active power filter and design parallel hybrid active filter topology. Filtering system consists of active power filter by coupling transformer series passive power filter in parallel with the power supply online. Active power filter can improve the filtering characteristics of passive power filter, to avoid the series and parallel resonance; passive power filter’s price is cheap,when full configuration can reduce the capacity of the active filter, the two complement each other to achieve the best filtering effect.This paper presents a problem of the multi-objective optimization filter parameters.It has been to take into account some factors, such as economic indicator, harmonic elimination and reactive power compensation, and can achieve multi-objectiveoptimization parameters. This paper proposes multi-objective optimization algorithm with PSO solution and giving the specific implementation steps and procedures. In Matlab/Simulink, the simulation results show that filter parameters which are obtained from the algorithm can take account of reactive power compensation and avoid a series-parallel resonance, making the initial cost of the smallest filter device,in order to achieve good economy.