A novel method of optimal parameter design of input filters for general purpose inverter

Harmonics and reactive power produced by the inverters will inject into the power system during their operation, if no any filter is inserted. Compared with active power harmonic filters and PWM technology, the passive harmonic filters are much more cost-effective, simple and reliable. At the same time we have not seen a series calculation which can be used for all inverters at different power ratings. Based on the research to general purpose inverters, a more practical model is put forth by an equivalent current source containing major harmonics, paralleled with equivalent impedance. The advantage of this equivalent system is that it can be applied to all different power ratings from one-phase to three-phase general purpose inverters avoiding complex analysis of the inverter system with high accuracy. Applying this model this paper gives the optimal filter parameters to minimize total current harmonic distortion (ITHD) with constraint of the value of the power factor (PF) using genetic algorithm program. The result of the actual experiment shows that parameters obtained from the genetic algorithm program make the value of ITHD, PF meet the industry application requirement.